Sea level influence on the nature and timing of a minibasin sedimentary fill (northwestern slope of the Gulf of Mexico)
Sea level influence on the nature and timing of a minibasin sedimentary fill (northwestern slope of the Gulf of Mexico)
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DOI：
10.1306/02210605058
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发表时间：
2006-07
期刊：
影响因子：
3.5
通讯作者：
Gianni Mallarino;R. Beaubouef;A. Droxler;V. Abreu;L. Labeyrie
中科院分区：
文献类型：
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作者：
Gianni Mallarino;R. Beaubouef;A. Droxler;V. Abreu;L. Labeyrie
本文主要研究了墨西哥湾西北部Brazos-Trinity小型盆地斜坡体系末端4号盆地的沉积充填。15个巨型柱塞岩心的多层地层分析结果提供了(1)关于沉积充填的性质（半深海与重力诱导的泥砂沉积）和时间的重要信息；(2)该体系演化的主要年代地层制约因素；(3)众所周知的海平面变化旋回与盆地填充物中清晰成像的沉积物之间存在密切联系。在115 - 15ka之间的海平面逐步下降过程中，盆地4的重力流沉积发生并增加了其重要性，并在墨西哥湾约14ka的融水高峰之前明显停止。盆地4的重力沉积发生在海洋同位素阶段（MIS） 5d （115 ka）。这一发现表明，砂质浊度流达到这种远端设置是在一般高海平面时间内海平面下降频率更高的结果（MIS 5）。90 ~ 45ka的半深海沉积间隔说明了盆地4重力沉积的停止。浊积砂沉积在MIS 3中期恢复，向MIS 2方向增加（大约在30 ~ 15 ka）。水库级砂质沉积物的最大比例沉积在末次盛冰期最高海平面低洼处，这与深水沉积的层序-地层模式的主流观点一致。
This study focuses on the sedimentary fill of basin 4, the termination of the Brazos-Trinity minibasin slope system in the northwestern Gulf of Mexico. Results from multistratigraphic analyses of 15 giant piston cores provided (1) important information regarding the nature (hemipelagic versus gravity-induced mud and sand deposits) and the timing of the sedimentary fill; (2) some key chronostratigraphic constraints for the evolution of this system; and (3) strong links between well-known cycles of sea level change to clearly imaged deposits in the fill of basin 4. Gravity-flow–induced sedimentation in basin 4 occurred and increased in importance during the stepwise sea level regression that developed between 115 and 15 ka and clearly ceased just prior to the meltwater spike in the Gulf of Mexico dated at about 14 ka. The onset of gravity-induced deposition in basin 4 is dated at marine isotope stage (MIS) 5d (115 ka). This finding implies that sandy turbidity currents reached this distal setting as a consequence of a higher frequency sea level fall within a time of general high sea level (MIS 5). An interval of hemipelagic sedimentation lasting from 90 to 45 ka illustrates cessation of gravity-induced deposits in basin 4. Turbidite sandy deposits resumed in mid-MIS 3 and increased toward MIS 2 (approximately from 30 to 15 ka). The largest proportion of reservoir-grade sandy sediment was deposited during the maximum sea level lowstand of the last glacial maximum, consistent with the prevailing view of sequence-stratigraphic models for deep-water deposition.