Dynamic versus flexural controls of Late Cretaceous Western Interior Basin, USA
Dynamic versus flexural controls of Late Cretaceous Western Interior Basin, USA
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DOI：
10.1016/j.epsl.2014.01.006
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发表时间：
2014-03
影响因子：
5.3
通讯作者：
Shaofeng Liu;D. Nummedal;M. Gurnis
中科院分区：
文献类型：
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作者：
Shaofeng Liu;D. Nummedal;M. Gurnis
美国白垩纪西部内陆盆地一直被认为是前陆盆地，由塞维尔逆冲断层和相关的盆地沉积物负荷驱动。然而，挠曲研究表明，这种影响只存在于冲断带前面的一个狭窄的带。盆地的大部分似乎是由于与Farallon板块俯冲有关的地幔流引起的动态沉降。在这里，我们展示了如何不断发展的长波动态沉降和挠曲沉降的组件创建的可容纳空间，并控制整个美国西部的地层，根据相关的地层剖面横跨中部犹他州和科罗拉多。这些回剥沉降数据揭示了西部内陆盆地的动态地形驱动的性质。结果似乎支持沉积中心以约1000 km的速度跟踪动力沉降槽的观点。1800万年的时空旋回和大规模剥蚀、沉积中心东移、区域性斜坡状下超的地层样式与动力沉降有关。这些数据的解释也提供了更多的见解重复，约。冲断带前缘2 ~ 600万年旋回的冲断沉降控制了冲断带砂体的局部东侵。动力、挠曲沉降和海平面变化相互作用，控制了不整合面的形成时间和分布。我们的工作显示了地层学如何精确地记录动态与挠曲沉降的时间、模式和位置，这些数据的组合导致了重要的地球物理发现，并为地球动力学建模提供了严格的约束。
The United States Cretaceous Western Interior Basin has long been considered a foreland basin, driven by the Sevier thrust and associated basin sediment loads. However, flexural studies demonstrate that this effect exists only within a narrow band in front of the thrust belt. Most of the basin appears to be due to mantle flow-induced dynamic subsidence associated with Farallon plate subduction. Here we show how the components of evolving long-wavelength dynamic subsidence and flexural subsidence created the accommodation space and controlled the stratigraphy across the western United States, based on a correlated stratigraphic section across central Utah and Colorado. These backstripped subsidence data reveal the dynamic-topography driven nature of the Western Interior Basin. The results seem to support that the depocenters track the trough of dynamic subsidence with ca. 18 Myr cycles through time and space and the stratigraphic patterns of large-scale progradation, eastward migration of depocenter, and regional clinoform-like downlap are related with the dynamic subsidence. Interpretation of these data also provides more insights into the repeated, ca. 2 to 6 Myr cycles of thrust-induced subsidence in front of the thrust belt, which control the local eastward progradation of the sand bodies from the thrust belt. The dynamic, flexural subsidence and eustatic sea level changes interacted and controlled the timing and distribution of unconformities. Our work shows how the stratigraphy precisely records the timing, patterns and position of dynamic versus flexural subsidences, and that combination of such data leads to important geophysical discoveries and supplies strict constraints for geodynamic modeling.