摘要：

中扬子地区指青峰-湘广断裂带以南，湘黔桂海盆以北，鄂西恩施—龙山一线以东的湖北省和湖南省的大部分地区。根据中扬子地区上震旦统—下寒武统十余条代表性剖面的沉积特征及其横向展布规律，应用等时面优势相成图方法编制了晚震旦世的陡山沱期、灯影期,早寒武世的筇竹寺期、沧浪铺早期、沧浪铺晚期、龙王庙期共6幅岩相古地理图。中扬子地区上震旦统发育了从碳酸盐潮坪、开阔台地、浅滩、台地边缘、斜坡到台地前缘盆地等沉积，下寒武统下部主要为细碎屑岩和碳酸盐岩组成的混合型浅海陆棚沉积，上部变成碳酸盐潮坪、开阔台地、台缘斜坡和台缘盆地沉积。晚震旦世岩相古地理格局由碳酸盐台地(鄂中台地)和南边的台缘盆地组成。由于地壳差异性升降运动，晚震旦世陡山沱期岩相古地理格局发生了急剧变化。早寒武世早—中期岩相古地理格局由鄂中古陆、围绕古陆的碳酸盐潮坪、陆棚及南边的陆棚边缘盆地组成。早寒武世中—晚期岩相古地理格局由碳酸盐潮坪、开阔台地、台缘斜坡和台缘盆地组成，该地区主体进入碳酸盐台地演化阶段。

Abstract:

The middle Yangtze region in this paper refers to the most part of Hubei and Hunan Provinces bounded on the north by the QingfengXiangguang Fracture, on the west by western border of Hubei Province, and on the south by HunanGuizhouGuangxi deep sea basin Based on field investigation, the sedimentary characteristics, horizontal correlation and facies distribution of Upper Sinian and Lower Cambrian for more than ten sections in the middle Yangtze region are comprehensively studied in this paper Six lithofacies palaeogeographic maps of Doushantuo, Dengying, Qiongzhusi, Canglangpu, and Longwangmiao Ages of Late Sinian and Early Cambrian have been made in the light of dominant facies and in the way to make stratigraphic map On the basis of lithofacies palaeogeographic map, the sedimentary and lithofacies palaeogeographic characteristics of the middle Yangtze region during the Late Sinian and Early Cambrian are also described There are four principal palaeogeographic units in the Late Sinian in the middle Yangtze region, ie carbonate tidal flat, open carbonate platform，platformmargin slopes and a basin in the south The major lithofacies palaeogeographic characteristics of the Qiongzhusi Age and early Canglangpu Age (Early Cambrian) are a land in middle Hubei, the carbonate tidal flat surrounding the land , shelf and a basin in the south The land disappeared during the Late Canglangpu Age and Longwangmiao Age (Early Cambrian) and the framework of palaeogeography consisted of tidal flat,open carbonate platform , platformmargin slopes and basin in the south