PALEOGEODYNAMICS OF MAGMATIC AND METAMORPHIC PROCESSES OF FORMATION OF ULTRAMAFIC ROCKS OF CHAGAN-UZUN MASSIF (OPHIOLITES OF GORNY ALTAI)
The Geochemical and mineralogical studies showed, that harzburgites of the Chagan-Uzun massif are restites with a degree of partial melting 15–20 %, which formed at temperatures 1520–1420 °С under the conditions of the mid-oceanic ridge and transformed during the evolution of paleooceanic structures...
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Russian Academy of Sciences, Siberian Branch, Institute of the Earth's crust
2021-12-01
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| Series: | Геодинамика и тектонофизика |
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| Online Access: | https://www.gt-crust.ru/jour/article/view/1367 |
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| author | V. A. Simonov A. V. Kulikova A. V. Kotlyarov T. B. Kolotilina |
| author_facet | V. A. Simonov A. V. Kulikova A. V. Kotlyarov T. B. Kolotilina |
| author_sort | V. A. Simonov |
| collection | DOAJ |
| description | The Geochemical and mineralogical studies showed, that harzburgites of the Chagan-Uzun massif are restites with a degree of partial melting 15–20 %, which formed at temperatures 1520–1420 °С under the conditions of the mid-oceanic ridge and transformed during the evolution of paleooceanic structures under the influence of magmatic processes at the initial stages of subduction and manifestation of boninite magmatism. The combined use of data on the geochemistry of rare and rare earth elements, as well as on the compositions of pyroxenes, Cr-spinels, melt inclusions in Cr-spinels and computational modeling, indicates the formation of clinopyroxenites of Chagan-Uzun ophiolites at the mid-oceanic ridge during crystallization of picrite and picrobasalt melts at temperatures 1315–1245 °C and pressures 4–2 kbar. The study of amphiboles showed high metamorphic parameters of transformation of harzburgites (5.1–1.9 kbar, 820–700 °С) and clinopyroxenites (2.6–1.4 kbar and 740–680 °С) of the Chagan-Uzun massif, typical for ultrabasites from the modern mid-oceanic ridges. In general, results of comprehensive studies made it possible to determine the sequence of paleogeodynamic processes of formation of ultramafic rocks of the Chagan-Uzun massif. Initial formation of harzburgites in the course of partial melting of mantle and crystallization of clinopyroxenites in the magma chamber occurred under the conditions of the mid-oceanic ridge. At the next stage, ultramafic rocks fell within the subduction-zone initiation area, where they were exposed to the influence of boninite melts. |
| format | Article |
| id | doaj-art-ea6ce252606c4487bd46468bbf886145 |
| institution | DOAJ |
| issn | 2078-502X |
| language | English |
| publishDate | 2021-12-01 |
| publisher | Russian Academy of Sciences, Siberian Branch, Institute of the Earth's crust |
| record_format | Article |
| series | Геодинамика и тектонофизика |
| spelling | doaj-art-ea6ce252606c4487bd46468bbf8861452025-08-20T03:02:40ZengRussian Academy of Sciences, Siberian Branch, Institute of the Earth's crustГеодинамика и тектонофизика2078-502X2021-12-0112482685010.5800/GT-2021-12-4-0557559PALEOGEODYNAMICS OF MAGMATIC AND METAMORPHIC PROCESSES OF FORMATION OF ULTRAMAFIC ROCKS OF CHAGAN-UZUN MASSIF (OPHIOLITES OF GORNY ALTAI)V. A. Simonov0A. V. Kulikova1A. V. Kotlyarov2T. B. Kolotilina3Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences; Novosibirsk State University; Kazan Federal UniversitySobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences; Novosibirsk State University; Kazan Federal UniversitySobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences; Kazan Federal UniversityVinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of SciencesThe Geochemical and mineralogical studies showed, that harzburgites of the Chagan-Uzun massif are restites with a degree of partial melting 15–20 %, which formed at temperatures 1520–1420 °С under the conditions of the mid-oceanic ridge and transformed during the evolution of paleooceanic structures under the influence of magmatic processes at the initial stages of subduction and manifestation of boninite magmatism. The combined use of data on the geochemistry of rare and rare earth elements, as well as on the compositions of pyroxenes, Cr-spinels, melt inclusions in Cr-spinels and computational modeling, indicates the formation of clinopyroxenites of Chagan-Uzun ophiolites at the mid-oceanic ridge during crystallization of picrite and picrobasalt melts at temperatures 1315–1245 °C and pressures 4–2 kbar. The study of amphiboles showed high metamorphic parameters of transformation of harzburgites (5.1–1.9 kbar, 820–700 °С) and clinopyroxenites (2.6–1.4 kbar and 740–680 °С) of the Chagan-Uzun massif, typical for ultrabasites from the modern mid-oceanic ridges. In general, results of comprehensive studies made it possible to determine the sequence of paleogeodynamic processes of formation of ultramafic rocks of the Chagan-Uzun massif. Initial formation of harzburgites in the course of partial melting of mantle and crystallization of clinopyroxenites in the magma chamber occurred under the conditions of the mid-oceanic ridge. At the next stage, ultramafic rocks fell within the subduction-zone initiation area, where they were exposed to the influence of boninite melts.https://www.gt-crust.ru/jour/article/view/1367paleogeodynamicsophiolitesharzburgitesclinopyroxenitesmagmatic and metamorphic processesmelt inclusionscr-spinelspt-conditions |
| spellingShingle | V. A. Simonov A. V. Kulikova A. V. Kotlyarov T. B. Kolotilina PALEOGEODYNAMICS OF MAGMATIC AND METAMORPHIC PROCESSES OF FORMATION OF ULTRAMAFIC ROCKS OF CHAGAN-UZUN MASSIF (OPHIOLITES OF GORNY ALTAI) Геодинамика и тектонофизика paleogeodynamics ophiolites harzburgites clinopyroxenites magmatic and metamorphic processes melt inclusions cr-spinels pt-conditions |
| title | PALEOGEODYNAMICS OF MAGMATIC AND METAMORPHIC PROCESSES OF FORMATION OF ULTRAMAFIC ROCKS OF CHAGAN-UZUN MASSIF (OPHIOLITES OF GORNY ALTAI) |
| title_full | PALEOGEODYNAMICS OF MAGMATIC AND METAMORPHIC PROCESSES OF FORMATION OF ULTRAMAFIC ROCKS OF CHAGAN-UZUN MASSIF (OPHIOLITES OF GORNY ALTAI) |
| title_fullStr | PALEOGEODYNAMICS OF MAGMATIC AND METAMORPHIC PROCESSES OF FORMATION OF ULTRAMAFIC ROCKS OF CHAGAN-UZUN MASSIF (OPHIOLITES OF GORNY ALTAI) |
| title_full_unstemmed | PALEOGEODYNAMICS OF MAGMATIC AND METAMORPHIC PROCESSES OF FORMATION OF ULTRAMAFIC ROCKS OF CHAGAN-UZUN MASSIF (OPHIOLITES OF GORNY ALTAI) |
| title_short | PALEOGEODYNAMICS OF MAGMATIC AND METAMORPHIC PROCESSES OF FORMATION OF ULTRAMAFIC ROCKS OF CHAGAN-UZUN MASSIF (OPHIOLITES OF GORNY ALTAI) |
| title_sort | paleogeodynamics of magmatic and metamorphic processes of formation of ultramafic rocks of chagan uzun massif ophiolites of gorny altai |
| topic | paleogeodynamics ophiolites harzburgites clinopyroxenites magmatic and metamorphic processes melt inclusions cr-spinels pt-conditions |
| url | https://www.gt-crust.ru/jour/article/view/1367 |
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