THERMOCHRONOLOGY OF MINGLING DYKES IN WEST SANGILEN (SOUTH‐EAST TUVA, RUSSIA): EVIDENCE OF THE COLLAPSE OF THE COLLISIONAL SYSTEM IN THE NORTH‐WESTERN EDGE OF THE TUVA‐MONGOLIA MASSIF
In West Sangilen (South‐East Tuva, Russia), there are outcrops of metamorphic and magmatic complexes of early Caledonides, which are related to the period of long‐term collisional and post‐collisional events in the north‐ western edge of the Tuva‐Mongolian massif. The evolution of orogenic structure...
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Russian Academy of Sciences, Siberian Branch, Institute of the Earth's crust
2017-06-01
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| Series: | Геодинамика и тектонофизика |
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| Online Access: | https://www.gt-crust.ru/jour/article/view/363 |
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| author | A. G. Vladimirov I. V. Karmysheva V. A. Yakovlev A. V. Travin A. A. Tsygankov G. N. Burmakina |
| author_facet | A. G. Vladimirov I. V. Karmysheva V. A. Yakovlev A. V. Travin A. A. Tsygankov G. N. Burmakina |
| author_sort | A. G. Vladimirov |
| collection | DOAJ |
| description | In West Sangilen (South‐East Tuva, Russia), there are outcrops of metamorphic and magmatic complexes of early Caledonides, which are related to the period of long‐term collisional and post‐collisional events in the north‐ western edge of the Tuva‐Mongolian massif. The evolution of orogenic structures in West Sangilen is an example of the collapse of folded structures in case of changes in tectonic regimes from compression and transpression (collision period) to intra‐ and marginal continental transform‐shear extension (post‐collision period). Numerous geologic fea‐ tures give evidence of changes in the kinematics and characteristics of deformations, as well as in the conditions of metamorphism and magmatism in the study region. However, thinning of the crust during the collapse of the colli‐ sional orogenic structure has not been supported by any direct data. Indicators of such events are the complexes of combined dykes, which are abundant in West Sangilen, especially in the area between the Erzin and Naryn rivers and on the right bank of the Erzin river. The most representative object is a combined basite‐granite dyke at the foot of the Tavit‐Dag mountain. Its position is controlled by the strike‐slip fault system. The thermochronological analysis of mingling rocks shows different ages of the closure of isotope systems: 494.8±5.4 Ma (U/Pb, zircon, basites), 489.7±7 Ma (U/Pb, zircon, granitoids), 471.2±1.9 Ma (Ar/Ar , amphibole, basites), and 462.5±1.0 Ma (Ar/Ar, biotite, basites). Taking into account the parameters of the closure of isotope systems (~800–900 °C, zircon, U/Pb; ~500 °C, amphi‐ bole, Ar/Ar; ~300 °C, biotite, Ar/Ar), the cooling curve of the mingling dyke is estimated. It corresponds to lowering of the temperature by 600 °C (900 °С 500 °С 300 °C) in the period from 500 (494.8±5.4) Ma to 461 (462.5±1.0) Ma. It is shown that the recent thermal events did not affect the mingling dyke located on the Tavit‐Dag site. The sequen‐ tial changes in the age of the closure of isotope systems are indicative of thinning of the crust in the study region during the post‐collisional collapse of the orogenic structure. According to the geological and thermochronological data, the mingling dykes on the Tavit‐Dag site were moved from the deep crust (~27 km) to a more shallow level (10 km) at a rate of about 0.5 km per 1.0 Ma. This process lasted for about 32 Ma, and the temperature was decreasing by 18.6 °С per 1.0 Ma. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2017-06-01 |
| publisher | Russian Academy of Sciences, Siberian Branch, Institute of the Earth's crust |
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| spelling | doaj-art-7aaeaa124f32474393a394119fa10fc42025-08-20T03:44:19ZengRussian Academy of Sciences, Siberian Branch, Institute of the Earth's crustГеодинамика и тектонофизика2078-502X2017-06-018228331010.5800/GT-2017-8-2-0242237THERMOCHRONOLOGY OF MINGLING DYKES IN WEST SANGILEN (SOUTH‐EAST TUVA, RUSSIA): EVIDENCE OF THE COLLAPSE OF THE COLLISIONAL SYSTEM IN THE NORTH‐WESTERN EDGE OF THE TUVA‐MONGOLIA MASSIFA. G. Vladimirov0I. V. Karmysheva1V. A. Yakovlev2A. V. Travin3A. A. Tsygankov4G. N. Burmakina5V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of RAS; Novosibirsk State UniversityV.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of RAS; Novosibirsk State UniversityV.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of RAS; Novosibirsk State UniversityV.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of RAS; Novosibirsk State University; Tomsk State UniversityGeological Institute, Siberian Branch of RAS; Buryat State UniversityGeological Institute, Siberian Branch of RASIn West Sangilen (South‐East Tuva, Russia), there are outcrops of metamorphic and magmatic complexes of early Caledonides, which are related to the period of long‐term collisional and post‐collisional events in the north‐ western edge of the Tuva‐Mongolian massif. The evolution of orogenic structures in West Sangilen is an example of the collapse of folded structures in case of changes in tectonic regimes from compression and transpression (collision period) to intra‐ and marginal continental transform‐shear extension (post‐collision period). Numerous geologic fea‐ tures give evidence of changes in the kinematics and characteristics of deformations, as well as in the conditions of metamorphism and magmatism in the study region. However, thinning of the crust during the collapse of the colli‐ sional orogenic structure has not been supported by any direct data. Indicators of such events are the complexes of combined dykes, which are abundant in West Sangilen, especially in the area between the Erzin and Naryn rivers and on the right bank of the Erzin river. The most representative object is a combined basite‐granite dyke at the foot of the Tavit‐Dag mountain. Its position is controlled by the strike‐slip fault system. The thermochronological analysis of mingling rocks shows different ages of the closure of isotope systems: 494.8±5.4 Ma (U/Pb, zircon, basites), 489.7±7 Ma (U/Pb, zircon, granitoids), 471.2±1.9 Ma (Ar/Ar , amphibole, basites), and 462.5±1.0 Ma (Ar/Ar, biotite, basites). Taking into account the parameters of the closure of isotope systems (~800–900 °C, zircon, U/Pb; ~500 °C, amphi‐ bole, Ar/Ar; ~300 °C, biotite, Ar/Ar), the cooling curve of the mingling dyke is estimated. It corresponds to lowering of the temperature by 600 °C (900 °С 500 °С 300 °C) in the period from 500 (494.8±5.4) Ma to 461 (462.5±1.0) Ma. It is shown that the recent thermal events did not affect the mingling dyke located on the Tavit‐Dag site. The sequen‐ tial changes in the age of the closure of isotope systems are indicative of thinning of the crust in the study region during the post‐collisional collapse of the orogenic structure. According to the geological and thermochronological data, the mingling dykes on the Tavit‐Dag site were moved from the deep crust (~27 km) to a more shallow level (10 km) at a rate of about 0.5 km per 1.0 Ma. This process lasted for about 32 Ma, and the temperature was decreasing by 18.6 °С per 1.0 Ma.https://www.gt-crust.ru/jour/article/view/363thermochronologyminglingcollisionstrike‐slip extensiontectonic denudationsangilentuva‐mongolia massifcentral asian folded belt |
| spellingShingle | A. G. Vladimirov I. V. Karmysheva V. A. Yakovlev A. V. Travin A. A. Tsygankov G. N. Burmakina THERMOCHRONOLOGY OF MINGLING DYKES IN WEST SANGILEN (SOUTH‐EAST TUVA, RUSSIA): EVIDENCE OF THE COLLAPSE OF THE COLLISIONAL SYSTEM IN THE NORTH‐WESTERN EDGE OF THE TUVA‐MONGOLIA MASSIF Геодинамика и тектонофизика thermochronology mingling collision strike‐slip extension tectonic denudation sangilen tuva‐mongolia massif central asian folded belt |
| title | THERMOCHRONOLOGY OF MINGLING DYKES IN WEST SANGILEN (SOUTH‐EAST TUVA, RUSSIA): EVIDENCE OF THE COLLAPSE OF THE COLLISIONAL SYSTEM IN THE NORTH‐WESTERN EDGE OF THE TUVA‐MONGOLIA MASSIF |
| title_full | THERMOCHRONOLOGY OF MINGLING DYKES IN WEST SANGILEN (SOUTH‐EAST TUVA, RUSSIA): EVIDENCE OF THE COLLAPSE OF THE COLLISIONAL SYSTEM IN THE NORTH‐WESTERN EDGE OF THE TUVA‐MONGOLIA MASSIF |
| title_fullStr | THERMOCHRONOLOGY OF MINGLING DYKES IN WEST SANGILEN (SOUTH‐EAST TUVA, RUSSIA): EVIDENCE OF THE COLLAPSE OF THE COLLISIONAL SYSTEM IN THE NORTH‐WESTERN EDGE OF THE TUVA‐MONGOLIA MASSIF |
| title_full_unstemmed | THERMOCHRONOLOGY OF MINGLING DYKES IN WEST SANGILEN (SOUTH‐EAST TUVA, RUSSIA): EVIDENCE OF THE COLLAPSE OF THE COLLISIONAL SYSTEM IN THE NORTH‐WESTERN EDGE OF THE TUVA‐MONGOLIA MASSIF |
| title_short | THERMOCHRONOLOGY OF MINGLING DYKES IN WEST SANGILEN (SOUTH‐EAST TUVA, RUSSIA): EVIDENCE OF THE COLLAPSE OF THE COLLISIONAL SYSTEM IN THE NORTH‐WESTERN EDGE OF THE TUVA‐MONGOLIA MASSIF |
| title_sort | thermochronology of mingling dykes in west sangilen south east tuva russia evidence of the collapse of the collisional system in the north western edge of the tuva mongolia massif |
| topic | thermochronology mingling collision strike‐slip extension tectonic denudation sangilen tuva‐mongolia massif central asian folded belt |
| url | https://www.gt-crust.ru/jour/article/view/363 |
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