关于浙东塘上组的时代问题

浙东塘上组中、下部火山岩的沉积夹层中首次发现?Halysestheria叶肢介及孢粉化石,并找到Pseudofrcneloysis parceramosa与P.cf.rapillosa为主的植物化石。本文综合各门类化石所反映的地质时代,认为浙东塘上组应归属早白垩世晚期。这与剖面上获得的同位素年龄值(110 Ma)相吻合。塘上组层位与邻区石帽山群上组、禾口组(闽),周家店组(赣东),徽州组上部(皖南)及葛村组上部(江苏)相当。

ON THE AGE OF THE TANGSHANG FORMATION IN EASTERN ZHEJIANG PROVINCE

The Tangshang formation are only distributed in Eastern Zhejiang region. It consists of volcanic rocks intercalated with a few sedimentary rocks. The Tangshang formation is generally referred to the early Late Cretaceous in age. Recently the present writers found some fossil plants from the typical section of the Tangshang formation at Tiantai district, they are Pseudofre-nelopsis parceramosa, P. cf. papillosa, Elatocladus sp., etc.. Of which, P. parceramosa was first recorded from the middle-late early Cretaceous in north America, and later discovered from the early Cretaceous in western and central Europe, north Africa and southern Korea. In China, it was reported from the lower Cretaceous in eastern Zhejiang eastern Jiangxi, Fujian, etc.. P.papillosa is known from the Liupanshan Group (early Cre-taceous)in Ningxia province and the Guantou formation (Early Cretaceous) in eastern Zhejiang province. So far as to the assemblage of the fossil plants, the authors consider it to be late early Cretaceous in age. On the same typical section, we first discovered an assemblage of fossil spore-pollen, it contains Classopollis (78.34%) , Exesispollenites (7.46%) , Psophosphaera (1.87%) , Sphaeripollenites (2.61%) , Araucariacites (3.36%) , Monosulcitos (0.38%), Pityosporites (0.38%), Schizacoisporites (2.25%), Cicatricosisporites (0.38%), Sphagnumsporites (1.12%), Deltoidospora (1.49%) , Panetetisporites (0.38%) . This assemblage belongs to early Cretaceous. According to the data of the lsotopic geological time (about 110 Ma) from the volcanic rocks of the Tangshang formation at Tiantai district, it indicates an age of early Cretaceous. From above, the age of the Tangshang formation should be assigned to late early Cretaceous.