浅析宁波盆地膏盐地层的时代──兼对“宁波盆地北部的长河群”之时代质疑

宁波盆地地下揭示的一套包含暗色膏硝质泥岩、泥质白云岩在内的紫红、灰紫色泥岩、棕褐色砂砾岩、细砂岩和玻屑凝灰岩的地层，均称方岩组，内含膏盐并具油色显示。对其时代有早、晚白垩世和早第三纪之认识，笔者从70～90年代地质工作中所获化石分析认为，虽然宁波盆地这一层位含化石不丰，但从分布及数量上比较，相对占优势的应该是孢粉和植物化石，其时代意见也较为一致，指示为早白垩世。

A PRELIMINARY ANALYSIS ON THE AGE OF GYPSUMSALT STRATA IN NINGBO BASIN: DOUBTS OF THE AGE OF THE CHNGHE GROUP IN NORTHERN NINGBO BASIN

The Fangyan Formation that revealed by drilling exploration in the Ningbo basin is com posed of purple-red and grey-purple mudstone, brown sandstone and conglomerate, fine sandstone and tuff, intercalated with dark-colored gypsum-salt mudstone and muddy dolomite, which contains gypsun, salt, oil and gas. There have been some diputes on whether it belongs to the Early Cretaceous or the Late Cretaceous or the Early Tertiary. By analyzing the available fossils in 70-90's, it is suggested that it yields barran fossils, but sporopollen and plants are more predominnant than the other fossils in felation to the distribution and quantity, both oI which are relatively agreed to be in the age of Early Cretaceous. This forma tion yields sporopollen of ClassoPOllis - Cicatricasis - Psophasphaera assemblage and Plants of "Frenelopsis" Group, which mainly includes PseudofrenelePsis parceromosa, P. cf. paillosa, Brachyphllum ningshiaensis, B. cf. obtusum etc.