浙江横山组的时代和区域地层对比

浙江横山组被认为与寿昌组上段呈整合接触而归入建德群,由于生物化石稀少,又无年龄资料,因而地层时代和层位认识分歧较大。对寿昌盆地横山组与寿昌组之间的接触关系作了重新研究,证实是假整合而不是整合。在兰溪墩头盆地、淳安甘坞盆地以及常山朱村盆地,横山组均假整合或不整合覆于老地层上,在墩头盆地横山组下部发现大量永康馆头组中常见的...

GEOLOGIC AGE AND STRATIGRAPHIC CORRELATION OF THE HENGSHAN FORMATION IN ZHEJIANG PROVINCE

It was considered that contact between the Hengshan Formation and the Upper Member of the Shouchang Formation in Zhejiang Province was conformable and they were referred to the Jiande Group.However,there has been no consensus about its age and composition because of the lack of fossils and reliable isotope data.A further geological survey demonstrated that the Hengshan Formation disconformitedly overlies the Shouchang Formation in the Shouchang Basin.The Hengshan Formation is unconformable or disconformitive with the underlying strata in Duntou Basin of Lanxi,Ganwu Basin of Chun’an and Zhuchun Basin of Changshan.Many specimens of Neolepidotes sp.which is common in Guantou Formation of the Yongkang Group had been collected in the lower part of the Hengshan Formation in Duntou Basin;in addition a well-preserved Trionychidae specimen.was collected too.The sedimentary ESR age of the Hengshan Formation in Duntou Basin is 110.0 Ma~84.5 Ma,in the Zhuchun Basin is 112.8 Ma~88.2 Ma.All these evidences indicate that the age of Hengshan Formation in Zhejiang ranges from the late Early Cretaceous to Late Cretaceous.It is comparable with Yongkang Group of southeastern Zhejiang in biostratigraphy,lithostratigraphy,choronostratigraphy.