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Munroe, Jeffrey S., Catherine M. Klem, and Matthew F. Bigl. "A lacustrine sedimentary record of Holocene periglacial activity from the Uinta Mountains, Utah, U.S.A." Quaternary Research 79, no. 2 (March 2013): 101–9. http://dx.doi.org/10.1016/j.yqres.2012.12.006.
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AbstractA lake sediment core from the Uinta Mountains of northern Utah was analyzed to constrain the timing of late Holocene periglacial activity. Records of numerous physical properties were converted to time series spanning the past 5300 years using a depth-age model based on four AMS 14C dates. Long-term decreases in organic content and increases in bulk density attest to increasing inputs of clastic sediment. Abundance of mineral P, signaling physical bedrock weathering, reaches maximum values ca. 2900, 2150, and 1400 cal yr BP, coincident with finer median grain size and a shift toward darker red sediment. These peaks, interpreted as signals of periglacial activity, align with pulses of rock glacier activity in Colorado determined from lichenometry. The youngest peak coincides with lichenometric ages previously determined for periglacial deposits upstream from the lake. A pulse of renewed periglacial activity ca. 400 cal yr BP represents the Little Ice Age. The late 20th century witnessed extremely high values of organic matter and biogenic silica, and unprecedented low values of C:N, reflecting greatly enhanced in-lake productivity, likely due to disturbance in the watershed.
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Sprinkel, Douglas. "The Palisades at Sheep Creek Canyon Geological Area." Geosites 1 (January 27, 2022): 1–10. http://dx.doi.org/10.31711/ugap.v1i1.95.
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The Palisades is an impressive ridge within the Sheep Creek Canyon Geological Area—an area nestled on the north flank of the eastern Uinta Mountains not far from Flaming Gorge National Recreation Area. Sheep Creek cuts through the Palisades, as well as the heart of the geological area, to reveal about 800 million years of geology, from ancient environments to the rise and ultimate erosion of the Uinta Mountains. The oldest rocks exposed at the Palisades comprise the upper part of the Neoproterozoic (about 770 million years ago) Uinta Mountain Group, which have been thrusted upon the Mississippian (about 350 million years ago) Deseret Limestone (equivalent to the upper Madison Limestone). That thrust fault and others exposed along the north and south sides of the Palisades are part of the Uinta thrust fault zone, which is responsible for intense folding of both formations. Although the uplift of the Uinta Mountains and related deformation along the Uinta fault zone set the stage for development of the Palisades, it was erosion that revealed and shaped this spectacular feature.
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Cruden, D. M. "The shapes of cold, high mountains in sedimentary rocks." Geomorphology 55, no. 1-4 (September 2003): 249–61. http://dx.doi.org/10.1016/s0169-555x(03)00143-0.
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Mitchelmore, Marlene Dredge, and Frederick A. Cook. "Inversion of the Proterozoic Wernecke basin during tectonic development of the Racklan Orogen, northwest Canada." Canadian Journal of Earth Sciences 31, no. 3 (March 1, 1994): 447–57. http://dx.doi.org/10.1139/e94-041.
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New deep seismic reflection data coupled with regional stratigraphic correlations, drill-hole information, and potential field data are interpreted to provide images of Middle Proterozoic Wernecke Supergroup (meta-)sedimentary layers that were uplifted during tectonic development of the ca. 0.9–1.3 Ga Racklan Orogen in Canada's western Northwest Territories. The reflection data are located at the eastern front of the Mackenzie Mountains portion of the Canadian Cordillera and on the western flank of the Fort Simpson structural trend that is a prominent Proterozoic structure in the subsurface throughout the region. Along three parallel profiles, layers that are correlated with thick Wernecke Supergroup sedimentary rocks produce prominent reflections between about 3.0 and 9.0 s (about 7.5 and 23 km) that were arched prior to deposition of younger Proterozoic (probably Mackenzie Mountains Supergroup) and Phanerozoic sedimentary rocks. The strata are considered to be Wernecke basin sedimentary rocks that were uplifted during deformation associated with the development of the Racklan Orogen.
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Webb, Casey, Michael Jensen, Bart Kowallis, Eric Christiansen, Douglas Sprinkel, and Sam Hudson. "Stratigraphic relationships of the Eocene Duchesne River Formation and Oligocene Bishop Conglomerate, northeastern Utah—pulsed sedimentary response to rollback of the subducted Farallon slab." Geology of the Intermountain West 9 (September 14, 2022): 153–79. http://dx.doi.org/10.31711/giw.v9.pp153-179.
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The Uinta Mountains are an east-west-trending, reverse fault-bounded, basement-cored Laramide uplift. The Eocene Duchesne River Formation and Oligocene Bishop Conglomerate represent late stage, intermontane basin fill of the Uinta Basin in northeastern Utah. Detailed mapping (1:24,000 scale), clast counts in conglomerate beds, description of lithology and stratigraphic contacts, and radiometric dating of pyroclastic fall beds of the Duchesne River Formation and Bishop Conglomerate in the Vernal NW quadrangle in northeastern Utah reveal stratal geometries of middle Cenozoic depositional units, the uplift and unroofing history of the eastern Uinta Mountains, and give evidence for the pulsed termination of Laramide uplift related to rollback of the Farallon slab and lithospheric delamination. These relationships show the continuation of Laramide uplift in this region until after 37.9 Ma and before 34 Ma, an age younger than the previously reported 45 to 40 Ma. The Duchesne River Formation consists of four members: the Brennan Basin, Dry Gulch Creek, Lapoint, and the Starr Flat. A normal unroofing signal is found within the formation with a downward increase in Paleozoic clasts and an upward increase in Proterozoic clasts. The oldest member, the Brennan Basin Member contains 80% to 90% Paleozoic clasts and less than 20% Proterozoic clasts. Conglomerate beds in the progressively younger Dry Gulch Creek, Lapoint, and Starr Flat Members of the Duchesne River Formation show significant increases in Proterozoic clasts (34% to 73%) and a decrease in Paleozoic clasts (27% to 66%). The Bishop Conglomerate overlies the Duchesne River Formation, but shows no clear change in clast composition. In the Duchesne River Formation, the proportion of beds containing fine gravel to boulder-sized clasts decreases significantly with distance from the Uinta uplift, from almost 100% near the source (<0.5 km) to 50% to 20% to the south (10 km). The lower part of the Duchesne River Formation exhibits a fining upward sequence that may represent a lull in tectonic uplift. The fine-grained lithofacies of the Dry Gulch Creek and Lapoint Members of the Duchesne River Formation pinch out within about 1 to 2 km from the Uinta uplift. In this proximal region conglomerates equivalent in age to the Lapoint Member cannot be separated from the younger conglomerates of the Starr Flat Member and are mapped together as one unit. Where the fine-grained lithologies appear farther from the uplift, the Starr Flat Member conglomerates deposited above Lapoint Member siltstones represent a southward progradation of alluvial fans away from the uplifting mountain front. The Starr Flat Member is overlain by the Bishop Conglomerate. These units are similar in sedimentary structure and clast composition and are distinguished by an angular unconformity that developed after 37.9 Ma. Stratigraphic and structural relationships between the Duchesne River Formation and Bishop Conglomerate reveal evidence of at least three episodes of Laramide-age uplift of the Uinta Mountains during the deposition of these formations: (1) deposition of fining upward sequences beginning with a basal coarse-grained unit within the Brennan Basin, Dry Gulch Creek, and Lapoint Members; (2) progradation of alluvial fans to the south form the younger Starr Flat Member resulted from an increase in sediment supply likely associated with renewed uplift; and (3) tilting and truncation of Duchesne River Formation to form the Gilbert Peak erosional surface, and prograding alluvial fans of the Bishop Conglomerate. These episodes of pulsed uplift are possibly the result of dripping lithosphere that occurred during Farallon slab rollback. New 40Ar/39Ar ages of 39.4 Ma from ash beds in the Dry Gulch Creek and Lapoint Members emplaced from Farallon rollback volcanism help to constrain the timing of deposition and uplift. These new ages and other existing radiometric and faunal ages suggest a significant unconformity of as much as 4 m.y. between the Duchesne River Formation and the overlying Bishop Conglomerate, which rangesfrom 34 to 30 Ma in age and show that Laramide uplift continued after 40 Ma in this region.
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Li, Mo, Xiaobing Zhou, Christopher H. Gammons, Mohamed Khalil, and Marvin Speece. "Aeromagnetic and spectral expressions of rare earth element deposits in Gallinas Mountains area, Central New Mexico, USA." Interpretation 6, no. 4 (November 1, 2018): T937—T949. http://dx.doi.org/10.1190/int-2017-0199.1.
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The Gallinas Mountains, located at the junction of Lincoln and Torrance Counties, New Mexico, USA, are a series of alkaline volcanic rocks intruded into Permian sedimentary rocks. The Gallinas Mountains area hosts fluorite and copper as veins containing bastnäsite, whereas deposits of iron skarns and iron replacement are in the area as well. These deposits produce iron. In this study, the multispectral band-ratio method is used for surface mineral recognition, whereas 2D subsurface structure inversion modeling was applied to explore the depth extent of the magnetic ore distribution from aeromagnetic data. Bastnäsite has higher magnetic susceptibility (0.009 SI) than the host rocks and surrounding sedimentary rock. The bastnäsite and iron oxides (magnetite + hematite) can contribute to a positive aeromagnetic anomaly. Results indicate that (1) the positive magnetic anomaly observed at Gallinas Mountains area can be accounted for by a mixture of bastnäsite and iron oxides at a depth of approximately 400 m and a thickness of approximately 13–15 m. The surface of this area is dominated by the hydrothermal alteration associated with iron oxides over the trachyte intrusions as detected by Landsat 8 band-ratio imaging.
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Friedman, R. M., J. W. H. Monger, and H. W. Tipper. "Age of the Bowen Island Group, southwestern Coast Mountains, British Columbia." Canadian Journal of Earth Sciences 27, no. 11 (November 1, 1990): 1456–61. http://dx.doi.org/10.1139/e90-154.
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A new U–Pb date of [Formula: see text] for foliated felsic metavolcanic rocks of the Bowen Island Group, from Mount Elphinstone in the southwesternmost Coast Mountains of British Columbia, indicates that there the age of this hitherto undated unit is early Middle Jurassic. These rocks grade along strike to the north-northwest into a more sedimentary facies, which north of Jervis Inlet contains a probable Sinemurian (Lower Jurassic) ammonite. The Bowen Island Group thus appears to include Lower and Middle Jurassic rocks and to be coeval in part with volcanic rocks of the Bonanza Formation on Vancouver Island to the west and the Harrison Lake Formation within the central Coast Mountains 75 km to the east.
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Buczyński, Sebastian. "Temporal variability of springs in catchment areas located in the Sudeten Mountains." Hydrology Research 49, no. 3 (November 9, 2017): 780–93. http://dx.doi.org/10.2166/nh.2017.229.
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Abstract This paper describes the results of research into the freshwater springs occurring in the crystalline and compact sedimentary rocks in the Sudeten Mountains. The research consisted of three series of measurements taken in the hydrological year 2013 in four test catchments (Machowski Stream, Inflow at the foot of Mount Grodziec, Podgórna, Mostowy Stream). Data analysis indicated that the number of springs, spring discharge and physicochemical properties of the water were subject to significant temporal variation. The temporal variability of the spring density index ranged from 7 to 31%. Temporal variations in the total yield of the springs fluctuated between 34 and 63% and the minimum discharge variability index exceeded 100%. The study indicated that water flow in areas consisting of compact sedimentary rocks such as sandstone and marl is much more diffuse than in areas that are comprised primarily of crystalline rocks, which accounts for a lower yield and a decrease in temporal spring discharge variability. In areas made up of crystalline rocks, the higher yield and the higher spring discharge variability index point to cracks and fissures as the main recharge component, a feature characteristic of aquifers with high conductivity and low storage capacities.
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Chidsey, Thomas, David Eby, and Douglas Sprinkel. "A Breccia Pipe in the Deseret Limestone, South Flank of the Uinta Mountains, Northern Utah." Geosites 1 (March 11, 2020): 1–10. http://dx.doi.org/10.31711/geosites.v1i1.55.
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A breccia pipe is a cylindrical- or irregular-shaped mass of brecciated rock. A breccia consists of broken, angular fragments of rock cemented together by a fine-grained matrix. Hydrothermal breccia pipes form when hydrothermal solutions force their way towards the surface through zones of weakness or fracture zones and naturally break up the rocks in the process, i.e., hydrofracturing; breccia pipes can also form by collapse. Hydrothermal breccia pipes can contain ore deposits and, as will be discussed later, are associated with some large oil and gas accumulations in southeastern Utah.
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WANG, JIALIN, CHAODONG WU, ZHUANG LI, WEN ZHU, TIANQI ZHOU, JUN WU, and JUN WANG. "The tectonic evolution of the Bogda region from Late Carboniferous to Triassic time: evidence from detrital zircon U–Pb geochronology and sandstone petrography." Geological Magazine 155, no. 5 (January 16, 2017): 1063–88. http://dx.doi.org/10.1017/s0016756816001217.
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AbstractField-based mapping, sandstone petrology, palaeocurrent measurements and zircon cathodoluminescence images, as well as detrital zircon U–Pb geochronology were integrated to investigate the provenance of the Upper Carboniferous – Upper Triassic sedimentary rocks from the northern Bogda Mountains, and further to constrain their tectonic evolution. Variations in sandstone composition suggest that the Upper Carboniferous – Lower Triassic sediments displayed less sedimentary recycling than the Middle–Upper Triassic sediments. U–Pb isotopic dating using the LA-ICP-MS method on zircons from 12 sandstones exhibited similar zircon U–Pb age distribution patterns with major age groups at 360–320 Ma and 320–300 Ma, and with some grains giving ages of > 541 Ma, 541–360 Ma, 300–250 Ma and 250–200 Ma. Coupled with the compiled palaeocurrent data, the predominant sources were the Late Carboniferous volcanic rocks of the North Tianshan and Palaeozoic magmatic rocks of the Yili–Central Tianshan. There was also input from the Bogda Mountains in Middle–Late Triassic time. The comprehensive geological evidence indicates that the Upper Carboniferous – Lower Permian strata were probably deposited in an extensional context which was related to a rift or post-collision rather than arc-related setting. Conspicuously, the large range of U–Pb ages of the detrital zircons, increased sedimentary lithic fragments, fluvial deposits and contemporaneous Triassic zircon ages argue for a Middle–Late Triassic orogenic movement, which was considered to be the initial uplift of the Bogda Mountains.
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Scharf, Andreas, Frank Mattern, Mohammed Al-Wardi, Gianluca Frijia, Daniel Moraetis, Bernhard Pracejus, Wilfried Bauer, and Ivan Callegari. "Chapter 4 Large-scale structure of the study area." Geological Society, London, Memoirs 54, no. 1 (2021): 61–66. http://dx.doi.org/10.1144/m54.4.
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AbstractThe Southeastern Oman Mountains are dominated by two major culminations: the Jabal Akhdar and Saih Hatat domes, surrounded by allochthonous and/or neo-autochthonous rocks. In the cores of both domes, folded autochthonous and par-autochthonous pre-Permian metasedimentary rocks are exposed, subjacent to the ‘Hercynian’ Unconformity. Above the unconformity are Permo--Mesozoic shelfal sedimentary rocks, characterized by carbonates. These sedimentary rocks were openly folded. The open folds are large-scale elongate structures that define the shapes of both domes. The main elongation direction is NW--SE. Doming is syn- to post-obductional. Most margins of the domes are marked by major post-obductional, extensional faults. Reactivated basement faults along the eastern margin of the Jabal Akhdar Dome may be responsible for the straight NNE-striking eastern margin which is perpendicular to the main elongation direction of the domes. The deep structure of both domes is poorly known. However, the Moho depth below the centre of the Jabal Akhdar Dome is at 50 km. We present a geological map of both domes, depicting the main faults and folds, and schematic cross-sections, parallel and perpendicular to the Oman Mountains.
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Patchett, P. J., G. E. Gehrels, and C. E. Isachsen. "Nd isotopic characteristics of metamorphic and plutonic rocks of the Coast Mountains near Prince Rupert, British Columbia." Canadian Journal of Earth Sciences 35, no. 5 (May 1, 1998): 556–61. http://dx.doi.org/10.1139/e98-007.
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Nd isotopic data are presented for a suite of metamorphic and plutonic rocks from a traverse across the Coast Mountains between Terrace and Prince Rupert, British Columbia, and for three contrasting batholiths in the Omineca Belt of southern Yukon. A presumed metamorphic equivalent of Jurassic volcanic rocks of the Stikine terrane gives epsilon Nd = +6, and a number of other metaigneous and metasedimentary rocks in the core of the Coast Mountains give epsilon Nd values from +3 to +7. A single metasedimentary rock approximately 3 km east of the Work Channel shear zone gives a epsilon Nd value of -9. Coast Belt plutons in the traverse yield epsilon Nd from -1 to +2. The Omineca Belt plutons give epsilon Nd from -10 to -17. All results are consistent with published data in demonstrating that (i) juvenile origins for both igneous and metamorphic rocks are common in the Coast Belt; (ii) representatives of a continental-margin sedimentary sequence with Precambrian crustal Nd are tectonically interleaved in the Coast Mountains; (iii) Coast Mountains plutons can be interpreted as derived from a blend of metamorphic rocks like those seen at the surface, or as arc-type melts contaminated with the older crustal component; and (iv) Omineca Belt plutons are dominated by remelted Precambrian crustal rocks.
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Stephenson, A. L., G. D. Spence, K. Wang, J. A. Hole, K. C. Miller, R. M. Clowes, S. H. Harder, and G. M. Kaip. "Crustal velocity structure of the southern Nechako basin, British Columbia, from wide-angle seismic traveltime inversion1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia." Canadian Journal of Earth Sciences 48, no. 6 (June 2011): 1050–63. http://dx.doi.org/10.1139/e11-006.
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In the BATHOLITHSonland seismic project, a refraction – wide-angle reflection survey was shot in 2009 across the Coast Mountains and Interior Plateau of central British Columbia. Part of the seismic profile crossed the Nechako Basin, a Jurassic–Cretaceous basin with potential for hydrocarbons within sedimentary strata that underlies widespread volcanic rocks. Along this 205 km-long line segment, eight large explosive shots were fired into 980 seismometers. Forward and inverse modelling of the traveltime data were conducted with two independent methods: ray-tracing based modelling of first and secondary arrivals, and a higher resolution wavefront-based first-arrival seismic tomography. Material with velocities less than 5.0 km/s is interpreted as sedimentary rocks of the Nechako Basin, while velocities from 5.0–6.0 km/s may correspond to interlayered sedimentary and volcanic rocks. The greatest thickness of sedimentary rocks in the basin is found in the central 110 km of the profile. Two sub-basins were identified in this region, with widths of 20–50 km and maximum sedimentary depths of 2.5 and 3.3 km. Such features are well-defined in the velocity model, since resolution tests indicate that features with widths greater than ∼13 km are reliable. Beneath the sedimentary rocks, seismic velocities increase more slowly with depth — from 6.0 km/s just below the basin to 6.3 km/s at ∼17 km in depth, and then to 6.8–7.0 km/s at the base of the crust. The Moho is found at a depth of 33.5–35 km beneath the profile, and mantle velocities are high at 8.05–8.10 km/s.
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Aalto, K. R. "Hermann Karsten, pioneer of geologic mapping in northwestern South America." History of Geo- and Space Sciences 6, no. 1 (June 25, 2015): 57–63. http://dx.doi.org/10.5194/hgss-6-57-2015.
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Abstract. In the late 19th century, a regional map of Nueva Granada (present-day Colombia, Panama and parts of Venezuela and Ecuador) was published by German botanist and geologist Hermann Karsten (1817–1908). Karsten's work was incorporated by Agustín Codazzi (1793–1859), an Italian who emigrated to Venezuela and Colombia to serve as a government cartographer and geographer, in his popular Atlas geográfico e histórico de la Republica de Colombia (1889). Geologic mapping and most observations provided in this 1889 atlas were taken from Karsten's Géologie de l'ancienne Colombie bolivarienne: Vénézuela, Nouvelle-Grenade et Ecuador (1886), as cited by Manual Paz and/or Felipe Pérez, who edited this edition of the atlas. Karsten defined four epochs in Earth history: Primera – without life – primary crystalline rocks, Segunda – with only marine life – chiefly sedimentary rocks, Tercera – with terrestrial quadrupeds and fresh water life forms life – chiefly sedimentary rocks, and Cuarta – mankind appears, includes diluvial (glacigenic) and post-diluvial terranes. He noted that Colombia is composed of chiefly of Quaternary, Tertiary and Cretaceous plutonic, volcanic and sedimentary rocks, and that Earth's internal heat (calor central) accounted, by escape of inner gases, for volcanism, seismicity and uplift of mountains. Karsten's regional mapping and interpretation thus constitutes the primary source and ultimate pioneering geologic research.
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Mair, David, Alessandro Lechmann, Marco Herwegh, Lukas Nibourel, and Fritz Schlunegger. "Linking Alpine deformation in the Aar Massif basement and its cover units – the case of the Jungfrau–Eiger mountains (Central Alps, Switzerland)." Solid Earth 9, no. 5 (September 25, 2018): 1099–122. http://dx.doi.org/10.5194/se-9-1099-2018.
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Abstract. The northwest (NW) rim of the external Aar Massif was exhumed from ∼ 10 km depth to its present position at 4 km elevation above sea level during several Alpine deformation stages. Different models have been proposed for the timing and nature of these stages. Recently proposed exhumation models for the central, internal Aar Massif differ from the ones established in the covering Helvetic sedimentary units. By updating pre-existing maps and collecting structural data, a structural map and tectonic section were reconstructed. Those were interpreted together with microstructural data and peak metamorphic temperature estimates from collected samples to establish a framework suitable for both basement and cover. Deformation temperatures range between 250 and 330 °C, allowing for semi-brittle deformation in the basement rocks, while the calcite-dominated sedimentary rocks deform in a ductile manner at these conditions. Although field data allow to distinguish multiple deformation stages before and during Aar Massif's exhumation, all related structures formed under similar P, T conditions at the investigated NW rim. In particular, we find that the exhumation occurred during two stages of shearing in Aar Massif's basement, which induced in the sedimentary rocks first a phase of folding and then a period of thrusting, accompanied by the formation of a new foliation.
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Talarico, F. M., D. Pace, and R. H. Levy. "Provenance of basement erratics in Quaternary coastal moraines, southern McMurdo Sound, and implications for the source of Eocene sedimentary rocks." Antarctic Science 25, no. 5 (March 12, 2013): 681–95. http://dx.doi.org/10.1017/s0954102013000072.
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AbstractThis paper summarizes fieldwork conducted in 2007 and presents results of petrographical analyses of basement rocks that occur along with fossil-rich Eocene sedimentary erratics in moraines along the north-east flank of Mount Discovery in southern McMurdo Sound. The Eocene rocks are significant as they provide a rare glimpse into greenhouse environments at high southern latitudes. Basement erratics recovered from the moraines are petrographically similar to metamorphic and igneous rocks exposed in the Transantarctic Mountains at locations between the Carlyon and Skelton glaciers and/or within the drainage catchments of Mulock and Skelton glaciers. These new clast provenance data imply that the Eocene sedimentary erratics are most likely derived from outcrops that are currently located beneath the Ross Ice Shelf south and/or immediately east of Minna Bluff. The suite of basement and sedimentary erratics were transported to their present location by ice that flowed north-eastwards from the Skelton-Mulock region and was pushed westwards into southern McMurdo Sound by grounded ice flowing north from West Antarctica. Results from this study support prior reconstructions of ice flow during peak glacial intervals during the Miocene–Pleistocene including the Last Glacial Maximum.
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Bustin, Amanda M. M., Ron M. Clowes, James W. H. Monger, and J. Murray Journeay. "The southern Coast Mountains, British Columbia: New interpretations from geological, seismic reflection, and gravity data." Canadian Journal of Earth Sciences 50, no. 10 (October 2013): 1033–50. http://dx.doi.org/10.1139/cjes-2012-0122.
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The southern Coast Mountains of British Columbia are characterized by voluminous plutonic and gneissic rocks of mainly Middle Jurassic to Eocene age (the Coast Plutonic Complex), as well as metamorphic rocks, folds, and thrust and reverse faults that mostly diverge eastward and westward from an axis within the present mountains, and by more localized Eocene and younger normal faults. In the southeastern Coast Mountains, mid-Cretaceous and younger plutons intrude Bridge River, Cadwallader, and Methow terranes and overlap Middle Jurassic through Early Cretaceous marine clastic rocks of the Tyaughton–Methow basin. The combination of geological data with new or reanalyzed geophysical data originating from Lithoprobe and related studies enables revised structural interpretations to be made to 20 km depth. Five seismic profiles show very cut-up and chaotic reflectivity that probably represents slices and segments of different deformed and rearranged rock assemblages. Surface geology, seismic interpretations, physical properties, and gravity data are combined in two profiles across the Coast Mountains to generate two new 2-D density models that are interpreted in terms of the geological units. The western part of the southern Coast Mountains consists primarily of Jurassic to mid-Cretaceous plutons to depths of 20 km with slices of Wrangellia (in the west) and Early Cretaceous volcanic and sedimentary rocks (Gambier group) in the upper 10 km. The eastern part, east of the Owl Creek fault, consists of slices of Cadwallader and Bridge River terranes and Tyaughton–Methow basin strata with limited slices of plutonic rocks at depths less than 10 km. Below that, Eocene and Late Cretaceous plutons dominate for another 10 km.
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Mitrovič-Petrovič, Jovanka, and Vladan Radulović. "Mesozoic sections of biostratigraphic and plalaeontological importance in the Stara Planina Mountains." Geologica Balcanica 26, no. 2 (June 30, 1996): 45–50. http://dx.doi.org/10.52321/geolbalc.26.2.45.
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The Stara Planina Mountains includes sedimentary rocks of different age, beginning with the Proterozoic and ending with the Plio-Quaternary. Most widespread are Mesozoic rock which are highly fossiliferous. The abundant fossil fauna was used in identifying the presence of all Triassic, Jurassic and Cretaceous stages. Most instructive sections with the three systems are presented, which in our opinion should be protected. Noteworthy is the traceable continuous transition from one stage to another within a relatively small area.
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Farahi, Farzaneh, Saeed Taki, and Mojgan Salavati. "Mineral chemistry and geothermobarometry of gabbroic rocks from the Gysel area, Alborz mountains, north Iran." Nexo Revista Científica 33, no. 02 (December 31, 2020): 392–408. http://dx.doi.org/10.5377/nexo.v33i02.10779.
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The gabbroic rocks in the Gysel area of the Central Alborz Mountains in north Iran are intruded into the Eocene Volcano-sedimentary units. The main gabbroic rocks varieties include gabbro porphyry, olivine gabbro, olivine dolerite and olivine monzo-gabbro. The main minerals phases in the rocks are plagioclase and pyroxene and the chief textures are sub-hedral granular, trachytoidic, porphyritic, intergranular and poikilitic. Electron microprobe analyses on minerals in the rock samples shows that plagioclase composition ranges from labradorite to bytonite, with oscillatory and normal chemical zonings. Clinopyroxene is augite and orthopyroxene is hypersthene to ferro-hypersthene. Thermometry calculations indicate temperatures of 650˚C to 750˚C for plagioclase crystallization and 950˚C to 1130˚C for pyroxene crystallization. Clinopyroxene chemistry reveals sub-alkaline and calc-alkaline nature for the parental magma emplaced in a volcanic arc setting.
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Vďačný, Marek, and Peter Bačík. "Provenance of the Permian Malužiná Formation sandstones (Malé Karpaty Mountains, Western Carpathians): evidence of garnet and tourmaline mineral chemistry." Geologica Carpathica 66, no. 2 (April 1, 2015): 83–97. http://dx.doi.org/10.1515/geoca-2015-0012.
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Abstract The chemistry of detrital garnets (almandine; spessartine-, grossular-, and pyrope-rich almandine; andradite) and mostly dravitic tourmalines from three sandstone samples of the Permian Malužiná Formation in the northern part of the Malé Karpaty Mts (Western Carpathians, SW Slovakia) reveals a great variability of potential source rocks. They comprise (1) low-grade regionally metamorphosed rocks (metacherts, blue schists, metapelites and metapsammites), (2) contact-thermal metamorphic calcareous rocks (skarns or rodingites), (3) garnet-bearing mica schists and gneisses resulting from the regional metamorphism of argillaceous sediments, (4) amphibolites and metabasic sub-ophiolitic rocks, (5) granulites, (6) Li-poor granites and their associated pegmatites and aplites as well as (7) rhyolites. Consequently, the post-Variscan, rift-related sedimentary basin of the Malužiná Formation originated in the vicinity of a low- to high-grade crystalline basement with granitic rocks. Such lithological types of metamorphic and magmatic rocks are characteristic for the Variscan terranes of the Central Western Carpathians (Tatricum and Veporicum Superunits).
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Rostovceva, J. I., A. N. Stafeev, T. V. Sukhanova, I. V. Latysheva, and V. L. Kosorukov. "Upper Bajocian of the Crimean Mountains: Paleogeography and sedimentary conditions based on palynological data." Moscow University Bulletin. Series 4. Geology, no. 3 (June 28, 2016): 3–10. http://dx.doi.org/10.33623/0579-9406-2016-3-3-10.
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The reconstruction of the sedimentation conditions and insular land landscapes on the site of modern Crimean Mountains for the Late Bajocian based on spore-pollen data, the mineral composition of clay rocks, textures and facies analysis and general paleogeographic analysis.It is shown that sublatitudinally elongated insular land had a width 30 km, the height not more than 1 km, steep northern slopes with mudflows and low-angle southern slopes with extensive river system.
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Pandita, Hita, Sukartono Sukartono, and Agustinus Isjudarto. "Geological Identification of Seismic Source at Opak Fault Based on Stratigraphic Sections of the Southern Mountains." Forum Geografi 30, no. 1 (August 3, 2016): 77. http://dx.doi.org/10.23917/forgeo.v30i1.1508.
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Earthquake is one of the unpredicted natural disasters on our earth. Despite of the absence of high-accuracy method to precisely predict the occurrence of earthquake, numerous studies have been carried out by seismologists to find it. One of the efforts to address the vulnerability of a region to earthquakes is by recognizing the type of rock as the source of the earthquake. Opak Fault is an active fault which was thought to be the source of earthquakes in Yogyakarta and adjacent areas. This study aimed to determine the seismic source types of rocks in Yogyakarta and adjacent areas. The methods were by measuring stratigraphic sections and the layer thickness in the western part of Southern Mountains. Field study was done in 6 (six) research sites. Results of stratigraphic measurement indicated the sedimentary rocks in the Southern Mountains was 3.823 km in thick, while the bedrock was more than 1.042 km in thick. Based on the result, the rock types as the seismic source were thought to originate from the continental crust rocks formed of granite and metamorphic complex.
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Osika, Aleksandra, Małgorzata Wistuba, and Ireneusz Malik. "Relief evolution of landslide slopes in the Kamienne Mts (Central Sudetes, Poland) – analysis of a high-resolution DEM from airborne LiDAR." Contemporary Trends in Geoscience 7, no. 1 (June 1, 2018): 1–20. http://dx.doi.org/10.2478/ctg-2018-0001.
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Abstract The aim of the study is to reconstruct the development of landslide relief in the Kamienne Mountains (Central Sudetes, SW Poland) based on a DEM from LiDAR data. Analyses of relief and geological maps in ArcGIS 10.5 and of slope cross-sections in Surfer 14 allowed to distinguish different types of landslide relief, developed in latites and trachybasalts lying above claystones and mudstones. The types vary from small, poorly visible landslides to vast landslides with complex relief. They were interpreted as consecutive stages of geomorphic evolution of hillslope-valley topography of the study area. Two main schemes have been established which explain the development of landslide slopes in the Kamienne Mts: (1) upslope, from the base of the slope towards the mountain ridge and (2) downslope, beginning on the top of the mountain ridge. The direction of landslide development depends on the thickness of volcanic rocks in relation to underlying sedimentary rocks. When the latter appear only in the lowest part of the slope, landslides develop upslope. If sedimentary rocks dominate on the slope and volcanic rocks form only its uppermost part, landslides develop downslope. The results show that landsliding leads to significant modifications of relief of the study area, including complete degradation of mountain ridges.
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Alexeev, N. L., V. A. Maslov, V. D. Kaminsky, V. S. Semenov, E. S. Bogomolov, I. N. Kapitonov, N. A. Gonzhurov, A. Yu Melnik, and M. S. Yegorov. "New data on the age of metamorphic rocks from the granite-greenstone ruker terrane (the southern Prince Charles Mountains, East Antarctica)." Доклады Академии наук 487, no. 6 (September 10, 2019): 644–49. http://dx.doi.org/10.31857/s0869-56524876644-649.
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Paper presents results of isotope studies of primary igneous and sedimentary rocks of Mawson and Menzies series from the southern Prince Charles Mountains, East Antarctica. Obtained data show that igneous protholith crystallization of Mawson orthogneiss occurred at 3164,2±9,2-3163,2±7,8 Ma ago. The Mawson orthogneiss were a basement for Menzies series sediment. The maximum time of sediment deposition is estimated to be in the range of 3,0-3,1 Ga. Sediment protholith involves an admixture of Paleoarchean material.
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Pletnev, S. P. "MAIN TYPES OF APTIAN-CENOMANIAN SEDIMENTARY ROCKS ON GUYOTS OF THE MAGELLAN MOUNTAINS, PACIFIC OCEAN." Tikhookeanskaya Geologiya 38, no. 5 (2019): 45–55. http://dx.doi.org/10.30911/0207-4028-2019-38-5-45-55.
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Pletnev, S. P. "Main Types of Aptian–Cenomanian Sedimentary Rocks on Guyots of the Magellan Mountains, Pacific Ocean." Russian Journal of Pacific Geology 13, no. 5 (September 2019): 436–45. http://dx.doi.org/10.1134/s1819714019050087.
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Jackson, Marie D., and David D. Pollard. "Flexure and faulting of sedimentary host rocks during growth of igneous domes, Henry Mountains, Utah." Journal of Structural Geology 12, no. 2 (January 1990): 185–206. http://dx.doi.org/10.1016/0191-8141(90)90004-i.
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Zhang, Xuebing, Fengmei Chai, Chuan Chen, Hongyan Quan, and Xiaoping Gong. "Geochronology, geochemistry and tectonic implications of late Carboniferous Daheyan intrusions from the Bogda Mountains, eastern Tianshan." Geological Magazine 157, no. 2 (July 29, 2019): 289–306. http://dx.doi.org/10.1017/s001675681900075x.
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AbstractThe Daheyan region, situated in the SW of the Bogda Mountains in eastern Tianshan, is important for understanding the accretionary history of the Central Asian Orogenic Belt. We investigated Carboniferous intrusions from the Daheyan area, SW Bogda Mountains, obtaining new zircon U–Pb ages, whole-rock geochemical data and Hf isotope data for these intrusions. Zircon U–Pb dating indicates that syenogranite, diorite, granodiorite and monzonite of the Daheyan intrusions were all formed during late Carboniferous (311–303 Ma) magmatism. The syenogranite has geochemical characteristics of A-type granites that were mainly sourced from melting of juvenile crust. In comparison, the low-Mg-number diorite intrusion, with tholeiite and metaluminous features, was derived from young crust and mixed some mantle materials. The granodiorite and monzonite are both I-type granites, and are both sourced from the melting of juvenile crust. Based on a comprehensive analysis of previous geochronological, geochemical and isotopic data of magmatic and sedimentary rocks in the Bogda–Harlik belt, we consider that late Carboniferous intrusive rocks of the Bogda Mountains formed in an intra-arc extension related to a continent-based arc setting.
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Scharf, Andreas, Frank Mattern, Mohammed Al-Wardi, Gianluca Frijia, Daniel Moraetis, Bernhard Pracejus, Wilfried Bauer, and Ivan Callegari. "Chapter 2 Tectonostratigraphy of the eastern part of the Oman Mountains." Geological Society, London, Memoirs 54, no. 1 (2021): 11–47. http://dx.doi.org/10.1144/m54.2.
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AbstractThis chapter provides comprehensive descriptions of 52 numbered formations/rock units of the Southeastern Oman Mountains, based on available literature. The oldest eight siliciclastic and carbonate formations are positioned below the ‘Hercynian’ Unconformity. The overlying formation (9–16) mostly represent carbonates which accumulated in a passive margin platform setting during or after the opening of the Neo-Tethys Ocean. The passive margin slope and platform collapsed during the late Cretaceous because of the obduction of the Semail Ophiolite along with the deep marine Hawasina sedimentary rocks. The collapsing passive margin interval was recorded within the syn-obductional Aruma Group (17; Muti Formation). Above this formation are the allochthonous units (18–42) of the tectonically lower Hawasina deep-sea basin and the structurally overlying Semail Ophiolite. The former contains Permian to Upper Cretaceous formations, while the latter is Cenomanian in age. Above the allochthonous rocks, the Neo-autochthonous formations were deposited, starting with the post-obductional uppermost Cretaceous Aruma Group (43; Al-Khod Formation) until the Quaternary deposits (52). All these formations/rock units are depicted on an accompanying map and stratigraphic chart.
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Kusumayudha, Sari Bahagiarti, and Heru Sigit Purwanto. "Enormous Mass Movements, and Gravitational Tectonics Model of the North Serayu Mountains, Karangkobar Area, Banjarnegara Regency, Central Java, Indonesia." International Journal of Geology and Earth Sciences 6, no. 1 (March 2020): 1–8. http://dx.doi.org/10.18178/ijges.6.1.1-8.
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North Serayu Mountains in the Central Java province, Indonesia, stretches with west - east axis, bordered by Slamet volcano to the Bogor Mountains in the west, and delimited by Ungaran volcano to the Kendeng Mountains in the east. In the north of these mountains there is coastal alluvial plain of Java, and in the south there is a depression zone of River Serayu. Overall geomorphostructures of the North Serayu Mountains form a faulted anticlinorium, which one of its flank relatively dipping to the south. In the bottom part of this ranges are such plastic, clastic, clayey sedimentary rocks, Eocene to Miocene aged. While at the upper portion there is a group of elastic, brittle, massive volcanic rocks, andesitic to basaltic composition, Pliocene to Pleistocene aged. A volcano, called Rogo Jembangan stands over the top of the North Serayu anticlinorium, with two of its eccentric cones, namely Mount Telagalele and Mount Pawinihan, situated in the Karangkobar District. North Serayu anticlinorium with a plastic bedrock, which is overlain by elastic, hard, and heavy rock has created such a tectonic model influenced by gravity. Parts of volcano’s body and volcanic rocks blocks in the Banjarnegara Regency area generally move slowly but surely southward over a giant slip plane in the form of orographic fields. Locally, this gravitational tectonic is manifested as mass slides, glides, and creeps, occur any time in the study area. Orogenetics of the North Serayu Mountains is still on going in line with the active tectonism of the Java island, caused by subduction of Indian-Australian plate beneath the Eurasian plate. As long as that is the case, gravitational tectonic will continue to run, and mass movements in the research area will regenerate to happen.
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Adams, C. J., J. D. Bradshaw, and T. R. Ireland. "Provenance connections between late Neoproterozoic and early Palaeozoic sedimentary basins of the Ross Sea region, Antarctica, south-east Australia and southern Zealandia." Antarctic Science 26, no. 2 (July 18, 2013): 173–82. http://dx.doi.org/10.1017/s0954102013000461.
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AbstractThick successions of turbidites are widespread in the Ross–Delamerian and Lachlan orogens and are now dispersed through Australia, Antarctica and New Zealand. U-Pb detrital zircon age patterns for latest Precambrian, Cambrian and Ordovician metagreywackes show a closely related provenance. The latest Neoproterozoic–early Palaeozoic sedimentary rocks have major components, at c. 525, 550, and 595 Ma, i.e. about 40–80 million years older than deposition. Zircons in these components increase from the Neoproterozoic to Ordovician. Late Mesoproterozoic age components, 1030 and 1070 Ma, probably originate from igneous/metamorphic rocks in the Gondwanaland hinterland whose exact locations are unknown. Although small, the youngest zircon age components are coincident with estimated depositional ages suggesting that they reflect contemporaneous and minor, volcanic sources. Overall, the detrital zircon provenance patterns reflect the development of plutonic/metamorphic complexes of the Ross–Delamerian Orogen in the Transantarctic Mountains and southern Australia that, upon exhumation, supplied sediment to regional scale basin(s) at the Gondwana margin. Tasmanian detrital zircon age patterns differ from those seen in intra-Ross Orogen sandstones of northern Victoria Land and from the oldest metasediments in the Transantarctic Mountains. A comparison with rocks from the latter supports an allochthonous western Tasmania model and amalgamation with Australia in late Cambrian time.
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Arne, Dennis C. "Phanerozoic exhumation history of northern Prince Charles Mountains (East Antarctica)." Antarctic Science 6, no. 1 (March 1994): 69–84. http://dx.doi.org/10.1017/s0954102094000106.
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Apatite fission-track data from samples of Precambrian basement, Late Permian Triassic sedimentary rocks and inferred Cretaceous intrusive bodies are used to constrain the low-temperature (i.e. sub ~110°C) thermal history of the northern Prince Charles Mountains, East Antarctica. Two discrete phases of cooling have been identified, both of which are attributed to regional exhumation associated with rifting episodes. A phase of late Palaeozoic cooling, that began during the Carboniferous, is inferred to have been associated with the initial formation of the Lambert Graben. A more recent phase of cooling was initiated during the Early Cretaceous and is estimated to have locally involved the removal of at least 2 km of material using an assumed palaeotemperature gradient of ~25°C km−1 at the time of cooling. This latter phase of exhumation was closely accompanied by the emplacement of a variety of mafic alkaline rocks at ambient palaeotemperatures less than ~60°C and was probably related to renewed extension of the Lambert Graben during the break-up of eastern Gondwana. The results of this study suggest that final exhumation of high-grade Precambrian basement of the northern Price Charles Mountains was largely controlled by Phanerozoic rifting events.
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Korinevsky, V. G., and E. V. Korinevsky. "Isotopic evidences of magmatic nature of the dolomite-calcite bodies of the Ilmeny Mountains and the Plastovsky district of the South Urals." Vestnik of Geosciences 11 (2020): 3–19. http://dx.doi.org/10.19110/geov.2020.11.1.
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The data obtained for the first time on the isotopic composition of oxygen and carbon of calcites and graphites of dolomitecalcite rocks of the Ilmeny Mountains and dykes of a similar composition in the Plastovsky district have confirmed their magmatic genesis. The temperature of formation of carbonate bodies (590—1000 °Ñ), determined from the isotopic ratios of C and O in calcite and graphite, corresponds to the temperature range (600—900 °Ñ) of the formation of carbonatite associations. According to the same ratios of isotopes in calcites, the protoliths of carbonate rocks are located within the carbonatite fields of the folded regions and in the transition zone to carbonates of marine origin. This is probably due to the fact that these rocks are a product of carbonate magma during remelting of sedimentary carbonate rocks in subduction zones, or under the influence of the heat of granite intrusions.
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Jiang, Yong. "Middle-Late Jurassic chronology and source-to-sink system of the Sikeshu section in the southern margin of the Junggar Basin, Xinjiang." Advances in Engineering Technology Research 3, no. 1 (November 8, 2022): 133. http://dx.doi.org/10.56028/aetr.3.1.133.
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With the improvement of isotopic testing technology, high-precision dating methods such as SHRIMP or LA-ICP-MS of detrital zircon have been used to analyze and infer the formation age of sedimentary basins, the source of detrital materials, and the tectonic background of the formation and widely used. The LA-ICP-MS zircon U-Pb dating method was used to study the detrital zircon in the Middle-Late Jurassic sandstone in the Sikeshu section of the southern margin of the Junggar Basin, Xinjiang. The results show that the detrital zircon ages are mainly 270~447Ma,240~440Ma,245~432Ma, and 286~360Ma. There are also several ancient zircon ages, mainly 945~1080Ma. Combined with zircon mineralogical characteristics, CL images, Th/U ratio, sandstone petrographic characteristics, and regional chronological data, the primary provenance of the Middle-Late Jurassic sandstone is mainly from the Yilinghabilga Mountains in the North Tianshan, and Carboniferous-Permian volcanic rocks, pyroclastic rocks and Carboniferous granites exposed in the Borokonu Mountains of the Central Tianshan Mountains. By comparing the age changes between the four sampling points, the change process of the North Tianshan-Middle Tianshan source-sink system is obtained. From west to east, the upper Devonian glutamate, the Middle Devonian carbonate, and the large granite bodies of the Carboniferous series constituted the early watershed. From the middle to late period of the Toutunhe Formation to the Xishanyao Formation, from east to west, the Cambrian and Silurian carbonate rocks and the large granites and other rocks formed the late water line.
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Isava, V., M. Grove, J. B. Mahoney, and J. W. Haggart. "Testing local and extraregional sediment sources for the Late Cretaceous northern Nanaimo basin, British Columbia, using 40Ar/39Ar detrital K-feldspar thermochronology." Geosphere 17, no. 6 (November 8, 2021): 2234–61. http://dx.doi.org/10.1130/ges02395.1.
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Abstract Detrital K-feldspar 40Ar/39Ar thermochronology was conducted on clastic sedimentary rock samples collected from northern exposures of the Upper Cretaceous Nanaimo Group on Vancouver Island and adjacent Gulf Islands of British Columbia to constrain the denudation history of the local Coast Mountains batholith source region and determine the origin of extraregional sediment supplied to the basin. Strata of the northern Nanaimo Group deposited between 86 and 83 Ma (Comox and Extension formations) exhibit a 130–85 Ma age distribution of detrital K-feldspar 40Ar/39Ar ages that lack age maxima. These are interpreted to have been sourced from the southwestern Coast Mountains batholith. Younger strata deposited between 83 and 72 Ma (Cedar District and De Courcy formations) yield a broader age range (150–85 Ma) with an age maximum near the depositional age. These results indicate focused denudation of deeper-seated rocks east of the Harrison Lake fault. The youngest units deposited after 72 Ma (Geoffrey, Spray, and Gabriola formations) primarily yield younger than 75 Ma detrital K-feldspar ages with pronounced age maxima near the depositional age. This sediment was sourced extraregionally relative to the Coast Mountains batholith. We sought to constrain the origin of the extraregional sediment by measuring the thermal histories of 74 samples of basement rocks from throughout the Pacific Northwest, and by compiling a database of over 2400 biotite 40Ar/39Ar and K/Ar cooling ages from predominantly Cretaceous batholiths along the western North American margin. This analysis focused upon two previously proposed source regions: the Idaho batholith and the Mojave-Salina margin of southern California. The Nanaimo detrital K-feldspar 40Ar/39Ar age distributions favor the peraluminous Late Cretaceous Idaho batholith and its Proterozoic Belt-Purcell Supergroup sedimentary wall rock as the more likely source of the extraregional sediment and disfavor the Baja–British Columbia hypothesis for 2000–4000-km-scale translation of rocks along the margin during the Late Cretaceous.
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Wang, Jialin, Chaodong Wu, Zhuang Li, Tianqi Zhou, Yanxi Zhou, Geng Feng, and Yue Jiao. "The Pennsylvanian Composite Volcanism in the Bogda Mountains, NW China: Evidence for Postcollisional Rift Basins." Lithosphere 2020, no. 1 (October 6, 2020): 1–22. http://dx.doi.org/10.2113/2020/8852440.
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Abstract In this paper, we present new petrological, zircon U–Pb–Hf isotopic, bulk-rock geochemical, and Sr–Nd isotopic data for the rocks from the Pennsylvanian Liushugou and Qijiagou Formations, Bogda Mountains (BMs), northwest China. The new data help in understanding the petrogenesis and geodynamic background of the two formations, further constraining the evolution of BMs during the Pennsylvanian. The eastern Liushugou Formation is composed mainly of bimodal volcanic rocks, while the western Liushugou Formation is dominated by pillow basalts with interstitial limestones, peperites, and pyroclastic rocks. The Qijiagou Formation consists principally of bioclastic limestones, peperites, and volcanic and volcaniclastic rocks with turbidites. Depositional environment analyses of the Liushugou and Qijiagou Formations reveal subaqueous volcanism and a progressively deepening shallow marine environment with times. Zircon LA-ICP-MS U–Pb dating of felsic volcanic rocks from the Liushugou Formation indicates that the subaqueous volcanism occurred at ca. 310–302 Ma, viz., the Pennsylvanian era. The basaltic rocks from the Liushugou and Qijiagou Formations are high-K calc-alkaline, enriched in light rare earth elements and large-ion lithophile elements, and depleted in high-field-strength elements (Nb, Ta, and Ti). The above characteristics, together with their depleted isotopic signature (εNdt=3.0-8.1, εHft=8.0-15.6, and ISr=0.703-0.707), suggest the derivation from a depleted mantle source metasomatized by slab-derived fluids and sediment-derived melts. Most felsic volcanic rocks of the high-K calc-alkaline to shoshonite series from the Liushugou and Qijiagou Formations show features of the A2-type granites and have similar trace and isotopic composition to the basaltic rocks, which were probably generated from the partial melting of juvenile continental crust. Combining the newly acquired data with the regional geology, we propose that the Pennsylvanian volcanic and sedimentary rocks in the BMs were formed in a series of postcollisional rift basins which were related to local strike-slip faulting. Moreover, the volcanic rocks in the east were derived from a relatively deeper mantle source (thick lithosphere) due to their smaller rifting.
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HUGHES, NIGEL C., PAUL M. MYROW, N. RYAN MCKENZIE, D. A. T. HARPER, O. N. BHARGAVA, S. K. TANGRI, K. S. GHALLEY, and C. M. FANNING. "Cambrian rocks and faunas of the Wachi La, Black Mountains, Bhutan." Geological Magazine 148, no. 3 (September 14, 2010): 351–79. http://dx.doi.org/10.1017/s0016756810000750.
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AbstractThe Pele La Group in the Wachi La section in the Black Mountains of central Bhutan represents the easternmost exposure of Cambrian strata known in the Himalaya. The group contains a succession of siliciclastic rocks with minor amounts of carbonate, the uppermost unit of which, the Quartzite Formation, bears age-diagnostic trilobite body fossils that are approximately 493 Ma old. Trilobite species includeKaolishania granulosa, Taipaikia glabraand the new speciesLingyuanaspis sangae.A billingsellid brachiopod,Billingsellacf.tonkiniana, is co-occurrent. This fauna is precisely correlated with that of a specific stratigraphic horizon within the upper part of theKaolishaniaZone, Stage 9 of the Cambrian System, Furongian Epoch of the North China block, and thus represents the youngest Cambrian sedimentary rocks yet known from the Himalaya. The faunal similarity suggests proximity between North China and the Himalayan margin at this time. This unit was deposited in a predominantly storm-influenced shelf and shoreface environment. U–Pb geochronological data from detrital zircon grains from the fossil-bearing beds of the Quartzite Formation and strata of the underlying Deshichiling Formation show grain age spectra consistent with those from Cambrian rocks of the Lesser and Tethyan Himalaya in Tibet, India and Pakistan. These data support continuity of the northern Gondwanan margin across the Himalaya. Prominent peaks of approximately 500 Ma zircons in both the Quartzite and Deshichiling formations are consistent with the Furongian (late Cambrian) age assignment for these strata. The presence of these relatively young zircon populations implies rapid post-cooling erosion of igneous bodies and subsequent deposition which may reflect the influence of a widespread Cambro-Ordovician orogenic event evident in the western Himalaya.
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Fan, Majie, Alex Mankin, and Kevin Chamberlain. "Provenance and Depositional Ages of Late Paleogene Fluvial Sedimentary Rocks In the Central Rocky Mountains, U.S.A." Journal of Sedimentary Research 85, no. 11 (November 2015): 1416–30. http://dx.doi.org/10.2110/jsr.2015.87.
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HAAS, JÁNOS, PÁL PELIKÁN, ÁGNES GÖRÖG, SÁNDOR JÓZSA, and PÉTER OZSVÁRT. "Stratigraphy, facies and geodynamic settings of Jurassic formations in the Bükk Mountains, North Hungary: its relations with the other areas of the Neotethyan realm." Geological Magazine 150, no. 1 (June 12, 2012): 18–49. http://dx.doi.org/10.1017/s0016756812000246.
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AbstractJurassic mélange complexes related to the subduction of the Neotethys Ocean occur in the Bükk Mountains, North Hungary. This paper characterizes the sedimentary sequence of basin and slope facies that occur in the southwestern part of the Bükk Mountains, placing special emphasis on the redeposited sedimentary rocks (olistostromes, olistoliths: Mónosbél Group) in order to obtain information on the provenance of the clasts, and the mode and time of their redeposition. The series of formations studied shows a general coarsening-upwards trend. Based on radiolarians and foraminifera, the Mónosbél Group formed in Early to Late Bathonian time. The lower part of the complex is typified by a predominance of pelagic carbonates, shale and radiolarite with andesitic volcaniclastic intercalations. The higher part of the succession is characterized by polymictic olistostromes. Large olistoliths that are predominantly blocks of Bathonian shallow marine limestone (Bükkzsérc Limestone) appear in the upper part of the sequence. Based on the biostratigraphic and sedimentological data, results of analyses of the redeposited clasts and taking into consideration the concepts of the development of the western Neotethys domain, the evolutionary stages of the sedimentary basins were defined. The onset of the compressional stage led to initiation of nappe stacking that led to the formation of polymict olistostromes and then to the redeposition of large blocks derived from out-of-sequence nappes of the former platform foreland.
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Maslarević, Ljubinka, and Branislav Krstić. "Paleozoic continental slope deposits in the Stara Planina Mountains, Eastern Serbia." Geologica Balcanica 27, no. 1-2 (August 30, 1997): 7–18. http://dx.doi.org/10.52321/geolbalc.27.1-2.7.
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Paleozoic (Devonian) marine sediments of the Inovo Formation in the Stara Planina Mountains consist of various metaclastic rock varieties: from conglomerates to siltstones and shales, composed of quartz, feldspar, rarely mica and abundant fragments of magmatic acid and basic rocks and intraclasts. On the basis of numerous typical sedimentary structures and textures, the clastics are interpreted as continental (lower or base of) slope deposits, resulting from a variety of mass gravity transports, viz.: debris flow, turbidity current, density-modified grainflow, and grain flow, intermittently combined with traction currents or laminar flows. In some intervals of its history, the continental slope became unstable due to tectonic movements which led to massive submarine sliding, slumping and tearing away of extrabasinal and intrabasinal blocks and olistoliths which slipped down the slope and mostly, by the debris flow mechanism, deposited with normal hemipelagic sediments.
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Korn, Dieter. "Historical subdivisions of the middle and late devonian sedimentary rocks in the rhenish mountains by ammonoid faunas." Senckenbergiana lethaea 82, no. 2 (December 2002): 545–55. http://dx.doi.org/10.1007/bf03042951.
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Chaib, Latifa, Abdelhak Ait Lahna, Hassan Admou, Nasrrddine Youbi, Warda El Moume, Colombo Celso Gaeta Tassinari, João Mata, et al. "Geochemistry and Geochronology of the Neoproterozoic Backarc Basin Khzama Ophiolite (Anti-Atlas Mountains, Morocco): Tectonomagmatic Implications." Minerals 11, no. 1 (January 9, 2021): 56. http://dx.doi.org/10.3390/min11010056.
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The Khzama ophiolite is a highly dismembered complex located in the Siroua inlier of the Moroccan Anti-Atlas Belt. It consists of ultramafic rocks, cumulate gabbros, sheeted dikes, pillow lavas, and an overlying volcano-sedimentary sequence. Three main tectonic slices of sheeted dike complexes are studied in detail along three rivers, exposing well preserved outcrops where individual dikes are clearly distinguishable from the intruded host rock (Assif n’Tinzla, Assif n’Tasriwine, and Assif n’Iriri). Sheeted dikes of the Khzama ophiolitic complex are basaltic to andesitic in composition, displaying a clear sub-alkaline nature. We identify two sets of dikes that originate from lower High-Ti series (HTS) lavas and overlying upper Low-Ti series (LTS) lava. The immobile trace-element signatures of these rocks point to a genesis on a backarc environment with magmas sourced in a supra-subduction zone (SSZ) at the spinel peridotite zone. The obtained SHRIMP U-Pb data of the gabbro represent the first radiometric age of zircon extracted from the mafic rocks that were intruded by the sheeted dike complex of the Khzama ophiolite. These grains yield a concordia age of 763 ± 5 Ma, which is consistent with the 761.1 + 1.9/−1.6 and 762 + 1/−2 Ma U-Pb zircon ages of plagiogranites of Siroua. Based on their mineralogy, modal proportions, and major element chemistry, the felsic dikes are classified as high silica–low alumina trondhjemites or plagiogranites. These plagiogranites were likely formed by the partial melting of mafic rocks rather than by extreme fractional crystallization. A plagiogranite dated at 777 ± 4.7 Ma (U-Pb on zircon) is significantly older than the ca. 762 Ma plagiogranites previously recorded for the Khzama locality, suggesting a long-lived supra-subduction zone (SSZ) with conditions for the hydrous melting of mafic rocks.
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Chaib, Latifa, Abdelhak Ait Lahna, Hassan Admou, Nasrrddine Youbi, Warda El Moume, Colombo Celso Gaeta Tassinari, João Mata, et al. "Geochemistry and Geochronology of the Neoproterozoic Backarc Basin Khzama Ophiolite (Anti-Atlas Mountains, Morocco): Tectonomagmatic Implications." Minerals 11, no. 1 (January 9, 2021): 56. http://dx.doi.org/10.3390/min11010056.
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The Khzama ophiolite is a highly dismembered complex located in the Siroua inlier of the Moroccan Anti-Atlas Belt. It consists of ultramafic rocks, cumulate gabbros, sheeted dikes, pillow lavas, and an overlying volcano-sedimentary sequence. Three main tectonic slices of sheeted dike complexes are studied in detail along three rivers, exposing well preserved outcrops where individual dikes are clearly distinguishable from the intruded host rock (Assif n’Tinzla, Assif n’Tasriwine, and Assif n’Iriri). Sheeted dikes of the Khzama ophiolitic complex are basaltic to andesitic in composition, displaying a clear sub-alkaline nature. We identify two sets of dikes that originate from lower High-Ti series (HTS) lavas and overlying upper Low-Ti series (LTS) lava. The immobile trace-element signatures of these rocks point to a genesis on a backarc environment with magmas sourced in a supra-subduction zone (SSZ) at the spinel peridotite zone. The obtained SHRIMP U-Pb data of the gabbro represent the first radiometric age of zircon extracted from the mafic rocks that were intruded by the sheeted dike complex of the Khzama ophiolite. These grains yield a concordia age of 763 ± 5 Ma, which is consistent with the 761.1 + 1.9/−1.6 and 762 + 1/−2 Ma U-Pb zircon ages of plagiogranites of Siroua. Based on their mineralogy, modal proportions, and major element chemistry, the felsic dikes are classified as high silica–low alumina trondhjemites or plagiogranites. These plagiogranites were likely formed by the partial melting of mafic rocks rather than by extreme fractional crystallization. A plagiogranite dated at 777 ± 4.7 Ma (U-Pb on zircon) is significantly older than the ca. 762 Ma plagiogranites previously recorded for the Khzama locality, suggesting a long-lived supra-subduction zone (SSZ) with conditions for the hydrous melting of mafic rocks.
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Aliyan, S. A., A. S. Bratanegara, H. M. Ihsan, A. J. Astari, and L. Somantri. "identification of lithological characteristics using multispectral landsat 8 oli imagery in the cipatujah area, west java, indonesia." IOP Conference Series: Earth and Environmental Science 1089, no. 1 (November 1, 2022): 012021. http://dx.doi.org/10.1088/1755-1315/1089/1/012021.
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Abstract The Cipatujah area is part of the Southern Mountains of West Java which has diverse and unevenly distributed lithology. The lithology that dominates the Cipatujah and surrounding areas originate from the volcanic activities such as lava, volcanic breccias, tuffs, and intrusions. While the sedimentary rocks that compose them are limestone and sandstone rocks. The lithology that dominates the southern region is carbonate sedimentary rocks, which are represented by sandstone units. In the northern part, the lithologies are dominated by deposition results volcanic activity consists of various materials originating from andesitic lava units that extend to the east of the research area, while the volcanic breccia deposited from north to the west of the research area. There is a tuff unit layer above the volcanic breccia to the south. In the eastern area deposited carbonate rock units that form the karst landscape. Lithology characterization and determination of rock units in the Cipatujah area were carried out using image processing techniques from color composite bands from Landsat-8 (OLI) data. Geological analysis using SWIR-2 (7), SWIR-1 (6), and blue (2) composite bands and lithology using near-infrared (5) composites SWIR-1 (6), and SWIR-2 (7) bands. Then the analysis results are examined with geological data from the mapping that has been done before. Approach to band composite analysis by verifying geological data taken directly to help improve the identification and validation of better and more measured lithological distribution.
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Mathews, W. H., and G. E. Rouse. "An Early Pleistocene proglacial succession in south-central British Columbia." Canadian Journal of Earth Sciences 23, no. 11 (November 1, 1986): 1796–803. http://dx.doi.org/10.1139/e86-165.
Full textAbstract:
A succession of conglomerates, sandstones, siltstones, and tills, herein named the Dog Creek Formation, is sandwiched between flat-lying basalts along Dog Creek (lat. 51°36′N, long. 122°02′–122°12′W) for about 15 km east of Fraser River. The sedimentary succession rests disconformably on underlying basaltic lavas (herein referred to as the Harpers Creek Formation), which have yielded K–Ar dates of 1.3–2.9 Ma, and in one place, on a glaciated surface carved in metavolcanic rocks of Permian(?) age. The sedimentary succession is capped by basalt flows yielding K–Ar whole-rock ages of 1.1 Ma. The occurrence of proglacial beds and a glaciated surface in south-central British Columbia, 70 km away from any high mountains capable of supporting glaciers today, testifies to a major glacial stage in Early Pleistocene time. The record of sedimentation and volcanism sheds light on early incision of the nearby valley of Fraser River.
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Árkai, P., and D. Sadek Ghabrial. "Chlorite crystallinity as an indicator of metamorphic grade of low-temperature meta-igneous rocks: a case study from the Bükk Mountains, Northeast Hungary." Clay Minerals 32, no. 2 (June 1997): 205–22. http://dx.doi.org/10.1180/claymin.1997.032.2.04.
Full textAbstract:
AbstractX-ray diffraction chlorite crystallinity (ChC) indices and major element chemical compositions of chlorites and bulk rocks were determined and correlated in meta-igneous rocks from different Mesozoic formations in various tectonic units of the Bükk Mountains, NE Hungary. The rocks, of basic to acidic compositions, range from ocean-floor metamorphic prehnite-pumpellyite facies (diagenetic zone) through regional metamorphic prehnite-pumpellyite facies (anchizone) up to the regional metamorphic pumpellyite-actinolite and greenschist facies (epizone). As in the case of meta-sedimentary rocks, chlorite crystallinity can be applied as an empirical, complementary petrogenetic tool to determine relative differences in grades of low-temperature meta-igneous rocks. Electron microprobe and XRD data show that ChC is controlled mainly by the decreasing amounts of contaminants (mixed-layered components or discrete, intergrown phases of mostly smectitic composition) in chlorite with advancing metamorphic grade, up to the epizone. The apparent increase in calculated Aliv content of chlorite with increasing temperature is related to the decrease of these contaminants, as stated earlier by Jiang et al. (1994). On the basis of the significant correlations found between ChC and temperatures, derived by the chlorite-Aliv geothermometer of Cathelineau (1988), both methods may be used for estimating the approximate temperatures of metamorphism, in spite of the contrasting interpretation of chemical data from chlorites obtained by electron microprobe analyses. After determining the effects of changing bulk chemistry on chlorite composition and ChC, the chlorite crystallinity method may complement the correlation of the illite crystallinity-based zonal classification of meta-sediments and the mineral facies classification of meta-igneous rocks.
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Kovacs, Marinel, Zoltán Pécskay, Alexandrina Fülöp, Maria Jurje, and Oscar Edelstein. "Geochronology of the Neogene intrusive magmatism of the Oaș—Gutâi Mountains, Eastern Carpathians (NW Romania)." Geologica Carpathica 64, no. 6 (December 1, 2013): 483–96. http://dx.doi.org/10.2478/geoca-2013-0033.
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Abstract Earlier geological work in the Oaș-Gutâi Mts (OG), Eastern Carpathians, has revealed the extensive presence of shallow subvolcanic intrusive bodies, both exposed on the surface and covered by Paleogene-Neogene sedimentary sequences and Neogene volcanic formations. This study is based on detailed mapping and sampling of the OG Neogene intrusive magmatic rocks. Thirty seven representative intrusions (sills, dykes, microlaccoliths, etc.) were selected for radiometric dating. These intrusions show a wide variety of petrographic rock-types: from microgabbros to microgranodiorites and from basalts to andesites. However, the intrusions consist of typical calc-alkaline, medium-K rocks, similar to the volcanic rocks which outcrop in the same areas. The K-Ar age determinations on whole-rock samples of intrusions yielded ages between 11.9 Ma and 7.0 Ma (from Late Sarmatian to Middle Pannonian). The results are in good agreement with the common assumption, based on the biostratigraphic and geological data, that large volumes of intrusions have formed during the paroxysm of the intermediate volcanic activity in the OG. Except for the Firiza basalt intrusive complex of the Gutâi Mts (8.1-7.0 Ma), the OG intrusions show similar K-Ar ages as the intrusions of the “Subvolcanic Zone” and Călimani Mts from Eastern Carpathians. The timing of the OG intrusive magmatism partially overlaps with the timing of the intrusive magmatic activity in the Eastern Moravia and Pieniny Mts. The systematic radiometric datings in the whole OG give clear evidence that the hydrothermal activity related to the epithermal systems always postdates intrusion emplacement.
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Leary, Ryan J., Paul Umhoefer, M. Elliot Smith, Tyson M. Smith, Joel E. Saylor, Nancy Riggs, Greg Burr, et al. "Provenance of Pennsylvanian–Permian sedimentary rocks associated with the Ancestral Rocky Mountains orogeny in southwestern Laurentia: Implications for continental-scale Laurentian sediment transport systems." Lithosphere 12, no. 1 (January 30, 2020): 88–121. http://dx.doi.org/10.1130/l1115.1.
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Abstract The Ancestral Rocky Mountains system consists of a series of basement-cored uplifts and associated sedimentary basins that formed in southwestern Laurentia during Early Pennsylvanian–middle Permian time. This system was originally recognized by aprons of coarse, arkosic sandstone and conglomerate within the Paradox, Eagle, and Denver Basins, which surround the Front Range and Uncompahgre basement uplifts. However, substantial portions of Ancestral Rocky Mountain–adjacent basins are filled with carbonate or fine-grained quartzose material that is distinct from proximal arkosic rocks, and detrital zircon data from basins adjacent to the Ancestral Rocky Mountains have been interpreted to indicate that a substantial proportion of their clastic sediment was sourced from the Appalachian and/or Arctic orogenic belts and transported over long distances across Laurentia into Ancestral Rocky Mountain basins. In this study, we present new U-Pb detrital zircon data from 72 samples from strata within the Denver Basin, Eagle Basin, Paradox Basin, northern Arizona shelf, Pedregosa Basin, and Keeler–Lone Pine Basin spanning ∼50 m.y. and compare these to published data from 241 samples from across Laurentia. Traditional visual comparison and inverse modeling methods map sediment transport pathways within the Ancestral Rocky Mountains system and indicate that proximal basins were filled with detritus eroded from nearby basement uplifts, whereas distal portions of these basins were filled with a mix of local sediment and sediment derived from marginal Laurentian sources including the Arctic Ellesmerian orogen and possibly the northern Appalachian orogen. This sediment was transported to southwestern Laurentia via a ca. 2,000-km-long longshore and aeolian system analogous to the modern Namibian coast. Deformation of the Ancestral Rocky Mountains slowed in Permian time, reducing basinal accommodation and allowing marginal clastic sources to overwhelm the system.
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Ahmed, Ibrahim, Mohamed Jalludin, and Moumtaz Razack. "Hydrochemical and Isotopic Assessment of Groundwater in the Goda Mountains Range System. Republic of Djibouti (Horn of Africa)." Water 12, no. 7 (July 15, 2020): 2004. http://dx.doi.org/10.3390/w12072004.
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The hydrogeological system of the Goda Mountains Range (GMR) in the Republic of Djibouti (Horn of Africa), hosted by volcanic and sedimentary formations, is the only water resource in the Tadjourah region for more than 85,000 inhabitants. Water needs are expected to drastically increase in the coming years, due to fast socio-economic development of the region. Accordingly, this system is under high pressure and should sustainably be exploited. However, little is known about the hydrogeology of this system. This study aims to improve the understanding of the hydrochemistry and the recharge processes of this system. The study is based on the combined interpretation of major ions, stable isotopes (18O, 2H), and radiogenic isotopes (3H, 14C). The interpretation of major ions contents using classical hydrochemical methods and principal component analysis highlighted that alteration of volcanic rocks minerals, coastal rainfall infiltration, and evaporation are the main processes from which groundwater acquires mineralization. Stable isotopes revealed that groundwater is of meteoric origin and has undergone high evaporation during infiltration. Radiogenic isotopes showed that groundwater in the basalts is mostly submodern to old, in relation with low hydraulic conductivity of the rocks and/or longer pathways through fissures from outcrop to subsurface. Groundwater in the rhyolites is much younger compared to the basalts due to faster infiltration. The sedimentary part, in connection with the rhyolites, has younger waters compared to the basalts, but older compared to the rhyolites. The overall results show that GMR is a fairly complex hydrogeological system, containing a resource made up of a mixture of waters of different ages. This study has made significant progress in understanding this system and is an initial step towards the sustainable exploitation of resources.
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Chigira, Masahiro, and Kenzo Kiho. "Deep-seated rockslide-avalanches preceded by mass rock creep of sedimentary rocks in the Akaishi Mountains, central Japan." Engineering Geology 38, no. 3-4 (December 1994): 221–30. http://dx.doi.org/10.1016/0013-7952(94)90039-6.
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