کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4682828 1348946 2008 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Age and kinematics of ductile deformation in the Cerro Durazno area, NW Argentina: Significance for orogenic processes operating at the western margin of Gondwana during Ordovician – Silurian times
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
Age and kinematics of ductile deformation in the Cerro Durazno area, NW Argentina: Significance for orogenic processes operating at the western margin of Gondwana during Ordovician – Silurian times
چکیده انگلیسی

The Cerro Durazno Pluton belongs to a suite of Paleozoic granitoid intrusions in NW-Argentina, that are central for understanding the tectonic setting of the western margin of Gondwana in Ordovician and Silurian times. The pluton and its host rocks were tectonically overprinted by metamorphic mineral shape fabrics formed under middle greenschist-facies metamorphic conditions and associated with the nearby Agua Rosada Shear Zone. Kinematic analysis of the shear zone based on the geometric relationship between individual segments of the shear plane and principal axes of mineral fabric ellipsoids indicates reverse-sense of shear with a minor component of left-lateral displacement. This is compatible with the kinematics of other ductile deformation zones in this area, collectively forming a network, which accomplished orogen-parallel extension in addition to vertical thickening. Using the Rb–Sr isotopic system, an undeformed pegmatite dike of the Cerro Durazno Pluton was dated at 455.8 ± 3.6 Ma and mineral fabrics of the Agua Rosada Shear Zone formed at middle greenschist-facies metamorphism gave deformation ages of 437.0 ± 3.8 Ma and ⩽428.4 ± 4.5 Ma. Thus, tectonic overprint at low metamorphic grade occurred about 20–30 Ma after terminal magmatism in the Cerro Durazno area. Our data from the Cerro Durazno area and regional considerations suggest that the western margin of Gondwana was characterized by orogen-parallel extension in addition to crustal thickening as well as episodes of magmatism and ductile deformation that varied greatly in time and space.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of South American Earth Sciences - Volume 26, Issue 1, July 2008, Pages 78–90
نویسندگان
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