摘要
综合分析岩心、露头剖面和测井资料,认为川中—川南地区上三叠统发育三角洲相和湖泊相,其中,三角洲相可进一步划分为三角洲平原、三角洲前缘和前三角洲三个亚相,湖泊相则可细分为滨湖和浅湖两个亚相。不同时期三角洲相和湖泊相发育程度不同。须一段、须三段、须五段和须六段以湖泊沉积为主,由东向西,水体逐渐加深。须二段和须四段以三角洲沉积为主,湖泊沉积分布范围较小。须二段发育时期,研究区北部构造活动强烈,沉积物供给充分,三角洲相主要由北向南延伸;须四段沉积时期,由于北部构造活动逐渐减弱,东南部沉积物供给增加,三角洲相主要由东南向西北方向延伸。随着周缘构造活动的变化,研究区沉积范围逐渐扩大。早期沉积范围仅局限于宜宾—泸州以北地区,中晚期沉积范围扩大,宜宾—泸州以南地区开始接收沉积。
Based on comprehensive investigation of a lot of coring data, outcrops and well logging data from Upper Triassic in central and south Sichuan Basin, delta facies and lacustrine facies are identified. Depending on the sedimentary environment and sedimentary developing features, the delta facies can be subdivided into three subfacies, namely, delta plain, delta front and predeha, and the lacustrine facies into shore lake subfacies and shallow lake subfacies. The distribution ranges of both facies fluctuated. During the sedimentary period of member 1, member 3, member 5 and member 6 of Xujiahe Formation, lacustrine facies predominated, with the water deepening increasingly from east to west. During the sedimentary period of member 2 and member 4 of Xujiahe Formation, delta facies predominated and the distribution range of lake was limited. During the sedimentary period of member 2 of Xujiahe Formation, because of strong tectonic action of source areas in north, delta spread mainly from north to south. During the sedimentary period of member 4 of Xujiahe Formation, tectonic action of source area in south-east enhanced, produ- cing increasingly more deposit which formed delta spreading from south-east to north-west. Along with the fading tectonic action of source areas, depositional area in the region of interest extended. During the early stage, the depositional area was limited to the north of Yibin-Luzhou, while during the middle and late stage, the depositional area extended to the south of Yibin-Luzhou.
出处
《沉积学报》
CAS
CSCD
北大核心
2008年第2期211-220,共10页
Acta Sedimentologica Sinica
基金
中国石油股份有限公司项目(编号:030104-1-02)资助
