Timing and record of foreland sedimentation during the initiation of the Sevier orogenic belt in central Utah
Timing and record of foreland sedimentation during the initiation of the Sevier orogenic belt in central Utah
复制标题
犹他州中部塞维尔造山带起始期间前陆沉积的时间和记录
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
P. Heller
中科院分区：
文献类型：
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作者：
Virginia L. Yingling;P. Heller
犹他州中部圣拉斐尔膨胀区的地层记录表明，在阿尔比期，塞维尔造山带的邻近部分开始发生逆冲加载和伴随的前陆沉积作用。区域地层学、等厚线、砾石成分和粒度趋势表明，晚侏罗世的莫里森组和早白垩世的雪松山组的Buckhorn砾岩段并非来自相邻的冲断带，因为它们既没有向西明显变粗，也没有向西明显变粗。相比之下，上成员的雪松山组的Albian年龄和达科他砂岩早期Cenomanian年龄迅速粗化和向西向冲断带，这表明这些单位的沉积在一个快速弯曲沉降的时间在历史上早期的推力加载的塞维尔带。因此，在犹他州中部的前陆盆地的情况下，盆地沉降速率和不对称性提供了最有力的证据，逆冲带加载相邻的塞维尔造山带的启动。
The stratigraphic record in the San Rafael Swell region of central Utah suggests that thrust loading and attendant foreland sedimentation began in adjacent parts of the Sevier orogenic belt during Albian time. Regional stratigraphy, isopachs, gravel composition and grain-size trends suggest that the Morrison Formation of Late Jurassic age and Buckhorn Conglomerate Member of the Cedar Mountain Formation of Early Cretaceous age were not derived from the adjacent thrust belt as they neither thicken nor coarsen significantly towards the west. In contrast, the upper member of the Cedar Mountain Formation of Albian age and Dakota Sandstone of early Cenomanian age rapidly coarsen and thicken westward towards the thrust belt, suggesting that these units were deposited during a time of rapid flexural subsidence early in the history of thrust loading by the Sevier belt. Hence, in the case of the foreland basin in central Utah, basin subsidence rates and asymmetry provides the strongest evidence of the initiation of thrust-belt loading by the adjacent Sevier orogenic belt.