Seismic stratigraphy and subsidence history of the United Arab Emirates (UAE) rifted margin and overlying foreland basins
Seismic stratigraphy and subsidence history of the United Arab Emirates (UAE) rifted margin and overlying foreland basins
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阿拉伯联合酋长国（UAE）裂谷边缘和上覆前陆盆地的地震地层和沉降历史
DOI：
10.1007/978-3-642-30609-9_6
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
M. Searle
中科院分区：
文献类型：
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作者：
Mohammed Y. Ali;Anthony B. Watts;M. Searle
区域地震反射剖面和深探井资料已被用于确定阿拉伯联合酋长国（UAE）裂陷边缘和上覆前陆盆地的结构和演化。我们在地震剖面上识别出三个主要的构造地层序列。一个较低的裂陷边缘层序，其特征为主要为晚二叠世的早期同裂陷层序，其上覆有三叠纪-侏罗纪至晚白垩世的裂陷后层序，以及Aruma（晚白垩世）和Pabdeh（古新世-渐新世）群的上部前陆盆地层序。回剥的井数据提供了新的约束裂陷的年龄，地壳和地幔的伸展量，以及阿联酋裂陷边缘和前陆盆地的发展。威尔斯井的构造沉降和隆升历史可以用一个统一的伸展模式来解释，其中至少有两幕裂谷被相对构造平静和热沉降时期打断。初始裂陷年龄为260 Ma，拉伸因子β为1.2，随后是第二期拉伸，初始裂陷年龄为180 Ma，β为1.1。该模型解释了在回剥构造沉降中观察到的一般指数下降。然而，该模型未能完全解释晚三叠世-早侏罗世陆缘缓慢沉降和隆升的历史。我们将这种缓慢的沉降归因于海平面下降和区域抬升的联合收割机效应，这种效应造成了主要的不整合面，特别是阿布扎比西部近海。后条带曲线表明，从伸展裂谷边缘到挤压前陆盆地的转变发生在~90 Ma，这是在塞麦尔蛇绿岩侵位的范围内（95-68 Ma）。这一时期的历史特征是隆起，然后是快速沉降。我们将这些差异性的垂直运动归因于塞梅尔蛇绿岩对阿拉伯裂谷边缘的造山加载和挠曲以及阿鲁马前陆盆地的发育。
Regional seismic reflection profiles and deep exploratory well data have been used to determine the structure and evolution of the United Arab Emirates (UAE) rifted margin and overlying foreland basins. We recognized three major tectonostratigraphic sequences in the seismic profiles. A lower rifted margin sequence which is characterised by an early syn-rift sequence of mainly Late Permian age that is overlain by a post-rift sequence of Triassic-Jurassic to Late Cretaceous age, and an upper foreland basin sequences of Aruma (Late Cretaceous) and Pabdeh (Palaeocene—Oligocene) Groups. Backstripping of the well data provides new constraints on the age of rifting, the amount of crustal and mantle extension, and the development of the UAE rifted margin and foreland basins. The tectonic subsidence and uplift history at the wells can be explained by a uniform extension model with at least two episodes of rifting punctuated by periods of relative tectonic quiescence and thermal subsidence. An initial age of rifting of 260 Ma and a stretching factor,β, of 1.2 was followed by second period of stretching with an initial age of rifting of 180 Ma, andβ, of 1.1. This model accounts for the general exponential decrease observed in the backstripped tectonic subsidence. The model, fails, however, to completely explain the slow subsidence and uplift history of the margin during Late Triassic to Early Jurassic. We attribute this slow subsidence to combine effect of a sea-level fall and regional uplift which caused major unconformity particularly offshore western Abu Dhabi. The backstrip curves suggest that the transition from an extensional rifted margin to a compressional foreland basin occurred at ~90 Ma, which is within the range for the emplacement of the Semail Ophiolite (95–68 Ma). The history during this time is characterised by uplift followed by rapid subsidence. We attribute these differential vertical movements to orogenic loading and flexure of the Arabian rifted margin by the Semail Ophiolite and development of Aruma foreland basin.