浙江白垩系的深化研究与新进展

根据岩石地层学、生物地层学和年代地层学资料，将浙江省陆相白垩系划分为３统、５群、１７组，并将其所含化石划分为建德、水康、衢江三个生物群。以综合地层学手段研究了白垩系的区域地层对比框架。在多学科综合研究，特别是在对一些岩石地层成因机制进行深层次研究的基础上，对浙江白垩系主要的关键性、疑难性地层问题，提出了一些新的认识：（１）“塘上组”底部砾岩为与火山爆发有成因联系的湖泊重力流沉积，并非底砾岩，因而“天台群”不是“新的构造亚层”，而基本上是火山岩型永康群；（２）“塘上组”、“小平田组”等人山活动成因的“组”，都是中白垩世时局部性火山事件形成的不等时、不连续的地质体，不是层位固定的岩石地层单位；（３）中戴组、方岩组、“赤城山组”都是晚白垩世早期地壳重力均衡调整作用中，在不同地区形成的同一套类磨拉石建造，并非层位不同的“三套”类磨拉石建造。

THE DETAILED STUDY AND ADVANCE OF CRETACEOUS IN ZHEJIANG PROVINCE

The terrestrial Cretaceous strata in Zhejiang province are devided into 3 series, 5 groups and 17 formations, and fossil hosted in strata are divided into Jiande, Yongkang and Qujiang biotas by the study of lithostratigraphy, biostratigraphy and chronostratigraphy. The regional comparison of Cretaceous strata have been studied by the methods above to set up serval regional strata comparison blocks. On the bases of reach results, some new considerations are suggested about Cretaceous strata problems in Zhejiang: (1) The "Tiantai group" is not "new tectonic sub-strata", which ought to be Yongkang group of volcanics, because the hasal conglomerate of "Tangshang formation" is lough gravity flow sedements related to volcano eruption. (2) "Tangshang formation" and "Xiaopingtian formation" et al. are nonisochornous and discontinueous geological bodies formed by local volcanic eruption, which are not lithostratigraphy units with fixed horizon. (3) Zhongdai formation, Fangyan formation and "Chichenshan formation" are the same suite similar molasse formation formed in different area by crust gravity isostatic adjustment in early stage of lute Cretaceous, not three suites of similar molass formation.