Fernandez, A.; Schreurs, Guido (2003). Tectonic evolution of the Proterozoic Itremo Group metasediments in central Madagascar. Geological Society Special Publications, 206(1), pp. 381-399. Geological Society 10.1144/GSL.SP.2003.206.01.18
Full text not available from this repository.The major geologic units of the Itremo region in central Madagascar include: (1) upper amphibolite to granulite facies (higher grade) Precambrian rocks, mainly para- and orthogneisses, and migmatites; (2) the newly defined Itremo Nappes, a fold-and-thrust belt containing the Proterozoic Itremo Group sediments, metamorphosed at greenschist to lower amphibolite facies (lower grade) conditions: (3) Middle Neoproterozoic and Late Neoproterozoic-Cambrian intrusives. The stratigraphic succession of the Itremo Group in the eastern part of the Itremo region is, from bottom to top: quartzites, metapelites, metacarbonates and metapelites overlain by metacarbonates. During D1 the Itremo Group sediments were detached from their continental substratum, deformed into a fold-and-thrust nappe (Itremo Nappes), and transported on top of higher grade rocks that are intruded by Middle Neoproterozoic (c. 797–780 Ma) granites and gabbros. A second phase of deformation shortening (D2) affected both the Itremo Sedimentary Nappes and structurally underlying higher-grade rocksunits, and formed large-scale N-S-trending F2 folds. S1 axial plane foliations in Itremo Group sediments are truncated by Late Neoproterozoic-Cambrian granites (c. 570–540 Ma). The age of the formation of the Itremo Nappes is not well constrained: they formed in Neoproterozoic times between 780 and 570 Ma.
Item Type: |
Journal Article (Original Article) |
|---|---|
Division/Institute: |
08 Faculty of Science > Institute of Geological Sciences |
UniBE Contributor: |
Schreurs, Guido |
Subjects: |
500 Science > 550 Earth sciences & geology |
ISSN: |
0305-8719 |
Publisher: |
Geological Society |
Language: |
English |
Submitter: |
Guido Schreurs |
Date Deposited: |
18 Jul 2016 14:06 |
Last Modified: |
05 Dec 2022 14:56 |
Publisher DOI: |
10.1144/GSL.SP.2003.206.01.18 |
URI: |
https://boris.unibe.ch/id/eprint/83593 |
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