Nature of metamorphism of low-temperature metamorphic rocks in the continent-ocean transition zone (by the example of Pensantain Sequence of Western Kamchatka)

The nature of low-temperature metamorphic rocks in the continent-ocean transition zone has been studied on the example of metamorphosed Late Cretaceous volcanic-sedimentary deposits of Western Kamchatka (Pensantain Sequence).The Pensantain Sequence consists of prevailing albite-actinolite-epidote-mu...

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Bibliographic Details
Published in:Bulletin of Kamchatka Regional Association «Educational-Scientific Center». Earth Sciences
Main Authors: Бадрединов ЗГ., Авченко О.В., Тарарин И.А., Ноздрачев Е.А.
Format: Article in Journal/Newspaper
Language:Russian
Published: Institute of Volcanology and Seismology FEB RAS 2020
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Online Access:https://doi.org/10.31431/1816-5524-2020-2-46-16-29
https://doaj.org/article/507777f1942242dc9384504010ad179c
Description
Summary:The nature of low-temperature metamorphic rocks in the continent-ocean transition zone has been studied on the example of metamorphosed Late Cretaceous volcanic-sedimentary deposits of Western Kamchatka (Pensantain Sequence).The Pensantain Sequence consists of prevailing albite-actinolite-epidote-muscovite-chlorite schists. Albit-lavsonite-muscovite-chlorite and кiebeckit-epidote-albite-chlorite schists also participate in Pensantain stratum. The temperature and pressure of the metamorphism of the Pensantain metamorphic rocks were determined by computer modeling using the «Selector C» program. P-T conditions of metamorphism (T = 360± 50°С; P = 3800 ± 500 bar) correspond to facies transition from the greenschist to the blueschist facies. Computer modeling was performed for two samples. This is the first application of the «Selector C» program to determine the P-T conditions of low-temperature metamorphism. The geodynamic conditions and the time of metamorphism were reconstructed. It has been established that rocks of the Pensantain Sequence were formed in the Early Paleogene during collisional metamorphism.