DOI: 10.1007/s00531-016-1415-z
Scopus记录号: 2-s2.0-84992740333
论文题名: Kinematics and significance of a poly-deformed crustal-scale shear zone in central to south-eastern Madagascar: the Itremo–Ikalamavony thrust
作者: Giese J. ; Schreurs G. ; Berger A. ; Herwegh M.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2017
卷: 106, 期: 6 起始页码: 2091
结束页码: 2108
语种: 英语
英文关键词: Antananarivo Block
; East African Orogen
; Gondwana
; Itremo–Ikalamavony thrust
; Madagascar
; Southwest Madagascar Block
; Thrust contact
Scopus关键词: crustal structure
; deformation
; Gondwana
; orogeny
; quartzite
; shear zone
; tectonics
; thrust
; Antananarivo [Madagascar]
; Madagascar
英文摘要:
Across the crystalline basement of Madagascar, late Archaean rocks of the Antananarivo Block are tectonically overlain by Proterozoic, predominantly metasedimentary units of the Ikalamavony and Itremo Groups of the Southwest Madagascar Block. The generally west-dipping tectonic contact can be traced for more than 750 km from NW to SE and is referred to here as the Itremo–Ikalamavony thrust. The basal units of the SW Madagascar Block comprise metasedimentary quartzites with the potential to preserve a multistage deformation history in their microstructures. Previous studies suggest contrasting structural evolutions for this contact, including eastward thrusting, top-to-the-west directed extension and right-lateral strike-slip deformation during the late Neoproterozoic/Ediacaran. In this study, we integrate remote sensing analyses, structural and petrological fieldwork, as well as microstructural investigations of predominantly quartz mylonites from the central southern segment of the contact between Ankaramena and Maropaika. In this area, two major phases of ductile deformation under high-grade metamorphic conditions occurred in latest Neoproterozoic/early Phanerozoic times. A first (Andreaba) phase produces a penetrative foliation, which is parallel to the contact between the two blocks and contemporaneous with widespread magmatism. A second (Ihosy) phase of deformation folds Andreaba-related structures. The investigated (micro-)structures indicate that (a) juxtaposition of both blocks possibly already occurred prior to the Andreaba phase, (b) (re-)activation with top-to-the-east thrusting took place during the latest stages of the Andreaba phase, (c) the Ihosy phase resulted in regional-scale open folding of the tectonic contact and (d) reactivation of parts of the contact took place at distinctively lower temperatures post-dating the major ductile deformations. © 2016, Springer-Verlag Berlin Heidelberg.
URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84992740333&doi=10.1007%2fs00531-016-1415-z&partnerID=40&md5=d0e3e7e036e67440eba4411f537de921
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69983
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Institute of Geological Sciences, Freie Universität Berlin, Malteserstrasse 74-100, Berlin, Germany; Institute of Geological Sciences, University of Bern, Baltzerstrasse 1 & 3, Bern, Switzerland
Recommended Citation:
Giese J.,Schreurs G.,Berger A.,et al. Kinematics and significance of a poly-deformed crustal-scale shear zone in central to south-eastern Madagascar: the Itremo–Ikalamavony thrust[J]. International Journal of Earth Sciences,2017-01-01,106(6)