Effects of contemporaneous orogenesis on sedimentation in the Late Cretaceous Western Interior Basin, northern Utah and southwestern Wyoming
Effects of contemporaneous orogenesis on sedimentation in the Late Cretaceous Western Interior Basin, northern Utah and southwestern Wyoming
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DOI：
10.1111/bre.12623
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发表时间：
2019-12
期刊：
影响因子：
3.2
通讯作者：
E. M. Davis;K. Rudolph;J. Saylor;T. Lapen;J. Wellner
中科院分区：
文献类型：
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作者：
E. M. Davis;K. Rudolph;J. Saylor;T. Lapen;J. Wellner
在西部内陆盆地中确认了三个沉降驱动因素：与薄皮向东传播的Sevier造山运动相邻的中生代-早新生代挠曲，与厚皮Laramide隆起相关的晚白垩世-始新世挠曲和晚白垩世动力沉降。本研究结合露头岩相，古水流测量，碎屑锆石地质年代学，生物地层学，地层对比和等厚图的Coniacian-Maastrichtian（89-66马）单位，以确定这些沉降机制对盆地几何形状和地层结构的影响在北方犹他州西南部怀俄明州段的北美科迪勒拉。碎屑锆石最大沉积年龄和生物地层学支持马斯特里赫特期哈姆斯福克砾岩沉积在楔顶和前渊沉积带的艾草不整合之上。艾草不整合面位于远前渊的跨大陆埃里克森组之下。然而，Hams Fork比Ericson Formation更年轻，相当于上Almond Formation。因此，与艾草不整合面相关的间断在褶皱带和近端盆地中比在远端前渊中持续了数百万年，而埃里克森组等效地层则向西覆盖在艾草不整合面上。区域厚度模式记录并限制了从Sevier到Laramide式构造体制过渡的时间。从88到83 Ma（上部巴克斯特组），一个向西增厚的地层楔，其特征是由逆冲带加载引起的岩石圈挠曲形成的前渊。然而，距离冲断前缘>200 km的>500 m沉降的存在表明与动力沉降一致的长波沉降机制。到83 Ma（布莱尔组），长波沉积中心从冲断带移开，没有证据表明塞维尔前渊。这一沉积中心在坎帕尼亚早期中期继续向东迁移。81-77 Ma）。Campanian-Maastrichtian（英语：Campanian-Maastrichtian）74-66 Ma）以靠近风河、花岗岩和Uinta山隆起的狭窄沉积楔为标志，并归因于Laramide变形的弯曲载荷。
Three drivers of subsidence are recognized in the Western Interior Basin: Mesozoic–early Cenozoic flexure adjacent to the thin‐skinned, eastward propagating Sevier Orogeny, Late Cretaceous–Eocene flexure associated with thick‐skinned Laramide Uplifts and Late Cretaceous dynamic subsidence. This study combines outcrop lithofacies, palaeocurrent measurements, detrital zircon geochronology, biostratigraphy, stratigraphic correlations and isopach maps of Coniacian–Maastrichtian (89–66 Ma) units to identify these subsidence mechanisms impact on basin geometry and stratigraphic architecture in the northern Utah to southwestern Wyoming segment of the North American Cordillera. Detrital zircon maximum depositional ages and biostratigraphy support that the Maastrichtian Hams Fork Conglomerate was deposited above the Moxa unconformity in the wedgetop and foredeep depozones. The Moxa unconformity underlies the progradational Ericson Formation in the distal foredeep. The Hams Fork, however, is younger than the Ericson Formation, and instead equivalent to upper Almond Formation. Therefore, the hiatus associated with the Moxa unconformity continued for several million years longer in the fold belt and proximal basin than in the distal foredeep, with Ericson Formation‐equivalent strata onlapping the Moxa unconformity towards the west. Regional thickness patterns record and constrain the timing of the transition from Sevier to Laramide‐style tectonic regimes. From 88 to 83 Ma (upper Baxter Formation) a westward‐thickening stratigraphic wedge characterized the foredeep developed by lithospheric flexure by thrust‐belt loading. Nevertheless, the presence of >500 m of subsidence >200 km from the thrust front suggests a long‐wavelength subsidence mechanism consistent with dynamic subsidence. By 83 Ma (Blair Formation) the long‐wavelength depocentre shifted away from the thrust belt, with no evidence of a Sevier foredeep. This depocentre continued migrating eastward during the early‐mid Campanian (ca. 81–77 Ma). The late Campanian–Maastrichtian (ca. 74–66 Ma) is marked by narrow sedimentary wedges adjacent to the Wind River, Granite and Uinta Mountain uplifts and attributed to flexural loading by Laramide deformation.