杨运军, 韩旭, 边小卫, 张满社, 张明运. 陕西勉略宁三角区略阳群沉积环境及原型盆地分析[J]. 地质通报, 2020, 39(10): 1549-1560.
    引用本文: 杨运军, 韩旭, 边小卫, 张满社, 张明运. 陕西勉略宁三角区略阳群沉积环境及原型盆地分析[J]. 地质通报, 2020, 39(10): 1549-1560.
    YANG Yunjun, HAN Xu, BIAN Xiaowei, ZHANG Manshe, ZHANG Mingyun. An analysis of sedimentary environment and prototype basin of Lueyang Group in the Mian-Lue-Ning triangle area Shaanxi Province[J]. Geological Bulletin of China, 2020, 39(10): 1549-1560.
    Citation: YANG Yunjun, HAN Xu, BIAN Xiaowei, ZHANG Manshe, ZHANG Mingyun. An analysis of sedimentary environment and prototype basin of Lueyang Group in the Mian-Lue-Ning triangle area Shaanxi Province[J]. Geological Bulletin of China, 2020, 39(10): 1549-1560.

    陕西勉略宁三角区略阳群沉积环境及原型盆地分析

    An analysis of sedimentary environment and prototype basin of Lueyang Group in the Mian-Lue-Ning triangle area Shaanxi Province

    • 摘要: 陕西勉略宁三角区北部晚古生代略阳群沉积岩系广泛发育,主要分布于南秦岭摩天岭地块东段及勉略结合带附近。长期以来对其地层划分、沉积环境及沉积盆地认识存在较大分歧,野外调查研究认为,略阳群具有分布广,岩石组合复杂、沉积环境多样(构造变形较强)的特点。其下部踏坡组发育粗→细碎屑岩构成的韵律型-旋回型沉积层序,按沉积水体自浅而深可分为3段:下段粗碎屑岩来自不同源区山前冲积扇相的近源沉积,古水流方向由南向北;中上段以发育中细粒碎屑岩局部夹海底扇水道沉积为特征,代表海陆交互三角洲相(三角洲前缘亚相和前扇三角洲亚相),踏坡组总体反映为受古地理地形限制的山前冲积扇-海陆交互三角洲相(局部海底扇亚相)环境;上部略阳组主体为碳酸盐台地相(台地边缘浅滩-生物礁-台地泻湖亚相)和斜坡相沉积环境。以略阳群为代表的沉积作用及物质记录了摩天岭地块北缘-勉略地区晚古生代裂陷→局限稳定台盆背景的沉积事件。其沉积环境研究表明,略阳群是摩天岭地块东段于晚古生代发育于褶皱基底之上的陆缘局限盆地,该认识有助于反演勉略宁三角区晚古生代盆地沉积机制和构造演化模型。

       

      Abstract: Lueyang Group sedimentary rock of the Late Paleozoic is located in the Mian-Lue-Ning triangle area, Shaanxi Province. It is mainly distributed in the east of Motianling block and Mian-Lue suture of South Qinling Mountain. According to field survey, there are differences in sedimentary environment and Prototype basin. Lueyang Group. is characterized by wide distribution, complex rock assemblage and diverse sedimentary environment. The rhythm-cyclic sedimentary sequence composed of coarse to fine clastic rocks developed in Tapo Formation can be divided into three sections. The lower section includes the coarse clastic rocks from alluvial fan of different source areas, and the ancient water direction is from south to north; the middle-upper section is characterized by the sedimentary deposits of the middle-high grained clastic rocks, which represent the delta environment. Lueyang Formation consists of carbonate platform facies and slope facies. The sedimentary action and material records represented by the Tapo Group marked the deposition events of late Paleozoic rifting and confined stabilization basin background on the east margin of the Motianling block and Mian-Lue suture. The research has great significance in the study of tectonic evolution in Mian-Lue-Ning triangle area.

       

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