Relation of thin-skinned thrusting of Colorado Plateau strata in southwestern Utah to Cenozoic magmatism
Relation of thin-skinned thrusting of Colorado Plateau strata in southwestern Utah to Cenozoic magmatism
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犹他州西南部科罗拉多高原地层薄皮逆冲与新生代岩浆作用的关系
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
Pierre A. Gourlay
中科院分区：
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作者：
O. Merle;G. Davis;R. P. Nickelsen;Pierre A. Gourlay
对犹他州西南部高原上白垩纪和始新世沉积岩的构造研究试图确定薄层逆冲断层和相关构造的区域尺度弧形模式所表示的层间平行缩短的原因。逆冲断层仅限于卡梅尔组的侏罗系碳酸盐岩。构造输导方向为125° ~ 215°放射状。应力分析显示，主挤压应力呈扇形，沿着横跨庞索冈高原35公里的弧形，以90°的角度从东南向南-南-向西扫过。Sevier和Laramide成因的区域挤压构造比薄皮变形更古老，而Basin和Range成因的区域伸展构造更年轻。逆冲推覆作用发生在始新世克拉伦组沉积之后，可能发生在30 ~ 20 Ma，即与位于逆冲推覆带西北40 ~ 60 km处的Marysvale火山中心的形成同期。形成冲断层的力量可能是通过与Marysvale火山中心形成动力学相关的过程组合而形成的，包括与岩基侵入体就位相关的重力滑动和/或挤压推动，以及与柱体垂直载荷相关的重力扩展和/或端部载荷，以及厚Marysvale火山堆重量造成的下方蒸发岩滑脱。
Structural studies in Upper Cretaceous and Eocene sedimentary rocks in the High Plateaus of southwestern Utah attempted to establish the cause of layer-parallel shortening expressed in a regional-scale arcuate pattern of thin-skinned thrusts and related structures. The thrusts sole into Jurassic evaporites of the Carmel Formation. Tectonic transport direction verges radially from 125° to 215°. Stress analysis reveals a fan-like pattern of the principal compressional stress sweeping southeastward to south-south-westward through 90° along an arc extending 35 km across the Paunsaugunt Plateau. Regional compressional structures of Sevier and Laramide origin are older than the thin-skinned deformation, and regional extensional structures of Basin and Range origin are younger. The thrusting postdates deposition of the Claron Formation (Eocene) and probably took place in the interval 30 Ma to 20 Ma, that is, coeval with the formation of the Marysvale volcanic center located 40 to 60 km northwest of the thrust belt. The forces that created the thrusts could have formed through a combination of processes related to the dynamics of formation of the Marysvale volcanic center, including gravity gliding and/or compressional push related to the emplacement of batholithic intrusions, and gravitational spreading and/or end-loading related to vertical loading of the column and the underlying evaporite decollement by the weight of the thick Marysvale volcanic pile.