摘要
鲁西南地区分布着近东西向大致平行排列的早第三纪盆地群。在蒙阴、莱芜盆地早第三纪沉积称为官庄组，在平邑盆地称为卞桥组。依据沉积物特征和沉积旋回都能分为下段、中段和上段。通过对哺乳动物、介形类、轮藻、腹足类和孢粉等化石的研究可确定中段的沉积时代为早始新世，通过对轮藻、介形类和哺乳类动物的研究能确定下段和上段分别为始新世早期和中期。在卞桥组中段和官庄组中段发现介形类Ｃｙｐｒｉｄｅａ属，该属起源于晚侏罗世或早白垩世，在早白垩世繁盛，晚白垩世逐渐衰落，灭绝于晚古新世或早始新世，在早始新世沉积中的发现，是迄今在我国发现的最高层位。
In Southwest Shandong,there lie a group of Early Tertiary basins nearly east west trending and parallelly orientating(Fig.1). Among them,Mengyin and Laiwu basins have the Early Tertiary sediments called as Guanzhuang Formation while Pingyi basin as Bianqiao Formation. Each Formation can be divided into Upper,Middle and Lower Members according to sedimentary characters and cycles. The Middle Members were proposed as Early Eocene by examining their fossils including mammal,ostracoda,charophyte,gasteropoda and sporopollen. Instead,the Lower and Upper Members were suggested respectively as Early Eocene and Middle Eocene as a result of researching on the similar fossils. At the Middle Members of Bianqiao and Guanzhuang Formation, Cypridea genus of ostracoda has been recognized,emerging in Late Jurassic or Early Cretaceous, flourishing for Early Cretaceous,declining in Late Cretaceous and becoming extinct in Late Paleocen or Early Eocen. Early Eocene sediments represent what is accepted to be the youngest in the country of all age varying ones in which the genus has ever been found.
出处
《化工矿产地质》
CAS
1997年第3期149-161,共13页
Geology of Chemical Minerals
基金
国家自然科学基金
关键词
盆地
早第三纪
地层
划分
对比
鲁西南
Southwest Shandong,Lower Middle Eocene,fossil , ostracoda
