Architecture and growth of normal fault zones in multilayer systems: A 3D field analysis in the South-Eastern Basin, France

详细信息	查看全文 | 推荐本文 |

• 作者：V. Roche^a ; ^b ; ^{vincent.roche@irsn.fr} ; ^{vincroche@hotmail.fr} ; C. Homberg^a ; M. Rocher^b
• 关键词：Fault growth ; 3D fault architecture ; Multilayer system ; Normal fault zone ; Clay sub-horizontal fault ; Displacement profile
• 刊名：Journal of Structural Geology
• 出版年：2012
• 期刊代码：52_01918141
• 类别：ear
• 出版时间：April, 2012
• 卷：37
• 期：Complete
• 页码：19-35
• 文件大小：5607 K

摘要

3D field data on mesoscale normal faults were collected to examine the geometries and growth of faults in multilayer systems. Observation and analysis of the fractures include the collection of geometric attributes such as fault dips and fault zone thicknesses, detailed mapping in cross-sections and plan views, and the construction of individual and cumulative displacement profiles. Fault zone growth is consistent with a 鈥渃oherent model鈥?and is strongly influenced by the multilayer system. In the limestone layers, faults grew in several steps, including opening and frictional sliding on 80掳 dipping segments. Faulting in clay layers was in the form of 40掳 dipping faults and sub-horizontal faults, the latter being mostly early features developed under the same extensional regime as normal faults and disturbing the fault architecture. The fault zone thickness increases with the limestone thickness and the presence of sub-horizontal faults in clay beds. Numerous connections occur in clay units. The moderate (鈮?.08) and low (<0.03) mean displacement gradients in clays and in limestones respectively indicate that the vertical propagation of faults is inhibited in clay layers. Analysis of displacement along fault strike indicates that a 0.08 displacement gradient is associated with the horizontal propagation of fault segments in limestones. According to this value, the fault zones are much longer than expected. It is associated with 鈥榝lat topped鈥?displacement profiles along some fault segments and connection between segments to form complex fault zones.