Quantification of the effects of eustasy, subsidence, and sediment supply on Miocene sequences, mid-Atlantic margin of the United States
Quantification of the effects of eustasy, subsidence, and sediment supply on Miocene sequences, mid-Atlantic margin of the United States
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DOI：
10.1130/b25551.1
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发表时间：
2006-05-01
影响因子：
4.9
通讯作者：
Hernández, JC
中科院分区：
文献类型：
--
作者：
Browning, JV;Miller, KG;Hernández, JC
我们使用回剥法来量化全球海平面（海平面）变化、沉降和沉积物供应对美国大西洋中部大陆边缘（新泽西州、特拉华州和马里兰州）中新世地层记录发展的作用。 Eustasy 对序列模式具有主要影响，确定序列的全局模板（即序列可以保存的时间）并解释世界各地中新世序列结构的相似性。整个大西洋中部地区的序列可以与 Sr 同位素年代学相关（+/- 0.6 m.y. 到 +/- 1.2 m.y.）。八个中新世序列在区域上相关，并且可以与全球 Delta O-18 增加相关，表明冰川平衡控制。该边缘主要是被动沉降，几乎没有证据表明活动的构造叠印，除了可能在中新世早期的马里兰州。然而，新泽西州和特拉华州的中新世早期序列显示出拼凑的分布，这可归因于较小（数十米）间隔的过度沉降。 Backstripping 量化了特拉华州大约于 1997 年开始的过度沉降。 21 Ma 一直持续到 12 Ma，最大速率从大约 12 Ma 开始。 21-16 马。我们将这种增强的沉降归因于近海和邻近该区域的厚层层进积的局部弯曲响应。消除特拉华州的过度沉降产生的记录与新泽西州的海平面上升估计值非常相似。我们得出的结论是，海平面上升和下降是对住宿的一阶控制，在所有边缘上提供与序列记录相似的时间。地壳运动引起的构造变化可能会叠印记录，导致地层记录出现较大间隙。序列中较小的差异可归因于局部弯曲载荷效应，特别是在经历大规模进积的区域。
We use backstripping to quantify the roles of variations in global sea level (eustasy), subsidence, and sediment supply on the development of the Miocene stratigraphic record of the mid-Atlantic continental margin of the United States (New Jersey, Delaware, and Maryland). Eustasy is a primary influence on sequence patterns, determining the global template of sequences (i.e., times when sequences can be preserved) and explaining similarities in Miocene sequence architecture on margins throughout the world. Sequences can becorrelated throughoutthe mid-Atlantic region with Sr-isotopic chronology (+/- 0.6 m.y. to +/- 1.2 m.y.). Eight Miocene sequences correlate regionally and can be correlated to global delta O-18 increases, indicating glacioeustatic control. This margin is dominated by passive subsidence with little evidence for active tectonic overprints, except possibly in Maryland during the early Miocene. However, early Miocene sequences in New Jersey and Delaware display a patchwork distribution that is attributable to minor (tens of meters) intervals of excess subsidence. Backstripping quantifies that excess subsidence began in Delaware at ca. 21 Ma and continued until 12 Ma, with maximum rates from ca. 21-16 Ma. We attribute this enhanced subsidence to local flexural response to the progradation of thick sequences offshore and adjacent to this area. Removing this excess subsidence in Delaware yields a record that is remarkably similar to New Jersey eustatic estimates. We conclude that sea-level rise and fall is a firstorder control on accommodation providing similar timing on all margins to the sequence record. Tectonic changes due to movement of the crust can overprint the record, resulting in large gaps in the stratigraphic record. Smaller differences in sequences can be attributed to local flexural loading effects, particularly in regions experiencing largescale progradation.