黑龙江省东部中侏罗世至早白垩世沟鞭藻组合序列

对近二十年来黑龙江省东部海相侏罗纪—白垩纪沟鞭藻地层资料进行了综合研究 ,首次为该地区建立起侏罗纪—白垩纪沟鞭藻地层序列 ,主要包含 7个组合带 (含 3个高峰带 ) ,其中绥滨地区 Callovian— Valanginian期有 4个带 ;鸡西盆地早白垩世也有 4个带 (其中包括与绥滨地区早白垩世早期同时异相的一个 )。它们自下而上为 :1)绥滨组的 Pareodinia ceratophora- N annoceratopsispellucida组合带 ;　 2 )东荣组下部的 Gonyaulacysta jurassica组合带 (高峰带 ) ;　 3)东荣组上部的 Amphorula delicata组合带 ;　 4 )东荣组最上部的海相 Oligosphaeridium pul-cherrimum组合带 (高峰带 )或鸡西盆地滴道组的微咸水—半咸水的 Vesperopsis didaoensis- L agenorhytis granoru-gosa组合带 ,两者为同时异相关系 ;　 5 )城子河组下部海相层的 Odontochitina operculata- Muderongia tetracantha组合带 (该带可进一步划分出 2个亚组合带 ) ;　 6 )城子河组上部海相层的 Canningia reticulata组合带 ;　 7)穆棱组下段的 Cribroperidinium ?parorthoceras组合带 (高峰带 )。

THE MIDDLE JURASSIC TO EARLY CRETACEOUS DINOFLAGELLATE ASSEMBLAGE SEQUENCE FROM EASTERN HEILONGJIANG

Marine Jurassic to Cretaceous strata in China, except Taiwan and the vast areas of SW China including Qinghai-Xizang (Tibet) Plateau and the western Tarim Basin, are only distributed in eastern Heilongjiang and contain rich bivalve and dinoflagellate fossils. They consists of the following five formations, in ascending order: the Callovian Suibin, Late Jurassic—Valanginian Dongrong, Early Cretaceous Didao, Chengzihe and Muling Formations. According to previously published data, seven dinoflagellate assemblage zones are proposed and described for the Middle Jurassic (Callovian) to Early Cretaceous (Berriasian—Barremian) sediments from subsurface and outcrop sections in the area. Middle to Late Jurassic strata are restricted only to the Suibin area of eastern Heilongjiang and contain three assemblage zones, in ascending order as Middle to Late Callovian Pareodinia ceratophora-Nannoceratopsis pellucida developed in the Suibin Formation, Late Oxfordian to Early Kimmeridgian Gonyaulacysta jurassica (peak zone) taken from the lower part of the Dongrong Formation, and Tithonian Amphorula delicata from the upper part of the Dongrong Formation; Early Cretaceous sediments developed largely in Jixi Basin of eastern Heilongjiang include four assemblage zones: Berriasian to Valanginian marine Oligosphaeridium pulcherrimum (peak zone) occurring only in the uppermost part of the Dongrong Formation of the Suibin area, or contemporary slightly brackish to brackish Vesperopsis didaoensis-Lagenorhytis granorugosa distributed in the Didao Formation of the Jixi Basin, Late Hauterivian Odontochitina operculata-Muderongia tetracantha recovered from the lower part of the Chengzihe Formation, Middle Barremian Canningia reticulata from the upper part of the Chengzihe Formation, and Late Barremian Cribroperidinium? parorthoceras peak zone from the lower part of the Muling Formation. Among them, Odontochitina operculata-Muderongia tetracantha zone is subdivided into two subzones. This is the first complete dinoflagellate zonation scheme for the Callovian to Barremian in eastern Heilongjiang, but the sequence of dinoflagellate zones (Table 1) is less continuous and preliminary because the Early Cretaceous sequence is interrupted by non-marine intervals. Ages of zones are based mainly on the first appearance or latest occurrence or the high abundance of dinoflagellate taxa and comparisons with some European dinoflagellate assemblages, with some additional control being provided by the associated bivalves, but without ammonite zonal control because the collected ammonites are poorly preserved and difficultly identified, of which, the ages of Upper Jurassic zones are in complete accord with those of bivalve Buchia zones proposed by Chen Jin-hua & Huang Guan-jun (1992).