Статті в журналах: "Tectonic provenance"

1

Chen, Xingyu, Zhijie Zhang, Xuanjun Yuan, Li Wan, Chuanmin Zhou, Yinhe Liu, and Dawei Cheng. "The Evolution of Permian Source-to-Sink Systems and Tectonics Implications in the NW Junggar Basin, China: Evidence from Detrital Zircon Geochronology." Minerals 12, no. 9 (September 15, 2022): 1169. http://dx.doi.org/10.3390/min12091169.

Повний текст джерела

Анотація:

The basin type of the Junggar Basin changed during the Permian, but the time constraint of the tectonic evolution remains unclear. Besides, the fan deltas developed in the Permian in the Mahu Sag in the northwestern of the oil-rich basin. However, the provenances of the sedimentary systems remain unclear. Based on petrology and detrital zircon U-Pb ages, this study investigates the source-to-sink systems evolution and tectonics implications. Abundant lithic clasts in sandstones with low compositional and textural maturity imply proximal sources. The dating results showed a dominant peak (310–330 Ma) and a secondary peak (400–440 Ma) in the northern Mahu Sag, only one peak at 295–325 Ma in the central Mahu Sag, several peaks at 270–350 Ma in the southern Mahu Sag, and multiple peaks at 370–450 Ma in the Zhongguai Uplift. Thus, the north-western Junggar Basin was divided into four major source-to-sink systems, with adjacent central West Junggar as the main provenance and northern and southern West Junggar as the secondary provenance. The proportion of sediment supply from the southern and northern West Junggar is higher during the Middle-Late Permian. It suggests that the source-to-sink systems show inheritance and evolve from a single provenance into a complex provenance, indicating the uplift of West Junggar. The tectonic inversion may occur early in the Middle Permian and the response to tectonic activity is stronger in the southern West Junggar than in the northern West Junggar.

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Zhang, Yue Qiao, Wei Hou, and Fang Zhang. "The Provenance Tectonic Background Analysis of the Upper Jurassic Mohe Basin in Northeast China." Advanced Materials Research 734-737 (August 2013): 476–79. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.476.

Повний текст джерела

Анотація:

The provenance tectonic background of Late Jurassic Mohe Basin was researched through the geochemical composition of sandstone. The Late Jurassic Mohe Basin is characterized by multiple provenances. One provenance is the active continental margin, and another is the island arc. Comparing with the regional lithology, the active continental margin may be from the Mongolia-Okhotsk orogenic belt, and the island arc may be from the northern of the Da Hingan Mountains. The characteristics are concerned with its geotectonic position.

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Baiyegunhi, Temitope Love, Kuiwu Liu, Oswald Gwavava, Christopher Baiyegunhi, and Maropene Rapholo. "Geochemistry of the mudrocks and sandstones from the Bredasdorp Basin, offshore South Africa: Implications for tectonic provenance and paleoweathering." Open Geosciences 13, no. 1 (January 1, 2021): 1187–225. http://dx.doi.org/10.1515/geo-2020-0260.

Повний текст джерела

Анотація:

Abstract An inorganic geochemical investigation of mudrocks and sandstone from the southern Bredasdorp Basin, off the south coast of South Africa was carried out to unravel the provenance, paleoweathering, and tectonic setting of the basin. Seventy-seven representative samples from exploration wells E-AH1, E-AJ1, E-BA1, E-BB1, and E-D3 underwent geochemical analysis involving major and trace elements. The major oxide compositions show that the sandstones could be classified as sub-arkose and sub-lithic arenite. The provenance discrimination diagrams based on major oxide geochemistry revealed that the sandstones are mainly of quartzose sedimentary provenance, while the mudrocks are of quartzose sedimentary and intermediate igneous provenances. The discrimination diagrams indicate that the Bredasdorp sediments were mostly derived from a cratonic interior or recycled orogen. The bivariate plots of TiO2 versus Ni, TiO2 against Zr, and La/Th versus Hf as well as the ternary diagrams of V–Ni–Th∗10 suggest that the mudrocks and sandstones were derived from felsic igneous rocks. The tectonic setting discrimination diagrams support passive-active continental margin setting of the provenance. Also, the closely similar compositions of the analysed samples and recent sedimentary rocks of the East African Rift System perhaps suggest a rifted basin tectonic setting for the Bredasdorp Basin. Chemical index of alteration (CIA) indices observed in the sandstones suggest that their source area underwent low to moderate degree of chemical weathering. However, the mudrocks have high CIA indices suggesting that the source area underwent more intense chemical weathering, possibly due to climatic and/or tectonic variations.

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Baiyegunhi, Temitope Love, Kuiwu Liu, Oswald Gwavava, and Christopher Baiyegunhi. "Petrography and Tectonic Provenance of the Cretaceous Sandstones of the Bredasdorp Basin, off the South Coast of South Africa: Evidence from Framework Grain Modes." Geosciences 10, no. 9 (August 28, 2020): 340. http://dx.doi.org/10.3390/geosciences10090340.

Повний текст джерела

Анотація:

The Cretaceous sandstones of the Bredasdorp Basin were investigated to recognize their composition, provenance, and tectonic setting. Ninety-two samples of sandstones from exploration wells E-AH1, E-AJ1, E-BA1, E-BB1, and E-D3 were investigated using both petrographic and X-ray diffraction (XRD) methods. Petrographic studies based on quantitative investigation of the detrital framework grain shows that the Bredasdorp sandstones chiefly consist of quartz (52.2–68.0%), feldspar (10.0–18.0%), and lithic fragments (5.0–10.2%). These sandstones are mostly fine grained, moderately well-sorted, and subrounded to rounded. The modal composition data shows that the sandstones could be classified as subarkosic arenite and lithic arkose. Such a composition of the sandstones perhaps indicates the interplay of pulses of fast uplift of the source area and rapid subsidence of the Bredasdorp Basin, with subsequent periods of calmness within the transgressive-regressive sequence in a rift tectonic regime. The provenance ternary diagrams revealed that the sandstones are mainly of continental block provenances (stable shields and basement uplifted areas) and complemented by recycled sands from an associated platform. The tectonic provenance studies of Bredasdorp Basin revealed that the sandstones are typically rift sandstones and have undergone long-distance transport from the source area along the rift. In the regional context of the evolution of the Bredasdorp Basin, the results presented in this study inferred that the basin developed on a rift passive setting (trailing edge) of the stable continental margins.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

McCarthy, Odhrán, Brenton Fairey, Patrick Meere, David Chew, Aidan Kerrison, David Wray, Mandy Hofmann, et al. "The provenance of Middle Jurassic to Cretaceous sediments in the Irish and Celtic Sea Basins: tectonic and environmental controls on sediment sourcing." Journal of the Geological Society 178, no. 5 (March 23, 2021): jgs2020–247. http://dx.doi.org/10.1144/jgs2020-247.

Повний текст джерела

Анотація:

The Jurassic and Cretaceous sedimentary infill of the Irish and Celtic Sea Basins is intimately associated with the breakup of the supercontinent Pangea, and the opening of the Atlantic margin. Previous basin studies have constrained tectonism, basin uplift and sediment composition, but sediment provenance and routing have not received detailed consideration. Current hypotheses for basin infill suggest localized sediment sourcing throughout the Jurassic and Cretaceous, despite a dynamic tectonic and palaeoenvironmental history spanning more than 100 million years. We present detrital zircon, white mica and apatite geochronology alongside heavy mineral data from five basins. Findings reveal that basin infill derived predominantly from distal sources with lesser periods of local sourcing. We deduce that tectonically induced marine transgression and regression events had a first-order control on distal v. proximal sedimentary sourcing. Additionally, tectonism which uplifted the Fastnet Basin region during the Middle–Late Jurassic recycled basin sediments into the connected Celtic and Irish Sea Basins. Detrital geochronology and heavy mineral evidence support three distinct provenance switches throughout the Jurassic and Cretaceous in these basins. Overall an integrated multi-proxy provenance approach provides novel insights to tectonic and environmental controls on basin infill as demonstrated in the Irish and Celtic Sea Basins.Supplementary material: Tables S1–S6 are available at https://doi.org/10.6084/m9.figshare.c.5343657

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Xu, Tao, Ling Feng, Wen Yin, Jinpeng Wei, Yarong Wang, and Xianli Zou. "Element Geochemical Characteristics and Provenance Conditions of the 1st Member of Jurassic Zhongjiangou Formation in Wudun Sag, Dunhuang Basin." Applied Sciences 12, no. 9 (April 20, 2022): 4110. http://dx.doi.org/10.3390/app12094110.

Повний текст джерела

Анотація:

In order to clarify the provenance of the 1st member of the Zhongjiangou formation in Wudun sag, Dunhuang basin, the structural attributes, weathering and sedimentary characteristics of the provenance area were analyzed by means of element geochemistry, so as to determine the differences of sediment sources in different well areas. The results show that the higher the Al2O3 and K2O contents, the higher the enrichment of large ion lithophile elements and high field strength elements, while the iron and magnesium elements are relatively deficient, and there are characteristics of medium degree differentiation of light and heavy rare earth elements in Well XC1 and Well D2. The lower the Al2O3 content and the higher the SiO2 content, a loss of large ion lithophile elements and high field strength elements are observed, while the ferrophilic magnesium elements show serious loss, as shown in the characteristics of the high degree of differentiation of light and heavy rare earth elements in Well D1. In the UCC-normalized element spidergrams, the trend of Well XC1 and Well D2 is similar, which is different from that of well D1, indicating that the sediments of Well XC1 and Well D2 come from the same provenance area, while the sediment of Well D1 comes from a different provenance area. The provenance area of Well XC1 and Well D2 shows strong tectonic activity and strong weathering, while the provenance area of well D1 exhibits relatively weak tectonic activity and weathering. Combined with previous research results, Wudun sag is mainly characterized by a faulted lacustrine basin controlled by the southern boundary fault in the Jurassic layer. Therefore, the sediments of Well XC1 and Well D2 mainly come from the southern Sanweishan uplift provenance area, with strong tectonic activity; the sediments of Well D1 mainly come from the northern Beishan provenance area, with relatively weak tectonic activity.

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Li, Yalong, Wei Yue, Xun Yu, Xiangtong Huang, Zongquan Yao, Jiaze Song, Xin Shan, Xinghe Yu, and Shouye Yang. "Tectonic Evolution of the West Bogeda: Evidences from Zircon U-Pb Geochronology and Geochemistry Proxies, NW China." Minerals 10, no. 4 (April 10, 2020): 341. http://dx.doi.org/10.3390/min10040341.

Повний текст джерела

Анотація:

The Bogeda Shan (Mountain) is in southern part of the Central Asian Orogenic Belt (CAOB) and well preserved Paleozoic stratigraphy, making it an ideal region to study the tectonic evolution of the CAOB. However, there is a long-standing debate on the tectonic setting and onset uplift of the Bogeda Shan. In this study, we report detrital zircon U-Pb geochronology and whole-rock geochemistry of the Permian sandstone samples, to decipher the provenance and tectonic evolution of the West Bogeda Shan. The Lower-Middle Permian sandstone is characterized by a dominant zircon peak age at 300–400 Ma, similar to the Carboniferous samples, suggesting their provenance inheritance and from North Tian Shan (NTS) and Yili-Central Tian Shan (YCTS). While the zircon record of the Upper Permian sandstone is characterized by two major age peaks at ca. 335 Ma and ca. 455 Ma, indicating the change of provenance after the Middle Permian and indicating the uplift of Bogeda Shan. The initial uplift of Bogeda Shan was also demonstrated by structural deformations and unconformity occurring at the end of Middle Permian. The bulk elemental geochemistry of sedimentary rocks in the West Bogeda Shan suggests the Lower-Middle Permian is mostly greywacke with mafic source dominance, and tectonic setting changed from the continental rift in the Early Permian to post rift in the Middle Permian. The Upper Permian mainly consists of litharenite and sublitharenite with mafic-intermediate provenances formed in continental island arcs. The combined evidences suggest the initial uplift of the Bogeda Shan occurred in the Late Permian, and three stages of mountain building include the continental rift, post-rift extensional depression, and continental arc from the Early, Middle, to Late Permian, respectively.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

van de Kamp, Peter C., and Bernard Elgey Leake. "Petrography and geochemistry of feldspathic and mafic sediments of the northeastern Pacific margin." Transactions of the Royal Society of Edinburgh: Earth Sciences 76, no. 4 (1985): 411–49. http://dx.doi.org/10.1017/s0263593300010646.

Повний текст джерела

Анотація:

ABSTRACTThis study attempts to ascertain whether the differing provenance sources and plate tectonic settings of deposition of clastic sediments and rocks can be identified by chemical means, thus opening the increased use of these rocks and their metamorphosed derivatives in plate tectonic modelling. Mineralogically immature feldspathic and mafic sands, muds, sandstones and shales from Mesozoic, Cenozoic and Holocene clastic deposits in California, Oregon, Alaska and Colorado have been both modally and chemically analysed providing a valuable data base (217 samples; 216 samples chemically analysed, many for 28 elements).There is significant upward chemical variation in the Great Valley sequence of California which mimics previously described petrographic variation and in turn reflects provenance changes with igneous episodes and erosional stripping of the Sierra Nevada in late Mesozoic time. Differing sandstone petrofacies result in varying chemical signatures and while the provenances of monomict sediments are easiest to identify, polymict sources involving granitoid or ophiolitic material can often be identified by potassium feldspar or Cr contents. The distinction of K which is derived from detrital potassium feldspar from K derived from detrital illite, micas or other sheet minerals, is best made by a Niggli al–alk plot against k. Mafic sandstones derived from mafic volcanic or plutonic rocks preserve essentially mafic igneous chemistry and could be possible parent sources of some amphibolites which grade into metasediments. The lithified erosion products of the Sierra Nevada calc-alkaline igneous rocks have higher Niggli al–alk and higher average Niggli si at any given mg value than the fresh igneous rocks enabling meta-arkoses to be distinguished from meta-igneous rocks.Applying previously published chemical criteria gives the actual plate tectonic setting of deposition of most of the sandstones studied. This suggests that the chemical composition of sandstones can yield much more information about the provenance and plate tectonic setting than hitherto recognised.

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Cui, Liwei, Nan Peng, Yongqing Liu, Dawei Qiao, and Yanxue Liu. "Detrital Zircon Geochronology and Tectonic Evolution Implication of the Middle Jurassic Zhiluo Formation, Southern Ordos Basin, China." Minerals 13, no. 1 (December 27, 2022): 45. http://dx.doi.org/10.3390/min13010045.

Повний текст джерела

Анотація:

The Ordos Basin’s southern part is a composite zone made up of numerous continental blocks and has long been influenced by surrounding tectonism. However, only a few studies have investigated the existence of southern provenance supply and the basin’s southern boundary in the Middle Jurassic Zhiluo Formation. Based on sandstone detrital zircon U-Pb dating and zircon rare earth element analyses, net-sand ratio maps, paleocurrent direction and the field outcrop survey, this study establishes the source area and boundary of the Zhiluo Formation in the southern basin, and discusses the tectonic events. The study shows that the four main age peaks in the detrital spectra occurs at 2283 Ma, 1788 Ma, 432.5 Ma and 218.7 Ma, with a few of the zircons dated at 794.5–1235.2 Ma. The North Qilian orogenic belt (N-QLOB), the western part of the North Qinling orogenic belt (NQOB), and the southern margin of the North China Block (SNCB) contributed to the provenance. According to an integrated analysis of the provenance and tectonic background of continental blocks in the basin’s southern margin, the boundary of the basin in the depositional period of the Zhiluo Formation should reach the N-QLOB in the southwest, the NQOB in the south, and the Sanmenxia–Lushan fault belt in the southeast. On the basis of the aforementioned findings, the tectonic evolution of the continental blocks at the southern periphery of the Ordos Basin was restored.

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Itiowe, K., F. A. Lucas, and E. O. Avwenagha. "Geochemical Analysis of Sediments from Sahaiawei-1 Well of the Northern Delta Depobelt in the Niger Delta Basin, Nigeria." Journal of Scientific Research 13, no. 1 (January 1, 2021): 125–35. http://dx.doi.org/10.3329/jsr.v13i1.48455.

Повний текст джерела

Анотація:

Geochemical analysis of sediments from Sahaiawei-1 Well of the Northern Delta Depobelt in the Niger Delta Basin was carried out to classify the sediments, determine the provenance, tectonic setting and depositional environment. Twenty (20) ditch cutting samples between 1500 and 10730 ft. were subjected to X-ray fluorescence analysis to determine the elemental composition. The result for the classification of the sediments shows that the sediments were classified as Fe-shale and Fe-sand. The discriminant function diagrams for provenance signature and tectonic setting show that the sediments were plotted within the quartzose sedimentary provenance and passive continental margin tectonic setting fields respectively. The depositional environment using inorganic geochemistry shows that the sediments were deposited with in the continental, transitional and marine environments. This research has provided up to date information on the geochemistry of the Northern Delta Depobelt which would help in hydrocarbon exploration in the area.

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Itiowe, K., F. A. Lucas, and E. O. Avwenagha. "Geochemical Analysis of Sediments from Sahaiawei-1 Well of the Northern Delta Depobelt in the Niger Delta Basin, Nigeria." Journal of Scientific Research 13, no. 1 (January 1, 2021): 125–35. http://dx.doi.org/10.3329/jsr.v13i1.48455.

Повний текст джерела

Анотація:

Geochemical analysis of sediments from Sahaiawei-1 Well of the Northern Delta Depobelt in the Niger Delta Basin was carried out to classify the sediments, determine the provenance, tectonic setting and depositional environment. Twenty (20) ditch cutting samples between 1500 and 10730 ft. were subjected to X-ray fluorescence analysis to determine the elemental composition. The result for the classification of the sediments shows that the sediments were classified as Fe-shale and Fe-sand. The discriminant function diagrams for provenance signature and tectonic setting show that the sediments were plotted within the quartzose sedimentary provenance and passive continental margin tectonic setting fields respectively. The depositional environment using inorganic geochemistry shows that the sediments were deposited with in the continental, transitional and marine environments. This research has provided up to date information on the geochemistry of the Northern Delta Depobelt which would help in hydrocarbon exploration in the area.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Pandita, Sundeep K., Sunil K. Bhat, Sham S. Kotwal, Yudhbir Singh, and Kuldeep K. Thakur. "Provenance and tectonic settings of the Lower Siwalik Subgroup, Jammu, Northwest Himalaya." Journal of Palaeosciences 63, no. (1-2) (December 31, 2014): 17–23. http://dx.doi.org/10.54991/jop.2014.290.

Повний текст джерела

Анотація:

The sandstones of the two representative stratigraphic sections of the Lower Siwalik Subgroup of Ramnagar area in Jammu region of Northwest Himalaya are studied to infer the provenance and tectonic settings of the source area. The sandstones are fine– to medium–grained and moderately to well sorted. These sandstones consist of three varieties of quartz with small amounts of feldspar, lithic fragments and micas and are classified as sublitharenites, subarkoses and litharenites. These rocks belong to the collision orogenic belt of tectonic regime and have been derived from a mixed provenance that includes plutonic basement, sedimentary and meta–sedimentary rocks.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Qin, Yang, Chiyang Liu, Lihua Yang, Heng Peng, and Xiaoqin Jiao. "Detrital-Zircon Geochronology of Jurassic–Cretaceous Strata in the Turpan-Hami Basin: Implication for the Late Mesozoic Tectonic Evolution of Eastern Tien Shan." Minerals 12, no. 8 (July 22, 2022): 926. http://dx.doi.org/10.3390/min12080926.

Повний текст джерела

Анотація:

Detrital-zircon U-Pb geochronology is extensively used to imply provenance histories as one of the most common methods to constrain the tectonic evolution of ancient sedimentary systems. The rapid accumulation of detrital-zircon thermochronology data in the eastern Tien Shan region brought great convenience for understanding the basin–mountain evolution in the region. In this work, 41 samples for zircon U-Pb dating from the Jurassic–Cretaceous strata of the Turpan-Hami basin and its adjacent region were compiled. Based on the systematic investigation, comparison, and summarization of Late Mesozoic sources in the eastern Tien Shan region and the quantitative characterization of source variations, we further explored and dissected the Late Mesozoic tectonic evolution of the eastern Tien Shan orogenic belt. Data from detrital-zircon age spectra, KS tests, MDS plots, Monte Carlo simulations, etc., suggested that eastern Tien Shan was also highly active during the Mesozoic, and especially, Bogda was the most remarkable. Moreover, there was a sig-nificant differential segmental exhumation before the Late Jurassic. In general, from the Early Ju-rassic to the Cretaceous, the proportion of Bogda provenance gradually increased, especially the large-scale uplift and denudation that occurred after the development of the Qigu Formation. The provenance of central Tien Shan and Jueluotag gradually stabilized before the Cretaceous. From the Late Jurassic to the Cretaceous, the decreasing tendency of the central-Tien-Shan-provenance percentages decreased, while that of Jueluotag provenance increased. Furthermore, central Tien Shan provenance had a slightly growing trend from the Early Jurassic (38%) to the Middle Jurassic (41.3%) and then gradually decreased to 20.3%. The Central Tien Shan still accounted for a sizeable proportion of the provenance, the genesis of which suggests that it may be that provenance as-cribable to central Tien Shan still crossed the poorly uplifted Jueluotag to the Turpan-Hami basin. Similar to central Tien Shan, the provenance ascribable to Jueluotag gradually decreased from an initial 51.8% to 14.9% in the Late Jurassic, but the proportion of the provenance increased again to 26% during the Cretaceous. These features opened the prelude to the Cenozoic tectonic activities in this region. In addition, the decomposition results revealed that the inverse Monte Carlo mixed model for dissecting the provenance of sandstone samples was subject to large biases in complex geological settings, such as detrital-zircon populations, the age spectra of source areas, contempo-raneous magmatism, and recovered older strata.

Стилі APA, Harvard, Vancouver, ISO та ін.

14

LANG, XINGHAI, DONG LIU, YULIN DENG, JUXING TANG, XUHUI WANG, ZONGYAO YANG, ZHIWEI CUI, et al. "Detrital zircon geochronology and geochemistry of Jurassic sandstones in the Xiongcun district, southern Lhasa subterrane, Tibet, China: implications for provenance and tectonic setting." Geological Magazine 156, no. 4 (April 18, 2018): 683–701. http://dx.doi.org/10.1017/s0016756818000122.

Повний текст джерела

Анотація:

AbstractJurassic sandstones in the Xiongcun porphyry copper–gold district, southern Lhasa subterrane, Tibet, China were analysed for petrography, major oxides and trace elements, as well as detrital zircon U–Pb and Hf isotopes, to infer their depositional age, provenance, intensity of source-rock palaeo-weathering and depositional tectonic setting. This new information provides important evidence to constrain the tectonic evolution of the southern Lhasa subterrane during the Late Triassic – Jurassic period. The sandstones are exposed in the lower and upper sections of the Xiongcun Formation. Their average modal abundance (Q21F11L68) classifies them as lithic arenite, which is also supported by geochemical studies. The high chemical index of alteration values (77.19–85.36, mean 79.96) and chemical index of weathering values (86.19–95.59, mean 89.98) of the sandstones imply moderate to intensive weathering of the source rock. Discrimination diagrams based on modal abundance, geochemistry and certain elemental ratios indicate that felsic and intermediate igneous rocks constitute the source rocks, probably with a magmatic arc provenance. The detrital zircon ages (161–243 Ma) and εHf(t) values (+10.5 to +16.2) further constrain the sandstone provenance as subduction-related Triassic–Jurassic felsic and intermediate igneous rocks from the southern Lhasa subterrane. A tectonic discrimination method based on geochemical data of the sandstones, as well as detrital zircon ages from sandstones, reveals that the sandstones were most likely deposited in an oceanic island-arc setting. These results support the hypothesis that the tectonic background of the southern Lhasa subterrane was an oceanic island-arc setting, rather than a continental island-arc setting, during the Late Triassic – Jurassic period.

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Hegner, E., M. Gruler, H. P. Hann, F. Chen, and M. GÜldenpfennig. "Testing tectonic models with geochemical provenance parameters in greywacke." Journal of the Geological Society 162, no. 1 (January 2005): 87–96. http://dx.doi.org/10.1144/0016-764904-029.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Carranza-Edwards, Arturo, Leticia Rosales-Hoz, and Susana Santiago-Pérez. "Provenance memories and maturity of holocene sands in northwest Mexico." Canadian Journal of Earth Sciences 31, no. 10 (October 1, 1994): 1550–56. http://dx.doi.org/10.1139/e94-137.

Повний текст джерела

Анотація:

Beach and fluvial sediments from the region around Todos Santos Bay, Baja California, have been studied to determine their maturity, provenance, chemical alteration, and tectonic relationships. Analysis of the CaO–Na2O–K2O content of several samples demonstrated a difference between those from a beach environment and those from a fluvial environment. Transport affects the characteristics of the sediment, producing an enrichment of material resistant to chemical and physical attack on the beach area. The beach sand samples are mineralogically and chemically more mature than those from the fluvial sands. The provenance index (feldspar/rock fragments) gives relatively low average values for fluvial sands, provided that they are richer in rock fragments. The chemical index of alteration has low average values for beach sands because the minerals are more resistant to energy from waves and currents. Tectonic settings, defined through the binary diagram from Roser and Korsch, suggest that the samples belong to active continental margin and arc domains. When tectonic fields are assigned, based on a Q–F–L triangular diagram analysis, the sediments from the study area fall in an active magmatic arc field, even though this region is not presently subject to subduction.

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Hou, Haihai, Shujun Liu, Longyi Shao, Yonghong Li, Ming’en Zhao, and Cui Wang. "Elemental geochemistry of the Middle Jurassic shales in the northern Qaidam Basin, northwestern China: Constraints for tectonics and paleoclimate." Open Geosciences 13, no. 1 (January 1, 2021): 1448–62. http://dx.doi.org/10.1515/geo-2020-0318.

Повний текст джерела

Анотація:

Abstract The elemental geochemical characteristics of mudstones/shales are good tracers for indicating the evolution of tectonics, paleoenvironment, and paleoclimate. Based on the continuous sampling of drilling cores from the Middle Jurassic Dameigou and Shimengou Formations in the northern Qaidam Basin, the major, trace, and rare earth elements of the 31 mudstones and shales were analyzed. The information on the evolution of tectonics, provenance, and paleoclimate during Middle Jurassic was also recovered. The results show that: (1) A couple of elements consisting of Sc, Y, V, Cr, Co, Ni, Cu, Zn, Th, and U are relatively enriched, indicating that the contents of siderophile and chalcophile elements are significantly high in the Middle Jurassic samples; (2) Changes in the chemical index of alteration, Ga/Rb, and K2O/Al2O3 ratios in the mudstone/shale samples suggest that the paleoclimate was changed from warm and humid in the early stage to cold and dry in the middle stage and to hot and arid in the late stage; (3) The Middle Jurassic provenance of the northern Qaidam Basin was predicted from upper crust and felsic rocks to the mixed felsic rocks and basic rocks; (4) The Middle Jurassic tectonic background was changed from passive continental margin to active continental margin and oceanic island arc. The paleoclimatic and paleogeographic evolution of northern Qaidam Basin were closely related to the surrounding paleo-oceanic and ancient plate activities. In the early stage of the Middle Jurassic, the extensional activity in the passive continental margin and the water vapor input was caused by the Tethys Ocean, resulting in a warm and humid paleoclimate. In the late stage of the Middle Jurassic, the tectonic background of the study area tended to be an oceanic island arc caused by compressive tectonic, which blocked the monsoon input and led to a hot and arid paleoclimate. The establishment of multiple geochemical profiles can provide a scientific basis for the climate changes in greenhouse–icehouses and source–sink systems of the Middle Jurassic in northwestern China.

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Li, Dinghua, Zhenning Yang, Yu Liu, Kunguang Yang, Dehai Wu, and Pingting Cai. "Timing and Provenance Transition of the Neoproterozoic Wuling Unconformity and Xihuangshan Unconformity of the Yangtze Block: Responses to Peripheral Orogenic Events." Minerals 12, no. 5 (May 7, 2022): 596. http://dx.doi.org/10.3390/min12050596.

Повний текст джерела

Анотація:

Middle Neoproterozoic sedimentary strata are widely distributed on the periphery of the Yangtze Block. In the western Jiangnan Orogen, they are divided into the Lengjiaxi and Banxi groups by the “Wuling unconformity,” and the Banxi Group is further divided into the Madiyi Formation and Wuqiangxi Formation by the “Xihuangshan unconformity.” However, the timing and tectonic significance of the Wuling and Xihuangshan unconformities remain unclear, which hampers our understanding of the Precambrian tectonic evolution of the Yangtze Block. Zircon U–Pb dating and Lu–Hf isotopic analysis were performed on the sedimentary rocks above and below the two unconformity boundaries in the western Jiangnan Orogen. These data were used to trace sedimentary provenance and provide new insights into the basin evolution and tectonic significance of the unconformities. Combined with previous studies, the Wuling unconformity is bracketed to have formed between ~830 and 813 Ma, and the provenance of the sediments above the unconformity remained unchanged. The detrital zircons from the upper parts of the Lengjiaxi Group and lower parts of the Banxi Group show the primary peak ages of 800–1000 Ma, 1.0–1.30 Ga, 1.40–1.90 Ga, and 2.30–2.60 Ga, and the provenance mainly derived from the southwestern margin of the Yangtze Block, Cathaysia Block, and Jiangnan Orogen. The provenance from the Cathaysia Block occurred in the upper part of the Lengjiaxi Group, indicating that the Yangtze Block and Cathaysia Block merged in the western Jiangnan Orogen earlier than the formation time of the Wuling unconformity (~830–813 Ma) and the collisional time in the eastern Jiangnan Orogen (~820–800 Ma). Thus, the collision between the Yangtze and Cathaysia blocks may have undergone a scissor-like closure process from west to east. The formation time of the Xihuangshan unconformity was at ~800–779 Ma. The field contact relationships changed from an angular unconformity to a disconformity and then to conformity, from north to south, indicating that the Xihuangshan unconformity was controlled by tectonic movement in the north. The provenance of the sedimentary strata changed above the Xihuangshan unconformity. The detrital zircon age peaks of the upper Banxi Group are 755–1000 Ma, 1.90–2.10 Ga, and 2.35–2.70 Ga, and the detritus were derived from the northern margin of the Yangtze Block and the Jiangnan Orogen. This unconformity is coeval with that of the ~800–780 Ma collisional orogeny at the northern and northwestern margins of the Yangtze Block. Thus, the Xihuangshan unconformity is likely a response to the collision orogeny in the northern and northwestern margins of the Yangtze Block and induces the transition of sedimentary provenance.

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Qasim, Muhammad, Javed Iqbal Tanoli, Luqman Ahmad, Lin Ding, Qasim Ur Rehman, and Umbreen Umber. "First U-Pb Detrital Zircon Ages from Kamlial Formation (Kashmir, Pakistan): Tectonic Implications for Himalayan Exhumation." Minerals 12, no. 3 (February 26, 2022): 298. http://dx.doi.org/10.3390/min12030298.

Повний текст джерела

Анотація:

This study reports the first-ever detrital zircon provenance investigation of sandstones of the Kamlial Formation, exposed in Kashmir Basin along the Kohala–Bagh road section (Muzaffarabad, Pakistan). Analysis of probability density plots of detrital U-Pb zircon ages displayed a major age population clustered around ≈400–1200 Ma and a minor age population clustered around ≈1600–1900 Ma. In addition, scattered ages existed between ≈2000 and 3000 Ma. This age pattern resembled strongly the Himalayan sources, including the Tethys Himalaya, Greater/Higher Himalaya, and Lesser Himalaya. The younger ages (<150 Ma) present in the studied samples indicated the Asian provenance. The Lesser Himalayan component (≈166–1900 Ma) was more pronounced in the 2015KM03 and 2015KM04 samples, representing the middle to the upper portion of the formation. The recycled orogen provenance of the Kamlial Formation as deduced from the sandstone petrography supports the mixed detrital zircon provenance. Considering the provenance, we propose a tectonic model that suggests that large-scale exhumation occurred in the Himalaya as a result of Panjal thrust activation during 25–14 Ma (age of Kamlial Formation), which uplifted the hinterland zone that acted as a source area that fed the foreland basin, where the Kamlial Formation deposited.

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Atabo, Nathaniel Odoma, and Ojochogwu Idakwo Sunday. "Geochemical evaluation of Campanian-Maastritchian clay-shale sediments of Patti formation, Southern Bida and Mamu Formation, northern Anambra basins." Global Journal of Geological Sciences 18 (November 3, 2020): 97–118. http://dx.doi.org/10.4314/gjgs.v18i1.9.

Повний текст джерела

Анотація:

Two basins (Southern Bida and Northern Anambra Basins) were investigated to deduce weathering, paleooxygenation, provenance, depositional environment and tectonic setting, as well as to establish a relationship between the two basins. The obtained high values of calculated weathering indices such as Chemical index of alteration (CIA > 90), Chemical Index of Weathering (CIW > 90), Plagioclase Index of Alteration (PIA > 90) and the Al2O3-(CaO + Na2O)-K2O ternary relationship for the clay – shale sediments from both basins indicate intense weathering in the source area. Important geochemical ratios such as V/Cr, Cu/Zn, Ni/Co, (Cu+Mo)/Zn, revealed predominantly oxic conditions for the clay – shale sediments from both basins, although, a more reducing or an anoxic condition cannot be ruled out for the clay – shale sediments from the Southern Bida basin due to high ratios of U/Th (1.93-5.67) and Cu/Zn (0.19-5.00). In addition, the Sr/Ba ratios (0.16–3.50) for the clay-shales from the Southern Bida basin indicated an alternated marine and continental paleo-depositional settings and only continental setting (Sr/Ba ratios = 0.22 – 0.50) for the Northern Anambra basin. The Th/Sc, La/Sc, Th/Co and the LREE/HREE ratios showed a derivation of the shale and clay deposits from similar felsic-rich source rock while the log of (K2O/Na2O) vs SiO2, revealed a Passive Margin tectonic setting for the two Basins. There is insignificant differences between the geochemical classifications, weathering, source rock/provenance and tectonic settings of clay-shale sediments of both sedimentary basins, however, there exist slight disparity in their salinity conditions and redox settings. Keywords: Geochemistry, Clay-shale, Provenance, Tectonic Setting, Northern Anambra and Southern Bida Basins

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Rizki, L. Muh Fathur, Nofrohu Retongga, Andika Gerardus Oratmangun, Abdurrahman Saputra, Atikah Zahidah, Diana Septiani Roos, Rohmad Bagus Abadi, and Oan Marcello Lukas Watania. "Studi Provenance Batupasir Karbonatan Formasi Kerek Dengan Metode Point Counting Di Daerah Kandangan Kabupaten Semarang." Jurnal Teknologi 14, no. 2 (December 19, 2021): 164–69. http://dx.doi.org/10.34151/jurtek.v14i2.3728.

Повний текст джерела

Анотація:

Carbonate sandstone in the study area was found around rivers and hills in the study area. Provenance of sandstones in the research area of interest to be examined, because not known provenance the sandstone rock formations karbonatan Kerek especially in the research area. The purpose of this study was to determine the provenance of Kerek carbonated sandstones in the study area using themethod point counting. The methodology used for the analysis of Provenance in the study area is using petrographic incisions. The results of the analysis of provenance on the five samples of carbonated sandstones of the Kerek Formation in the study area obtained data in the form of: rock types including lithic arenite (Pettijohn, 1975), the climate of the source area is semiarid (Nelson, 2007), the source rock type is plutonic rock (Tartosa, et al, 1991). ) and its tectonic setting is in the magmatic arc transitional arc sub-zone (Dickinson and Suczek, 1979).

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Chiemezie, Ohanyiri C., and Omotowo B. Aminat. "Geochemical assessment of claystone deposits from the Patti Formation, Southern Bida Basin, Nigeria." Materials and Geoenvironment 65, no. 4 (December 1, 2018): 207–18. http://dx.doi.org/10.2478/rmzmag-2018-0018.

Повний текст джерела

Анотація:

AbstractGeochemical studies of claystone deposits from the Patti Formation in the southern Bida Basin, north-Central Nigeria, were carried out on representative samples to determine the basin’s depositional conditions, provenance and tectonic setting. The localities within the study area included Gegu, Ahoko, Ahoko-Etigi, Omu and Idu.Semi-quantitative phase analysis using the Rietveld method and X-ray powder diffraction data revealed that the claystone samples had prominent kaolinite with other constituents such as quartz, illite–muscovite, K-feldspar, pyrite, marcasite, anatase, rutile and gorceixite.Enrichment of Al2O3, Ba, Th, Sr, Cr and La suggests that these elements are primarily controlled by the dominant clay minerals.Geochemical parameters such as U, U/Th, Ni/Co, V/Cr and Cu/Zn ratios strongly implied that these claystones were deposited in an oxidising environment. Provenance deducing ratios for felsic, mafic and basic igneous rocks were compared. Al2O3/TiO2 ratio suggested intermediate to felsic rocks as the probable source rocks for the claystone samples; however, Y/Ni, Cr/V, La/Sc and Th/Sc ratios suggested a felsic progenitor. The tectonic discrimination diagram showed that the samples’ plot was within the region specified for passive margin-type tectonic setting.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Koshnaw, Renas I., Fritz Schlunegger, and Daniel F. Stockli. "Detrital zircon provenance record of the Zagros mountain building from the Neotethys obduction to the Arabia–Eurasia collision, NW Zagros fold–thrust belt, Kurdistan region of Iraq." Solid Earth 12, no. 11 (November 3, 2021): 2479–501. http://dx.doi.org/10.5194/se-12-2479-2021.

Повний текст джерела

Анотація:

Abstract. Recognition of a new angular unconformity and the synthesis of new detrital zircon U–Pb and (U–Th) / He provenance records, including zircon (U–Th) / He double dating, from the NW Zagros region elucidate the basin dynamics of the foreland wedge-top and intermontane units, as well as the tectonic processes in the source terranes in response to the different geodynamic phases. In this contribution, we present field observations and detrital zircon provenance data from hinterland basins to reconstruct the basin dynamics and the underlying tectonic controls in the NW Zagros area in the Kurdistan region of Iraq. Results reveal that the deposition of the suture zone units of the Red Beds Series (RBS; Suwais Group, Govanda Formation, Merga Group) occurred in an intermontane basin on top of folded Upper Cretaceous units and that the RBS deposits rest with an angular unconformity on the underlying older strata. The RBS provenance data point to the Paleogene Walash–Naopurdan–Kamyaran (WNK) complex as a source area and imply a substantial decrease in magmatism by ∼ 36 Ma, as reflected by the youngest age peaks. New detrital zircon provenance data from the hinterland wedge-top units of the proto-Zagros foreland basin (the Tanjero, Kolosh, and Gercus formations) exhibit exclusive derivation from the Upper Cretaceous Neotethys ophiolitic terranes, which differs from the provenance of the older Lower Cretaceous and Paleozoic units that are dominated by the Paleozoic and Neoproterozoic age spectra. These shifts in provenance between different tectonostratigraphic units argue for a sediment source reversal from the west to the east in response to ophiolite obduction, arrival of the WNK complex, and commencement of the Arabia–Eurasia continental collision during the latest Eocene (< 36 Ma). According to the provenance data, the incipient collision was followed by the deposition of the RBS in the hinterland of the proto-Zagros fold–thrust belt as well as the connection of drainages with the collision-related Neogene foreland basin.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Song, Dongfang, Wenjiao Xiao, Brian F. Windley, and Chunming Han. "Provenance and tectonic setting of late Paleozoic sedimentary rocks from the Alxa Tectonic Belt (NW China): Implications for accretionary tectonics of the southern Central Asian Orogenic Belt." GSA Bulletin 133, no. 1-2 (June 9, 2020): 253–76. http://dx.doi.org/10.1130/b35652.1.

Повний текст джерела

Анотація:

Abstract The Central Asian Orogenic Belt has long been considered the largest Phanerozoic accretionary orogen in the world; it developed through the subduction and final closure of the Paleo–Asian Ocean. However, the architecture and duration of the accretionary orogenesis of the Central Asian Orogenic Belt are still controversial despite decades of investigation. In this study, we present field, compositional, and stratigraphically controlled detrital zircon geochronological data for late Paleozoic sedimentary rocks from the Alxa Tectonic Belt to constrain their provenance, tectonic setting, and the overall tectonic configuration of the southern Central Asian Orogenic Belt. A Devonian sample yields a unimodal age peak (ca. 424 Ma) and broad late Mesoproterozoic ages. A Carboniferous sample has Early Silurian (ca. 438 Ma) and Late Devonian (ca. 382 Ma) peaks along with Neoproterozoic to Archean ages. The Permian samples are dominated by Ordovician–Devonian and Carboniferous–Permian ages. They yield maximum depositional ages ranging from ca. 291 Ma to 248 Ma and contain abundant zircon ages that are close to their depositional ages. These data reveal Ordovician–Silurian and Carboniferous–Permian magmatic flare-ups separated by a Devonian magmatic lull in the southern Central Asian Orogenic Belt. The arc terranes in southern Mongolia, central Beishan, and northern Alxa provided major detritus for the late Paleozoic sediments. An abrupt shift of zircon εHf(t) values at ca. 400 Ma reveals significant late Paleozoic crustal growth and excludes southern Alxa as a source. Oceanic basins prevented detritus from southern Alxa from reaching northern Alxa during Permian–Early Triassic time. A geological and provenance comparison of Permian basins in the southern Central Asian Orogenic Belt reveals the existence of two separate forearcs ascribed to bipolar subduction of the Paleo–Asian Ocean. Combined with recent paleomagnetic data, this leads us to advocate for an archipelago-style accretionary process induced by subduction retreat for the late Paleozoic tectonic evolution of the southern Central Asian Orogenic Belt, which continued into Late Permian–Early Triassic.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Peng, Yuan, Yongsheng Zhang, Eenyuan Xing, and Linlin Wang. "Provenance and tectonic significance of the Zhongwunongshan Group from the Zhongwunongshan Structural Belt in China: insights from zircon geochronology." Open Geosciences 12, no. 1 (February 28, 2020): 25–43. http://dx.doi.org/10.1515/geo-2020-0003.

Повний текст джерела

Анотація:

AbstractThe Zhongwunongshan Structural Belt (ZWSB) locates between the Olongbruk Microblock of North Qaidam and the South Qilian Block in China, and it has important implication for understanding the tectonic significance of North Qaidam. Nowadays, there are few discussion on the Caledonian tectonothermal events of the Zhongwunongshan Structural Belt, and there exist different opinions on provenance and tectonic environment of the Zhongwunongshan Group in the ZWSB and its adjacent North Qaidam. In this study, a comprehensive analysis of the detrital zircon geochronological research was carried out on the Zhongwunongshan Group. The detrital zircon U-Pb dating results showed two major populations. The first was Neoproterozoic (966-725 Ma) with a ∈Hf(t) = −15.9 to 9.5, and the other was late Early Paleozoic (460-434Ma) with a ∈Hf(t) = −9.6 to −3.1. In combination with previous research, the dominated provenances were found to be the Neoproterozoic granitic gneiss of the Yuqia-Shaliuhe HP-UHP metamorphic belt and the late Early Paleozoic granite of the Tanjianshan ophiolite-volcanic arc belt in North Qaidam. The Zhongwunongshan Group was deposited in the back-arc sedimentary basin related to the Caledonian collisional orogeny during Middle Silurian-Early Devonian (434-407.9 Ma).

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Thomas, William A., George E. Gehrels, Kurt E. Sundell, and Mariah C. Romero. "Detrital-zircon analyses, provenance, and late Paleozoic sediment dispersal in the context of tectonic evolution of the Ouachita orogen." Geosphere 17, no. 4 (May 14, 2020): 1214–47. http://dx.doi.org/10.1130/ges02288.1.

Повний текст джерела

Анотація:

Abstract New analyses for U-Pb ages and εHft values, along with previously published U-Pb ages, from Mississippian–Permian sandstones in synorogenic clastic wedges of the Ouachita foreland and nearby intracratonic basins support new interpretations of provenance and sediment dispersal along the southern Midcontinent of North America. Recently published U-Pb and Hf data from the Marathon foreland confirm a provenance in the accreted Coahuila terrane, which has distinctive Amazonia/Gondwana characteristics. Data from Pennsylvanian–Permian sandstones in the Fort Worth basin, along the southern arm of the Ouachita thrust belt, are nearly identical to those from the Marathon foreland, strongly indicating the same or a similar provenance. The accreted Sabine terrane, which is documented by geophysical data, is in close proximity to the Coahuila terrane, suggesting the two are parts of an originally larger Gondwanan terrane. The available data suggest that the Sabine terrane is a Gondwanan terrane that was the provenance of the detritus in the Fort Worth basin. Detrital-zircon data from Permian sandstones in the intracratonic Anadarko basin are very similar to those from the Fort Worth basin and Marathon foreland, indicating sediment dispersal from the Coahuila and/or Sabine terranes within the Ouachita orogen cratonward from the immediate forelands onto the southern craton. Similar, previously published data from the Permian basin suggest widespread distribution from the Ouachita orogen. In contrast to the other basins along the Ouachita-Marathon foreland, the Mississippian–Pennsylvanian sandstones in the Arkoma basin contain a more diverse distribution of detrital-zircon ages, indicating mixed dispersal pathways of sediment from multiple provenances. Some of the Arkoma sandstones have U-Pb age distributions like those of the Fort Worth and Marathon forelands. In contrast, other sandstones, especially those with paleocurrent and paleogeographic indicators of southward progradation of depositional systems onto the northern distal shelf of the Arkoma basin, have U-Pb age distributions and εHft values like those of the “Appalachian signature.” The combined data suggest a mixture of detritus from the proximal Sabine terrane/Ouachita orogenic belt with detritus routed through the Appalachian basin via the southern Illinois basin to the distal Arkoma basin. The Arkoma basin evidently marks the southwestern extent of Appalachian-derived detritus along the Ouachita-Marathon foreland and the transition southwestward to overfilled basins that spread detritus onto the southern craton from the Ouachita-Marathon orogen, including accreted Gondwanan terranes.

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Sun, Lin Hua. "Geochemistry of Shales from Cambrian Mantou Formation, Northern Anhui Province, China." Advanced Materials Research 734-737 (August 2013): 352–55. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.352.

Повний текст джерела

Анотація:

The Cambrian Mantou Formation shales in northern Anhui Province, China were analyzed for major oxides and trace elements to infer their provenance of the source rocks and their depositional tectonic setting. Ternary plot of Al2O3-Zr-TiO2 and Zr/Sc-Th/Sc diagram suggest that the shales were first order sedimentary of igneous rocks, and then can be used for evaluating their source provenance. Diagrams of (SiO2/20)- (Na2O+K2O)- (MgO+TiO2+FeO*), TiO2-Ni, Th-Hf-Co and Hf-La/Th, some ratios of elements (e.g. Co/Th, La/Sc and Zr/Sc), as well as the source SiO2 contents calculated by Al2O3/TiO2 ratios indicate that intermediate to felsic igneous rocks constitute the source rocks in the provenance.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Yu, Junjie, Wei Yue, Ping Liu, Bo Peng, Jie Zhang, Dandan Sun, Jilong Wang, Hailong Lv, and Jing Chen. "Provenance Shift during the Plio-Pleistocene in the Vertex of Yangtze Delta and Its Geomorphological Implications." Minerals 10, no. 11 (November 10, 2020): 996. http://dx.doi.org/10.3390/min10110996.

Повний текст джерела

Анотація:

One of the key issues of the Source-to-Sink process is revealing the geomorphological evolutions of large rivers from the perspective of river sink areas. This study aims to reveal the provenance change near the vertex of the Yangtze delta during the late Cenozoic and provide insight into the Yangtze channelization into the sea due to regional tectonic subsidence. Heavy minerals and zircon geochronology in the Plio-Pleistocene sediments of the vertex of the modern Yangtze delta (core RGK15) reveal that a significant provenance shift occurred at ~2.6 Ma (the beginning of the Pleistocene). During the Pliocene, ultra-stable heavy minerals and pre-Mesozoic zircon grains predominated in the sediments, probably derived from contemporary outcrops of sedimentary rock that were widely distributed in the delta and its surrounding area. They are completely different from those in the Pliocene sediments of the south delta, indicating that decentralized, local, small watersheds dominated the Yangtze delta during the Pliocene. This resulted from the relatively elevated terrain of this region due to the adjacent ancient Zhejiang–Fujian Uplift (ZFU) at that time. However, diversified heavy minerals and zircon geochronology similar to those of the modern upper Yangtze fingerprints occur in the Pleistocene sediments of core RGK15, implying that a significant provenance shift to the Yangtze River occurred here at ~2.6 Ma. The provenance shift recorded by the cores in the south delta mainly occurred at ~1.2 Ma, indicating that the Yangtze River channel was dragged southward with the further subsidence of the ancient Zhejiang–Fujian Uplift. This study reveals the southward migration process of the Yangtze River channel with the regional tectonic subsidence from the perspective of provenance evolution, which contributes to an understanding of when the Yangtze River channelized into the sea.

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Di Giulio, Andrea, Chiara Amadori, Pierre Mueller, and Antonio Langone. "Role of the Down-Bending Plate as a Detrital Source in Convergent Systems Revealed by U–Pb Dating of Zircon Grains: Insights from the Southern Andes and Western Italian Alps." Minerals 10, no. 7 (July 16, 2020): 632. http://dx.doi.org/10.3390/min10070632.

Повний текст джерела

Анотація:

In convergent zones, several parts of the geodynamic system (e.g., continental margins, back-arc regions) can be deformed, uplifted, and eroded through time, each of them potentially delivering clastic sediments to neighboring basins. Tectonically driven events are mostly recorded in syntectonic clastic systems accumulated into different kinds of basins: trench, fore-arc, and back-arc basins in subduction zones and foredeep, thrust-top, and episutural basins in collisional settings. The most widely used tools for provenance analysis of synorogenic sediments and for unraveling the tectonic evolution of convergent zones are sandstone petrography and U–Pb dating of detrital zircon. In this paper, we present a comparison of previously published data discussing how these techniques are used to constrain provenance reconstructions and contribute to a better understanding of the tectonic evolution of (i) the Cretaceous transition from extensional to compressional regimes in the back-arc region of the southern Andean system; and (ii) the involvement of the passive European continental margin in the Western Alps subduction system during impending Alpine collision. In both cases, sediments delivered from the down-bending continental block are significantly involved. Our findings highlight its role as a detrital source, which is generally underestimated or even ignored in current tectonic models.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Knox, Robert W. O’B, Stephen G. Franks, and Joshua D. Cocker. "Stratigraphic evolution of heavy-mineral provenance signatures in the sandstones of the Wajid Group (Cambrian to Permian), southwestern Saudi Arabia." GeoArabia 12, no. 4 (October 1, 2007): 65–96. http://dx.doi.org/10.2113/geoarabia120465.

Повний текст джерела

Анотація:

ABSTRACT The Wajid Group of southwestern Saudi Arabia consists of a dominantly sandy succession of Cambrian to Permian age that spans several discrete phases in the tectonic evolution of the Arabian Peninsula. The principal aim of this study was to determine whether successive changes in the tectonic setting are reflected in changes in provenance-related mineralogy. Because of the relatively limited compositional range of the Wajid sandstones, heavy-mineral assemblages have been used as the primary tool for assessing changes in provenance signature. A comparison of heavy-mineral and petrological data has, however, also been carried out. Variation in the relative abundances of zircon, rutile, monazite, tourmaline and apatite has revealed significant changes in provenance signature between the Dibsiyah (Cambrian–Ordovician), Sanamah (Ordovician–Silurian), Khusayyayn (Devonian–Carboniferous) and Juwayl (Carboniferous–Permian) sandstones. Since previous studies have established that northward-flowing rivers deposited the fluvial sandstones of the Wajid Group, it appears that the source area lay to the south. In the absence of data from the region to the south, it is not possible to identify specific source areas. It is clear, however, that the successive changes in provenance signature must reflect exposure of new source rocks through progressive denudation, changes in the pattern of tectonic uplift or changes in the drainage system. It is also possible that some of the observed mineral variation is related to lateral influx of sands through long-shore drift during times of high sea level. Two distinct mineral compositions occur within the Dibsiyah sandstones, indicating that a major change in provenance took place during deposition of the Upper Dibsiyah sands. The boundary between the Dibsiyah and Sanamah formations is sharply defined, although the overall composition of the Sanamah sandstones is in many respects similar to that of the Dibsiyah sandstones. There is a relatively small difference in composition between the Sanamah sandstones and the associated diamictites. A major change in provenance is indicated at the base of the Khusayyayn Formation, with an increase in the proportion of monazite and staurolite. This change in composition persists into the Juwayl Formation although the greater variability displayed by the Juwayl heavy-mineral assemblages indicates contribution from several sources. Heavy-mineral assemblages in the Juwayl sandstones are comparable to those of the Unayzah C and B sandstones of central Saudi Arabia, but differences suggest mixing between a southern (Juwayl) and western (Shield) source for the Unayzah sandstones. Compositionally, Wajid sandstones range from quartz arenite to arkose. Comparison of the petrographic and heavy-mineral data is hampered by the different grain-size ranges studied. However, it would appear that samples with similar heavy-mineral provenance character do not necessarily possess similar feldspar percentages, even when the latter are corrected for in-situ kaolinization. The data set is too small to establish an explanation for this apparent discrepancy.

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Evans, Jane A., Vanessa Pashley, Katy Mee, Doris Wagner, Mike Parker Pearson, Delphine Fremondeau, Umberto Albarella, and Richard Madgwick. "Applying lead (Pb) isotopes to explore mobility in humans and animals." PLOS ONE 17, no. 10 (October 26, 2022): e0274831. http://dx.doi.org/10.1371/journal.pone.0274831.

Повний текст джерела

Анотація:

Lead (Pb) isotopes provide a complementary method to other provenance tools for tracking the origin and movement of humans and animals. The method is founded in the geographic distribution of Pb isotope ratios. However, unlike the Sr isotope method that is closely linked to the lithology of underlying rocks, Pb more closely reflects the tectonic regimes. This makes it particularly pertinent to use in Britain as there is major tectonic boundary (the Iapetus Suture) that runs between Berwick-upon-Tweed and the Solway Firth providing a compositional boundary in Pb isotope domains that approximates to the geographic areas of Scotland versus England and Wales. Modern pollution makes it difficult to use modern floral or faunal samples to characterize biosphere variation, and so we use geological datasets to define isoscape variation and present the first Pb isotope map of Britain. We have validated the use of these data form biosphere studies using well provenanced samples. Reference fields of diagnostic compositions, are created in μ-T space and these have been used in a test case to assess the geographic origins of Neolithic animals in Great Britain.

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Khan, Zuhi, and A. H. M. Ahmad. "Provenance, tectonic setting and palaeoclimate of the Ridge Sandstone of Jumara Dome, Kachchh, Gujarat." Journal of Palaeosciences 65, no. (1-2) (December 31, 2016): 189–201. http://dx.doi.org/10.54991/jop.2016.310.

Повний текст джерела

Анотація:

This study deals with petrography, provenance, tectonic setting and palaeoclimate of the Ridge Sandstone Member encountered in the Jumara Dome, Kachchh, Gujarat. The sandstones in this member are medium to coarse grained, poorly to moderately sorted and sub angular to sub rounded. Framework grains are sand–sized to silt–sized particles of mainly detrital origin. Among the main detrital framework grains, quartz constitutes 55.42–96.09%, feldspar 4.9–27.76%, and lithic fragments 0–3.73%. These sandstones have been classified as sub–arkose to arkose in composition and were deposited in continental block provenance with stable craton in rifted continental margin basin setting in a humid climate with the source material from either the Aravalli or Nagar Parker massif.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Mahoney, J. Brian, James W. Haggart, Marty Grove, David L. Kimbrough, Virginia Isava, Paul K. Link, Mark E. Pecha, and C. Mark Fanning. "Evolution of the Late Cretaceous Nanaimo Basin, British Columbia, Canada: Definitive provenance links to northern latitudes." Geosphere 17, no. 6 (November 8, 2021): 2197–233. http://dx.doi.org/10.1130/ges02394.1.

Повний текст джерела

Анотація:

Abstract Accurate reconstruction of the Late Cretaceous paleogeography and tectonic evolution of the western North American Cordilleran margin is required to resolve the long-standing debate over proposed large-scale, orogen-parallel terrane translation. The Nanaimo Basin (British Columbia, Canada) contains a high-fidelity record of orogenic exhumation and basin subsidence in the southwestern Canadian Cordillera that constrains the tectonic evolution of the region. Integration of detrital zircon U-Pb geochronology, conglomerate clast U-Pb geochronology, detrital muscovite 40Ar/39Ar thermochronology, and Lu-Hf isotopic analysis of detrital zircon defines a multidisciplinary provenance signature that provides a definitive linkage with sediment source regions north of the Sierra Nevada arc system (western United States). Analysis of spatial and temporal provenance variations within Nanaimo Group strata documents a bimodal sediment supply with a local source derived from the adjacent magmatic arc in the southern Coast Mountains batholith and an extra-regional source from the Mesoproterozoic Belt Supergroup and the Late Cretaceous Atlanta lobe of the Idaho batholith. Particularly robust linkages include: (1) juvenile (εHf >+10) Late Cretaceous zircon derived from the southern Coast Mountains batholith; (2) a bimodal Proterozoic detrital zircon signature consistent with derivation from Belt Supergroup (1700–1720 Ma) and ca. 1380 Ma plutonic rocks intruding the Lemhi subbasin of central Idaho (northwestern United States); (3) quartzite clasts that are statistical matches for Mesoproterozoic and Cambrian strata in Montana and Idaho (northwestern United States) and southern British Columbia; and (4) syndepositional evolved (εHf >−10) Late Cretaceous zircon and muscovite derived from the Atlanta lobe of the Idaho batholith. These provenance constraints support a tectonic restoration of the Nanaimo Basin, the southern Coast Mountains batholith, and Wrangellia to a position outboard of the Idaho batholith in Late Cretaceous time, consistent with proposed minimal- fault- offset models (<~1000 km).

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Igbinigie, N. S., and A. Ogbamikhumi. "Provenance and tectonic setting of Leuma Field sediments, Coastal Swamp Depobelt, Niger Delta Basin, Nigeria." Journal of Applied Sciences and Environmental Management 26, no. 1 (March 10, 2022): 131–38. http://dx.doi.org/10.4314/jasem.v26i1.20.

Повний текст джерела

Анотація:

Geochemical analysis of sediments recovered from NS-1 well and NS-2 well, Leuma Field, Coastal Swamp Depobelt, Niger Delta Basin was done to establish tectonic setting and provenance. Data for ten major elements and forty-three trace elements were obtained from two boreholes. The geochemical signals display systematic stratigraphic trends in the two wells that depict one source terrain. To determine the provenance of NS-1 well and NS-2 well sediments, Th/Co vs La/Sc plot was utilized which inferred that the sediments from NS-1 and NS-2 wells were derived from felsic source rocks. TiO2 versus Ni bivariate plot was also used to establish the provenance and it revealed that the source of the sediments penetrated by NS-1 and NS-2 wells is predominantly acidic in nature. The provenance of NS-1 and NS-2 wells sediments was further confirmed by considering the ratios of Thorium/Scandium (Th/Sc), Thorium/Cobalt (Th/Co), Chromium/Thorium (Cr/Th) and Lanthanum/Scandium (La/Sc). For NS-1 well, Thorium/Scandium (Th/Sc) range from 1.12-2.01, Thorium/Cobalt (Th/Co) range from 0.91-1.66, Chromium/Thorium (Cr/Th) range from 4.21-16.04 and Lanthanum/Scandium (La/Sc) range from 3.69-8.78. For NS-2 well, Thorium/Scandium (Th/Sc) range from 0.95-2.05, Thorium/Cobalt (Thko/Co) range from 0.94-1.91, Chromium/Thorium (Th/Cr) range from 4.32-15.43 and Lanthanum/Scandium (La/Sc) range from 2.58-6.66. These values inferred that the sediments recovered from NS-1 and NS-2 wells were transported from felsic source rocks.Inorganic geochemical results infer that the tectonic setting for NS-1 and NS-2 wells facies is passive continental margin.

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Ning, HUO, GUO QianQian, CHEN YiChao, and SONG DongFang. "Provenance and tectonic setting of the Gudongjing Group in Beishan Orogen." Acta Petrologica Sinica 38, no. 4 (2022): 1253–79. http://dx.doi.org/10.18654/1000-0569/2022.04.17.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Babeesh, C., Aasif Lone, and Hema Achyuthan. "Geochemistry of Manasbal lake sediments, Kashmir: Weathering, provenance and tectonic setting." Journal of the Geological Society of India 89, no. 5 (May 2017): 563–72. http://dx.doi.org/10.1007/s12594-017-0645-4.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Meinhold, Guido, and Dimitrios K. Kostopoulos. "The Circum-Rhodope Belt, northern Greece: Age, provenance, and tectonic setting." Tectonophysics 595-596 (June 2013): 55–68. http://dx.doi.org/10.1016/j.tecto.2012.03.034.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

38

A. Brako, Blestmond, Gordon Foli, Etornam B. Fiadonu, Chiri Amedjoe, Derrick Aikins, and Simon K. Y. Gawu. "PROVENANCE AND TECTONIC SETTING OF SOME PALEOPROTEROZOIC SEDIMENTARY ROCKS IN THE CHAGUPANA AND TARKWA AREAS OF GHANA: PETROGRAPHIC AND STRUCTURAL CONSTRAINTS." Earth Science Malaysia 4, no. 1 (February 10, 2020): 01–07. http://dx.doi.org/10.26480/esmy.01.2020.01.07.

Повний текст джерела

Анотація:

Paleoproterozoic sedimentary rocks associated with the Man Shield of West Africa are perceived to be similar, irrespective of their locality. This research seeks to establish the provenance and tectonic setting of these rocks to ascertain any such similarity perception, based on information from two localities. The study uses modal mineral estimations to reconstruct the source, paleocurrent, paleoclimate and relief of some conglomerates and sandstones from Chagupana and Tarkwa areas in Ghana. Chagupana conglomerate has igneous and metamorphic provenances, while Kawere conglomerate has metamorphic provenance. Average mineralogical composition of Chagupana sandstone is Q53-F45-R3 and classify as arkose. Tarkwa suites of Huni, Kawere and Banket sandstones are composed of Q48-F34-R18, Q51-F25-R23 and Q76-F7-R17, and classify as lithic arkose, lithic arkose-feldspathic litharenite, and sublitharenite, respectively. Detritus of all the sandstones suggest acid igneous rock source, with minor sedimentary and metamorphic imprints, with an order of maturity as Banket>Kawere>Huni>Chagupana. Detritus in the Chagupana, Huni and Kawere sandstones are from the transitional continental margin. The Chagupana is from the cold arid climate, while the Huni and Kawere are from the semi-arid/semi-humid climates. The Banket sandstone mobilises from craton interior with recycled orogenic materials in a humid environment. The angular-subangular feldspars in Chagupana sandstone indicate low relief and low-moderate recycling close to the source. Huni, Kawere and Banket sandstones derive from low-moderate reliefs with multiple recycling episodes. The Chagupana and Huni sandstones show paleo-current directions from the north and east, respectively. Similarities between the Chagupana and Tarkwa rocks can only be limited to the tectonic setting and not from source area, paleo-climate, paleo-current and relief.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Kan, Wenguang, Zailin Yang, Liangliang Yu, and Menghan Sun. "Provenance and Tectonic Setting of Formation of Quaternary Sedimentary Successions from the Songhua River, Northeast China." Applied Sciences 12, no. 15 (July 22, 2022): 7356. http://dx.doi.org/10.3390/app12157356.

Повний текст джерела

Анотація:

Drilling has been conducted to investigate the petrogeochemistry of the Late Pleistocene Guxiangtun Formation and Holocene Wenquanhe Formation in Northeast China. Both Guxiangtun and Wenquanhe Formations are fluvial facies, which are composed mainly of quartz and feldspar, with minor mica and clay minerals. To understand the provenance and tectonic setting of these sediments, geochemical analyses of fifteen selected samples from the drill core have been carried out. Compared to the composition of the upper continental crust (UCC), the sediments exhibit higher SiO2, similar TiO2 and K2O, and lower Fe2O3, MgO, MnO, CaO, and Na2O contents. The bivariant plot of Th/Sc versus Zr/Sc ratios indicates the contribution from recycled sedimentary provenance for our studied sediments; furthermore, the low to medium degree of weathering of these sediments is commonly indicated by the chemical index of alteration (CIA) of 52. The discriminant function diagram using major elements shows a mixed provenance of the sediments, including quartzose sedimentary and felsic igneous rocks. According to the Fe2O3+MgO vs. K2O/Na2O plot and Th–Sc–Zr/10 diagram, the sediments under the investigation fall mostly within the active continent margin field.

Стилі APA, Harvard, Vancouver, ISO та ін.

40

WILLIAMS, GEORGE E. "Neoproterozoic (Torridonian) alluvial fan succession, northwest Scotland, and its tectonic setting and provenance." Geological Magazine 138, no. 2 (March 2001): 161–84. http://dx.doi.org/10.1017/s0016756801005064.

Повний текст джерела

Анотація:

The presence of alluvial fan deposits in the lower Neoproterozoic Torridon Group in northwest Scotland illuminates Torridonian basin development at the eastern Laurentian margin. The 450 m thick Cape Wrath Member of the Applecross Formation consists of alluvial fan conglomerate and arkose succeeded by more distal, braidplain feldspathic sandstone. Palaeocurrent data comprising >2650 measurements on trough cross-bedding are of low variability and show overall eastward flow. The projection upcurrent of regionally divergent flow directions for the lower part of the member indicates a fan of c. 50 km radius with its apex 30 km to the west near a basement (pre-Caledonian) normal fault with downthrow to the east beneath the north Minch Basin. Extensional tectonics controlled deposition of the Applecross Formation. Regional uplift, causing erosion of a youthful topography on the Lewisian Gneiss, was followed by the development of the Applecross extensional basin in two main stages. Uplift of a western source area by movement on basin-bounding normal faults occurred first in the north and caused pediplanation and alluvial fan deposition in the Cape Wrath area, with subsequent uplift of the source area for the main body of the Applecross Formation occurring further to the west and south along the line of the Minch Fault. The bulk of the Applecross Formation was derived from a weathered terrain of felsic crystalline and related supracrustal rocks reaching from the Outer Hebrides region westward for up to c. 250 km onto what are now the continental margins of the North Atlantic. The tectonic events may mark an early phase in the crustal extension that led ultimately to the opening of the Iapetus ocean.

Стилі APA, Harvard, Vancouver, ISO та ін.

41

WILLIAMS, GEORGE E. "Neoproterozoic (Torridonian) alluvial fan succession, northwest Scotland, and its tectonic setting and provenance." Geological Magazine 138, no. 4 (July 2001): 471–94. http://dx.doi.org/10.1017/s0016756801009876.

Повний текст джерела

Анотація:

The presence of alluvial fan deposits in the lower Neoproterozoic Torridon Group in north-west Scotland illuminates Torridonian basin development at the eastern Laurentian margin. The 450 m thick Cape Wrath Member of the Applecross Formation consists of alluvial fan conglomerate and arkose succeeded by more distal, braidplain feldspathic sandstone. Palaeocurrent data comprising > 2650 measurements on trough cross-bedding are of low variability and show overall eastward flow. The projection upcurrent of regionally divergent flow directions for the lower part of the member indicates a fan of c. 50 km radius with its apex 30 km to the west near a basement (pre-Caledonian) normal fault with downthrow to the east beneath the north Minch Basin. Extensional tectonics controlled deposition of the Applecross Formation. Regional uplift, causing erosion of a youthful topography on the Lewisian Gneiss, was followed by the development of the Applecross extensional basin in two main stages. Uplift of a western source area by movement on basin-bounding normal faults occurred first in the north and caused pediplanation and alluvial fan deposition in the Cape Wrath area, with subsequent uplift of the source area for the main body of the Applecross Formation occurring further to the west and south along the line of the Minch Fault. The bulk of the Applecross Formation was derived from a weathered terrain of felsic crystalline and related supracrustal rocks reaching from the Outer Hebrides region westward for up to c. 250 km onto what are now the continental margins of the North Atlantic. The tectonic events may mark an early phase in the crustal extension that led ultimately to the opening of the Iapetus ocean.

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Yan, Zhen, Wenjiao Xiao, Zongqi Wang, and Jilian Li. "Integrated analyses constraining the provenance of sandstones, mudstones, and conglomerates, a case study: the Laojunshan conglomerate, Qilian orogen, northwest China." Canadian Journal of Earth Sciences 44, no. 7 (July 1, 2007): 961–86. http://dx.doi.org/10.1139/e07-010.

Повний текст джерела

Анотація:

The Qilian orogenic belt in the northern Tibetan plateau connects the Altaids to the north with the Tethyan orogenic system to the south and occupies a key tectonic position in the evolution and assembly of Asia. The belt contains a wide range of subduction–accretion-related petrotectonic units. The Early–Middle Devonian Laojunshan conglomerate, deposited unconformably upon Cambrian–Silurian strata along the northern margin of the North Qilian terrane, contains a record of the late Paleozoic tectonism of the Qilian orogen. Its provenance and tectonic setting are critical in understanding not only the tectonic evolution of Tibetan plateau, but Paleozoic global reconstructions as well. The composition of clastic conglomerates and heavy mineral assemblages of sandstones suggests that coeval mafic, felsic, metamorphic, and sedimentary rocks were the main sources. The geochemistry of volcanic clasts and paleocurrent and paleogeographic data suggest derivation from subduction–accretion complexes in the North Qilian terrane. The geochemistry of siltstones and mudstones indicates that the Laojunshan conglomerate was derived from an arc and accumulated in an active continental margin. Geochemical data of granitoid clasts suggest that they were derived from Ordovician–Silurian subduction-related magmatic rocks. Mafic and ultramafic clasts, chromite, and magnetite decrease upwards in the stratigraphy whereas metamorphic, sedimentary and granitoid clasts, and garnet increase. These data imply that mafic rocks were the predominant source during initial deposition. Regional studies suggest that the North China plate subducted southwards and produced subduction-related arc magmatism along the southern margin of the North Qilian terrane during the Early–Middle Devonian. Therefore, we interpret the Laojunshan conglomerate as a fore-arc basin fill.

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Denge, Elelwani, and Christopher Baiyegunhi. "Geochemical and Petrographical Characteristics of the Madzaringwe Formation Coal, Mudrocks and Sandstones in the Vele Colliery, Limpopo Province, South Africa: Implications for Tectonic Setting, Provenance and Paleoweathering." Applied Sciences 11, no. 6 (March 19, 2021): 2782. http://dx.doi.org/10.3390/app11062782.

Повний текст джерела

Анотація:

The sedimentary rocks of the Madzaringwe Formation in the Tuli Basin have been investigated using geochemical and petrographic methods to reveal their source area composition, tectonic setting, provenance and paleoweathering conditions. The petrographic studies show that the rocks consist mostly of clay minerals and quartz. The major elements geochemistry indicates that the rocks of the Madzaringwe Formation have the same source area. Based on the discriminant function plots, it can be inferred that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The binary plots of TiO2 versus Zr and La/Sr against Th/Co shows that the rocks were derived from silicic or felsic igneous rocks. The tectonic setting discrimination diagrams of SiO2 against Log (K2O/Na2O), Th–Sc–Zr/10, and TiO2 versus (Fe2O3 + MgO) support passive-active continental margin settings of the provenance. The A–CN–K (Al2O3–CaO + Na2O–K2O) ternary diagram and binary plot of the index of compositional variability (ICV) against chemical index of alteration (CIA) shows that the rocks have been subjected to moderate to intensive weathering. Geochemical and petrographic characteristics of the rocks point to uplifted basement source areas predominantly composed of sedimentary rocks and/or granite-gneiss rocks. These source areas might have been from adjacent areas near the Tuli coalfield which include the Limpopo Belt (igneous and sedimentary rocks), and basement uplifted rocks of the Beit-Bridge Complex, consisting of the granite, granite-gneisses and schists.

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Tang, Xin, Yuanchen Guo, Tingqiang Zhou, and Sen Guo. "Distribution Characteristics of Nanopores and Discriminant Characteristics of Sedimentary Environment of the Longmaxi Formation in the Southern Sichuan Basin." Journal of Nanoscience and Nanotechnology 21, no. 1 (January 1, 2021): 431–37. http://dx.doi.org/10.1166/jnn.2021.18741.

Повний текст джерела

Анотація:

Shale contains a large number of nanopores. The nanopores control the reservoir structure. The formation of nanopores in shale is closely related to the sedimentary environment. The palaeosedimentary structural background determines the provenance and sedimentary diagenesis of mud shale during shale deposition, refines the palaeo-shale and palaeo-sedimentary-tectonic environments of the Longmaxi Formation in the southern Sichuan Basin by elemental geochemical means, and determines the palaeo-deposition of the Longmaxi Formation. The tectonic setting and a numerical simulation method are used to explore the sedimentary tectonic evolution characteristics of the Longmaxi Formation. The results show that the parent rock of the Longmaxi Formation is relatively enriched with light rare earth elements, and the distribution of heavy rare earth elements is relatively stable. The vertical direction shows a trend of increasing from the bottom of the formation to the top of the formation, showing a mixed genesis; the tectonic setting is a passive continental margin, and the active continental margin is the main margin.

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Cantine, Marjorie D., Jacob B. Setera, Jill A. Vantongeren, Chiza Mwinde, and Kristin D. Bergmann. "Grain size and transport biases in an Ediacaran detrital zircon record." Journal of Sedimentary Research 91, no. 9 (September 17, 2021): 913–28. http://dx.doi.org/10.2110/jsr.2020.153.

Повний текст джерела

Анотація:

ABSTRACT Detrital-zircon records of provenance are used to reconstruct paleogeography, sediment sources, and tectonic configuration. Recognition of biases in detrital-zircon records that result from grain-size-dependent processes adds new complexity and caution to the interpretation of these records. We begin by investigating possible size-dependent biases that may affect interpretation of detrital-zircon provenance records in an idealized sedimentary system. Our modeling results show that settling and selective entrainment can differentially affect detrital-zircon spectra if an initial size variation between source zircon populations exists. We then consider a case study: a detrital-zircon record from Ediacaran to Terreneuvian strata of Death Valley, USA, with a focus on the Rainstorm Member of the Johnnie Formation. The detrital-zircon record of the Rainstorm Member shows that despite its unusual, heavy-mineral-rich character, the provenance of the unit is like other units in the succession. Size and density measurements of the grains of the deposit suggest that its enriched heavy-mineral suite is best explained through concentration by selective entrainment and winnowing. The relationship between detrital-zircon grain size and age for samples from the Johnnie Formation are consistent with grain-size influence on the interpretation of provenance, especially for large Grenville-age (1.0–1.2 Ga) zircons. Grain size can exert significant bias on a provenance interpretation and must be accounted for in provenance studies.

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Johannson, Gary G., Paul L. Smith, and Steven P. Gordey. "Early Jurassic evolution of the northern Stikinian arc: evidence from the Laberge Group, northwestern British Columbia." Canadian Journal of Earth Sciences 34, no. 7 (July 1, 1997): 1030–57. http://dx.doi.org/10.1139/e17-085.

Повний текст джерела

Анотація:

This study resolves fundamental questions concerning the age, provenance, and depositional history of Laberge Group strata in the Whitehorse Trough. The Jurassic Inklin Formation straddles the Stikine and Cache Creek terranes along much of the length of the Whitehorse Trough. Ammonite biochronology indicates an age range of early Sinemurian to late Pliensbachian and provides the temporal framework for interpreting basin history. Strong temporal trends in both paleocurrent patterns and sandstone–conglomerate petrofacies allow definition of three discrete phases in basin-fill history. Stable tectonics characterized by relative volcanic quiescence and low sedimentation rates prevailed during the Sinemurian. Sinemurian sandstone–conglomerate petrofacies record a transitional-arc provenance derived from erosion of the Upper Triassic volcanic pile, flanking coastal sediments, and arc roots of Stikinia to the southwest. During the early Pliensbachian, arc dissection was interrupted by a major magmatic episode with widespread rejuvenated volcanism that caused a strong provenance shift to volcanigenic sources, indicating derivation from a largely undissected Stikinian arc. Southwest-derived, northerly longitudinal paleoflow during the Sinemurian changed to opposed bidirectional radial or transverse paleoflow systems in the early Pliensbachian. Cannibalism of broadly coeval basinal strata and (or) reflected sediment gravity flows were the result of episodic growth of a mobile outer forearc rise, initiating southwest-directed paleoflow systems during the early Pliensbachian and the possible development of a ridged forearc phase. U–Pb dates of [Formula: see text] and 186 ± 1 Ma from a granite clast and tuff unit, respectively, of the Kunae Zone (early late Pliensbachian) and sandstone–conglomerate petrofacies indicate a late Pliensbachian depositional regime dominated by tectonic controls. The influx of granitic detritus indicates a rapid transition to a fully dissected arc provenance, where accelerated uplift of segments of the arc massif, accompanied by intra-arc strike-slip faulting, resulted in rapid arc dissection and unroofing of comagmatic Pliensbachian plutons.

Стилі APA, Harvard, Vancouver, ISO та ін.

47

Zhang, Zhiguo, Junsheng Nie, and Xiaomin Fang. "Provenance analysis reveals mountain uplift in the midsection of the Altyn Tagh Fault during the Middle Miocene." Canadian Journal of Earth Sciences 54, no. 3 (March 2017): 278–89. http://dx.doi.org/10.1139/cjes-2016-0090.

Повний текст джерела

Анотація:

The Altyn Tagh Fault (ATF) defines the northern margin of the Tibetan Plateau; therefore, its tectonic history is key to understanding the plateau’s northward growth. However, our understanding of ATF tectonics is incomplete, owing in part to a lack of constraints in detailed basin evolution studies of this region. Approximately 1700 m of Middle Miocene – Pliocene clastic strata extracted from a section of the Yitunbulake Basin adjacent to the midsection of the ATF records the uplift of the Altyn Tagh Range. This paper reports 490 concordant detrital zircon U–Pb ages derived from this set of strata. In addition, paleocurrents and conglomerate clastic compositions were measured to determine the provenance of the basin. The dominant detrital zircon age populations within these sedimentary rocks are 260–240, 500–400, and 950–900 Ma. The 260–240 Ma component decreases sharply above the Lower (Xia) Youshashan (XYSS) Formation. Moreover, we performed (U–Th)/He dating on 260–240 Ma detrital zircons from the XYSS Formation to determine its source region. The results indicate that sandstones in this formation are most likely sourced immediately from plutonic rocks widely distributed in the Eastern Kunlun Mountains. The upward change in detrital zircon U–Pb age components in the section demonstrates that widespread surface uplift of the Akatengneng Mountains in the midsection of the ATF likely occurred after ∼16–15 Ma, which is synchronous with accelerated tectonic deformation along the ATF and a rapid increase in the sedimentation rate in the Qaidam Basin since the Middle Miocene.

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Oni, S. O., A. S. Olatunji, and O. A. Ehinola. "Determination of Provenance and Tectonic Settings of Niger Delta Clastic Facies Using Well-Y, Onshore Delta State, Nigeria." Journal of Geochemistry 2014 (December 28, 2014): 1–13. http://dx.doi.org/10.1155/2014/960139.

Повний текст джерела

Анотація:

Provenance analysis serves to reconstruct the predepositional history of a sediment/sedimentary rock. This paper focuses on the reconstruction of the provenance and tectonic settings of the Niger delta clastic facies using geochemical approach. The main types of geochemical tests include major, trace, and rare earth element (REE) tests. Twenty-one samples of shales and sandstones units were purposely collected from a depth between 1160 and 11,480 m, grinded, pulverized, and sieved with a <75 μm. About 5 g was packed and sent to Acme analytical Laboratory Ltd., Vancouver, Canada. The analyses were carried out by both induced coupled plasma-mass spectrometry (ICP-MS) and induced coupled plasma-emission spectrometry (ICP-ES). Bulk-rock geochemistry of major oxides, trace elements, and rare earth elements was utilized for the provenance and tectonic setting determination. Based on the discrimination diagram for major oxides, the probable provenance of the south eastern Delta clastic sediments was mainly of the active continental margins. The bivariate plots of La versus Th, La/Y versus Sc/Cr, and Ti/Zr versus La/Sc and the trivariate plots of La-Th-Sc, Th-Sc-Zr/10, and Th-Co-Zr/10 are all plotted on the fields of active continental margin sediments which is consistent with the known actively opening of a failed arm of triple junction. The trace elements and REE analysis indicates that they are virtually Fe-rich, lithic/quartz arkosic sandstones. The normalizing factors used for the REE are Wakita chondrite. Their rare earth elements (REE) pattern displays high light REE/heavy REE (LREE/HREE) ratio, flat HREE, and a significant negative Eu anomaly which correlate well with the UCC and PAAS average composition. The source area may have contained felsic igneous rocks.

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Likhanov, Igor I. "Provenance, Age, and Tectonic Settings of Rock Complexes (Transangarian Yenisey Ridge, East Siberia): Geochemical and Geochronological Evidence." Geosciences 12, no. 11 (October 29, 2022): 402. http://dx.doi.org/10.3390/geosciences12110402.

Повний текст джерела

Анотація:

The tectonic evolution of the Siberian Cratonic margins offers important clues for global paleogeographic reconstructions, particularly with regard to the complex geological history of Central Asia and Precambrian supercontinents Columbia/Nuna and Rodinia and its subsequent breakup with the opening of the Paleo-Asian Ocean. Here, we present an overview of geochemical, petrological, and geochronological data from a suite of various rocks to clarify the age, tectonic settings, and nature of their protolith, with an emphasis on understanding the tectonic history of the Yenisey Ridge fold-and-thrust belt at the western margin of the Siberian Craton. These pre-Grenville, Grenville, and post-Grenville episodes of regional crustal evolution are correlated with the synchronous successions and similar style of rocks along the Arctic margin of Nuna-Columbia and Rodinia and support the possible spatial proximity of Siberia and North Atlantic cratons (Laurentia and Baltica) over a long period ~1.4-0.55 Ga.

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Cai, Yelei, Fei Ouyang, Xianrong Luo, Zilong Zhang, Meilan Wen, Xiaoneng Luo, and Rui Tang. "Geochemical Characteristics and Constraints on Provenance, Tectonic Setting, and Paleoweathering of Middle Jurassic Zhiluo Formation Sandstones in the Northwest Ordos Basin, North-Central China." Minerals 12, no. 5 (May 10, 2022): 603. http://dx.doi.org/10.3390/min12050603.

Повний текст джерела

Анотація:

To further explore the uranium-bearing prospects of the Zhiluo Formation, the petrography, major elements, trace elements and rare earth elements of Zhiluo sandstone samples collected from four boreholes were analyzed in this research to determine the provenance, tectonic setting and paleoweathering of the formation. The results of the analysis reveal that the Zhiluo Formation sandstone comprises primarily feldspar sandstone, with quartz, feldspar, and mica as the main mineral components. The rare earth elements are mainly characterized by enrichment in light rare earth elements and loss of heavy rare earth elements. The ratio of light to heavy rare earth elements (LREEs/HREEs) is 5.55–7.79, with an average of 6.33. The value of (La/Yb)CN is 12.96–22.33, with an average value of 17.41, indicating obvious fractionation of LREEs and HREEs. The chemical index of alteration (CIA) value of this sandstone is 56.30–63.04, with an average of 59.75, which indicates that the parent rock experienced weak chemical weathering in a dry climate. The discrimination diagrams of the source area and parent rock show that the source area of the Zhiluo sandstones had a mixed intermediate-felsic composition, and that the main parent rocks were andesite and granite. The tectonic setting discrimination diagram indicates that the tectonic setting of the source area was the passive margin. Thus, the provenance of the sandstone of the Zhiluo Formation is proposed to be the volcanic-sedimentary rock series developed on the northern margin of the Ordos Basin.

Стилі APA, Harvard, Vancouver, ISO та ін.

Статті в журналах з теми "Tectonic provenance"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями