黔南地区早二叠世大幅度冰川性 海平面下降的沉积学新证据

众所周知,石炭纪-二叠纪期间冈瓦纳大陆冰盖的推进和消融在低纬度地区形成了许多高频海平面升降变化和广泛分布的旋回沉积.最新研究表明,石炭纪-二叠纪冰室气候时期的大陆冰盖是由一系列不连续的冰期组成.因此石炭纪-二叠纪期间既存在高频低幅的海平面变化,也发育多次大幅度海平面下降.前者在华南地区已有研究证实,后者仍需要深入研究.描述了贵州龙吟和紫云扁平剖面早二叠世碳酸盐岩地层中古岩溶特征,包括垮塌角砾岩及相关沉积构造,分别对应早二叠世两次冰期导致的显著海平面下降,对深入了解华南地区早二叠世古地理演化具有重要意义. 

Sedimentary Records of Early Permian Major Glacial Sea-Level Falls in Southern Guizhou Province,China

As is well-known, the waxing and waning of the Gondwanan ice sheet contributed to high-frequency glacioeustatic sea 1eve1 fluctuations and widely distributed cyc1othems in the1ow-1atitudes during the Carboniferous-Permian Period. Recent inves- tigations suggest that the Permo-Carboniferous Ice Age is composed of a series of distinct episodes of glaciation and interglacia- tion.It has been confirmed thc glaciocustatic sca-level changes controlled thc high ircqucncy and1ow amplitudc sca-level changcs in South China during the Carboniferous-Permian Period, but the high amplitude sealeve1 fa11s still needs further exploration. Inthis paper we describe the characteristics of paleokarst in the Early Permian in Iongyin and Bianping sections at south Guizhou, including solution-collapse breccias and related sedimentary structures, which correlate in time with the two major sealevel fa11s in the Early Permian. This study could facilitate our understanding on the evolution of the Early Permian Palaeo- geography of South China.