Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1016/j.sedgeo.2009.11.002 |
Glaciation and deglaciation of the Libyan Desert: The Late Ordovician record | |
Le Heron, D. P.1; Armstrong, H. A.2; Wilson, C.2; Howard, J. P.3; Gindre, L.4 | |
通讯作者 | Le Heron, D. P. |
来源期刊 | SEDIMENTARY GEOLOGY
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ISSN | 0037-0738 |
出版年 | 2010 |
卷号 | 223期号:1-2页码:100-125 |
英文摘要 | Detailed outcrop studies at the flanks of Al Kufrah Basin, Libya, reveal the nature of glacially-related sedimentation and post-depositional deformation styles produced in association with the Late Ordovician glaciation, during which ice sheets expanded northward over North Africa to deposit the Mamuniyat Formation. At the SE basin flank (Jabal Azbah), the Mamuniyat Formation is sand-dominated, and incises interfingering braidplain and shallow marine deposits of the Hawaz Formation. The glacially-related sediments include intercalations of mud-chip bearing tabular sandstones and intraformational conglomerates, which are interpreted as turbidite and debrite facies respectively. These record aggradation of an extensive sediment wedge in front of a stable former ice margin. An increase in mudstone content northward is accompanied by the occurrence of more evolved turbidites. A widespread surface, bearing streamlined NW-SE striking ridges and grooves, punctuates this succession. The structures on the surface are interpreted to have formed during a regional north-westward ice advance. Above, siltstones bearing Arthrophycus burrows, and Orthocone-bearing sandstones beneath tidal bars testify to glaciomarine conditions for deposition of the underflow deposits beneath. By contrast, the northern basin margin (Jabal az-Zalmah) is appreciably different in recording shallower water/paralic sedimentation styles and major glaciotectonic deformation features, although facies analysis also reveals northward deepening. Here, a siltstone wedging from 8 to 50 m toward the north was deposited (lower delta plain), succeeded by climbing ripple cross-laminated sandstones up to 60 m in thickness (distal through proximal delta mouth bar deposits) with occasional diamictite interbeds. These rocks are deformed by thrusts and > 50 m amplitude fault-propagation folds, the deformation locally sealed by a diamictite then overlain by conglomeratic lag during ultimate deglaciation. Integrating observations from both basin margins, a model of fluvial-dominated delta systems feeding a pulsed debrite and turbidite fan system in a shallow proglacial shelf is proposed. (c) 2009 Elsevier B.V. All rights reserved. |
英文关键词 | Glacial North Africa Ordovician Reservoir |
类型 | Review |
语种 | 英语 |
国家 | England ; Norway |
收录类别 | SCI-E |
WOS记录号 | WOS:000274546500008 |
WOS关键词 | BASIN SE LIBYA ; ICE-SHEET ; MURZUQ BASIN ; TUNNEL VALLEYS ; NORTH-SEA ; TURBIDITY CURRENTS ; LINKED DEBRITES ; MASS EXTINCTION ; GROUNDING-LINE ; SAUDI-ARABIA |
WOS类目 | Geology |
WOS研究方向 | Geology |
来源机构 | University of London |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/166378 |
作者单位 | 1.Royal Holloway Univ London, Dept Earth Sci, Egham TW20 0EX, Surrey, England; 2.Univ Durham, Dept Earth Sci, Sci Labs, Durham DH1 3LE, England; 3.CASP, Cambridge CB3 0DH, England; 4.StatoilHydro ASA, Res Ctr, N-7005 Trondheim, Norway |
推荐引用方式 GB/T 7714 | Le Heron, D. P.,Armstrong, H. A.,Wilson, C.,et al. Glaciation and deglaciation of the Libyan Desert: The Late Ordovician record[J]. University of London,2010,223(1-2):100-125. |
APA | Le Heron, D. P.,Armstrong, H. A.,Wilson, C.,Howard, J. P.,&Gindre, L..(2010).Glaciation and deglaciation of the Libyan Desert: The Late Ordovician record.SEDIMENTARY GEOLOGY,223(1-2),100-125. |
MLA | Le Heron, D. P.,et al."Glaciation and deglaciation of the Libyan Desert: The Late Ordovician record".SEDIMENTARY GEOLOGY 223.1-2(2010):100-125. |
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