摘要
辽西义县盆地下白垩统义县组大康堡沉积层分布范围广,为"热河生物群"的重要产出层位。通过对王家沟西山典型剖面的沉积学研究,识别出11种岩相类型,包括基质支撑砾岩相、凝灰质中-粗粒砂岩相、平行层理中-细砂岩相等,并将该时期的湖泊沉积划分为滨浅湖和深-半深湖环境。分析大康堡层垂向序列特征及纹泥特征,将该时期的湖泊演化划分为4个阶段:早期浅水湖泊沉积,见大量浅水生物化石;中期深-半深湖沉积,处于相对封闭-半封闭的状态,盐度增加;晚期湖泊水体变浅,水文动力条件增强,盐度降低;末期深-半深湖环境,纹泥指示陆源碎屑供给极少,降水较少。湖泊的演化过程受古气候控制明显。
Widely distributed in Yixian Basin in western Liaoning, Dakangpu layer of the Yixian Formation belongs to Lower Creta- ceou and is an important horizon of uJehol Biota”. A typical section was measured in detail for sedimentology and 11 lithofacies types were recognized, such as matrix supported conglomerate facies, tuffaceous medium-coarse grained sandstone facies and medium-fine grained sandstone facies with parallel bedding. Dakangpu layer comprises mainly lacustrine sediments including shore shallow lake fa-cies and deep and semi-deep lake facies. Based on analyzing the changes of vertical sequence characteristics and varves characteristics of Dakangpu layer, the authors divided it into four depositional stages. At the initial stage, the lake was just formed with a large num-ber of shallow water fossils. After that it entered into the middle-range stage with deep and semi-deep water in the relatively closed and semi-closed state, during which the salinity increased. In the late depositional stage, the lake became shallow with higher hydro-dynamic condition and low salinity. At the end of the deposition the lake had deep and semi-deep water, and the varves were devel-oped which indicated poor terrigenous clast and little precipitation. The evolution of the lake was controlled by paleoclimate obviously.
作者
王铁晖
巩恩普
陈晓红
崔莹
高飞
黄文韬
WANG Tiehui;GONG Enpu;CHEN Xiaohong;CUI Ying;GAO Fei;HUANG Wentao(Resources and Civil Engineering College,Northeast University,Shenyang 110004,Liaoning,China;Normal College of Shenyang University,Shenyang 110004,Liaoning,China)
出处
《地质通报》
CAS
CSCD
北大核心
2018年第6期1166-1175,共10页
Geological Bulletin of China
基金
国家自然科学基金项目<辽西地区下白垩统义县组碳酸盐岩沉积环境及热河生物群古地理景观研究>(批准号:411720)
国家重点基础研究发展规划(973计划)项目<我国中
新生代主要陆地生物群的年代框架和沉积环境演变>(编号:2012CB821905)
中央高校基本科研业务费专项<辽西地区古环境研究境演变>(编号:N120601001)
