Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1016/j.jafrearsci.2017.02.017 |
Origin of an extensive network of non-tectonic synclines in Eocene limestones of the Western Desert, Egypt | |
Tewksbury, Barbara J.1; Tarabees, Elhamy A.2; Mehrtens, Charlotte J.3 | |
通讯作者 | Tewksbury, Barbara J. |
来源期刊 | JOURNAL OF AFRICAN EARTH SCIENCES
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ISSN | 1464-343X |
EISSN | 1879-1956 |
出版年 | 2017 |
卷号 | 136页码:148-167 |
英文摘要 | Satellite images of the Western Desert of Egypt display conspicuous sinuous color patterning that previous workers have interpreted as erosional flutes formed by catastrophic flooding. Our work with high resolution satellite imagery shows that the patterning is not erosional but, rather, the result of a network of thousands of narrow synclines in the Eocene bedrock capping the Limestone Plateau. Synclines form as isolated, 200-400 meter-wide downwarps in otherwise flat-lying strata. Limb dips are shallow, and doubly plunging hinges form multiple basin closures along syncline lengths. Anticlines form "accidentally" in inter-syncline areas where two adjacent synclines lie close together. Synclines have two dominant orientations, WNW-ESE and NNW-SSE, parallel to two prominent joint and fault sets, and synclines branch, merge, and change orientation along their lengths. Synclines are all at the same scale with neither larger structures nor parasitic structures and are best described as non-tectonic sag synclines. An Egypt-wide inventory reveals that these synclines are both confined to Eocene limestones and developed, albeit it sporadically, over nearly 100,000 km(2). The syncline network predates plateau gravels of the Katkut Formation, which have been interpreted as Oligocene or early Miocene in age, and the network is cut by faults related to Western Desert extension associated with Red Sea rifting. The mechanism that caused sag of overlying layers is not clear. Modern karst collapse, subsurface dissolution of evaporites, and collapse of paleokarst are all unlikely mechanisms given the timing of formation and the underlying stratigraphy. Silica diagenesis and downslope mobilization of underlying shales are possibilities, although uncertainty about the origin of silica in the limestones, plus the consistency of syncline orientations over large areas, make these models problematic. Hypogene karst, perhaps related to aggressive fluids associated with basaltic intrusions, may be the model most consistent with the admittedly limited data we currently have for the network. (C) 2017 The Authors. Published by Elsevier Ltd. |
英文关键词 | Non-tectonic folds Satellite image analysis Hypogene karst Western Desert Egypt |
类型 | Article |
语种 | 英语 |
国家 | USA ; Egypt |
收录类别 | SCI-E |
WOS记录号 | WOS:000418219400010 |
WOS关键词 | SEDIMENTARY BASINS ; FAULT SYSTEMS ; CARBONATE ; STRATIGRAPHY ; KARST ; DEFORMATION ; GROUNDWATER ; EVOLUTION ; COLLAPSE ; DRAINAGE |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/199965 |
作者单位 | 1.Hamilton Coll, Dept Geosci, Clinton, NY 13323 USA; 2.Damanhour Univ, Dept Geol, Damanhour 22516, Egypt; 3.Univ Vermont, Dept Geol, Burlington, VT 05405 USA |
推荐引用方式 GB/T 7714 | Tewksbury, Barbara J.,Tarabees, Elhamy A.,Mehrtens, Charlotte J.. Origin of an extensive network of non-tectonic synclines in Eocene limestones of the Western Desert, Egypt[J],2017,136:148-167. |
APA | Tewksbury, Barbara J.,Tarabees, Elhamy A.,&Mehrtens, Charlotte J..(2017).Origin of an extensive network of non-tectonic synclines in Eocene limestones of the Western Desert, Egypt.JOURNAL OF AFRICAN EARTH SCIENCES,136,148-167. |
MLA | Tewksbury, Barbara J.,et al."Origin of an extensive network of non-tectonic synclines in Eocene limestones of the Western Desert, Egypt".JOURNAL OF AFRICAN EARTH SCIENCES 136(2017):148-167. |
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