湘西北渔塘地区寒武系清虚洞组风暴岩及其地质意义

在湘西北渔塘地区,下寒武统的清虚洞组下部发育一套地质特征典型、沉积序列特殊的风暴岩。其底面侵蚀构造清楚,覆盖于底面上的各层段厚度变化较大,在各层段内由下向上碎屑粒度依次变细,并相继出现叠加式丘状交错层理、平行层理和浪成沙纹层理等沉积构造,是典型的浅海风暴岩。该风暴沉积的发现,对建立湘西北地层的沉积学剖面、探讨该区风暴沉积模式的空间变化、明确成矿环境和成矿地质特征等具有重要意义。

Significance of Tempestite from the Cambrian Qingxudong Formation in Yutang Area of Northwestern Hunan Province

There is a unique succession of tempestite,with typical geological characteristics and special sedimentary sequence,from the Lower Cambrian Qingxudong Formation of Yutang area in northwestern of Hunan Province.Erosional bases at the tempestite sequences are clear.Thickness variation of each section is great,grain size of clastic sediments is fining-upward.Superposed hummocky cross-lamination,parallel bedding and ripple-bedding are common.All of these features indicate sedimentation in an offshore environment.The succession of tempestite had important fundamental implication for us to creat sedimentological section and proble into the space variation characteristics of tempestite sedimentary pattern and make sure metallogenical environment or metallogenical geological characteristics.