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Batkhuyag Enkhdalai - One of the best experts on this subject based on the ideXlab platform.
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early middle paleozoic volcanic rocks from the ereendavaa terrane tsarigiin gol area ne mongolia with implications for Tectonic Evolution of the kherlen massif
Journal of Asian Earth Sciences, 2019Co-Authors: Tserendash Narantsetseg, Tao Wang, Ying Tong, Demberel Orolmaa, Chao Yuan, Xinyu Wang, Orsoo Enkhorshikh, Tumenulzii Oyunchimeg, Puntsag Delgerzaya, Batkhuyag EnkhdalaiAbstract:Abstract We report our newly obtained geochronological and geochemical data of volcanic rocks in the Tsarigiin gol area, Ereendavaa terrane to better understand of the Early-Middle Paleozoic Tectonic Evolution of the Kherlen massif, NE Mongolia. LA-ICP-MS zircon U-Pb dating reveals two stages of magmatism in the southern part of the Ereendavaa terrane: one in Late Ordovician (∼462 to 455 Ma) and the other in Early Devonian (∼418 Ma). The Late Ordovician Tsarig volcanic rocks are medium to high-K calc-alkaline and intermediate to felsic in composition and characterized by relative enrichment of LREE and LILEs (e.g., Rb and U) and also by relative depletion of HFSEs (e.g. Nb, Ta, P and Ti), a typical feature of subduction-related magmas. These rocks have mostly positive whole-rock ƐNd(t) (+1.65 to +1.35) and zircon ƐHf(t) (+0.1 to +4.07) values with Mesoproterozoic Nd and Hf model ages of 1.59–1.09 Ga. They were likely generated in a continental arc setting, and their parental magmas were originated from a common source as the product of extensive fractional crystallization of mafic melts and their interaction with arc crust. The Early Devonian Chandmana volcanic rocks consist of rhyolite and minor trachybasalt, displaying a typical bimodal distribution. The trachybasaltic rocks are characterized by low Lan/Smn (2.08–2.60), Tbn/Ybn (1.42–1.50) and La/Yb (7.51–8.96) ratios and relatively flat MREE to HREE patterns with ƐNd(t) values being close to zero (−1.36 to +0.13). The rhyolites are high-K calc-alkaline and possess variably negative ƐHf(t) (−4.96 to −0.29) and ƐNd(t) (−2.14 to −0.57) values, exhibiting a strong affinity to A2-type granites. Considering the distinct compositional gap between the end-members and geochemical and isotopic signature of the bimodal suite, the felsic magma is interpreted to have derived from partial melting of a hybrid crustal source composed of both Pre-Neoproterozoic and juvenile crustal materials, while the mafic rocks were probably derived from a mantle source previously metasomatized by slab-derived melt. The two phases of magmatism in the southern part of the Ereendavaa terrane reflected two stages of Tectonic Evolution: Early-Middle Paleozoic subduction of the Paleo-Asian Ocean plate that gave rise to the Late Neoproterozoic-Early Cambrian Undur-Khaan island arc and Late Cambrian to Late Ordovician Ereendavaa active continental margin. Silurian amalgamation of the Ereendavaa and Idermeg terranes (Kherlen massif) caused the break-off of the subducted slab and the Early to Middle Devonian extension in the area.
Simon A Wilde - One of the best experts on this subject based on the ideXlab platform.
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structure and Tectonic Evolution of the southwestern trinidad dome escambray complex central cuba insights into deformation in an accretionary wedge
Tectonophysics, 2017Co-Authors: Ana Ibis Despaignediaz, Antonio Garcia Casco, Damaso Caceres Govea, Simon A Wilde, Guillermo Millan TrujilloAbstract:Abstract The Trinidad dome, Escambray complex, Cuba, forms part of an accretionary wedge built during intra-oceanic subduction in the Caribbean from the Late Cretaceous to Cenozoic. The structure reflects syn-subduction exhumation during thickening of the wedge, followed by extension. Field mapping, metamorphic and structural analysis constrain the Tectonic Evolution into five stages. Three ductile deformation events (D1, D2 and D3) are related to metamorphism in a compressional setting and formation of several nappes. D1 subduction fabrics are only preserved as relict S1 foliation and rootless isoclinal folds strongly overprinted by the main S2 foliation. The S2 foliation is parallel to sheared serpentinised lenses that define Tectonic contacts, suggesting thrust stacks and underthrusting at mantle depths. Thrusting caused an inverted metamorphic structure with higher-grade on top of lower-grade nappes. Exhumation started during D2 when the units were incorporated into the growing accretionary wedge along NNE-directed thrust faults and was accompanied by substantial decompression and cooling. Folding and thrusting continued during D3 and marks the transition from ductile to brittle-ductile conditions at shallower crustal levels. The D4–5 events are related to extension and contributed to the final exhumation (likely as a core complex). D4 is associated with a regional spaced S4 cleavage, late open folds, and numerous extension veins, whereas D5 is recorded by normal and strike-slip faults affecting all nappes. The P-t path shows rapid exhumation during D2 and slower rates during D3 when the units were progressively incorporated into the accretionary prism. The domal shape formed in response to Tectonic denudation assisted by normal faulting and erosion at the surface during the final stages of structural development. These results support Tectonic models of SW subduction of the Proto-Caribbean crust under the Caribbean plate during the latest Cretaceous and provide insights into the Tectonic Evolution of accretionary wedges in an intra-arc setting.
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the crustal accretion history and Tectonic Evolution of the ne china segment of the central asian orogenic belt
Gondwana Research, 2013Co-Authors: Simon A Wilde, Jianbo ZhouAbstract:Abstract The basement rocks in parts of NE China constitute a khondalitic sequence of sillimanite- and garnet-bearing gneisses, hornblende–plagioclase gneiss and various felsic paragneisses. Zircon U–Pb dating of garnet–sillimanite gneiss samples from the Erguna, Xing'an, Jiamusi and Khanka blocks indicates that high-grade metamorphism occurred at ~ 500 Ma. Evidence from detrital zircons in Paleozoic sediments from the Songliao Block also indicates the former presence of a ~ 500 Ma component. This uniformity of U–Pb ages across all crustal blocks in NE China establishes a > 1300 km long Late Pan-African khondalite belt which we have named the ‘NE China Khondalite Belt’. This indicates the blocks of NE China were amalgamated prior to ~ 500 Ma, contrary to current belief. One scenario is that this amalgamated terrane had a Tectonic affinity to the Siberia Craton, once forming part of the Late Pan-African (~ 500 Ma) Sayang–Baikal orogenic belt extensively developed around the southern margin of the Siberia Craton. This belt was the result of collision between currently unidentified terranes with the Southeastern Angara–Anabar Province at about 500 Ma, where the rocks were deformed and metamorphosed to granulite facies. It appears likely that at sometime after ~ 450 Ma, the combined NE China blocks rifted away from Siberia and moved southward to form what is now NE China. The combined block collided with the North China Craton along the Solonker–Xar Moron–Changchun suture zone at ~ 230 Ma rather than in the end-Permian as previously thought. Local rifting at the eastern extremity of the developing Central Asian Orogenic Belt (CAOB) resulted in the splitting away of the Jiamusi/Khanka(/Bureya) blocks. However, this was only transient and sometime between 210 and 180 Ma, these were re-united with the CAOB by the onset of Pacific plate subduction, which has dominated the Tectonic Evolution of the region since that time.
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the crustal accretion history and Tectonic Evolution of the ne china segment of the central asian orogenic belt
Gondwana Research, 2013Co-Authors: Simon A Wilde, Jianbo ZhouAbstract:Abstract The basement rocks in parts of NE China constitute a khondalitic sequence of sillimanite- and garnet-bearing gneisses, hornblende–plagioclase gneiss and various felsic paragneisses. Zircon U–Pb dating of garnet–sillimanite gneiss samples from the Erguna, Xing'an, Jiamusi and Khanka blocks indicates that high-grade metamorphism occurred at ~ 500 Ma. Evidence from detrital zircons in Paleozoic sediments from the Songliao Block also indicates the former presence of a ~ 500 Ma component. This uniformity of U–Pb ages across all crustal blocks in NE China establishes a > 1300 km long Late Pan-African khondalite belt which we have named the ‘NE China Khondalite Belt’. This indicates the blocks of NE China were amalgamated prior to ~ 500 Ma, contrary to current belief. One scenario is that this amalgamated terrane had a Tectonic affinity to the Siberia Craton, once forming part of the Late Pan-African (~ 500 Ma) Sayang–Baikal orogenic belt extensively developed around the southern margin of the Siberia Craton. This belt was the result of collision between currently unidentified terranes with the Southeastern Angara–Anabar Province at about 500 Ma, where the rocks were deformed and metamorphosed to granulite facies. It appears likely that at sometime after ~ 450 Ma, the combined NE China blocks rifted away from Siberia and moved southward to form what is now NE China. The combined block collided with the North China Craton along the Solonker–Xar Moron–Changchun suture zone at ~ 230 Ma rather than in the end-Permian as previously thought. Local rifting at the eastern extremity of the developing Central Asian Orogenic Belt (CAOB) resulted in the splitting away of the Jiamusi/Khanka(/Bureya) blocks. However, this was only transient and sometime between 210 and 180 Ma, these were re-united with the CAOB by the onset of Pacific plate subduction, which has dominated the Tectonic Evolution of the region since that time.
Chao Yuan - One of the best experts on this subject based on the ideXlab platform.
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early middle paleozoic volcanic rocks from the ereendavaa terrane tsarigiin gol area ne mongolia with implications for Tectonic Evolution of the kherlen massif
Journal of Asian Earth Sciences, 2019Co-Authors: Tserendash Narantsetseg, Tao Wang, Ying Tong, Demberel Orolmaa, Chao Yuan, Xinyu Wang, Orsoo Enkhorshikh, Tumenulzii Oyunchimeg, Puntsag Delgerzaya, Batkhuyag EnkhdalaiAbstract:Abstract We report our newly obtained geochronological and geochemical data of volcanic rocks in the Tsarigiin gol area, Ereendavaa terrane to better understand of the Early-Middle Paleozoic Tectonic Evolution of the Kherlen massif, NE Mongolia. LA-ICP-MS zircon U-Pb dating reveals two stages of magmatism in the southern part of the Ereendavaa terrane: one in Late Ordovician (∼462 to 455 Ma) and the other in Early Devonian (∼418 Ma). The Late Ordovician Tsarig volcanic rocks are medium to high-K calc-alkaline and intermediate to felsic in composition and characterized by relative enrichment of LREE and LILEs (e.g., Rb and U) and also by relative depletion of HFSEs (e.g. Nb, Ta, P and Ti), a typical feature of subduction-related magmas. These rocks have mostly positive whole-rock ƐNd(t) (+1.65 to +1.35) and zircon ƐHf(t) (+0.1 to +4.07) values with Mesoproterozoic Nd and Hf model ages of 1.59–1.09 Ga. They were likely generated in a continental arc setting, and their parental magmas were originated from a common source as the product of extensive fractional crystallization of mafic melts and their interaction with arc crust. The Early Devonian Chandmana volcanic rocks consist of rhyolite and minor trachybasalt, displaying a typical bimodal distribution. The trachybasaltic rocks are characterized by low Lan/Smn (2.08–2.60), Tbn/Ybn (1.42–1.50) and La/Yb (7.51–8.96) ratios and relatively flat MREE to HREE patterns with ƐNd(t) values being close to zero (−1.36 to +0.13). The rhyolites are high-K calc-alkaline and possess variably negative ƐHf(t) (−4.96 to −0.29) and ƐNd(t) (−2.14 to −0.57) values, exhibiting a strong affinity to A2-type granites. Considering the distinct compositional gap between the end-members and geochemical and isotopic signature of the bimodal suite, the felsic magma is interpreted to have derived from partial melting of a hybrid crustal source composed of both Pre-Neoproterozoic and juvenile crustal materials, while the mafic rocks were probably derived from a mantle source previously metasomatized by slab-derived melt. The two phases of magmatism in the southern part of the Ereendavaa terrane reflected two stages of Tectonic Evolution: Early-Middle Paleozoic subduction of the Paleo-Asian Ocean plate that gave rise to the Late Neoproterozoic-Early Cambrian Undur-Khaan island arc and Late Cambrian to Late Ordovician Ereendavaa active continental margin. Silurian amalgamation of the Ereendavaa and Idermeg terranes (Kherlen massif) caused the break-off of the subducted slab and the Early to Middle Devonian extension in the area.
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prolonged magmatism juvenile nature and Tectonic Evolution of the chinese altai nw china evidence from zircon u pb and hf isotopic study of paleozoic granitoids
Journal of Asian Earth Sciences, 2011Co-Authors: Chao Yuan, Guochun Zhao, Wenjiao Xiao, Xiaoping Long, Fuyuan WuAbstract:Abstract Paleozoic granitoid magmatism played an important role in the Tectonic Evolution of the Chinese Altai, and zircon U–Pb and Hf isotopic compositions have been determined for samples from eleven granitic plutons/batholiths. The Jiadengyu gneissic granitic pluton yielded a zircon U–Pb age of 479 Ma, and thus it does not represent Precambrian basement as suggested previously. Our results and published data demonstrate that voluminous granitoids were continuously emplaced over more than 30% area of the Chinese Altai during the period from 447 Ma to 368 Ma with a climax at ca. 400 Ma. Ages for zircon overgrowth rims demonstrate additional thermal events at ca. 360 and 280 Ma, respectively. Positive e Hf ( t ) values (0 to +9) of normal magmatic zircons suggest that the granitoid magmas were derived from juvenile sources. Xenocrystic zircon cores are 543–421 Ma old and also give positive e Hf ( t ) values (+2.5 to +12), suggesting their origin as early crystallized minerals in the magma chambers or as inherited cores from newly-accreted meterials. The strong magmatism at ca. 400 Ma significantly changed the Hf isotopic composition of the magma source by substantial input of juvenile material in a relatively short period. Geophysical, geological and geochemical data support that ridge subduction was a possible mechanism for the strong magmatism ca. 400 Ma and the above mentioned change of Hf isotopic composition in the magma source.
Tserendash Narantsetseg - One of the best experts on this subject based on the ideXlab platform.
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early middle paleozoic volcanic rocks from the ereendavaa terrane tsarigiin gol area ne mongolia with implications for Tectonic Evolution of the kherlen massif
Journal of Asian Earth Sciences, 2019Co-Authors: Tserendash Narantsetseg, Tao Wang, Ying Tong, Demberel Orolmaa, Chao Yuan, Xinyu Wang, Orsoo Enkhorshikh, Tumenulzii Oyunchimeg, Puntsag Delgerzaya, Batkhuyag EnkhdalaiAbstract:Abstract We report our newly obtained geochronological and geochemical data of volcanic rocks in the Tsarigiin gol area, Ereendavaa terrane to better understand of the Early-Middle Paleozoic Tectonic Evolution of the Kherlen massif, NE Mongolia. LA-ICP-MS zircon U-Pb dating reveals two stages of magmatism in the southern part of the Ereendavaa terrane: one in Late Ordovician (∼462 to 455 Ma) and the other in Early Devonian (∼418 Ma). The Late Ordovician Tsarig volcanic rocks are medium to high-K calc-alkaline and intermediate to felsic in composition and characterized by relative enrichment of LREE and LILEs (e.g., Rb and U) and also by relative depletion of HFSEs (e.g. Nb, Ta, P and Ti), a typical feature of subduction-related magmas. These rocks have mostly positive whole-rock ƐNd(t) (+1.65 to +1.35) and zircon ƐHf(t) (+0.1 to +4.07) values with Mesoproterozoic Nd and Hf model ages of 1.59–1.09 Ga. They were likely generated in a continental arc setting, and their parental magmas were originated from a common source as the product of extensive fractional crystallization of mafic melts and their interaction with arc crust. The Early Devonian Chandmana volcanic rocks consist of rhyolite and minor trachybasalt, displaying a typical bimodal distribution. The trachybasaltic rocks are characterized by low Lan/Smn (2.08–2.60), Tbn/Ybn (1.42–1.50) and La/Yb (7.51–8.96) ratios and relatively flat MREE to HREE patterns with ƐNd(t) values being close to zero (−1.36 to +0.13). The rhyolites are high-K calc-alkaline and possess variably negative ƐHf(t) (−4.96 to −0.29) and ƐNd(t) (−2.14 to −0.57) values, exhibiting a strong affinity to A2-type granites. Considering the distinct compositional gap between the end-members and geochemical and isotopic signature of the bimodal suite, the felsic magma is interpreted to have derived from partial melting of a hybrid crustal source composed of both Pre-Neoproterozoic and juvenile crustal materials, while the mafic rocks were probably derived from a mantle source previously metasomatized by slab-derived melt. The two phases of magmatism in the southern part of the Ereendavaa terrane reflected two stages of Tectonic Evolution: Early-Middle Paleozoic subduction of the Paleo-Asian Ocean plate that gave rise to the Late Neoproterozoic-Early Cambrian Undur-Khaan island arc and Late Cambrian to Late Ordovician Ereendavaa active continental margin. Silurian amalgamation of the Ereendavaa and Idermeg terranes (Kherlen massif) caused the break-off of the subducted slab and the Early to Middle Devonian extension in the area.
Jianbo Zhou - One of the best experts on this subject based on the ideXlab platform.
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the crustal accretion history and Tectonic Evolution of the ne china segment of the central asian orogenic belt
Gondwana Research, 2013Co-Authors: Simon A Wilde, Jianbo ZhouAbstract:Abstract The basement rocks in parts of NE China constitute a khondalitic sequence of sillimanite- and garnet-bearing gneisses, hornblende–plagioclase gneiss and various felsic paragneisses. Zircon U–Pb dating of garnet–sillimanite gneiss samples from the Erguna, Xing'an, Jiamusi and Khanka blocks indicates that high-grade metamorphism occurred at ~ 500 Ma. Evidence from detrital zircons in Paleozoic sediments from the Songliao Block also indicates the former presence of a ~ 500 Ma component. This uniformity of U–Pb ages across all crustal blocks in NE China establishes a > 1300 km long Late Pan-African khondalite belt which we have named the ‘NE China Khondalite Belt’. This indicates the blocks of NE China were amalgamated prior to ~ 500 Ma, contrary to current belief. One scenario is that this amalgamated terrane had a Tectonic affinity to the Siberia Craton, once forming part of the Late Pan-African (~ 500 Ma) Sayang–Baikal orogenic belt extensively developed around the southern margin of the Siberia Craton. This belt was the result of collision between currently unidentified terranes with the Southeastern Angara–Anabar Province at about 500 Ma, where the rocks were deformed and metamorphosed to granulite facies. It appears likely that at sometime after ~ 450 Ma, the combined NE China blocks rifted away from Siberia and moved southward to form what is now NE China. The combined block collided with the North China Craton along the Solonker–Xar Moron–Changchun suture zone at ~ 230 Ma rather than in the end-Permian as previously thought. Local rifting at the eastern extremity of the developing Central Asian Orogenic Belt (CAOB) resulted in the splitting away of the Jiamusi/Khanka(/Bureya) blocks. However, this was only transient and sometime between 210 and 180 Ma, these were re-united with the CAOB by the onset of Pacific plate subduction, which has dominated the Tectonic Evolution of the region since that time.
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the crustal accretion history and Tectonic Evolution of the ne china segment of the central asian orogenic belt
Gondwana Research, 2013Co-Authors: Simon A Wilde, Jianbo ZhouAbstract:Abstract The basement rocks in parts of NE China constitute a khondalitic sequence of sillimanite- and garnet-bearing gneisses, hornblende–plagioclase gneiss and various felsic paragneisses. Zircon U–Pb dating of garnet–sillimanite gneiss samples from the Erguna, Xing'an, Jiamusi and Khanka blocks indicates that high-grade metamorphism occurred at ~ 500 Ma. Evidence from detrital zircons in Paleozoic sediments from the Songliao Block also indicates the former presence of a ~ 500 Ma component. This uniformity of U–Pb ages across all crustal blocks in NE China establishes a > 1300 km long Late Pan-African khondalite belt which we have named the ‘NE China Khondalite Belt’. This indicates the blocks of NE China were amalgamated prior to ~ 500 Ma, contrary to current belief. One scenario is that this amalgamated terrane had a Tectonic affinity to the Siberia Craton, once forming part of the Late Pan-African (~ 500 Ma) Sayang–Baikal orogenic belt extensively developed around the southern margin of the Siberia Craton. This belt was the result of collision between currently unidentified terranes with the Southeastern Angara–Anabar Province at about 500 Ma, where the rocks were deformed and metamorphosed to granulite facies. It appears likely that at sometime after ~ 450 Ma, the combined NE China blocks rifted away from Siberia and moved southward to form what is now NE China. The combined block collided with the North China Craton along the Solonker–Xar Moron–Changchun suture zone at ~ 230 Ma rather than in the end-Permian as previously thought. Local rifting at the eastern extremity of the developing Central Asian Orogenic Belt (CAOB) resulted in the splitting away of the Jiamusi/Khanka(/Bureya) blocks. However, this was only transient and sometime between 210 and 180 Ma, these were re-united with the CAOB by the onset of Pacific plate subduction, which has dominated the Tectonic Evolution of the region since that time.
