羌塘地块东南部上三叠统巴贡组软沉积变形特征及其意义  

Characteristics and Its Significance of Soft Sedimentary Deformations of the Upper Triassic Bagong Formation in Southeastern Qiangtang Block

作　　者：杜芳鹏 王建强[1] 牛军强[2] 谭富荣[2] 杨创[2] 闫明明 

机构地区：[1]大陆动力学国家重点实验室/西北大学地质学系,西安710069 [2]中国煤炭地质总局航测遥感局,西安710054 [3]中石油煤层气有限责任公司忻州分公司,山西忻州036600

出　　处：《吉林大学学报（地球科学版）》2016年第3期661-670,共10页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41330315);中国地质调查局地质调查项目(12120113074300)~~

摘　　要：羌塘地块东南部巴青、索县一带,在上三叠统巴贡组内发育大量未固结状态下发生的软沉积变形。其形态特征主要表现为枕状、球状、链状以及卷曲状,在平面较大范围内均有发现,纵向上密集分布,100余米长的扎德改剖面中发育有7层明显的软沉积变形构造。经过详细地变形特征描述与比对,认为这些软沉积变形主要是与地震振动相关的震积岩,部分变形清晰地显示出受伸展背景的控制。震积岩是软沉积物对古构造活动的记录,研究区内巴贡组震积岩的密集发育表明巴贡组沉积期区域构造活动强烈,对比晚三叠世早期地层中震积岩的发育状况,发现构造活动在诺利中晚期更加强烈,与羌塘地块中晚三叠世火山岩的年代呼应。Within the Bagong Formation of Upper Triassic in Suoxian-Baqing,southeastern Qiangtang block,there are a large number of soft sedimentary deformation which formed in unconsolidated sediments. Their morphological characteristics mainly figured as pillow, ball, chain and curl. There are 7 layers of soft sedimentary deformation have been recognized along Zhadegai section with a total length of 100 m. Based on a detailed description and comparison of the deformation characteristics,these soft sedimentary deformations are classified as seismite,some deformations clearly show that the deformation is controlled by tensile stress.Seismite is the record of palaeotectonic activities in soft sediments. Densely dispersed soft sedimentarydeformations in Bagong Formation shows that it was a tectonic active area at Upper Triassic. Compared with seismites in earlier Upper Triassic strata,we find that the tectonic activities are more intensely in Middle-Late Norian,which responds to ages of volcanic rocks in central Qiangtang block.

关 键 词：羌塘地块 巴青地区 软沉积变形 巴贡组 晚三叠世 

分 类 号：P642.22[天文地球—工程地质学]