辽东半岛南部震旦系葛屯组、寒武系大林子组及碱厂组沉积相分析

辽东半岛南部震旦系葛屯组为一套中—细碎屑岩沉积,寒武系大林子组和碱厂组以碎屑岩—碳酸盐岩混合沉积为特征。沉积相分析表明,葛屯组为滨岸三角洲相沉积;大林子组为障壁海岸陆源碎屑沉积,碱厂组则是障壁海碳酸盐台地沉积。葛屯组与大林子组之间在沉积物质组成和沉积环境等方面存在较大差异。葛屯组水体循环好,为混水沉积,古植物宏观藻类繁盛,大林子组水体循环差,盐度不正常,上部出现干旱蒸发环境,几乎无生物可生存,葛屯组与大林子组沉积物的物源供给区的母岩相同,重矿物分析表明二者均为含水硅酸盐—变质岩;Ca/Mg值葛屯组低而到大林子组变高;葛屯组沉积时气候温暖、潮湿,沉积界面经常处于氧化基准面之下,而大林子组则表现为干燥、炎热的环境,沉积界面几乎始终位于氧化基准面之上。碱厂组与大林子组在沉积作用特征上基本相似。这一演化过程说明了地壳由活动至稳定的渐进脉动过程。

ANALYSIS OF THE SEDIMENTARY FACIES IN SINIAN GETUN FORMATION, THE CAMBRIAN DALINZI AND JIANCHANG FORMATION IN SOUTHERN LIAODONG PENINSULA

The Sinian Getun Formation in southern Liaodong Peninsula is a set of finemiddle fragmental deposits.And the Cambrian Dalinzi and Jianchang Formation are the mixture of fragment-carbonate deposits. The analysis of the sedimentary facies shows that Getun Formation is the littoral delta facies, Dalinzi Formation is the terrigeneous fragmental deposit of barrier coast and Jianchang Formation is the carbonate-platform. There is quite a difference between Getun Formation and Dalinzi Formation in the sedimentary composition and environment. In Getun Formation the water circulation, normal in saltity, is better, and the Mega-Algae fossils are very rich. And Dalinzi Formation is poor in the water circulation, innormal in the saltity, almost no biont existing for the evaporation environment on the top. The analysis of the heavy minerals shows that the mother rocks of Dalinzi and Getun Formation are alike, being hydrosilicates-metamorphic rocks. Ca/Mg ratio of Dalinzi Formationis higher than that of Getun Formation. The climate is warm and moist in Getun Formation, but arid in Dalinzi Formation: the depositional plane is often below the oxidation base level in Getun Formation, but above that in Dalinzi Formation. Jianchang and Dalinzi Formation have the same character of deposition The evolutionary process shows the gradual pulse advance of crustal movements are from activity to stability.