作　　者： ; ;

机构地区： 中国科学院南海海洋研究所

出　　处： 《海洋地质与第四纪地质》 1994年第1期11-22,共12页

摘　　要： 本文所依据的分析样品是取自珠江最大的一个河口湾伶仃洋中部的水下钻孔岩芯，其底部到达花岗岩基底。通过对第四纪有孔虫群与孢粉化石带特征的分析，阐明在相同的钻孔岩芯中，有孔虫分布变化所反映的古沉积环境特征与孢粉分析的古气候特征较为吻合，并与相应的沉积相对应，结合￣（１４）Ｃ和￣（２３０）Ｔｈ／￣（２３２）Ｔｈ比值法测年数据，从而较好地重塑本区晚更新世中期以来的地质历史。 Lingdingyang Estuary is the largest estuary of the Zhujiang(Pearl)River.Two corescollected from the central part of the estuary(one of them throughout the Quaternarysediments)were used in the study of Quaternary foraminiferal group and sporopollenzones.The results showed that, in the same core,paleo-environments given byforaminifera were in correspondence with paleoclimates by palynology. In addition,cor-responding depositional facies and ￣(14)C and￣(230)Th/￣(232)Th dating data can also help establisha correct geological history since middle Epipleistocene in this area.According to the variation of foraminiferal distribution in the cores,two transgres-sion-regression cycles were found in the Quaternary period(since middle Epipleistocene,about 40000 a B.P.).In the meantime,four series of sediments were formed in thisarea.The first transgressive formation deposited during 3600O-20000 a B.P.and thesecond since 9560 a B.P..The largest advance of sea occurred in about 7750 a B.P.andgave L_2 and L_(16) the highest foraminiferal information function values,2.194 and 1.641respectively,which corresponded to the 5th sporopollen zone representing a hot and moist climate.Based on the analysis of sporopollen assemblages in cores L_2 and L_(16),six sporopollenzones were recognized since middle Epipleistocene。Zones 1,2 and 3 had ages of about4000O-36000 a B.P.3600O-20000 a B.P.and 2000O-9560 a B.P.respectively,and zones4-6 appeared since 9560 a B.P..We should pay attention to the fact that only few foraminiferal specimens exist inthe sediments of the first transgressive formation in the area,This was probably at-tributed to the surrounding acid soil or acidite which made acidic water that consequent-ly affected the living and growing of foraminifera at the distributary mouth.Acidifiedground water could also dissolve calcareous tests of foraminifera in the antecedent sedi- ments.

关 键 词： 伶仃洋 第四纪 有孔虫群 孢粉 化石

领　　域： [天文地球] [生物学]