Evolution of the Grenada and Tobago basins and implications for arc migration
Evolution of the Grenada and Tobago basins and implications for arc migration
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DOI：
10.1016/j.marpetgeo.2009.10.003
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发表时间：
2011-01-01
影响因子：
4.2
通讯作者：
Christeson, Gail L.
中科院分区：
文献类型：
--
作者：
Aitken, Trevor;Mann, Paul;Christeson, Gail L.
在动态俯冲环境中，控制火山弧在空间和地质时间内如何迁移的构造机制是一个基本的构造过程，但人们对其了解甚少。本文利用地震反射数据、广角地震折射数据、钻井数据和陆上地质数据，展示了加勒比海东南部晚白垩世至今火山弧及相关盆地的综合地层和构造演化。我们基于三个地震大层序的测绘，为格林纳达盆地和多巴哥盆地的张开以及火山弧火山活动从晚白垩世艾耶斯海岭向东跳跃50 - 250千米到加勒比海东南部的中新世至今的小安的列斯弧提出了一个新的构造模型。格林纳达盆地和多巴哥盆地位于小安的列斯弧两侧，其半地堑结构、相似的平滑基底特征、相似的深海地震相以及在区域地震数据网格上测绘到的相似的古近系沉积厚度惊人地相似，这表明这两个盆地是作为一个单一的、碟形的、与现已休眠的艾耶斯海岭相邻的洋壳古近系弧前盆地形成的。这个单一的弧前盆地在始新世早期到中期可能由于俯冲的大西洋洋壳板块的缓慢后撤而通过挠曲沉降继续延伸和加宽。艾耶斯海岭南部和小安的列斯弧南部与南美洲大陆的斜向碰撞可能加速了后撤。小安的列斯弧南部的抬升和生长在中新世早期到中期将格林纳达盆地和多巴哥盆地分隔开来。小安的列斯弧两侧边缘的正断层反转和抬升效应在其与南美洲大陆碰撞的南部区域最为显著。由于新近纪小安的列斯火山脊的生长和抬升使格林纳达盆地孤立，格林纳达盆地和多巴哥盆地晚中新世至今的沉积历史截然不同。(C) 2009爱思唯尔有限公司。保留所有权利。
The tectonic mechanisms controlling how volcanic arcs migrate through space and geologic time within dynamic subduction environments is a fundamental tectonic process that remains poorly understood. This paper presents an integrated stratigraphic and tectonic evolution of Late Cretaceous to Recent volcanic arcs and associated basins in the southeastern Caribbean Sea using seismic reflection data, wide-angle seismic refraction data, well data, and onland geologic data. We propose a new tectonic model for the opening of the Grenada and Tobago basins and the 50-250-km eastward jump of arc volcanism from the Late Cretaceous Ayes Ridge to the Miocene to Recent Lesser Antilles arc in the southeast Caribbean based on the mapping of three seismic megasequences. The striking similarity of the half-graben structure of the Grenada and Tobago basins that flank the Lesser Antilles arc, their similar smooth basement character, their similar deep-marine seismic facies, and their similar Paleogene sediment thickness mapped on a regional grid of seismic data suggest that the two basins formed as a single, saucer-shaped, oceanic crust Paleogene forearc basin adjacent to the now dormant Ayes Ridge. This single forearc basin continued to extend and widen through flexural subsidence during the early to middle Eocene probably because of slow rollback of the subducting Atlantic oceanic slab. Rollback may have been accelerated by oblique collision of the southern Ayes Ridge and southern Lesser Antilles arc with the South American continent. Uplift and growth of the southern Lesser Antilles arc divided the Grenada and Tobago basins by early to middle Miocene time. Inversion of normal faults and uplift effects along both edges of the Lesser Antilles arc are most pronounced in its southern zone of arc collision with the South American continent. The late Miocene to Recent depositional histories of the Grenada and Tobago basins are distinct because of isolation of the Grenada basin by growth and uplift of the Neogene Lesser Antilles volcanic ridge. (C) 2009 Elsevier Ltd. All rights reserved.