地质通报2016，Vol.35Issue(7)：1123-1133,11.
西秦岭上白垩统红层空间分布及其对青藏高原东北缘隆升的地质约束
Spatial distribution of Upper Cretaceous red beds in the West Qinling Mountains on the northeastern margin of the Tibetan Plateau uplift and its geological constraints
摘要
Abstract
Based on the research on sedimentary characteristics of Upper Cretaceous red bed strata in the West Qinling Mountains and its spatial elevation distribution analysis, this paper discusses possible tectonic geomorphology of the West Qinling Mountains in Late Cretaceous and spatial variation of crustal uplift in the West Qinling Mountains since Cenozoic. The following opinions are sug⁃gested:①According to existence of middle-fine grained red sandstones with aeolian sandstone features on the bottom of alluvial-allu⁃vial gravel layers and appearance of upmost mudstone and muddy siltstone with lake facies sedimentation characteristics in the Upper Cretaceous red bed strata in the West Qinling Mountains, in combination with their present distribution on the different river water⁃shed summit surfaces and similar elevation distributions between two sides of Tanchang-Minxian-Lintan faulted zone and north mar⁃gin fault of West Qinling Mountains, it is believed that no matter how West Qinling Mountains experienced geological evolution his⁃tory before Late Cretaceous period, West Qinling Mountains had the overall stability characterized by ancient tectonic geomorpholo⁃ gy status of a desert and a lake during Late Cretaceous period, and regional faults did not have any control over Cretaceous sedimenta⁃ry strata. ②Prototype basin of Upper Cretaceous red bed sedimentary strata presently discretely distributed in West Qinling Moun⁃tains may be not a series of isolated and regional faults-controlled intermountain basins, but a unified inland lake. Its present discrete distribution results from uneven crustal uplift and erosion since Cenozoic. ③Although the angle unconformity surface on the bottom of the Cretaceous red bed strata in West Qinling Mountains is not horizontal now due to late tectonic deformation events, it is gentle overall. Therefore, from the large-scale regional analysis, it can be regarded as approximate original sub-horizontal palaeogeomorpho⁃logic surface. The angular unconformity surface elevation information extraction and simulation results show that distribution of its el⁃evation gradually decreases from the southwest to the northeast and from the northwest to southeast;the elevation across the fault has no significant gradient, indicating that since Cenozoic uplifting of the West Qinling Mountains has been characterized by integrality and continuous uplift and decrease of uplift amplitude from southwest to northeast. This may indicate that the West Qinling uplift since Cenozoic has not been mainly controlled by the upper crust compression-shortening and thrusting, but may be controlled by the continuous flow of lower crust or upper mantle under the dynamic action of Indo-Eurasian plate collision convergence, which led to northeastward crust thickening and arc-shaped uplift on the northeast margin of the Tibetan Plateau.关键词
青藏高原东北缘/西秦岭/上白垩统/红层地层/角度不整合/数字高程模型/地壳隆升Key words
northeast margin of the Tibetan Plateau/West Qinling Mountains/Upper Cretaceous/red bed strata/unconformity/digi-tal elevation model/uplifting分类
地质学引用本文复制引用
郭进京,向光娅,王利晓,惠浪波,王丽丽..西秦岭上白垩统红层空间分布及其对青藏高原东北缘隆升的地质约束[J].地质通报,2016,35(7):1123-1133,11.基金项目
国家自然科学基金项目 （）
