浙江墩头盆地横山组孢粉化石的发现及其地层意义

浙江墩头盆地红色岩层中上部首获丰富的以Cassopllis为主(58.39—62.54％)伴有Exesipollenites(15.21—15.84％),Hsuisporites(0.56—0.62％),Cicatricosisporites(0—0.31％)等孢粉化石。该孢粉组合特征既与国内外晚侏罗世孢粉组合面貌差别较大,又与早白垩世中晚期孢粉组合面貌存在明显差异,显示了早白垩世早期孢粉组合的色彩。笔者认为这套红色岩层应归早白垩世早期横山组为宜。

DISCOVERY OF SPORO-POLLEN FROM HENGSHAN FORMATION OF DUNTOU BASIN IN WEST ZHEJIANG AND ITS STRATIGRAPHIC SIGNIFICANCE

The Hengshan formation is widely cropped out and well developed at the Duntnu basin of West Zhejiang . It consists of purple red siltstone intercalated with the Same colour sandstone, mudstone and conglomerate, approximately 1400m. in total thickness . However , according to the previous data , no fossils had been found before in the Hengshan formation of the Dunton basin . In 1985. the authors made field geological investigation at the Duntou basin . and first obtained abundant sporo-pollens . This now discovery has a great significance for determination of the geological age and stratigraphical correlation . The sporo-pollen assemblage characteristics are as follows :1. This assemblage is dominated by the Gymnospermous pollens ( 88.52% ). and contains some Pteridophyta spores ( 11 .48% ).2. The Gymnospermous pollens include Classopollis ( 58.39% ). Exesipollenites( 15.84% ),Mo-nosulcites ( 6. 53% ). Psophospharea ( 1.86% ) and Araucariacites (0. 53 % ) ete.3. The Pteridophyta spores contain Schizaeoisporites ( 6. 83 % ) and very rare Deltoidospnrit-cs . Toroisporites Cicatricosisporites, Hsuisporites . ete.4. No Angiospermous pollens have been found .According to the above-mentioned sporo-pollen assemblage , the Hengshan formation of the Duntou basin is referred to Early Cretaceous in age . This assemblage indicates a hot arid palaeoclimatical environment .