苏北盆地洪泽凹陷古新世时期的古环境:来自蒸发岩的证据

Paleoenvironment during Paleocene in Hongze Depression,North Jiangsu Basin:Evidence from Evaporites

中文关键词:  PETM事件  古新世  蒸发岩  洪泽凹陷  无水芒硝  钙芒硝  苏打石

英文关键词:PETM event  Paleocene  Evaporites  Hongze depression  Anhydrous mirabilite  Glauberite  Nahcolite

中文摘要:

      第三纪古新世—始新世极热事件(PETM事件,Paleocene-Eocene Thermal Maximum),被认为是最类似于现今的温室效应时期。江苏省苏北盆地洪泽凹陷沉积了一套巨厚的古新世时期的蒸发岩,提供了该时期的陆地记录。蒸发岩对气候极为敏感,因此可以记录古代气候的信息。从苏北盆地洪泽凹陷钻孔中,通过SEM-EDS的方法识别出了无水芒硝和钙芒硝,这些暖相矿物的出现吻合第三纪古新世—始新世极热事件时期的极端高温环境；而苏打石的出现则表明该时期大致为现代大气三倍浓度的极高CO₂含量。

英文摘要:

      The PETM event(Paleocene-Eocene thermal maximum)is considered to be the most similar to the present greenhouse effect.A set of evaporites in Paleocene were found deposited in Hongze Depression of north Jiangsu Basin,which provides terrestrial sediment record in this period.Evaporites are very sensitive to climate,so it can record information of ancient climate.In this study,anhydrous mirabilite and glauberite were identified by SEM-EDS from the borehole of Hongze Depression of northern Jiangsu Basin.The occurrence of these minerals indicating high temperature environment coincides with the extremely high temperature environment during the Paleocene-Eocene extreme heat event period；the occurrence of nahcolite shows that the CO₂content in this period is about 3 times higher than that in recent times.