中国东部中上元古宇发育特征及其对板块和地体构造研究的意义

<正> 本文涉及的中上元古宇包括下寒武统之下,吕梁运动面(即相当于长城系底面)以上的一套地层。中、晚元古宙的沉积在我国东部分布较广,在不同的小区内,在沉积建造和地层序列上常显示出各自的特色。可按沉积时限、地壳构造活动性、沉积物特征和生物群面貌将东部中上元古宇分为四种沉积类型,简称蓟县型、旅大型、扬子型和江南型,名称来源于代表性剖面所在地或沉积区的地名。

Developmental features of the Middle-Upper Proterozoic Eon in East China and its significance in the study of plates and geotexture

The Middle-Late Proterozoic deposits in East China have been divided into four types: The Jixian, Luda, Yangtze and Jiangnan types. The differences between them are very obvious. No facies changes are observable in the sections of these four types. Based on the present data, the authors consider that during the Late Precambrian, North and South China belonged to different plates. The collision of North and South China plates represents a long-term continuous geological process from Ordovician (probably Cambrian) to Triassic. The North China plate may be divided into, at least, the Jixian and Luda terranes. The amalgamation of the Jixian and Luda terranes took place probably at the end of the Proterozoic. The South China plate may be divided into the Yangtze and Jiangnan terranes. The Jiangnan terrane approached or coalesced with the Yangtze terrane and had become the old island arc in continental margin near the close of the Proterozoic, The whole East China was probably a large-sized compound terrane.