DOI: 10.1007/s00531-012-0815-y
Scopus记录号: 2-s2.0-84874018096
论文题名: Lower Palaeozoic unconformities in an intracratonic platform setting: Glacial erosion versus tectonics in the eastern Murzuq Basin (southern Libya)
作者: Ghienne J.-F. ; Moreau J. ; Degermann L. ; Rubino J.-L.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2013
卷: 102, 期: 2 起始页码: 455
结束页码: 482
语种: 英语
英文关键词: Dor el Gussa
; Erosional truncations
; Murizidié
; Palaeohighs
; Sequence stratigraphy
Scopus关键词: Caledonian orogeny
; Cambrian
; deformation
; glacial erosion
; glaciotectonics
; Gondwana
; intracratonic basin
; Ordovician
; Paleozoic
; sequence stratigraphy
; stratigraphy
; tectonics
; Libyan Arab Jamahiriya
; Murzuq Basin
英文摘要: The stratigraphic record of the eastern Murzuq Basin has been importantly influenced by deformation resulting in angular and/or deeply erosional unconformities, though the overall context is intracratonic. Major transgressive events and the Ordovician glaciation are nevertheless documented, allowing the delineation of tectonic-, eustasy- or climate-driven unconformities. Lower Palaeozoic key events and related unconformities that characterize the North Gondwana platform have therefore a signature in the eastern Murzuq Basin. The basement/cover unconformity, also known as the infra-Tassilian surface, truncates all the deformed and metamorphosed Lower Cambrian and older rocks. Above is a? Middle Cambrian to Lower Ordovician megasequence (Murizidié and Hasawnah Fms.), which is in turn truncated by an intra-Ordovician, angular unconformity. This megasequence is unconformably overlain by a Middle Ordovician (Hawaz Fm.) to Silurian (Tanzzuft and Akakus Fms) megasequence, which includes the Upper Ordovician glaciogenic unit (Mamuniyat Fm.), bounded at the base by a polygenic glacial erosion surface showing corrugated glacial lineations, tillites, and glaciotectonic structures. The Middle Ordovician to Silurian megasequence is finally truncated by a base-Devonian, angular unconformity overlain by fluvial sandstones. Regarding the possibility that those fluvial deposits may be as younger as Late Devonian in the eastern Murzuq Basin based on palaeoflora, the so-called Caledonian unconformity might be here a much younger (mid-Eifelian?) surface, and the occurrence of the Lower Devonian "Tadrart Fm." is questioned. The Upper Ordovician glacial erosion surface, which is sometimes referred to as the Taconic unconformity, usually truncates Middle Ordovician strata in the Murzuq Basin but reaches significantly deeper stratigraphic levels in places that have been previously involved in the intra-Ordovician deformation event. In the Murizidié (southeastern Murzuq Basin), the infra-Tassilian surface, the intra-Ordovician unconformity, and the Upper Ordovician glacial erosion surface amalgamate together. Here, an estimate of the glacial erosion depth cannot be derived from the stratigraphic hiatus beneath the glacial incision, the main part of which relate to the intra-Ordovician tectonic event. The Upper Ordovician climate-related glacial erosion surface is not a valid unconformity for a sequence hierarchy framework of the Lower Palaeozoic, although it presents most of the physical attributes of tectonic-driven unconformities. © 2012 Springer-Verlag. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874018096&doi=10.1007%2fs00531-012-0815-y&partnerID=40&md5=f6003fccd6f37edc54157c2711faef7e
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70595
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: Institut de Physique du Globe de Strasbourg, UMR 7516 CNRS-Université de Strasbourg (EOST), 1 rue Blessig, 67084 Strasbourg Cedex, France; Department of Geography and Geology, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen, Denmark; Eriksfiord, Postboks 8034, 4068 Stavanger, Norway; CSTJF, Total, Avenue Laribeau, 64018 Pau, France; Cva-engineering, Immeuble Toki Lana, 7 chemin de la Marouette, 64100 Bayonne, France
Recommended Citation:
Ghienne J.-F.,Moreau J.,Degermann L.,et al. Lower Palaeozoic unconformities in an intracratonic platform setting: Glacial erosion versus tectonics in the eastern Murzuq Basin (southern Libya)[J]. International Journal of Earth Sciences,2013-01-01,102(2)