Multiphased tectonic evolution of the Central Algerian margin from combined wide‐angle and reflection seismic data off Tipaza, Algeria
Multiphased tectonic evolution of the Central Algerian margin from combined wide‐angle and reflection seismic data off Tipaza, Algeria
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DOI：
10.1002/jgrb.50318
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发表时间：
2013-08
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通讯作者：
A. Leprêtre;Frauke Klingelhoefer;D. Graindorge;P. Schnurle;M. Beslier;K. Yelles;J. Déverchère;R. Bracène
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文献类型：
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作者：
A. Leprêtre;Frauke Klingelhoefer;D. Graindorge;P. Schnurle;M. Beslier;K. Yelles;J. Déverchère;R. Bracène
阿尔及利亚边缘的起源仍然是西地中海仍在讨论的关键问题之一，由于不精确的性质和运动学的相关盆地在新近纪。在SPIRAL地震勘测期间，首次探索了马格里布边缘的深部结构。在这项工作中，我们提出了一个N-S样带关闭蒂帕萨（阿尔及尔以西），一个地方的边缘扩大，由于地形高（Khayr‐al‐Din银行）。新的深穿透地震剖面使我们能够对阿尔及利亚盆地的沉积序列和大陆-海洋边界的地壳结构进行成像。广角数据的建模显示，基底变薄，从大陆上边缘的15公里以上到阿尔及利亚盆地的5- 6公里的海洋型基底，并揭示了一个非常狭窄或不存在的过渡带。对边缘深部结构的分析表明，其复杂演化继承了以下特征：（1）深盆中的洋壳;（2）与转换型环境中形成的边缘相似;（3）整个沉积盖层逐渐加深，边缘脚的上新世-第四纪沉积物增厚，与（4）盆地基底向下弯曲。这些特征表明边缘的多阶段演化，包括（1）早期裂陷和/或扩张阶段，（2）与Alboran域向西迁移有关的晚期横流事件，以及（3）边缘的扩散Plio-第四纪压缩再活化。
The origin of the Algerian margin remains one of the key questions still discussed in the Western Mediterranean sea, due to the imprecise nature and kinematics of the associated basin during the Neogene. For the first time, the deep structure of the Maghrebian margin was explored during the SPIRAL seismic survey. In this work, we present a N‐S transect off Tipaza (west of Algiers), a place where the margin broadens due to a topographic high (Khayr‐al‐Din Bank). New deep penetration seismic profiles allow us to image the sedimentary sequence in the Algerian basin and the crustal structure at the continent‐ocean boundary. Modeling of the wide‐angle data shows thinning of the basement, from more than 15km in the continental upper margin to only 5–6km of oceanic‐type basement in the Algerian basin, and reveals a very narrow or absent transitional zone. Analysis of the deep structure of the margin indicates features inherited from its complex evolution: (1) an oceanic‐type crust in the deep basin, (2) similarities with margins formed in a transform‐type setting, (3) a progressive deepening of the whole sedimentary cover, and the thickening of the Plio‐Quaternary sediments at the margin foot, coeval with (4) a downward flexure of the basement in the basin. These features argue for a multiphased evolution of the margin, including (1) an early stage of rifting and/or spreading, (2) a late transcurrent episode related to the westward migration of the Alboran domain, and (3) a diffuse Plio‐Quaternary compressional reactivation of the margin.