西秦岭造山带泥盆纪沉积地质学和动力沉积学研究:西秦岭中带泥盆纪小型克拉通盆地的沉积特征及盆地格局
SEDIMENTARY GEOLOGY AND DYNAMIC SEDIMENTOLOGY OF THE DEVONIAN STRATA IN THE WEST QINLING OROGENIC BELT: SEDIMENTARY CHARACTERISTICS AND FRAMEWORK OF THE SMALL-SCALE DEVONIAN CRATONIC BASIN IN THE MIDDLE BELT OF THE WEST QINLING OROGENIC BELT
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摘要: 秦岭微板块位于商丹-武山和勉略-巴山弧断裂之间。泥盆纪时期,微板块主体处于稳定的小型克拉通盆地背景。本文仅从西秦岭中带泥盆系入手,探讨该区泥盆系的沉积体系和盆地格局。小型克拉通盆地北带的西汉水小区以古岛屿滨岸-陆棚沉积体系(艾菲尔期)、碳酸盐台地-生物礁沉积体系(吉维特-弗拉斯期)、深水盆地和泥质浊积岩沉积体系(法门期)为特征。南带武都小区则以陆棚碎屑岩(艾菲尔期)和缓坡型台地-陆棚沉积体系(吉维特-法门期)为主,该小型克拉通,泥盆纪时期是一稳定块体,到二叠纪-三叠纪才受中秦岭裂陷槽分隔成两个块体。Abstract: The Qinling microplate lies between the Shangnan-Danfeng-Wushan and Mianxian-Lueyang-Bashan arc faults.During the Devonian,the bulk of it was in a stable small cra-tonic basin.The present paper focuses on the Devonian sedimentary systems and basin framework viewed from stratigraphy and sedimentology of the Devonian strata in the mid-dle belt of West Qinling orogenic belt.The Xihanhui microprovince in northern cratonic basin is characterized by the terrigenous littoral-shelf depositional systems around palaeo-islands (Eifelian),carbonate platform-organic reef depositional systems (Givetian to Frasian),and deep-water basin and muddy turbidite depositional systems (Famennian), while the Wudu microprovince in southern cratonic basin is dominated by the terrigenous shelf depositional (Eifelian) and ramp-type carbonate platform-shelf depositional systems (Givetian to Famennian).The stable cratonic basin was broken up into two parts by the central Qinling rift trough during the Permian to Triassic.