川西北晚三叠世卡尼期浅水碳酸盐生产工厂构成及其转换过程定量化研究  

Quantitative Study on the Composition and Evolution of the Late Triassic Carnian Shallow-Water Carbonate Factories in Northwestern Sichuan

作　　者：柳晶晶 王夏 孟令赞[1] 曾雨涵 冯翼妍 金鑫 张磊[1,2,3,4] LIU JingJing;WANG Xia;MENG LingZan;ZENG YuHan;FENG YiYan;JIN Xin;ZHANG Lei(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources,Chengdu University of Technology,Chengdu 610059,China;Key Laboratory of Sedimentary Basin and Oil and Gas Resources,Ministry of Natural Resources,Chengdu 610081,China)

机构地区：[1]成都理工大学沉积地质研究院,成都610059 [2]油气藏地质及开发工程全国重点实验室,成都理工大学,成都610059 [3]自然资源部深时地理环境重建与应用重点实验室,成都理工大学,成都610059 [4]自然资源部沉积盆地与油气资源重点实验室,成都610081

出　　处：《沉积学报》2024年第2期445-465,共21页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(42293291,42102143);自然资源部沉积盆地与油气资源重点实验室开放基金(cdcgs2022003)。

摘　　要：【目的】准确识别碳酸盐工厂类型并阐明其发育控制因素,定量化评价工厂发育过程的环境条件,厘清其在沉积体系转换过程中的古生态学和沉积学信号是探究碳酸盐岩沉积体系演化的关键。【方法】以川西北绵竹市汉旺镇观音崖剖面的马鞍塘组为例,通过系统的碳酸盐岩微相分析,结合粒径统计分析方法对20391个颗粒定量分析,在此基础上对该时期热带浅水碳酸盐生产工厂的构成、特征、转变过程、驱动因素等进行了详细阐述。【结果】研究区热带浅水碳酸盐生产工厂可进一步划分为似球粒、鲕粒、生屑及生物礁等多个细分特异化工厂类型,指示多样化的碳酸盐生产路径。通过分析研究区热带浅水工厂的构成,沉积环境、水动力条件和营养水平等因素,发现各个细分工厂类型有着非常强烈的“生境”特点,工厂类型的转变更多地受区域海平面变化控制。【结论】频繁的海平面变化导致营养水平、水动力条件和碳酸盐矿物饱和度等因素快速变化,进而驱动了具体细分工厂的转变。而众多细分工厂在沉积序列上的快速变化指示了它们在横向上的共生关系。因此,较短时间尺度下细分工厂类型的转变主要与区域海平面控制的横向生产工厂类型的迁移有关,与极端事件和沉积体系的转变可能无关。[Objective]The precipitation and accumulation of massive carbonates are called the"carbonate factory".Environmental and biological factors,such as water depth,light intensity,nutrients,hydrodynamics,climatic conditions,and sea-water chemistry control the composition of different carbonate factories.To properly understand the evolution of the carbonate sedimentary system,it is essential to accurately identify different types of carbonate factories and the factors controlling their development.To achieve this,the quantitative evaluation of the environmental and biological parameters in the transition of sedimentary systems is key.[Methods]In this study,the composition,characteristics,type transitions,and driving forces of tropical shallow-water carbonate factories within the Ma'antang Formation were studied in detail.We applied a systematic microfacies analysis in the deposition of the Ma'antang Formation at the Guanyinya section,Hanwang town,Mianzhu city,northwest Sichuan.Microfacies characteristics,including types and percentages of carbonate grains,matrix,and fossils,combined with quantitative analysis of the size and morphological parameters of 20,391 carbonate grains,including circularity,roundness,solidity,and aspect ratio,were analyzed from the thin sections.The size data were corrected and then used to calculate the average particle sizes,degree of sorting,skewness,and kurtosis following the Folk and Ward method.The analyses of the above-mentioned morphological parameters were accomplished in ImageJ using high-resolution scanning photos of the studied thin sections.[Results]Eleven carbonate microfacies are recognized in the study area.Based on the microfacies characteristics,the 11 microfacies types are further classified into five lithofacies associations(LA):LApeloids,LA-ooids,LA-skeletal grain,LA-sponge reef,and LA-shale,correlating to four specific carbonate factories,including peloids,ooids,skeletal grains,and sponge reef.The statistical data reveal that the LA-peloids exhibit the smallest average grai

关 键 词：四川盆地 晚三叠世 卡尼期 碳酸盐生产工厂 碳酸盐岩沉积过程 颗粒统计 

分 类 号：P588.245[天文地球—岩石学]