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Vozárová, Anna, Katarína Šarinová, Dušan Laurinc, Elena Lepekhina, Jozef Vozár, Nickolay Rodionov, and Pavel Lvov. "Exhumation history of the Variscan suture: Constrains on the detrital zircon geochronology from Carboniferous–Permian sandstones (Northern Gemericum; Western Carpathians)." Geologica Carpathica 70, no. 6 (December 1, 2019): 512–30. http://dx.doi.org/10.2478/geoca-2019-0030.
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Abstract The Late Paleozoic sedimentary basins in the Northern Gemericum evolved gradually in time and space within the collisional tectonic regime of the Western Carpathian Variscan orogenic belt. The detrital zircon age spectra, obtained from the Mississippian, Pennsylvanian and Permian metasediments, have distinctive age distribution patterns that reflect the tectonic setting of the host sediments. An expressive unimodal zircon distribution, with an age peak at 352 Ma, is shown by the basal Mississippian metasediments. These represent a relic of the convergent trench-slope sedimentary basin fill. In comparison, the Pennsylvanian detrital zircon populations display distinct multimodal distributions, with the main age peaks at 351, 450, 565 Ma and smaller peaks at ~2.0 and ~2.7 Ga. This is consistent with derivation of clastic detritus from the collisional suture into the foreland basin. Similarly, the Permian sedimentary formations exhibit the multimodal distribution of zircon ages, with main peaks at 300, 355 and 475 Ma. The main difference, in comparison with the Pennsylvanian detrital zircon assemblages, is the sporadic occurrence of the Kasimovian– Asselian (306–294 Ma), as well as the Artinskian–Kungurian (280–276 Ma) igneous zircons. The youngest magmatic zircon ages nearly correspond to the syn-sedimentary volcanic activity with the depositional age of the Permian host sediments and clearly indicate the extensional, rift-related setting.
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Chang, Zhe, Zhiqian Gao, Liangliang Zhang, Tailiang Fan, Duan Wei, and Jingbin Wang. "Provenance of Ordovician Malieziken Group, Southwest Tarim and Its Implication on the Paleo-Position of Tarim Block in East Gondwana." Minerals 13, no. 1 (December 27, 2022): 42. http://dx.doi.org/10.3390/min13010042.
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Tarim is inferred to have a close connection with East Gondwana during the Ordovician, but the position in East Gondwana remains controversial. In this study, we report 316 detrital zircons U-Pb data from three samples of Ordovician Malieziken Group sedimentary rocks, collected in the Qiate Section, Southwest Tarim, provided new insight into the position of Tarim in East Gondwana. Detrital zircons data indicated the maximum depositional age for the three samples is 489.5 Ma, 478.1 Ma, and 465 Ma, respectively, indicating the Qiate and Kandilike Formation of the Malieziken Group was deposited in Early—Middle Ordovician. The detrital zircons are characterized by two main peaks at ~490 Ma and ~1100 Ma, and three subordinate peaks at ~880 Ma, ~1400 Ma, and ~1650 Ma, suggesting most of the detritus of Malieziken Group from the South Kunlun Terrane (SKT) itself. However, the source of the ~1650 Ma peak is not found in the Tarim block, and the ~1400 Ma and the ~1650 Ma peak are absent in the middle of the three samples, which implied that there is an exotic source. The Paleoproterozoic sediment strata in the Albany–Fraser belt shows dominant peaks at ~1400 Ma and ~1650 Ma may have been transported to SKT and redeposited in the Malieziken Group during the Ordovician. The Malieziken Group shows detrital zircon age patterns resembling those of East Sumatra, Lhasa, and Western Australia which, in combination with the Albany–Fraser belt provenance, enables us to propose that the Tarim block has a close linkage with Western Australia, East Sumatra, and Lhasa in East Gondwana.
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Xu, Zhongjie, Yizhi Lan, Jintao Kong, Rihui Cheng, and Liaoliang Wang. "Detrital zircon U–Pb dating of Late Triassic Wenbinshan Formation in southwestern Fujian, South China, and its geological significance." Canadian Journal of Earth Sciences 55, no. 8 (August 2018): 980–96. http://dx.doi.org/10.1139/cjes-2018-0007.
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Based on research of the petrology, geochemistry, and zircon U–Pb dating of detrital rocks in the Late Triassic Wenbinshan Formation in southwestern Fujian, and comparing the detrital zircon ages of Wenbinshan Formation with those of Late Paleozoic – Early Mesozoic main basins in South China, the sedimentary provenance of the Late Triassic in southwestern Fujian and its implications for changes in basin properties are discussed. The research results demonstrate that there is a major age peak at 222 Ma, two subordinate age peaks at 275 Ma and 1851 Ma, and two minor age peaks at 413 Ma and 2447 Ma in the detrital zircon age spectra of the upper samples (YGP–6) of the Wenbinshan Formation, whereas there are two major age peaks at 229 Ma and 1817 Ma and other minor age peaks 265 Ma 309 Ma, 415 Ma, 1968 Ma, and 2435 Ma in the detrital zircon age spectra of the lower samples (YGP–26) of the Wenbinshan Formation. The upper samples contain fewer old detrital zircons than the lower samples, but the upper and lower samples of Wenbinshan Formation are similar in major age composition, which indicates the main provenances of the upper and lower sediments are very similar. The source rocks are mainly sedimentary rocks and their provenances are derived from a source area of recycled orogenic belt and volcanic arc orogenic belt (acidic island arc). The detrital zircon composition of the Wenbinshan Formation is mainly composed of Paleoproterozoic zircon and Late Paleozoic – Early Mesozoic zircon. In the Paleoproterozoic, sedimentary provenances were mainly derived from the Wuyi Massif and partly from northwestern Fujian-southwestern Zhejiang. As for the period of Late Paleozoic – Early Mesozoic, the provenances of the Wenbinshan Formation were derived from magmatic active belts of the Early Indosinian Epoch of northern South China, eastern South China, and the Indosinian Period of northern South China and coastal areas of eastern South China. The similarities and differences between detrital zircon age peaks of the Wenbinshan Formation in southwestern Fujian and that of the main basins in South China during the period of Late Paleozoic – Early Mesozoic indicate that from eastern coastal areas of South China to the north and interior of South China, the age composition of basin sediments has changed from simple to relatively complex, and from young sediments to older sediments. There are similarities and differences in the detrital zircon compositions of the different basins, which can indicate differences in the nature of the basins.
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Thomas, William A., George E. Gehrels, Timothy F. Lawton, Joseph I. Satterfield, Mariah C. Romero, and Kurt E. Sundell. "Detrital zircons and sediment dispersal from the Coahuila terrane of northern Mexico into the Marathon foreland of the southern Midcontinent." Geosphere 15, no. 4 (June 26, 2019): 1102–27. http://dx.doi.org/10.1130/ges02033.1.
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AbstractNew analyses of U-Pb ages along with previously published analyses of detrital zircons from sandstones in the foreland of the Marathon orogen in west Texas have significant implications regarding provenance. The most prominent concentrations of U-Pb ages are at 1200–1000, 700–500, and 500–290 Ma. The accreted Coahuila terrane in the Marathon hinterland and nearby terranes with Gondwanan (Amazonia) affinity include Paleozoic volcanic and plutonic rocks, as well as Precambrian basement rocks. Late Paleozoic Las Delicias arc rocks have ages of 331–270 Ma. Detrital zircons from Upper Jurassic and Lower Cretaceous sandstones, which were deposited in local basins around the Coahuila terrane, provide a record of detritus available from proximal sources within Coahuila, including important peaks at 1040, 562, 422, 414, 373, and 282 Ma. Components of the detrital-zircon populations in the Marathon foreland have unique matches with primary and/or detrital sources in the Coahuila terrane. Although some components of the Marathon populations also have age matches in Laurentia (Appalachians), others do not; however, all components of the Marathon populations have potential sources in Coahuila. Analyses of εHft show generally more negative values in Amazonia than in Laurentia, and εHft values for Marathon sandstones have distributions similar to those in Amazonia. Therefore, the Coahuila terrane provides a provenance for all of the detrital-zircon ages in the Marathon foreland, requiring no mixing from other sources.
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Papapavlou, K., A. Moukhsil, A. Poirier, and J. H. F. L. Davies. "The Pre-Grenvillian assembly of the southeastern Laurentian margin through the U–Pb–Hf detrital zircon record of Mesoproterozoic supracrustal sequences (Central Grenville Province, Quebec, Canada)." Geological Magazine 159, no. 2 (November 15, 2021): 199–211. http://dx.doi.org/10.1017/s0016756821001023.
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AbstractThe detrital zircon perspective on the pre-collisional crustal evolution of the Grenville Province remains poorly explored. In this study, we conducted in situ laser ablation U–Pb–Hf isotopic microanalysis on detrital zircon grains from three pre-orogenic (>1 Ga) supracrustal sequences that crop out in the Central Grenville Province (Lac Saint-Jean region, QC, CA). Detrital zircon grains from vestiges of these sequences record three dominant age peaks at c. 1.46 Ga, 1.62 Ga, 1.85 Ga, and a subordinate peak at 2.7 Ga. The 1.46 Ga and 1.62 Ga age peaks are recorded in detrital zircon grains from a quartzite associated with a metavolcanic sequence (i.e. Montauban Group) with a maximum depositional age of c. 1.44 Ga. In contrast, the c.1.85 Ga age peak is observed from recycled zircon grains in metasediments with maximum depositional ages between 1.2 and 1.3 Ga. The suprachondritic Hf isotope composition in detrital zircon grains of the 1.46 Ga and 1.62 Ga age populations records juvenile crustal growth during peri-Laurentian accretionary orogenesis related to the Pinwarian (1.4–1.5 Ga) and Mazatzalian–Labradorian (1.6–1.7 Ga) events. The detrital zircon grains associated with Penokean–Makkovikian (1.8–1.9 Ga) source rocks record reworking of c. 2.7 Ga continental crust derived from a near-chondritic mantle reservoir. Overall, crust-forming and basement reworking events associated with accretionary orogenesis in southeastern Laurentia are retained in the detrital zircon load of Precambrian basins even after the terminal Grenvillian collision and assembly of Rodinia.
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Kanygina, N. A., A. A. Tretyakov, K. E. Degtyarev, K. N. Pang, K. L. Van, H. Y. Lee, and J. V. Plotkina. "First results of dating detrital zircons from the late precambrian quartzite-schist sequences of Chu block (Southern Kazakhstan)." Доклады Академии наук 489, no. 1 (November 10, 2019): 57–61. http://dx.doi.org/10.31857/s0869-5652489157-61.
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U-Pb geochronological studies of detrital zircons from quartzite-schist sequences of the Akbastau Formations of the Chu block (northwest of the Chu-Kendyktas terrane, Southern Kazakhstan) have been provided. The concordant ages of detrital zircons are predominantly within the intervals of 1672-2115 Ma with peaks at 1697, 1780, 1857 and 2066 Ma. Individual zircon grains display ages of 2291-2332 Ma with peaks at 2303 and 2322 Ma. Neoarchean ages 2608-2747 with peak at 2681 Ma characterize another significant zircon population. The lower limit of deposition for the Akbastau Formations of the Chu block, corresponding to the youngest statistically significant zircon population, is estimated at 1,7 billion years.
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Ovchinnikov, R. O., A. A. Sorokin, V. P. Kovach, and A. B. Kotov. "Geochemical features, sources and geodynamic settings of accumulation of the cambrian sedimentary rocks of the Mel’gin trough (Bureya continental massif)." Геохимия 64, no. 5 (May 23, 2019): 503–19. http://dx.doi.org/10.31857/s0016-7525645503-519.
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The first data about geochemical features of the Cambrian sedimentary rocks of the Mel’gin trough of the Bureya continental Massif, as well as ages of detrital zircons of them are obtained. It is established, that among the detrital zircons from the sandstones of the Chergilen and Allin formations of the Mel’gin trough zircons with Late Riphean (peaks on relative probability plots – 0.78, 0.82, 0.94, 1.04 Ga) and Early Riphean (peaks on relative probability plots – 1.38, 1.45, 1.64 Ga) ages predominate. The single grains have a Middle Riphean, Early Proterozoic and Late Archean ages. We can suppose, that the sources of Late Riphean detrital zircons from sandstones of the Chergilen and Allin formations are igneous rocks of gabbro-granitoids (940–933 Ma) and granite- leucogranites (804–789 Ma) association, identified in the Bureya continental Massif. We can`t assume, what kind of rocks were the source for Middle Riphean and older detrital zircons from the Cambrian sedimentary rocks of the Bureya continental Massif, because in this massif still do not identified complexes older Late Riphean age. The most probable geodynamic conditions of accumulation of the Cambrian deposits of the Mel’gin trough is the conditions of active continental margin, which is corresponding to of Early Cambrian granitoids magmatism.
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MA, XIAO, KUNGUANG YANG, and ALI POLAT. "U–Pb ages and Hf isotopes of detrital zircons from pre-Devonian sequences along the southeast Yangtze: a link to the final assembly of East Gondwana." Geological Magazine 156, no. 06 (August 22, 2018): 950–68. http://dx.doi.org/10.1017/s0016756818000511.
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AbstractThe Early Palaeozoic geology of the South China Craton (SCC) is characterized by an Early Palaeozoic intracontinental orogen with folded pre-Devonian strata and migmatites, MP/MT metamorphic rocks and Silurian post-orogenic peraluminous magmatic rocks in both the Yangtze and the Cathaysia blocks. In this contribution, we present new zircon U–Pb ages and Hf isotope data for detrital zircons from the Neoproterozoic to Silurian sedimentary sequences in the southeastern Yangtze Block. Samples from Neoproterozoic rocks generally display a major peak at 900–560 Ma, whereas samples from Lower Palaeozoic rocks are characterized by several broader peaks within the age ranges 600–410 Ma, 1100–780 Ma, 1.6–1.2 Ga and 2.8–2.5 Ga. Provenance analysis indicates that the 900–630 Ma detritus in Cryogenian to Ediacaran samples was derived from the Late Neoproterozoic igneous rocks in South China that acted as an internal source. The occurrence of 620–560 Ma detritus indicates the SE Yangtze was associated with Late Neoproterozoic arc volcanism along the north margin of East Gondwana. The change of provenance resulted in the deposition of 550–520 Ma and 1.1–0.9 Ga detrital zircons in the Cambrian–Ordovician sedimentary rocks. The εHf(t) values of these detrital zircons are similar to those of zircons from NW Australia–Antarctica and South India. This change of provenance in the Cambrian can be attributed to the intracontinental subduction between South China and South Qiangtang, and the convergence of India and Australia when East Gondwana finally amalgamated.
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YAO, WEI-HUA, ZHENG-XIANG LI, and WU-XIAN LI. "Was there a Cambrian ocean in South China? – Insight from detrital provenance analyses." Geological Magazine 152, no. 1 (July 18, 2014): 184–91. http://dx.doi.org/10.1017/s0016756814000338.
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AbstractWe use detrital provenance data from Cambrian sandstones to examine whether the Yangtze and Cathaysia blocks in South China were separated by an ocean during the Cambrian period. Zircons from the Cambrian sandstones exhibit a dominant ~ 800 Ma age peak in the central Yangtze Block, being sourced from the western Yangtze Block, whereas a ~ 980 Ma peak dominates in the northwestern Cathaysia Block, being sourced from an exotic continent once connected to Cathaysia. A mixed provenance with both age peaks is found in Cambrian sandstones from the southeastern Yangtze Block, indicating that detritus can travel from the Cathaysia Block to the Yangtze Block, and therefore arguing against the existence of a broad Cambrian ocean.
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Wang, Yanpeng, Wentao Yang, Shenyuan Peng, Shuaishuai Qi, and Deshun Zheng. "Early Triassic Conversion from Source to Sink on the Southern Margin of the North China Craton: Constraints by Detrital Zircon U-Pb Ages." Minerals 10, no. 1 (December 19, 2019): 7. http://dx.doi.org/10.3390/min10010007.
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Provenance analysis of sediments provides important constraints on basin formation and orogenic processes. With the aim to define the sedimentary provenance and tectonic evolution of the southern margin of the North China Craton, this paper presents new detrital zircon U-Pb data from Early Triassic sediments in the Yiyang area. The results showed major peaks at 1848, 458, 425, and 268 Ma and subordinate peaks at ca. 2500, 872, and 957 Ma on age spectra from the Liujiagou Formation. The Heshanggou Formation exhibited a major age peak at 445 Ma and subordinate peaks at 755 and 947 Ma. Integrated with the analysis of sandstone detrital compositions, we suggest that the sources of the Liujiagou Formation were mainly a mixture of the southern margin of the North China Craton and the North Qinling Orogenic Belt, whereas the Heshanggou Formation was derived primarily from the North Qinling Orogenic Belt. Age comparisons of detrital zircon geochronology collected from different basins in the North China Craton indicated that the paleogeography of the North China Craton during the Early Triassic was strongly asymmetric, wherein the uplifted highland along the southern margin of the North China Craton was relatively lower than the northern margin. Meanwhile, the marked shift in source region from the Liujiagou to the Heshanggou formations provides a constraint regarding the conversion from denuded zone to deposited zone along the southern margin of the North China Craton in the Early Triassic, which controlled the evolution of the provenance and sedimentary system.
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Khubanov, V. B., A. A. Tsygankov, and G. N. Burmakina. "The Duration and Geodynamics of Formation of the Angara–Vitim Batholith: Results of U–Pb Isotope (LA-ICP-MS) Dating of Magmatic and Detrital Zircons." Russian Geology and Geophysics 62, no. 12 (December 1, 2021): 1331–49. http://dx.doi.org/10.2113/rgg20204223.
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Abstract —We present results of U–Pb (LA-ICP-MS) dating of detrital zircons from the alluvial deposits of the Angarakan River (North Muya Ridge, northern Baikal region), whose drainage basin is composed mainly of granitoids of the Barguzin Complex, typomorphic for the late Paleozoic Angara–Vitim batholith (AVB). Three age clusters with peaks at 728, 423, and 314 Ma have been identified in the studied population of detrital zircons. It is shown that small outliers of igneous and metamorphic rocks, probably similar to the large AVB roof pendants mapped beyond the drainage basin, are the source of Neoproterozoic and early Paleozoic zircons. The late Paleozoic cluster comprises two close peaks at 314 and 28 Ma, which totally “overlap” with the time of the AVB formation and mark a granitoid source of the zircons. The results of detrital-zircon geochronology, together with the data on bedrocks, point to the prolonged (~40 Myr) formation of the AVB, but the intensity of magmatism during this period calls for additional study. Based on the analysis of published geological, geochemical, and geochronological data, we assume that the AVB resulted from the plume–lithosphere interaction that began in the compression setting and gave way to extension 305–300 Ma (the Carboniferous–Permian boundary), which caused replacement of “crustal” granitoids by granitoids formed from a mixed mantle–crustal source.
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Xu, Ya-Jun, Peter A. Cawood, Hang-Chuan Zhang, Jian-Wei Zi, Jin-Bo Zhou, Li-Xing Li, and Yuan-Sheng Du. "The Mesoproterozoic Baoban Complex, South China: A missing fragment of western Laurentian lithosphere." GSA Bulletin 132, no. 7-8 (November 5, 2019): 1404–18. http://dx.doi.org/10.1130/b35380.1.
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Abstract New age data for the Baoban Complex, South China establishes that it lay outboard of western Laurentia in the early Mesoproterozoic but was not part of the Cathaysia Block, with which it is traditional linked, until the mid-Paleozoic. Our geochronology data for detrital zircon and authigenic monazite grains from metasedimentary rocks indicate accumulation between ca. 1.55 Ga and 1.45 Ga for the Gezhencun succession of the Baoban Complex and ca. 1.45 Ga and 1.30 Ga for the Ewenling succession. The former unit is dominated by detrital zircon populations between 1900 Ma and 1500 Ma with two peaks at 1780 Ma and 1580 Ma. The Ewenling succession has detrital zircon peaks at 1720 Ma and 1450 Ma. Newly discovered gneissic granites were emplaced at 1550 Ma and intruded by 1450 Ma leucogranite dykes that are coeval with 1460–1430 Ma bimodal magmatism. The whole Baoban Complex was metamorphosed over the range of 1.3–0.9 Ga based on ages of authigenic zircon and monazite. Depositional ages of metasedimentary rocks are coeval with successions of the Belt-Purcell Basin, western Laurentia. Detrital zircon from the two regions have similar age populations and Lu-Hf compositions, and display a synchronous provenance shift at ca. 1.45 Ga. Basement lithologies on Hainan Island range in age from ca. 1.55–1.43 Ga and underwent metamorphism during 1.3–0.9 Ga. This is younger than basement rocks on the mainland of the Cathaysia Block in South China, suggesting the two regions are spatially unrelated at this time and hence the Mesoproterozoic record of the island cannot constrain the location of the Cathaysia Block in the Nuna and Rodinia supercontinents.
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Wang, Ce, Letian Zeng, Yaping Lei, Ming Su, and Xinquan Liang. "Tracking the Detrital Zircon Provenance of Early Miocene Sediments in the Continental Shelf of the Northwestern South China Sea." Minerals 10, no. 9 (August 25, 2020): 752. http://dx.doi.org/10.3390/min10090752.
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Sediment provenance studies have become a major theme for source-to-sink systems and provide an important tool for assessing paleogeographic reconstruction, characterizing the depositional system, and predicting reservoir quality. The lower Miocene is an important stratigraphic unit for deciphering sediment evolution in the continental shelf of the northwestern South China Sea, but the provenance characteristics of this strata remain unclear. In this study, detrital zircon U-Pb geochronology and Lu-Hf isotopes from the lower Miocene Sanya Formation in the Yinggehai-Song Hong Basin were examined to study the provenance and its variation in the early Miocene. U-Pb dating of detrital zircons yielded ages ranging from Archean to Cenozoic (3313 to 39 Ma) and displayed age distributions with multiple peaks and a wide range of εHf(t) values (from −27.2 to +8.5). Multi-proxy sediment provenance analysis indicates that the Red River system was the major source for the sediments in the northern basin, with additional contribution from central Vietnam, and the Hainan played the most important role in contributing detritus to the eastern margin of the basin in the middle Miocene. This paper highlights the provenance of early Miocene sediments and contributes to paleogeographic reconstruction and reservoir evaluation.
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Metillo, Ephrime B., Emily E. Cadelinia, Ken-ichi Hayashizaki, Takashi Tsunoda, and Shuhei Nishida. "Feeding ecology of two sympatric species of Acetes (Decapoda: Sergestidae) in Panguil Bay, the Philippines." Marine and Freshwater Research 67, no. 10 (2016): 1420. http://dx.doi.org/10.1071/mf15001.
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Sergestid shrimps of the genus Acetes are important in global shrimp fisheries and nearshore food-webs. The feeding habits of the sympatric species Acetes erythraeus and A. intermedius from Panguil Bay, Philippines were studied using gut contents and stable isotopes analyses. Both species are omnivorous suspension feeders of plankton, macrophyte detritus, and amorphous particulate organic materials. However, the diet of adults and juveniles differed by prey type. Gut fullness differed over 24h with a night-time peak in A. erythraeus and morning and midnight peaks in A. intermedius. Over 1 year gut fullness peaked during July to September for both species, with a minor peak during January for A. intermedius. Stable isotope analysis revealed similar δ15N values, but both species showed ontogenetic and interspecific separation of δ13C. A. erythraeus seemed to assimilate highly depleted carbon food sources by mangrove-based detrital and plankton trophic pathways, whereas A. intermedius relied on plankton and macroalgal and seagrass detrital pathways. These trophic differences may be mechanisms of partitioning the feeding niche, but allotopy in the two species with A. erythraeus confined to more brackish waters and A. intermedius dwelling in more saline marine waters may indicate that habitat niche segregation underlies these contrasting carbon trophic pathways.
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Luo, Liang, Lianbo Zeng, Kai Wang, Xiaoxia Yu, Yihang Li, Chenxi Zhu, and Shuning Liu. "Provenance investigation for the Cambrian–Ordovician strata from the northern margin of the western Yangtze Block: implications for locating the South China Block in Gondwana." Geological Magazine 157, no. 4 (October 25, 2019): 551–72. http://dx.doi.org/10.1017/s0016756819001110.
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AbstractWe report new U–Pb isotopic data for detrital zircons from Cambrian–Ordovician strata on the northern margin of the western Yangtze Block, which together with published U–Pb isotopic data for coeval strata in the South China Block, provide critical constraints on the provenance of these sediments and further shed light on the early Palaeozoic position of the South China Block in the context of Gondwana. Detrital zircons in this study yield four major age peaks in the early Palaeoproterozoic, early Neoproterozoic, middle Neoproterozoic and late Neoproterozoic – early Palaeozoic. The dominant age population of 900–700 Ma matches well with magmatic ages from the nearby Panxi–Hannan Belt, which indicates that Cambrian–Ordovician sedimentary rocks in the western Yangtze Block were mainly of local derivation. However, compilations of detrital zircon ages for the Cambrian–Ordovician strata from the Cathaysia Block and the eastern Yangtze Block show that both blocks are dominated by late Mesoproterozoic- and early Neoproterozoic-aged detrital zircons, which suggests a remarkable exotic input with typical Gondwana signatures. According to the integrated detrital zircon age spectra of the Cambrian–Ordovician sedimentary rocks from the entire South China Block and palaeocurrent data, the South China Block should have been linked with North India and Western Australia within East Gondwana. Specifically, the Cathaysia Block was located adjacent to Western Australia, while the Yangtze Block was connected with North India.
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Xu, Zhongjie, Jintao Kong, Rihui Cheng, and Liaoliang Wang. "U–Pb dating of detrital zircons in the eastern Guangdong Basin, South China, and constraints on the tectonic transformation from the Early to Middle Jurassic." Canadian Journal of Earth Sciences 57, no. 4 (April 2020): 477–93. http://dx.doi.org/10.1139/cjes-2019-0050.
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Controversies exist regarding the mechanism of formation of basins located on the continental margin of South China as well as when they formed. It was ascertained based on clastic petrology, geochemical analysis, and zircon U–Pb dating that the sedimentary provenances in the eastern Guangdong Basin are mainly felsic igneous rocks from the late Early Jurassic to the Middle Jurassic. The late Early Jurassic Qiaoyuan Formation mainly shows major age peaks at approximately 238 Ma, 259 Ma, and 1858 Ma, and the Middle Jurassic Tangxia Formation shows major age peaks at approximately 169 Ma and 172 Ma. From the late Early Jurassic to the Middle Jurassic in the eastern Guangdong Basin, the source region changes from southwestern South China and southern South China to the eastern Nanling Range. It was determined by comparing the detrital zircon ages of the Qiaoyuan Formation and the Tangxia Formation with those of the late Paleozoic to early Mesozoic basins, and analyzing both the geochemical data and sedimentation, that the eastern Guangdong Basin changed from the basin-arc foreland basin of the late Early Jurassic to the back-arc extension basin of the Middle Jurassic. The changes in early Mesozoic detrital zircon age peaks indicate that the tectonic regime of the eastern Guangdong Basin ended the transformation from the Tethyan tectonic domain to the paleo-Pacific tectonic domain in the early Middle Jurassic (approximately 172 Ma).
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Wu, Li-Guang, Xian-Hua Li, Weihua Yao, Xiao-Xiao Ling, and Kai Lu. "Insights into Polyphase Phanerozoic Tectonic Events in SE China: Integrated Isotopic Microanalysis of Detrital Zircon and Monazite." Lithosphere 2020, no. 1 (October 5, 2020): 1–17. http://dx.doi.org/10.2113/2020/8837978.
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Abstract Widespread Paleozoic and Mesozoic granites are characteristics of SE China, but the geodynamic mechanisms responsible for their emplacement are an issue of ongoing debate. To shed new light on this issue, we present an integrated geochronological and isotopic study of detrital zircon and monazite from Cambrian metasandstones and modern beach sands in the Yangjiang region, SE China. For the Cambrian metasandstone sample, detrital zircon displays a wide age range between 490 and 3000 Ma, while monazite grains record a single age peak of 235 Ma. The results suggest that a significant Triassic (235 Ma) metamorphic event is recorded by monazite but not zircon. For the beach sand sample, detrital zircon ages show six peaks at ca. 440, 240, 155, 135, 115, and 100 Ma, whereas detrital monazite yields a dominant age peak at 237 Ma and a very minor age peak at 435 Ma. Beach sand zircon displays features that are typical of a magmatic origin. Their Hf–O isotopes reveal two crustal reworking events during the early Paleozoic and Triassic, in addition to one juvenile crustal growth event during the Jurassic–Cretaceous. The beach sand monazite records intense Triassic igneous and metamorphic events with significant crustal reworking. Such early Paleozoic and Triassic geochemical signatures of detrital zircon and monazite suggest they were derived from granitoids and metamorphic rocks which formed in intraplate orogenies, i.e., the early Paleozoic Wuyi–Yunkai Orogeny and Triassic Indosinian Orogeny. The Jurassic–Cretaceous signature of detrital zircon may reflect multistage magmatism that was related to subduction of the Paleo-Pacific Plate beneath SE China.
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Kämpf, Lucas, Birgit Plessen, Stefan Lauterbach, Carla Nantke, Hanno Meyer, Bernhard Chapligin, and Achim Brauer. "Stable oxygen and carbon isotopes of carbonates in lake sediments as a paleoflood proxy." Geology 48, no. 1 (October 16, 2019): 3–7. http://dx.doi.org/10.1130/g46593.1.
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Abstract Lake sediments are increasingly explored as reliable paleoflood archives. In addition to established flood proxies including detrital layer thickness, chemical composition, and grain size, we explore stable oxygen and carbon isotope data as paleoflood proxies for lakes in catchments with carbonate bedrock geology. In a case study from Lake Mondsee (Austria), we integrate high-resolution sediment trapping at a proximal and a distal location and stable isotope analyses of varved lake sediments to investigate flood-triggered detrital sediment flux. First, we demonstrate a relation between runoff, detrital sediment flux, and isotope values in the sediment trap record covering the period 2011–2013 CE including 22 events with daily (hourly) peak runoff ranging from 10 (24) m3 s−1 to 79 (110) m3 s−1. The three- to ten-fold lower flood-triggered detrital sediment deposition in the distal trap is well reflected by attenuated peaks in the stable isotope values of trapped sediments. Next, we show that all nine flood-triggered detrital layers deposited in a sediment record from 1988 to 2013 have elevated isotope values compared with endogenic calcite. In addition, even two runoff events that did not cause the deposition of visible detrital layers are distinguished by higher isotope values. Empirical thresholds in the isotope data allow estimation of magnitudes of the majority of floods, although in some cases flood magnitudes are overestimated because local effects can result in too-high isotope values. Hence we present a proof of concept for stable isotopes as reliable tool for reconstructing flood frequency and, although with some limitations, even for flood magnitudes.
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Piper, David J. W., Georgia Pe-Piper, Mike Tubrett, Stavros Triantafyllidis, and Greg Strathdee. "Detrital zircon geochronology and polycyclic sediment sources, Upper Jurassic – Lower Cretaceous of the Scotian Basin, southeastern Canada 1This article is one of a series of papers published in this CJES Special Issue on the theme of Mesozoic–Cenozoic geology of the Scotian Basin." Canadian Journal of Earth Sciences 49, no. 12 (December 2012): 1540–57. http://dx.doi.org/10.1139/e2012-072.
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Sources of Tithonian–Albian sediment in the Scotian Basin are interpreted from detrital zircon geochronology to test previous hypotheses about the sources and pathways of sediment to thick deltaic successions that are important hydrocarbon reservoirs. Sediment provenance influences reservoir quality, but also provides information on tectonism during rifting of the North Atlantic Ocean. More than 760 zircons were dated by laser ablation U–Pb methods from nine offshore wells and one borehole on land and were characterized by external morphology, internal zoning, and Th/U ratio. A Meguma terrane source to the LaHave Platform was confirmed by peaks in detrital zircon abundance at 550–650 Ma, 1.0–1.2 Ga, and ∼2.1 Ga. Samples from the Sable Subbasin show a large peak in detrital zircon abundance at ∼1050 Ma, with lower peaks from 400–650, ∼1480, ∼1650, ∼1860 Ma and 2.7 Ga, characteristic of inboard Appalachian terranes of Laurentide affinity. Many late Paleozoic to Neoproterozoic zircons are euhedral or subhedral, and apparently first cycle, as are a few older zircons that indicate transport from the rising rift shoulder in southern Labrador as far north as the Makkovik Province (∼1860 Ma). About half the zircons are rounded and polycyclic. Samples from the Abenaki Subbasin are similar, but late Paleozoic to Neoproterozoic zircons are rare and ∼40% of the Mesoproterozoic zircons are subhedral, implying a different Laurentide source through the Humber valley. Euhedral–subhedral unzoned zircons yielded two groups of Cretaceous dates: ∼105 Ma from the Cree Member, and ∼120 Ma from the Missisauga Formation.
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Papapavlou, Konstantinos, Rob A. Strachan, Craig D. Storey, and Dean Bullen. "Tectonic significance of a supra-ophiolitic sedimentary cover succession, Unst, Shetland, Scottish Caledonides: insights from the U–Pb–Hf detrital zircon record." Journal of the Geological Society 178, no. 5 (March 4, 2021): jgs2020–169. http://dx.doi.org/10.1144/jgs2020-169.
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The tectonic significance of the Muness Phyllite, which overlies the Unst–Fetlar ophiolite in Shetland, Scottish Caledonides, is poorly understood. U–Pb analyses of detrital zircons show that it was deposited after c. 469 Ma. Early Paleozoic grains have εHf values of −0.3 to +12.3 and were probably derived from the extension of the Midland Valley arc. Psammite clasts and the matrix of the Muness Phyllite contain Proterozoic and Archean detrital zircons with age peaks of c. 1, 1.4–1.5, 1.6–1.7, 1.8–1.9 and 2.7 Ga. These are consistent with ultimate derivation from NE Laurentia sources and were probably recycled from the Neoproterozoic East Mainland Succession that underlies the Mesozoic East Shetland Basin. The Muness Phyllite is interpreted to have been deposited soon after the Grampian I orogeny in a successor basin that overstepped and received detritus from the Midland Valley arc, the East Mainland Succession and the Unst–Fetlar ophiolite. It was then deformed and metamorphosed, probably at c. 450 Ma during the Grampian II orogenic event. The Muness Phyllite therefore provides a record of middle to late Ordovician tectonic events along the Scottish sector of the Laurentian margin following ophiolite obduction.Supplementary material: Analytical details and instrumentation parameters and U–Pb and Lu–Hf isotopic data are available at https://doi.org/10.6084/m9.figshare.c.5324986
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Sabbeth, Leah, Brian P. Wernicke, Timothy D. Raub, Jeffrey A. Grover, E. Bruce Lander, and Joseph L. Kirschvink. "Grand Canyon provenance for orthoquartzite clasts in the lower Miocene of coastal southern California." Geosphere 15, no. 6 (October 16, 2019): 1973–98. http://dx.doi.org/10.1130/ges02111.1.
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Abstract Orthoquartzite detrital source regions in the Cordilleran interior yield clast populations with distinct spectra of paleomagnetic inclinations and detrital zircon ages that can be used to trace the provenance of gravels deposited along the western margin of the Cordilleran orogen. An inventory of characteristic remnant magnetizations (CRMs) from >700 sample cores from orthoquartzite source regions defines a low-inclination population of Neoproterozoic–Paleozoic age in the Mojave Desert–Death Valley region (and in correlative strata in Sonora, Mexico) and a moderate- to high-inclination population in the 1.1 Ga Shinumo Formation in eastern Grand Canyon. Detrital zircon ages can be used to distinguish Paleoproterozoic to mid-Mesoproterozoic (1.84–1.20 Ga) clasts derived from the central Arizona highlands region from clasts derived from younger sources that contain late Mesoproterozoic zircons (1.20–1.00 Ga). Characteristic paleomagnetic magnetizations were measured in 44 densely cemented orthoquartzite clasts, sampled from lower Miocene portions of the Sespe Formation in the Santa Monica and Santa Ana mountains and from a middle Eocene section in Simi Valley. Miocene Sespe clast inclinations define a bimodal population with modes near 15° and 45°. Eight samples from the steeper Miocene mode for which detrital zircon spectra were obtained all have spectra with peaks at 1.2, 1.4, and 1.7 Ga. One contains Paleozoic and Mesozoic peaks and is probably Jurassic. The remaining seven define a population of clasts with the distinctive combination of moderate to high inclination and a cosmopolitan age spectrum with abundant grains younger than 1.2 Ga. The moderate to high inclinations rule out a Mojave Desert–Death Valley or Sonoran region source population, and the cosmopolitan detrital zircon spectra rule out a central Arizona highlands source population. The Shinumo Formation, presently exposed only within a few hundred meters elevation of the bottom of eastern Grand Canyon, thus remains the only plausible, known source for the moderate- to high-inclination clast population. If so, then the Upper Granite Gorge of the eastern Grand Canyon had been eroded to within a few hundred meters of its current depth by early Miocene time (ca. 20 Ma). Such an unroofing event in the eastern Grand Canyon region is independently confirmed by (U-Th)/He thermochronology. Inclusion of the eastern Grand Canyon region in the Sespe drainage system is also independently supported by detrital zircon age spectra of Sespe sandstones. Collectively, these data define a mid-Tertiary, SW-flowing “Arizona River” drainage system between the rapidly eroding eastern Grand Canyon region and coastal California.
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Bozkaya, Ö., H. Yalçin, and P. A. Schroeder. "Two-step mode of clay formation in the extensional basins: Cambrian–Ordovician clastic rocks of the Antalya unit, SW Turkey." Clay Minerals 52, no. 3 (September 2017): 365–89. http://dx.doi.org/10.1180/claymin.2017.052.3.07.
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AbstractOrdovician clastic rocks of the Antalya unit in SW Turkey bear mineralogical/geochemical evidence of Triassic extensional rift timing and spatial relations. The crystal chemistry of the phyllosilicate assemblages (illite, chlorite, kaolinite, mixed-layer illite-smectite, chlorite-vermiculite and chlorite-smectite) is consistent with the rock experiencing a multi-generational burial history. The appearance of kaolinite and illite-smectite-bearing rocks in the Antalya unit is characteristic of diagenetic-anchimetamorphic conditions and is of higher grade than their anchi-epizonal equivalents in other regions of the Tauride belt. Illites and chlorites are of both detrital and authigenic origin, whereas I-S and kaolinites are authigenic. Detrital micas have been altered to chlorite and K-white mica stacks in which relicts suggest the chlorites were derived from detrital biotites. The broad X-ray diffraction illite peaks show that they are composed both of illite and illite-smectite. Na,K-mica and paragonite occur within the chlorite-mica stacks as replacements of muscovite, probably driven by Na-rich solutions. The authigenic clays were formed within the microporous matrix and the interplanar spaces of {001} planes of chlorite-mica stacks, with textures independent of the bedding and foliation planes of the rocks. The authigenic chlorites exhibit higher Si and Fe and lower Mg contents than their detrital counterparts. Authigenic chlorite thermometry indicates rift-related temperatures of 50–150°C, whereas pre-rift detrital chlorites formed at temperatures of >200°C. Authigenic illite and illite-smectite are phengitic in composition and contain more Si, Mg, Fe and Ca and less Al and K than detrital K-white micas. The textural, mineralogical and chemical characteristics support the hypothesis that the mineral assemblages were a result of a two-step mode of formation with diagenetic overprints of previously anchizonal rocks in extensional basin conditions.
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Awais, Muhammad, Muhammad Qasim, Javed Iqbal Tanoli, Lin Ding, Maryam Sattar, Mirza Shahid Baig, and Shahab Pervaiz. "Detrital Zircon Provenance of the Cenozoic Sequence, Kotli, Northwestern Himalaya, Pakistan; Implications for India–Asia Collision." Minerals 11, no. 12 (December 11, 2021): 1399. http://dx.doi.org/10.3390/min11121399.
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This study reported the detrital zircon U-Pb geochronology of the Cenozoic sequence exposed in Kotli, northwestern Himalaya, Pakistan, which forms part of the Kashmir foreland basin. The U-Pb detrital age patterns of the Paleocene Patala Formation show a major age cluster between ~130–290 Ma, ~500–1000 Ma and ~1000–1500 Ma, which mainly resembles the lesser and higher Himalayan sequence. However, the younger age pattern (~130–290 Ma) can be matched to the ages of the ophiolites exposed along the Indus–Tsangpo suture zone. In addition, two younger grains with 57 Ma and 55 Ma ages may indicate a contribution from the Kohistan-Ladakh arc. The detrital zircons in the upper Tertiary sequence show the increased input of younger detrital ages <100 Ma, with more pronounced peaks at ~36–58 Ma, ~72–94 Ma and ~102–166 Ma, indicating the strong resemblance to the Asian sources including the Kohistan–Ladakh arc, Karakoram block and Gangdese batholith. This provenance shift, recorded in the upper portion of Patala Formation and becoming more visible in the upper Tertiary clastic sequence (Kuldana and Murree formations), is related to the collision of the Indian and Asian plates in the northwestern Himalayas. Considering the age of the Patala Formation, we suggest that the Indian and Asian plates collided during 57–55 Ma in the northwestern Himalayas, Pakistan.
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Zhou, Guangyan, Christopher M. Fisher, Yan Luo, D. Graham Pearson, Long Li, Yu He, and Yuanbao Wu. "A clearer view of crustal evolution: U-Pb, Sm-Nd, and Lu-Hf isotope systematics in five detrital minerals unravel the tectonothermal history of northern China." GSA Bulletin 132, no. 11-12 (April 3, 2020): 2367–81. http://dx.doi.org/10.1130/b35515.1.
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Abstract Much of the global picture of crustal evolution has been constructed using zircon. While this has revealed a rich and complex history, this view is necessarily incomplete because of the lithology-specific affinity of zircon and the high temperatures needed to reset the U-Pb and Lu-Hf systems inherent within it. Here we use a five mineral, multi-isotope system approach to compare the record of crustal evolution recorded by zircon versus the picture provided by monazite, titanite, apatite, and rutile from the Yong-Ding and Luan rivers, northern China. These other minerals sample more diverse lithologies and temperature-pressure conditions that reflect additional tectonothermal events to those recorded solely by zircon. Zircon from both studied rivers predominantly reflects magmatic features, yielding age peaks at 2.6–2.3, 2.0–1.8, and 0.38–0.13 Ga, corresponding to the major magmatic events in their catchments. However, the detrital zircon record from both catchments fails to record and detail several important tectonothermal events. Specifically, the detrital monazite U-Pb ages cluster into two Paleoproterozoic peaks of ca. 1.95 and 1.85 Ga, while detrital apatite and rutile ages document unimodal and protracted U-Pb age peaks at 1.9–1.6 Ga. The different U-Pb closure temperatures of monazite, apatite, and rutile likely record two metamorphic events and the subsequent cooling history—key details that are absent from or obscured in the zircon record. The Phanerozoic mineral U-Th-Pb ages correspond to multiple magmatic events between 0.40 and 0.24 Ga and subsequent 0.24–0.20 Ga metamorphism. The 0.60–0.25 Ga rutile U-Pb ages along with 0.33–0.24 Ga U-Pb ages in some zircon grains with radiogenic Hf isotope compositions from the Luan River do not match the geological records in the North China Craton, but instead reflect the protracted subduction-accretionary history of the Central Asian Orogenic Belt. In addition to their U-Th-Pb ages, Nd model ages of monazite, titanite, and apatite, plus zircon Hf model ages provide additional constraints on regional crustal evolution. The Nd model age information is blurred by the fact that the relationship between the Sm/Nd of these minerals and their former host rocks is not precisely known. Taken at face value, the monazite Nd model ages have two Neoarchean peaks at 2.9–2.7 and ca. 2.5 Ga, that may correspond to two crustal growth episodes, while the titanite Nd model ages with predominant peaks at 2.2–1.8 and 1.5–1.3 Ga broadly correspond with those derived from the whole-rock analyses of the wide spread Phanerozoic granitoids, and hence record extensive crustal reworking. In contrast, the zircon Hf model ages are strongly skewed to a 2.9–2.7 Ga period and fail to record the post-Archean evolution of this region. These data highlight the power of integrating the U-Th-Pb age and Lu-Hf/Sm-Nd isotope compositions of multiple detrital minerals, with a broad range in geochemical behavior and closure temperatures, to gain a more complete understanding of tectonothermal history and crustal evolution than zircon alone.
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Wang, Peng, Guochun Zhao, Peter A. Cawood, Yigui Han, Shan Yu, Qian Liu, Jinlong Yao, and Donghai Zhang. "South Tarim tied to north India on the periphery of Rodinia and Gondwana and implications for the evolution of two supercontinents." Geology 50, no. 2 (October 8, 2021): 131–36. http://dx.doi.org/10.1130/g49238.1.
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Abstract Constraining the positions of, and interrelationships between, Earth's major continental blocks has played a major role in validating the concept of the supercontinent cycle. Minor continental fragments can provide additional key constraints on modes of supercontinent assembly and dispersal. The Tarim craton has been placed both at the core of Rodinia or on its periphery, and differentiating between the two scenarios has widespread implications for the breakup of Rodinia and subsequent assembly of Gondwana. In the South Tarim terrane, detrital zircon grains from Neoproterozoic–Silurian strata display two dominant populations at 950–750 and 550–450 Ma. Similarly, two main peaks at 1000–800 and 600–490 Ma characterize Neoproterozoic–Ordovician strata in northern India. Moreover, the two dominant peaks of South Tarim and north India lag two global peaks at 1200–1000 and 650–500 Ma, which reflect Rodinia and Gondwana assembly, arguing against a position within the heart of the two supercontinents. Ages and Hf isotopes of Tarim's detrital zircons argue for a position on the margin of both supercontinents adjacent to north India with periodic dispersal through opening and closing of small ocean basins (e.g., the Proto-Tethys). Alternating tectonic transitions between advancing and retreating subduction in North Tarim coincide with periodic drift of South Tarim from north India in Rodinia and Gondwana, emphasizing the importance of retreating subduction in supercontinent dispersal. Moreover, the Rodinia-related orogenic belts spatially overlap the Gondwana-related orogenic belts in the two blocks, indicating no significant relative rotation of India and Tarim during the evolution from Rodinia to Gondwana.
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Lin, Xu, Marc Jolivet, Jing Liu-Zeng, Feng Cheng, Zhonghai Wu, Yuntao Tian, Lingling Li, and Jixin Chen. "The Formation of the North Qilian Shan through Time: Clues from Detrital Zircon Fission-Track Data from Modern River Sediments." Geosciences 12, no. 4 (April 7, 2022): 166. http://dx.doi.org/10.3390/geosciences12040166.
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Understanding the formation of the North Qilian Shan in the NE Tibetan Plateau provides insights into the growth mechanisms of the northern region of the plateau across time. Detrital zircon fission-track (ZFT) analyses of river sediments can provide a comprehensive understanding of the exhumation history during prolonged orogenesis. Here, we applied the detrital thermochronology approach to the Qilian Shan orogenic belt. This work presents the first single-grain detrital ZFT data from river-bed sediments of the upper Hei River catchment in North Qilian Shan. The single ZFT ages are widely distributed between about 1200 Ma and about 40 Ma. These data record the protracted history of the Qilian Shan region from the Neoproterozoic evolution of Rodinia and late Paleozoic amalgamation of Central Asia to the accretion of the Gondwanian blocks during the Meso-Cenozoic era. Strong post-magmatic cooling events occurred in North Qilian Shan at 1200~1000 Ma, corresponding to the assembly of the Rodinia supercontinent. The age population at 800 Ma documents the oceanic spreading in the late Neoproterozoic dismantling of Rodinia. ZFT ages ranging from about 750 Ma to 550 Ma (with age peaks at 723 Ma and 588 Ma) are consistent with the timing of the opening and spreading of the Qilian Ocean. The age peaks at 523 Ma and 450 Ma mark the progressive closure of that ocean ending with the collision of the Qilian block with the Alxa block—North China craton in the Devonian. The Qilian Ocean finally closed in Late Devonian (age peak at 375 Ma). In the late Paleozoic (275 Ma), the subduction of the Paleotethys Ocean led to extensive magmatic activity in the North Qilian Shan. During the Lower Cretaceous (145 Ma), the accretion of the Lhasa block to the south (and potentially the closure of the Mongol-Okhotsk Ocean to the northeast) triggered a renewed tectonic activity in the Qilian Shan. Finally, a poorly defined early Eocene exhumation event (50 Ma) suggests that the NE Tibetan Plateau started to deform nearly synchronously with the onset of the India-Asia collision. This study demonstrates the usefulness of combining modern-river detrital thermo-/geochronological ages and bedrock geochronological ages to understand large-scale orogenic evolution processes.
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Zaika, V. A., A. A. Sorokin, and A. P. Sorokin. "Age and sources of the metasedimrntary rocks of the Tokur terrane in the Mongol-Okhotsk fold belt: results of the U–Pb geoсhronological and Lu–Hf isotope studies." Доклады Академии наук 486, no. 4 (June 10, 2019): 446–50. http://dx.doi.org/10.31857/s0869-56524864446-450.
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This paper presents the results of U–Pb (LA–ICP–MS) and Lu–Hf isotope studies of detrital zircons from metasedimentary rocks of the Tokur Terrane. It has been shown that metasedimentary rocks of the Tokur and Ekimchan formations are characterized by similar age peaks of detrital zircons, which indicates a close (or same) age of these formations. The lower age of the sedimentation is determined by the age of the youngest zircons of 326–323 Ma. The upper age boundary is determined of 254–251 Ma, based on the intruded of the Late Permian granitoids. The main sources of zircons in the metasedimentary rocks of the Tokur Terrane are the igneous and metamorphic complexes of the southeast framing of the North Asia Craton. The Tokur Terrane can be considered as a fragment of the Paleozoic accretionary complex, the formation in front of the southeastern margin of the North Asia Craton.
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Deng, Bin, David Chew, Chris Mark, Shugen Liu, Nathan Cogné, Lei Jiang, Gary O’Sullivan, Zhiwu Li, and Jinxi Li. "Late Cenozoic drainage reorganization of the paleo-Yangtze river constrained by multi-proxy provenance analysis of the Paleo-lake Xigeda." GSA Bulletin 133, no. 1-2 (June 5, 2020): 199–211. http://dx.doi.org/10.1130/b35579.1.
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Abstract The Late Cenozoic evolution of the major river networks draining eastern Tibet has major tectonic implications for the development of the plateau but remains highly contentious. In this study from the southeastern margin of the Tibetan Plateau, we constrain the evolution of the Paleo-lake Xigeda (recorded by the lacustrine Plio-Pleistocene Xigeda Formation) using combined fission-track (FT) dating, U-Pb and trace-element analysis of detrital apatite, along with U-Pb dating of detrital rutile and zircon. Critically, the detrital apatite U-Pb age data from the Xigeda Formation exhibit a major Late Triassic to Jurassic peak that is also seen in the U-Pb rutile and zircon data. When integrated with apatite fission-track (AFT) age peaks at ca. 60–40 Ma and ca. 20–10 Ma and apatite trace-element analyses, these U-Pb ages support provenance from the Songpan-Ganzi and southern Longmenshan terranes to the north. Thus, the Paleo-Xigeda lake was fed by south-flowing paleo-Dadu and paleo-Yalong rivers during Plio-Pleistocene time. Pliocene tectonic activity on the Xianshuihe-Daliangshan-Xiaojiang fault zone likely formed Paleo-lake Xigeda by damming of the Middle Yangtze River; subsequent capture of the Upper Yangtze by the Middle Yangtze after ca. 1.3 Ma likely breached the Paleo-lake Xigeda.
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Syzdek, Joseph, David Malone, and John Craddock. "Detrital Zircon U-Pb Geochronology and Provenance of the Sundance Formation, Western Powder River Basin, Wyoming." Mountain Geologist 56, no. 3 (August 1, 2019): 295–317. http://dx.doi.org/10.31582/rmag.mg.56.3.295.
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This study uses detrital zircon U-Pb geochronology to investigate the provenance of the Jurassic Sundance Formation in the western Powder River Basin, Wyoming. Understanding the provenance of the Sundance Formation is critical as it was deposited during the transition from cratonic to synorogenic sedimentation derived from the Sevier-Laramide foreland. The Sundance in the western Powder River Basin consists of an oolitic limestone and green glauconitic sandstone at the base, green shales in the middle, and a yellow quartz arenite with coquina “oyster” beds at the top. U-Pb analyses of detrital zircons using LA-ICP-MS were conducted on two samples collected in the Bud Love Wildlife Habitat Management Area, 20 km northwest of Buffalo, WY. The two samples were taken from the upper and lower sandstone members of the Sundance Formation (n=289 concordant U-Pb zircon ages). The samples show a distinct difference in detrital zircon age spectra. The lower sandstone age spectrum ranges from 260-3172 Ma with 23% of the ages being Paleozoic, 71% being Proterozoic, and 6% being Archean. This lower stratum has detrital zircon age peaks at 343, 432, 686, 1039, 1431, 1662, 1748, 1941, 2433, and 3179 Ma. The lower sandstone shows an easterly Appalachian-Ouachita provenance, which persisted in the region beginning in the Carboniferous. In comparison to the upper strata, ages range from 157-2949 Ma and age peaks at 170, 243, 440, 545, 1082, 1467, 1681, and 1985 Ma. The maximum deposition age for the upper member is 160 Ma. Mesozoic aged grains make up 15.6% of the zircons, 14.7% were Paleozoic, 65.7% were Proterozoic, and 4% were Archean in age. The appearance of Mesozoic zircons in the upper sandstone marks the first significant appearance of westerly sourced zircons, and perhaps reflects the earliest uplift of the Sevier fold and thrust belt. Previous research has found this same signature in the Sundance but not in the underlying Triassic Chugwater Formation, resulting in a broad boundary of the change in sediment dispersal and the onset of the Sevier Orogeny between the Triassic and Jurassic. This study was conducted for a higher resolution to the provenance of the Sundance Formation and to further narrow the boundary of differing sedimentation from an eastern recycled to western synorogenic source.
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Zhongjie, Xu, Kong Jintao, Cheng Rihui, Lan Yizhi, and Wang Liaoliang. "LA-ICP-MS U–Pb ages of detrital zircons from Middle Jurassic sedimentary rocks in southwestern Fujian: Sedimentary provenance and its geological significance." Open Geosciences 12, no. 1 (October 3, 2020): 958–76. http://dx.doi.org/10.1515/geo-2020-0185.
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AbstractIn order to determine the tectonic regime change of the early Mesozoic in the South China Block, this study analyzed sedimentary rocks in the Middle Jurassic of southwestern Fujian by modal analysis of sandstones, elemental geochemical analysis of mudstones, and detrital zircons U–Pb dating. The results show that the detrital zircons in Southwestern Fujian mainly consist of Paleoproterozoic to early Mesozoic zircons in the Middle Jurassic. Within the Dongkeng profile of the Zhangping Formation, DK5 sample (lower part) showed a major age peak at ca. 1,848 Ma and two secondary age peaks at ca. 235 and 180 Ma, while DK15 sample (middle part) showed a major age peak at ca. 1,876 Ma and two secondary age peaks at ca. 233 and 190 Ma; the age compositions of these two samples’ were similar. Modal analysis of sandstones indicated that sediments of Zhangping Formation might source from arc orogen and recycled orogen, and element geochemical analysis showed that source rocks of Zhangping Formation might be sedimentary rocks and granites. The Indosinian zircons were mainly derived from the Wuyi region, and the Yanshanian zircons were mainly derived from the Nanling region. The major age group changes from ca. 230 to 220 Ma of the Late Triassic – Early Jurassic to ca. 190 to 180 Ma of the Middle Jurassic in Southwestern Fujian, and main sources changed from Indosinian magmatic rocks in the Late Triassic – Early Jurassic to early Yanshanian magmatic rocks in the Middle Jurassic.
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Zaika, V. A., A. A. Sorokin, V. P. Kovach, A. P. Sorokin, and A. B. Kotov. "Age and sources of the Lower Mesozoic metasedimentary rocks of the Un'ja-Bom terrane in the Mongol-Okhotsk fold belt: results of the U–Th–Pb geohronological (LA–ICP–MS) AND Sm–Nd isotope studies." Доклады Академии наук 484, no. 4 (May 5, 2019): 455–59. http://dx.doi.org/10.31857/s0869-56524844455-459.
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The results of the U—Th—Pb geochronological studies indicate that in the Un’ja-Bom terrane the youngest peaks on the relative probability curves of ages are 207 and 212 Ma for zircons from the metasiltstone of the Kurnal formation and from the metasiltstone of the Amkan formation. Similar age estimates for the youngest peaks were obtained for the detrital zircons from the metasedimentary rocks of the Tukuringra terrain of the eastern part of the Mongol-Okhotsk belt, which indicates that the Lower Mesozoic flyschoid complexes in the structure of this belt are developed much wider than is currently believed. The results obtained in our U—Th—Pb geochronological and Sm—Nd isotope geochemical studies suggest’s that the sedimentary rocks material was carried to the sedimentation basin mainly from the continental massifs of the Amur superterrane.
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MEINHOLD, GUIDO, and DIRK FREI. "Detrital zircon ages from the islands of Inousses and Psara, Aegean Sea, Greece: constraints on depositional age and provenance." Geological Magazine 145, no. 6 (September 16, 2008): 886–91. http://dx.doi.org/10.1017/s0016756808005505.
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AbstractU–Pb LA–SF–ICP–MS analyses of detrital zircons from a metalitharenite on Inousses Island, Greece, gave major age groups of 310–350, 450–500, 550–700, 900–1050 and 1880–2040 Ma and minor peaks between 2600 and 2800 Ma. The youngest concordant zircon grains of 310–330 Ma indicate the maximum age of deposition to be Late Carboniferous, rather than Ordovician, as had been earlier assumed. The lack of zircon ages between 1.1 and 1.8 Ga, coupled with the occurrence ofc.2-Ga-old zircons, imply a northern Gondwana-derived source. Detrital zircons from a garnet–mica schist on Psara Island yielded a major age group ofc.295–325 Ma and only minor Early Palaeozoic and Late Neoproterozoic ages. The youngest grains around 270 Ma indicate the maximum age of deposition to be Late Permian. The Early Palaeozoic ages support a source from terranes at the southern margin of Laurussia during the Late Palaeozoic and hence clarify the palaeotectonic position of units from the eastern Aegean Sea within the Palaeotethyan realm.
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Cai, Fulong, Lin Ding, Qinghai Zhang, Devon A. Orme, Honghong Wei, Jinxiang Li, Ji’en Zhang, Than Zaw, and Kyaing Sein. "Initiation and evolution of forearc basins in the Central Myanmar Depression." GSA Bulletin 132, no. 5-6 (October 14, 2019): 1066–82. http://dx.doi.org/10.1130/b35301.1.
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Abstract The forearc basin in Myanmar is significant in understanding the development of continental forearc basins. We present stratigraphic, sandstone petrographic, and U-Pb detrital data from Upper Cretaceous–Eocene strata of Chindwin and Minbu sub-basins in the Central Myanmar Depression. The Upper Cretaceous lower Kabaw Formation consists of turbiditic conglomerate, sandstone, and mudstone in the Minbu sub-basin. The composition of conglomerates are mainly schist and subordinate quartz. Prominent detrital zircon age probability peaks are between 260 and 223 Ma, similar with that of Upper Triassic Pane Chaung turbidites and Kanpetlet schist on the West Burma plate. In the upper Kabaw Formation, turbiditic volcanic-rich sandstones have major age populations ranging from 103 to 70 Ma in both Minbu and Chindwin sub-basins. The Paleocene slope environment Paunggyi Formation, which overlies the Kabaw Formation, mainly consists of conglomerate, sandstone, mudstone, and tuff beds in the Minbu sub-basin. In contrast, the Paunggyi Formation in the Chindwin sub-basin is composed of sandstone and mudstone; major detrital zircon age populations from the Paunggyi Formation are between 100 and 60 Ma. Eocene strata in both basins are composed mainly of shallow marine to delta sandstone and mudstone. Major detrital zircon age populations are 100–36 Ma and 600–500 Ma. The Late Cretaceous–Eocene ages from Upper Cretaceous–Eocene strata overlap with igneous crystallization ages from the Western Myanmar Arc. We propose that the Chindwin and Minbu sub-basins developed as parts of a forearc basin along the west flank of Western Myanmar Arc (present coordinate). The forearc basin initiated in Albian time atop the continental West Burma plate due to the formation of a structural high along the western margin of West Burma plate.
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Tevelev, A. V., A. A. Borisenko, I. D. Sobolev, A. Yu Kazansky, N. V. Pravikova, E. V. Kopte, E. A. Volodina, and V. S. Chervyakovskiy. "The areas of manifestation of the Intravisean orogeny in the Eastern Zones of the Southern Urals (According to the detrital zircons U-Pb dating data from the Solnechnaya Formation of the Upper Visean)." Moscow University Bulletin. Series 4. Geology, no. 5 (December 17, 2022): 47–56. http://dx.doi.org/10.33623/0579-9406-2022-5-47-56.
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The aim of this work is to determine the provenance for the Upper Visean Solnechnay formation (The Southern Urals) using the U-Pb dating of detrital zircons. 138 zircon grains with discordance range of ± 10% were selected for the analysis. The vast majority of the zircons yielded the Ordovician and Cambrian ages. The main peak corresponds to the beginning of the Ordovician period (circa 480 Ma), and the secondary peaks correspond to the beginning of the Late Ordovician, the middle Cambrian, and the early Cambrian. The clastic material was derived from the East Ural megazone exclusively.
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Condie, K. C. "Growth of continental crust: a balance between preservation and recycling." Mineralogical Magazine 78, no. 3 (June 2014): 623–37. http://dx.doi.org/10.1180/minmag.2014.078.3.11.
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AbstractOne of the major obstacles to our understanding of the growth of continental crust is that of estimating the balance between extraction rate of continental crust from the mantle and its recycling rate back into the mantle. As a first step it is important to learn more about how and when juvenile crust is preserved in orogens. The most abundant petrotectonic assemblage preserved in orogens (both collisional and accretionary) is the continental arc, whereas oceanic terranes (arcs, crust, mélange, Large Igneous Provinces, etc.) comprise <10%; the remainder comprises older, reworked crust. Most of the juvenile crust in orogens is found in continental arc assemblages. Our studies indicate that most juvenile crust preserved in orogens was produced during the ocean-basin closing stage and not during the collision. However, the duration of ocean-basin closing is not a major control on the fraction of juvenile crust preserved in orogens; regardless of the duration of subduction, the fraction of juvenile crust preserved reaches a maximum of ∼50%. Hafnium and Nd isotopic data indicate that reworking dominates in external orogens during supercontinent breakup, whereas during supercontinent assembly, external orogens change to retreating modes where greater amounts of juvenile crust are produced. The most remarkable feature of εNd (sedimentary rocks and granitoids) and εHf (detrital zircons) distributions through time is how well they agree with each other. The ratio of positive to negative εNd and eHf does not increase during supercontinent assembly (coincident with zircon age peaks), which suggests that supercontinent assembly is not accompanied by enhanced crustal production. Rather, the zircon age peaks probably result from enhanced preservation of juvenile crust. Valleys between zircon age peaks probably reflect recycling of continental crust into the mantle during supercontinent breakup. Hafnium isotopic data from zircons that have mantle sources, Nd isotopic data from detrital sedimentary rocks and granitoids and whole-rock Re depletion ages of mantle xenoliths collectively suggest that ≥70% of the continental crust was extracted from the mantle between 3500 and 2500 Ma.
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Guan, Ming, Jiahao Li, Guoqing Jia, Shenglian Ren, and Chuanzhong Song. "U–Pb Zircon Ages and Geochemistry of the Wuguan Complex and Liuling Group: Implications for the Late Paleozoic Tectonic Evolution of the Qinling Orogenic Belt, Central China." Minerals 12, no. 8 (August 15, 2022): 1026. http://dx.doi.org/10.3390/min12081026.
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The tectonic evolution of the Qinling orogen is key to understanding the process of convergence between the North China Block (NCB) and the South China Block (SCB). The Wuguan Complex and Liuling Group, situated along the southern margin of the Shangnan–Danfeng suture zone (SDSZ) between the North Qinling Terrane (NQT) and the South Qinling Terrane (SQT), are important indicators of the late Paleozoic tectonic evolution of the Qinling orogen. In this paper, the detrital zircon U–Pb geochronology and geochemical analysis of the Wuguan Complex and Liuling Group are carried out. Detrital zircons from two metasedimentary rock samples of the Liuling Group yield a major age peak at 460 Ma and two subordinate peaks at 804 Ma and 920 Ma, with a few older grains having formed between 1000–2549 Ma. One metasedimentary rock sample of the Wuguan Complex has a similar age spectrum as that of the Liuling Group, which shows the main age peak at 440 Ma and two subordinate peaks at 786 and 927 Ma, indicating all detrital zircon age results have the same source area. Geochemical analyses suggest that the sedimentary rocks of the Liuling Group and part of the Wuguan Complex were deposited in the tectonic setting of the continental island arc (CIA), while the geochemical characteristics of the other group of sedimentary rocks of the Wuguan Complex indicate the mixing of basic rock sources. The protolith of garnet amphibolite and hornblende schist, which were collected from the Wuguan Complex, were classified as andesite and basalt, with the nature of arc andesite and oceanic island basalt, respectively. In combination with regional data, we suggest that the Liuling Group and the Wuguan Complex were deposited in a fore-arc basin. Additionally, the Wuguan Complex was subsequently incorporated into the tectonic mélange by the northward subduction of the Paleo-Qinling Ocean. Zircons from the subduction-related metamorphic igneous rocks in the Wuguan Complex yielded a weighted mean age of 365 ± 19 Ma, indicating that the Paleo-Qinling Ocean between the SQT and NQT was still subducted at the end of Devonian.
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Li, Shuang-Qing, Song He, and Fukun Chen. "Provenance changes across the mid-Cretaceous unconformity in basins of northeastern China: Evidence for an integrated paleolake system and tectonic transformation." GSA Bulletin 133, no. 1-2 (June 1, 2020): 185–98. http://dx.doi.org/10.1130/b35660.1.
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Abstract Detrital zircon U-Pb dating and whole-rock Nd isotopic analyses were carried out on selected stratigraphic horizons across a major unconformity between synrift and postrift stages in the Songliao Basin and Dasanjiang basin group of NE China to constrain the crustal evolution of the source area providing detritus into these basins. The strata underlying the mid-Cretaceous unconformity in the Songliao Basin show regionally distinct detrital zircon age populations and Nd isotopic compositions, which generally are characterized by Phanerozoic age peaks and relatively depleted Nd isotopic compositions, indicating derivation from nearby highlands. In contrast, the overlying strata are dominated by Proterozoic zircon ages and enriched Nd isotopic compositions, which imply that the provenance source region shifted to the northern part of the North China craton. A coeval provenance change also affected the sedimentary architecture in the eastern Dasanjiang basin group, marking the migration of erosion centers from west to east. The contribution from Lesser Xing’an–Zhangguangcai ranges was pronounced during deposition of synrift strata but became negligible afterward in the Songliao and Dasanjiang areas, which is consistent with both basin complexes temporarily forming an extensive lake system during the early Late Cretaceous. This paleolake was likely responsible for transgressive events recorded in the Late Cretaceous strata of basins in NE China. Combining observations from seismic reflection profiles and the stratigraphic record of neighboring intracontinental sedimentary basins as well as widespread contemporaneous exhumation and denudation events, we suggest that the provenance variation in basin strata was controlled by large-scale tectonic transitions in East Asia. The switch from extension to contraction during the mid-Cretaceous is attributed to the docking of the Okhotomorsk block along the East Asian continental margin. The resulting lithospheric buckling might have been responsible for reshaping the basin-and-range configuration in NE Asia.
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Liu, Chaohui, Guochun Zhao, Fulai Liu, Jianrong Shi, and Lei Ji. "Detrital zircon records of late Paleoproterozoic to early Neoproterozoic northern North China Craton drainage reorganization: Implications for supercontinent cycles." GSA Bulletin 132, no. 9-10 (March 9, 2020): 2135–53. http://dx.doi.org/10.1130/b35506.1.
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Abstract Statherian through Tonian strata of the Langshan–Zha’ertai–Bayan Obo–Huade rift zone (LZBH) at the northern margin of the North China Craton provide an excellent record of changes in sediment provenance related to the supercontinent dispersal and amalgamation. During the late Paleoproterozoic to early Neoproterozoic, the LZBH developed over the Yinshan Block and was flanked by the Khondalite Belt to the south, the Trans–North China Orogen and Yanliao rift zone to the east, ultimately preserving a >7000-m-sequence of fluvial, marginal marine, and offshore marine sediments. In order to decipher the influence of these tectonic features on sediment delivery to the area, we evaluated 4955 U-Pb and 1616 Lu-Hf analyses from 66 samples across the entire LZBH, of which 1002 U-Pb and 271 Lu-Hf analyses from 12 samples are newly reported herein. The detrital zircon results indicate three stratigraphic intervals with internally consistent age peaks: (1) Changcheng to lower Jixian system (Statherian–lower Calymmian), (2) upper Jixian system (upper Calymmian), and (3) Qingbaikou system (Tonian). Statistical analysis of the detrital zircon results reveals two distinct changes in sediment provenance. The first transition, between the lower and upper Calymmian, reflects a provenance change from the basement of the Yinshan Block and the Khondalite Belt to a mixed signature, indicating derivation from both basement and Statherian rift-related magmatic products. Such a transition implies establishment of east–west drainage systems traversing the Paleoproterozoic Trans–North China Orogen caused by continued rifting since Statherian and pre-magmatic uplift during breakup of the North China Craton from the Columbia supercontinent. The second transition is indicated by the presence of Mesoproterozoic detrital zircons with juvenile Hf isotopic features since Tonian time and the up-section and northward increase of Mesoproterozoic detrital zircons. Their provenance is interpreted to be the Fennoscandian shield by a pancontinental drainage system related to aggregation of the Rodinia supercontinent. Thus, the detrital zircon spectra in the LZBH document the transition from initial unroofing of local uplifted basement of the Yinshan Block and Khondalite Belt to the distant Yanliao rift zone, then to the more distant Fennoscandian shield.
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Lemieux, Yvon, Thomas Hadlari, and Antonio Simonetti. "Detrital zircon geochronology and provenance of Devono-Mississippian strata in the northern Canadian Cordilleran miogeoclineThis article is one of a series of papers published in this Special Issue on the theme of Geochronology in honour of Tom Krogh.Northwest Territories Geoscience Office Contribution 0047. Geological Survey of Canada Contribution 20100432." Canadian Journal of Earth Sciences 48, no. 2 (February 2011): 515–41. http://dx.doi.org/10.1139/e10-056.
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U–Pb ages have been determined on detrital zircons from the Upper Devonian Imperial Formation and Upper Devonian – Lower Carboniferous Tuttle Formation of the northern Canadian Cordilleran miogeocline using laser ablation – multicollector – inductively coupled plasma – mass spectrometry. The results provide insights into mid-Paleozoic sediment dispersal in, and paleogeography of, the northern Canadian Cordillera. The Imperial Formation yielded a wide range of detrital zircon dates; one sample yielded dominant peaks at 1130, 1660, and 1860 Ma, with smaller mid-Paleozoic (∼430 Ma), Neoproterozoic, and Archean populations. The easternmost Imperial Formation sample yielded predominantly late Neoproterozoic – Cambrian zircons between 500 and 700 Ma, with lesser Mesoproterozoic and older populations. The age spectra suggest that the samples were largely derived from an extensive region of northwestern Laurentia, including the Canadian Shield, igneous and sedimentary provinces of Canada’s Arctic Islands, and possibly the northern Yukon. The presence of late Neoproterozoic – Cambrian zircon, absent from the Laurentian magmatic record, indicate that a number of grains were likely derived from an exotic source region, possibly including Baltica, Siberia, or Arctic Alaska – Chukotka. In contrast, zircon grains from the Tuttle Formation show a well-defined middle Paleoproterozoic population with dominant relative probability peaks between 1850 and 1950 Ma. Additional populations in the Tuttle Formation are mid-Paleozoic (∼430 Ma), Mesoproterozoic (1000–1600 Ma), and earlier Paleoproterozoic and Archean ages (>2000 Ma). These data lend support to the hypothesis that the influx of sediments of northerly derivation that supplied the northern miogeocline in Late Devonian time underwent an abrupt shift to a source of predominantly Laurentian affinity by the Mississippian.
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Trueman, C. N., G. Johnston, B. O'Hea, and K. M. MacKenzie. "Trophic interactions of fish communities at midwater depths enhance long-term carbon storage and benthic production on continental slopes." Proceedings of the Royal Society B: Biological Sciences 281, no. 1787 (July 22, 2014): 20140669. http://dx.doi.org/10.1098/rspb.2014.0669.
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Biological transfer of nutrients and materials between linked ecosystems influences global carbon budgets and ecosystem structure and function. Identifying the organisms or functional groups that are responsible for nutrient transfer, and quantifying their influence on ecosystem structure and carbon capture is an essential step for informed management of ecosystems in physically distant, but ecologically linked areas. Here, we combine natural abundance stable isotope tracers and survey data to show that mid-water and bentho-pelagic-feeding demersal fishes play an important role in the ocean carbon cycle, bypassing the detrital particle flux and transferring carbon to deep long-term storage. Global peaks in biomass and diversity of fishes at mid-slope depths are explained by competitive release of the demersal fish predators of mid-water organisms, which in turn support benthic fish production. Over 50% of the biomass of the demersal fish community at depths between 500 and 1800 m is supported by biological rather than detrital nutrient flux processes, and we estimate that bentho-pelagic fishes from the UK–Irish continental slope capture and store a volume of carbon equivalent to over 1 million tonnes of CO 2 every year.
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Malone, David, John Craddock, Eric Deck, Tenley Banik, and Brian Hampton. "Detrital zircon geochronology of quartzite clasts in the Permian Abo Formation, Sacramento Mountains, New Mexico, USA." Mountain Geologist 54, no. 2 (April 2017): 53–68. http://dx.doi.org/10.31582/rmag.mg.54.2.53.
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More than 2500 m of Paleozoic strata, ranging in age from Cambrian to Permian occur in the Sacramento Mountains of New Mexico, making these rocks the largest and most complete exposures of Paleozoic strata in North America. The core of the Sacramento Mountains reveals compressional structures associated with the Pennsylvanian-Permian Ancestral Rocky Mountain orogeny. The Permian Abo Formation is 120–450 m in thickness, and consists of interbedded sandstone, conglomerate, limestone and shale and rests above the Ancestral Rocky Mountain unconformity. U-Pb analysis of detrital zircons extracted from quartzite clasts in basal conglomerates reveal a maximum depositional age of their protolith to be 1110 ± 15 Ma. Most (∼40%) of the detrital zircon age spectrum is Grenville (1000–1300 Ma) in age, with a peak age of 1209 Ma. Midcontinent Granite-Rhyolite (1300–1500 Ma) ages comprise about 33% of the data, and have a peak age of 1431 Ma. Smaller age populations of Yavapai-Mazatzal (1600–1800 Ma; age peak =1676 Ma), Trans-Hudson (1800–2000 Ma; peak age = 1820 Ma), and Archean (>2.5 Ga, age peak = 2819 Ma) also are present. U-Pb detrital zircon ages from these quartzite clasts indicate that they were likely derived from the Proterozoic Lanoria Formation, which is exposed now in the Franklin Mountains >150 km to the south. The Lanoria is identical to the Abo clasts in terms of maximum depositional age and detrital zircon age peaks. The protolith sandstone of these quartzite clasts and quartzites of the Lanoria were derived from the Grenville high-lands of the Llano region of central Texas, and then transported west to the Rodinian continental margin at ∼1110 Ma, where they were eventually buried and metamorphosed to quartzite. These quartzites were subsequently uplifted and eroded during the Ancestral Rocky Mountain orogeny and transported north and west along the Pedernal Uplift to the adjacent Orogrande Basin during the early Permian.
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Lodes, Emma, Nancy R. Riggs, Michael E. Smith, and Paul Stone. "Cordilleran Subduction Initiation: Retroarc Timing and Basinal Response in the Inyo Mountains, Eastern California." Lithosphere 2020, no. 1 (December 24, 2020): 1–20. http://dx.doi.org/10.2113/2020/9406113.
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Abstract Subduction zones drive plate tectonics on Earth, yet subduction initiation and the related upper plate depositional and structural kinematics remain poorly understood because upper plate records are rare and often strongly overprinted by magmatism and deformation. During the late Paleozoic time, Laurentia’s western margin was truncated by a sinistral strike-slip fault that transformed into a subduction zone. Thick Permian strata in the Inyo Mountains of central-eastern California record this transition. Two basins that were separated by a transpressional antiform contain sedimentary lithofacies that record distinct patterns of shoaling and deepening conditions before and during tectonism associated with subduction initiation. Sandstone petrography and lithofacies analysis show that rocks in a southeastern basin are dominated by carbonate grains derived from adjacent carbonate shelves, whereas sandstones in a northwestern basin are predominantly quartzose with likely derivation from distant ergs or underlying strata. Detrital zircon spectra from all but the youngest strata in both basins are typical of Laurentian continent spectra with prominent peaks that indicate ultimate sources in Appalachia, Grenville, Yavapai/Mazatzal, and the Wyoming or Superior cratons. The first Cordilleran arc-derived detrital zircon grains appear in the uppermost strata of the northwestern basin and record Late Permian (ca. 260 Ma) Cordilleran arc magmatism at this approximate latitude, and a possible source area is suggested by geochemical similarities between these detrital zircons and broadly coeval magmatic zircons in the El Paso Mountains to the southwest. Deformation responsible for basin partitioning is consistent with sinistrally oblique contraction in the earliest Permian time. The data presented from the Inyo Mountains shed more light on the nature of Cordilleran subduction initiation and the upper-crustal response to this transition.
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Sickmann, Zachary T., Theresa M. Schwartz, Matthew A. Malkowski, Stephen C. Dobbs, and Stephan A. Graham. "Interpreting large detrital geochronology data sets in retroarc foreland basins: An example from the Magallanes-Austral Basin, southernmost Patagonia." Lithosphere 11, no. 5 (July 12, 2019): 620–42. http://dx.doi.org/10.1130/l1060.1.
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Abstract The Magallanes-Austral retroarc foreland basin of southernmost South America presents an excellent setting in which to examine interpretive methods for large detrital zircon data sets. The source regions for retroarc foreland basins generally, and the Magallanes-Austral Basin specifically, can be broadly divided into (1) the magmatic arc, (2) the fold-and-thrust belt, and (3) sources around the periphery of foreland flexural subsidence. In this study, we used an extensive detrital zircon data set (30 new, 87 previously published samples) that is complemented by a large modal provenance data set of 183 sandstone petrography samples (32 new, 151 previously published) and rare earth element geochemical analyses (130 previously published samples) to compare the results of empirical (multidimensional scaling) and interpretive (age binning based on source regions) treatments of detrital zircon data, ultimately to interpret the detailed evolution of sediment dispersal patterns and their tectonic controls in the Magallanes-Austral Basin. Detrital zircon sample groupings based on both a priori age binning and multidimensional scaling are required to maximize the potential of the Magallanes-Austral Basin data set. Multidimensional scaling results are sensitive to differences in major unimodal arc-related U-Pb detrital zircon ages and less sensitive to differences in multimodal, thrust belt–related age peaks. These sensitivities complicate basin-scale interpretations when data from poorly understood, less densely sampled sectors are compared to data from better-understood, more densely sampled sectors. Source region age binning alleviates these biases and compares well with multidimensional scaling results when samples from the less well-understood southern basin sector are excluded. Sample groupings generated by both multidimensional scaling and interpretive methods are also compatible with compositional provenance data. Together, this integration of provenance data and methods facilitates a detailed interpretation of sediment dispersal patterns and their tectonic controls for the Late Cretaceous to Eocene fill of the Magallanes-Austral retroarc foreland basin. We interpret that provenance signatures and dispersal patterns during the retroarc foreland phase were fundamentally controlled by conditions set by a predecessor extensional basin phase, including (1) variable magnitude of extension with latitude, (2) the composition of lithologies emplaced on the antecedent western flank, and (3) long-lasting structural discontinuities associated with early rifting that may have partitioned dispersal systems or controlled the location of long-lived drainage networks.
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Aziz, Nabaz. "U-Pb ZIRCON DATING OF MIDDLE EOCENE CLASTIC ROCKS FROM THE GERCUS MOLASSE, NE IRAQ: NEW CONSTRAINTS ON THEIR PROVENANCE, AND TECTONIC EVOLUTION." Iraqi Geological Journal 54, no. 1C (March 31, 2021): 1–15. http://dx.doi.org/10.46717/igj.54.1c.1ms-2021-03-21.
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The provenance of Middle Eocene clastic rock from the Gercus Molasse, NE Iraq was determined by detrital zircon (DZ) U-Pb geochronology. The Gercus Molasse in the Iraqi segment of the north-eastern Zagros Thrust Zone provides an ideal example of foreland system evolution with respect to the transition from passive margin to the accretionary complex terrene-flexural foreland basins. The DZ U-Pb age spectra from the Gercus Molasse suggest that the foreland sediments either influx from multiple provenances or are the result of recycling from the accretionary complex terrane. During pre-accretion, however, the radiolarite basin (Qulqula Radiolarite, 221 Ma) located along Arabian passive margin likely acted as an intermediate sediment repository for most or all of the DZ. Representative DZ U-Pb measurements revealed that the Gercus clastic rocks fall into several separable age population ranges of 92-102 (Albian-Cenomanian), 221 (Upper Triassic), 395-511 (Cambrian), 570- 645 (Neoproterozoic), 1111 (Mesoproterozoic), and lesser numbers of Paleoproterozoic (1622-1991 Ma) ages. The source of Proterozoic detrital Zircons is enigmatic; the age peaks at 1.1, 1.5, 1.6, and 1.9 Ga (Proterozoic) does not correspond to any known outcrops of Precambrian rocks in Iraq, and it may be useful to continue to search for such basement. The detrital zircons with age populations at 0.63–0.86 Ga probably originated from the Arabian-Nubian Shield. The age peak at 0.55 Ga correlates with Cadomian Magmatism reported from north Gondwana. The age peaks at ~0.4 Ga is interpreted to represent Gondwana rifting and the opening of Paleotethys. The youngest ages populations at 93 Ma indicate that fraction of DZ were transported directly from the contemporaneously active magmatic arc (Zagros Ophiolite segments). The paleogeography and tectonic evolution of the Neogene Zagros foreland basin were reconstructed and divided into two tectonic stages. The early stage is defined by the Campanian accreted terranes (i.e. orogenic wedge) form loads sufficient to produce flexural basin with a deepest part is situated next to the tip of the loads. This flexural basin is filled by the flysch clastics of the Maastrichtian– Early Eocene (i.e. referred to by the Tanjero-Kolosh flysch sequence). The late stage is marked by a synchronized modification of the clastics fill of the basin and changes in dip directions to compensate for the reduction of the load by both erosion and extension and the basin, therefore, was sealed by a shallowing upwards depositional sequence ending with the terrestrial Gercus Formation.
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Malone, David, John Craddock, and Stuart Kenderes. "Detrital zircon geochronology and provenance of the Middle Cambrian Flathead Sandstone, Park County, Wyoming." Mountain Geologist 54, no. 2 (April 2017): 86–103. http://dx.doi.org/10.31582/rmag.mg.54.2.86.
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We report the results of analyses of detrital zircon from the middle Cambrian Flathead Sandstone from four locations in Park County, WY. The Flathead U-Pb zircon age spectra (n=355) includes one peak at 2702–3345 Ma (95%) and two small age peaks at 1784 Ma (4%) and ∼1830 Ma (1%). Regional paleocurrent data for the Flat-head indicate sediment transport from east to west but the dominant Archean detrital zircons in our sample suite indicates a proximal source in structurally and topographically high Wyoming Province crust. The Archean ages are consistent with the >3.0 Ga fraction being derived from basement rocks present in the northern Beartooth Range and areas further to the west. The 2.8–3.0 Ga grains were derived from the Beartooth-Bighorn magmatic zone, which directly underlies and extends to the south and east of these Flathead sampling localities. The 1.7–1.8 Ga grains were derived from 100s of km to the south and east, in the Cheyenne Belt or more distal Yavapai Province rocks. This 1.7–1.8 Ga crust was uplifted along the Transcontinental Arch during late Precambrian time. The Transcontinental Arch, and perhaps the Midcontinent Rift further to the east as well, prevented easterly-sourced (i.e. Grenville) zircons from reaching the Wyoming Sauk shoreline.
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Nelson, JoAnne, and George Gehrels. "Detrital zircon geochronology and provenance of the southeastern Yukon–Tanana terrane." Canadian Journal of Earth Sciences 44, no. 3 (March 1, 2007): 297–316. http://dx.doi.org/10.1139/e06-105.
Full textAbstract:
Two samples of late Paleozoic grit and Late Mississippian quartzite–chert conglomerate collected from southeastern Yukon–Tanana terrane (YTT) — a composite thrust sheet resting structurally above North American parautochthonous strata and intervening imbricate sheets of the late Paleozoic oceanic Slide Mountain terrane — yielded, respectively, 89 and 74 concordant or nearly concordant (<20% discordant) U–Pb ages on single detrital zircons. They provide constraints on the provenance of this allochthonous pericratonic terrane. Zircons in the grit range from 1770 to 2854 Ma, with a well-defined Early Proterozoic peak between 1800 and 2100 Ma. Precambrian zircons in the conglomerate also show a dominant peak between 1800 and 2100 Ma and smaller peaks between 2200 and 3200 Ma, with a few older grains, and younger grains with ages of 998, 1219, 1255, 1256, and 1417 Ma. The conglomerate also yielded three Devonian grains, with ages of 366 ± 23, 373 ± 12, and 379 ± 23 Ma. Their ages are approximately coeval with the oldest felsic to intermediate arc- and rift-related magmatism in the YTT. The age spectra from southeastern YTT units compare closely with those from Mississippian and older pericratonic units in the Coast Mountains, confirming correlations previously made on lithologic grounds. They also strongly resemble detrital zircon populations from craton-derived Paleozoic units of the northern North American autochthon. This robust U–Pb data set lends support to the idea that YTT once formed part of the outer, active margin of the North American continent, prior to Mississippian rifting and marginal ocean basin development.
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Morata, Nathalie, Emma Michaud, Marie-Aude Poullaouec, Jérémy Devesa, Manon Le Goff, Rudolph Corvaisier, and Paul E. Renaud. "Climate change and diminishing seasonality in Arctic benthic processes." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2181 (August 31, 2020): 20190369. http://dx.doi.org/10.1098/rsta.2019.0369.
Full textAbstract:
The iconic picture of Arctic marine ecosystems shows an intense pulse of biological productivity around the spring bloom that is sustained while fresh organic matter (OM) is available, after which ecosystem activity declines to basal levels in autumn and winter. We investigated seasonality in benthic biogeochemical cycling at three stations in a high Arctic fjord that has recently lost much of its seasonal ice-cover. Unlike observations from other Arctic locations, we find little seasonality in sediment community respiration and bioturbation rates, although different sediment reworking modes varied through the year. Nutrient fluxes did vary, suggesting that, although OM was processed at similar rates, seasonality in its quality led to spring/summer peaks in inorganic nitrogen and silicate fluxes. These patterns correspond to published information on seasonality in vertical flux at the stations. Largely ice-free Kongsfjorden has a considerable detrital pool in soft sediments which sustain benthic communities over the year. Sources of this include macroalgae and terrestrial runoff. Climate change leading to less ice cover, higher light availability and expanded benthic habitat may lead to more detrital carbon in the system, dampening the quantitative importance of seasonal pulses of phytodetritus to seafloor communities in some areas of the Arctic. This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.
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Zhang, Peng-Cong, Shan-Shan Li, Bo Liu, Deng-Yang He, Quan-Sheng Cai, Germain Bishikwabo Kaningu, and Xin-Chun Sun. "Timing, Provenance, and Tectonic Implications of Ore-Hosting Metasedimentary Rocks in the Giant Liba Gold Deposit, West Qinling Belt, China." Minerals 12, no. 7 (July 19, 2022): 903. http://dx.doi.org/10.3390/min12070903.
Full textAbstract:
The closure time of the Shangdan Ocean is critical for understanding the tectonic evolution of the Proto-Tethys Ocean. However, the proposed closure time was prolonged from Ordovician to Devonian. In the present study, detrital zircon from the metasedimentary rocks of the Liba Group in the West Qinling Belt was analyzed to constrain the closure time of the Shangdan Ocean. The three youngest grains from the Liba Group yield a maximum deposition age of 418 ± 13 Ma, indicating the Middle Devonian deposition. Detrital zircon grains show two main U–Pb age peaks of 810 Ma and 440 Ma with εHf(t) values spanning from −24.3 to +8.8 and −6.3 to +4.1, respectively, suggesting that the sediments of the Liba Group were derived from both the North and South Qinling Belts. The Lower Devonian in the South Qinling Belt shows similar provenance to the Liba Group, whereas sediments from the North Qinling Belt are absent in the Silurian strata of the South Qinling Belt. From Late Silurian to Early Devonian, the tectonic setting changed from subduction to collision. This evidence consistently suggests the disappearance of the Shangdan Ocean. The noticeable decrease in magmatism from 510–420 Ma to 420–390 Ma and the shrinking of εHf(t) values from −15.5–+12.8 to −8.4–+4.2 reveal that the Shangdan Ocean, as the eastmost embranchment of the Proto-Tethys Ocean, was closed at ca. 420 Ma.
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Ershova, Victoria, Andrei Prokopiev, Daniel Stockli, Daria Zbukova, and Anton Shmanyak. "Provenance and Stratigraphy of the Upper Carboniferous—Lower Permian Strata of October Revolution Island (Severnaya Zemlya Archipelago): Implications for Geological History of the Russian High Arctic." Minerals 12, no. 10 (October 20, 2022): 1325. http://dx.doi.org/10.3390/min12101325.
Full textAbstract:
Small depressions across the north-eastern part of October Revolution Island (Severnaya Zemlya archipelago, Kara terrane) are filled with continental terrigenous rocks, dated as Upper Carboniferous–Lower Permian in age based on palynological data. These rocks overlie Ordovician volcaniclastic rocks above a prominent angular unconformity. U-Pb dating of detrital zircons from the Late Carboniferous–Lower Permian rocks reveals that most grains are Ordovician in age, ranging between 475–455 Ma. A subordinate population of Silurian detrital zircons is also present, contributing up to 15% of the dated population, while Precambrian grains mainly yield Neo-Mesoproterozoic ages and do not form prominent peaks. The combined U-Pb and (U-Th)/He ages indicate that most zircon (U-Th)/He ages were reset and average at ca. 317 Ma, suggesting ~6–7 km of Late Carboniferous uplift within the provenance area. This provenance area, mainly comprising Ordovician magmatic and volcanic rocks, was located close to the study area based on the coarse-grained nature of Late Carboniferous–Lower Permian rocks of north-eastern October Revolution Island. Therefore, we propose that Late Paleozoic tectonism significantly affected both the southern margin of the Kara terrane, as previously supposed, and also its north-eastern part. We propose that the Late Paleozoic Uralian suture zone continued to the north-eastern October Revolution Island and was responsible for the significant tectonic uplift of the studied region. This suture zone is now hidden beneath the younger Arctic basins.
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Xiong, Chen, Yaoling Niu, Hongde Chen, Anqing Chen, Chenggong Zhang, Feng Li, Shuai Yang, and Shenglin Xu. "Detrital zircon U–Pb geochronology and geochemistry of late Neoproterozoic – early Cambrian sedimentary rocks in the Cathaysia Block: constraint on its palaeo-position in Gondwana supercontinent." Geological Magazine 156, no. 9 (March 6, 2019): 1587–604. http://dx.doi.org/10.1017/s0016756819000013.
Full textAbstract:
AbstractWe present updated U–Pb ages and Hf isotopic compositions of detrital zircons and whole-rock geochemical data to investigate the provenance and tectonic setting of late Neoproterozoic and early Cambrian sandstones from the Cathaysia Block, in order to offer new constraints on its tectonic evolution and its palaeo-position within the supercontinent. The source rocks for the studied sandstones were dominated by felsic–intermediate materials with moderate weathering history. U–Pb dating results show major populations atc. 2500 Ma, 1000–900 Ma and 870–716 Ma with subordinate peaks at 655–532 Ma, consistent with the global Neoarchean continental crust growth, assembly and break-up of Rodinia, and Pan-African Event associated with the formation of Gondwana. Zircon U–Pb ages and Hf isotopic data suggest that most derived from exotic terranes once connected to the Cathaysia Block. Using whole-rock geochemical analysis, it was determined that the studied sedimentary rocks were deposited in a passive continental margin and the Cathaysia and Yangtze blocks were part of the same continent; no Cambrian ocean existed between them. Compiling a detrital zircon dataset from Qiangtang, northern India, the Lhasa Terrane and Western Australia, the Cathaysia Block seems to be more similar to the Qiangtang and western part of the northern India margin, instead of having a direct connection with the Lhasa Terrane and Western Australia in the Gondwana reconstruction during the late Neoproterozoic and Cambrian eons.