Sea‐level and ocean‐current control on carbonate‐platform growth, Maldives, Indian Ocean
Sea‐level and ocean‐current control on carbonate‐platform growth, Maldives, Indian Ocean
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DOI：
10.1111/j.1365-2117.2012.00554.x
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发表时间：
2013-04
期刊：
影响因子：
3.2
通讯作者：
C. Betzler;J. Fürstenau;T. Lüdmann;Christian Hübscher;S. Lindhorst;A. Paul;J. Reijmer;A. Droxler
中科院分区：
文献类型：
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作者：
C. Betzler;J. Fürstenau;T. Lüdmann;Christian Hübscher;S. Lindhorst;A. Paul;J. Reijmer;A. Droxler
从印度洋马尔代夫孤立的碳酸盐平台获得了多通道高分辨率地震和多波束数据，以详细描述这座建筑物的新近系岸边建筑。这项研究的目的是破译平台演化的控制因素，特别是海平面变化和洋流变化。早中新世沉积层序的堆积模式，随着斜坡几何形状向平顶台地的演化，反映了可容空间的变化，这里提出主要受相对海平面的波动控制。在河岸增长的这一阶段，东流控制了河岸边缘不对称的向东推进。在中新世晚期，这一体系被银行发展的双重格局所取代。随着部分岸滩的消亡和伴随的泥沙-漂流沉积，岸坡继续同步增长。这种转变归因于印度季风的开始和/或加强以及与之相关的上升流和洋流的出现，局部环境条件的变化和对碳酸盐体系的冲击。由逆流形成的巨型溢流形成了大规模的进积杂岩，以前被解释为强迫海退期间形成的沉积。在区域尺度上，可发生复杂的碳酸盐台地生长，岸缘进积与沉积并存，部分淹没。进一步表明，碳酸盐岩台地的床面形态和叠置几何形状的下移并不一定预示着海平面驱动的强迫海退。这些发现预计将适用于印度-太平洋地区其他新生代平台的例子。
Multichannel high‐resolution seismic and multibeam data were acquired from the Maldives‐isolated carbonate platform in the Indian Ocean for a detailed characterization of the Neogene bank architecture of this edifice. The goal of the research is to decipher the controlling factors of platform evolution, with a special emphasis on sea‐level changes and changes of the oceanic currents. The stacking pattern of Lower to Middle Miocene depositional sequences, with an evolution of a ramp geometry to a flat‐topped platform, reflects variations of accommodation, which here are proposed to be primarily governed by fluctuations of relative sea level. Easterly currents during this stage of bank growth controlled an asymmetric east‐directed progradation of the bank edge. During the late middle Miocene, this system was replaced by a twofold configuration of bank development. Bank growth continued synchronously with partial bank demise and associated sediment‐drift deposition. This turnover is attributed to the onset and/or intensification of the Indian monsoon and related upwelling and occurrence of currents, locally changing environmental conditions and impinging upon the carbonate system. Mega spill over lobes, shaped by reversing currents, formed as large‐scale prograding complexes, which have previously been interpreted as deposits formed during a forced regression. On a regional scale, a complex carbonate‐platform growth can occur, with a coexistence of bank‐margin progradation and aggradation, as well as partial drowning. It is further shown that a downward shift of clinoforms and offlapping geometries in carbonate platforms are not necessarily indicative for a sea‐level driven forced regression. Findings are expected to be applicable to other examples of Cenozoic platforms in the Indo‐Pacific region.