Filter Or Conveyor? Establishing Relationships Between Clinoform Rollover Trajectory, Sedimentary Process Regime, and Grain Character Within Intrashelf Clinothems, Offshore New Jersey, U.S.A.
Filter Or Conveyor? Establishing Relationships Between Clinoform Rollover Trajectory, Sedimentary Process Regime, and Grain Character Within Intrashelf Clinothems, Offshore New Jersey, U.S.A.
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DOI：
10.2110/jsr.2018.44
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发表时间：
2018-08
影响因子：
2
通讯作者：
G. I. Cosgrove;D. Hodgson;M. Poyatos‐Moré;N. Mountney;W. McCaffrey
中科院分区：
文献类型：
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作者：
G. I. Cosgrove;D. Hodgson;M. Poyatos‐Moré;N. Mountney;W. McCaffrey
摘要斜形几何形状和轨迹被广泛用于预测沙分布的时空演变，但大多数分析方法低估了顶置和陆架过程机制在确定沉积物如何以及何时向下倾输送或储存在大陆架上的重要性。我们提出了一个综合研究的斜坡翻转轨迹和详细的颗粒特征分析，以评估顶置过程制度的作用，在确定砂分布和沉积物的性质，在整个斜坡。本研究的目标是顶置，前积和底置存款的四个连续的中新世intrashelf斜坡序列，这代表沉积下，无论是河流为主或波浪为主的条件。将地震反射数据与从三个取芯研究钻孔收集的664个样品的岩心分析和颗粒特征数据相结合。在河流为主的斜坡，粗颗粒泥沙的转移发生在上升和平坦下降的斜坡翻转轨迹，这表明过程制度是更重要的，在确定泥沙输送比斜坡轨迹;河流为主的系统是有效的输送机的泥沙进入更深的水。波浪主导的斜坡层沉积完全在上升的斜坡翻转轨迹主要保留砂顶积层和前积层沉积;波浪主导的系统是有效的沉积物过滤器。值得注意的是，沉积下无论是河流或波浪为主的顶置过程制度的结果在颗粒特征属性沿着斜坡剖面可量化的差异。河流为主的系统中的沉积物是粗糙的，不太圆润，更差的排序，并表现出更大的序列间和序列内的变化比那些在波浪为主的系统，预测沉积物的特点是更具挑战性的河流为主的系统。这项研究强调了需要谨慎时，试图预测下倾砂体分布单独从斜坡轨迹，并提供了一个新的视角下下倾颗粒特征配置文件端元顶置工艺制度条件。研究结果可用于更好地约束沉积物粒度和粒度形状分布在基于过程的正演模型，并在预测储层质量的边缘和成熟的油气盆地具有广泛的应用。
Abstract Clinoform geometries and trajectories are widely used to predict the spatial and temporal evolution of sand distribution, but most analytical approaches underplay the significance of topset and shelf process regime in determining how and when sediment is conveyed downdip or stored on the continental shelf. We present an integrated study of clinoform rollover trajectory and detailed grain character analysis to assess the role of topset process regime in determining sand distribution and sediment character across clinothems. This study targets the topset, foreset, and bottomset deposits of four successive Miocene intrashelf clinothem sequences, which represent deposition under either river-dominated or wave-dominated conditions. Seismic reflection data was combined with core analysis and grain character data derived from 664 samples collected from three cored research boreholes. In river-dominated clinothems, the transfer of coarse-grained sediment occurs under both rising and flat-to-falling clinoform rollover trajectories, suggesting that process regime is more important in determining sediment delivery than clinoform trajectory; river-dominated systems are effective conveyors of sediment into deeper water. Wave-dominated clinothems deposited exclusively under rising clinoform rollover trajectories largely retain sand within topset and foreset deposits; wave-dominated systems are effective sediment filters. Notably, deposition under either river- or wave-dominated topset process regimes results in quantifiable differences in grain character attributes along clinoform profiles. Sediments in river-dominated systems are coarser, less well-rounded, and more poorly sorted, and show greater intersequence and intrasequence variability than those in wave-dominated systems; prediction of sediment character is more challenging in river-dominated systems. This study highlights the need for caution when attempting to predict downdip sand distribution from clinoform trajectory alone, and provides a novel perspective into downdip grain character profiles under end-member topset process regime conditions. The results of this study can be used to better constrain sediment grain-size and grain-shape distributions in process-based forward models, and have widespread applications in prediction of reservoir quality in both frontier and mature hydrocarbon basins.