FAULT SYSTEMS IN THE UPPER CRUST OF THE FENNOSCANDIAN SHIELD, THE EAST EUROPEAN PLATFORM

Directions of 683 faults located in the southeastern part of the Fennoscandian (Baltic) shield were statistically analyzed, and three orthogonal associations of fault systems were identified in the study area. According to the dynamic analysis of the fault systems and their associations, the main NW...

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Bibliographic Details
Published in:Geodynamics & Tectonophysics
Main Authors: V. S. Burtman, S. Yu. Kolodyazhny, В. С. Буртман, С. Ю. Колодяжный
Other Authors: This study carried out under Assignment № 0135-2019-0055 of the Geological Institute RAS was financially supported by RFBR (grant № 18-05-00485)., Работа выполнена в соответствии с темой Геологического института РАН № 0135-2019- 0055, при финансовой поддержке РФФИ (грант № 18-05-00485).
Format: Article in Journal/Newspaper
Language:Russian
Published: Institute of the Earth's crust of the Russian Academy of Sciences, Siberian Branch 2020
Subjects:
Балтийский щит
fault system
Paleoproterozoic
transtension
transpression
geodynamic reconstruction
Fennoscandian Shield
система разломов
палеопротерозой
транстенсия
транспрессия
геодинамическая реконструкция
Fennoscandian
Online Access:https://www.gt-crust.ru/jour/article/view/1123
https://doi.org/10.5800/GT-2020-11-4-0505
Description
Summary:Directions of 683 faults located in the southeastern part of the Fennoscandian (Baltic) shield were statistically analyzed, and three orthogonal associations of fault systems were identified in the study area. According to the dynamic analysis of the fault systems and their associations, the main NW-striking faults belong to the fault network originating mainly from the early Paleoproterozoic. These faults functioned in the Paleoproterozoic during four main deformation stages: D1 – sinistral shear transtension and asymmetric rift genesis (2.1–1.9 Ga); D2 – sinistral shear transpression under oblique accretion and convergence (1.9 Ga); D3 – sinistral shear transpression under oblique collision (1.89–1.80 Ga); D4 – dextral strike-slip displacements at the background of complex escape tectonics of the late collision stage (1.80–1.78 Ga). The regional stress field changed as follows: D1 – northeast- or east-trending extension; D2 – northeast compression; D3 – sub-latitudinal compression; D4 – sub-meridian compression. Changes in dynamic loading conditions led to multiple kinematic inversions of the fault networks. Widespread transtension and transpression settings in the southeastern parts of the Baltic Shield give evidence of asymmetric rifting, oblique accretion and collision in the Paleoproterozoic, which must be taken in to account in geodynamic reconstructions. Статистический анализ направлений 683 разломов юго-восточной части Фенноскандинавского (Балтийского) щита позволил выделить три ортогональные ассоциации систем дизъюнктивных нарушений. Динамический анализ систем разломов и их ассоциаций показал, что главные структурообразующие разломы территории, имеющие северо-западное простирание, принадлежат сети разломов, которая была создана преимущественно в раннем палеопротерозое. В палеопротерозое они функционировали на протяжении четырех главных этапов деформаций: D1 – левосдвиговая транстенсия и асимметричный рифтогенез (2.2–1.9 млрд лет), D2 – левосдвиговая транспрессия в обстановке косой аккреции и ...

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