粘土矿物含量分析中的几个问题

储层岩石中粘土矿物种类及含量分析是划分沉积相带和成岩相带的基础，也是油气层钻井、完井、开发改造中储层保护的关键。本文在分析传统粘土矿物抽提分离方法及其缺点的基础上，提出了多级粒度抽提分离方法，为分析储层岩石中的粘土矿物种类和含量提供了首要的保障。

Response of Terrigenous Sediment Input to Sea Level Change and East Asian Monsoon Evolution Since 30kyr in the Southwestern Taiwan Basin

The compositions of grain size,clay minerals,and geochemical elements in core sediments(TS4)from the southwestern Taiwan Basin(South China Sea)were investigated to assess the response of terrigenous sediment input to sea level change and the East Asian monsoon evolution since 30 kyr.The chronology was discussed based on foraminiferal AMS14C dates.Our results indi-cated that rivers in Taiwan have been the major sediment contributors since 30 kyr,followed by the Pearl River;and Luzon Island contribute little sediments to the southwestern Taiwan Basin.In this study,we reconstructed the variations in terrigenous sediment input by using the proxies such as Al2O_(3)(%),F1 score,and TiO_(2)/CaO.The F1 score can be used to indicate the flux of terrigenous sediments.The contribution of Taiwan Residents rivers and the Pearl River were evaluated by using the value of(illite+chlorite)/kaolinite.The variations of Al2O_(3)(%),F1 score,and TiO_(2)/CaO values along the core were clearly correlated to the evolution of the East Asian summer monsoon since 30 kyr.Based on these records,we recognized three evolutionary stages of terrigenous sediment input in the southwestern Taiwan Basin.During stage Ⅰ(29-24kyr),the input of terrigenous sediments continued to increase.During stage Ⅱ(24-11.5 kyr),the sediment input decreased at first and then increased,with the lowest value during the last glacial period(21-17kyr).Terrigenous sediment input during stage Ⅲ(11.5 kyr-)showed the decreasing first and then increasing trends,generally higher than those in the first and second stages.The variations of terrigenous sediment input in the study area corresponded well with the evolu-tion of the East Asian summer monsoon since 30 kyr.Increased terrigenous sediment input during 4-1.8 kyr was suggested to be caused by the enhanced ENSO activity.Sea level change does not alter the overall trend of terrigenous sediment input,but does change the relative contributions of rivers in Taiwan and the Pearl River.

短源河流碎屑矿物在河道、河口和海滩的组分变化及其控制因素——以山东半岛辛安河为例

山东半岛诸多小河沉积物大多来源明确,矿物沉积分异相对较小,对其研究能为大河入海物源分析提供区域相似性,也可为黄、渤海陆架沉积提供山东半岛物质来源特征。本文以山东半岛东北部短源小河辛安河为例,对取自河床、河口、海滩的表层沉积样品的碎屑矿物分布规律进行了多粒级分析。研究表明,辛安河流域和海滩沉积物多为中砂和细砂,全样重矿物含量中等,在1.47%~8.19%之间。出现重矿物27种,轻矿物8种,主要重矿物为普通角闪石(41.7%)、绿帘石(16.7%)、阳起石(10.6%)和褐铁矿(6.7%),主要轻矿物为石英(49.0%)、斜长石(26.5%)和钾长石(20.7%),这些矿物的含量在河床、河口和海滩远高于其他碎屑矿物,且矿物组合保持不变,相对含量变幅不大;非主要矿物种类与碎屑粒径存在显著的非线性相关关系。辛安河矿物种类和含量受控于区域岩性物源,即酸性、中酸性侵入岩和区域变质岩。闪石族矿物在辛安河不同地貌中的相对稳定输出是其同宗同源属性所在,矿物组成变化主要受水动力控制下的粒度分选影响。山东半岛短源河流虽碎屑矿物种类和含量不尽相同,但它们来源于相似的地质地貌和岩石类型,矿物组成变化的主要控制因素为区域物源和粒度分选,其次为沉积环境差异。相比而言,黄河闪石族矿物的低含量、云母族和碳酸盐类矿物在特定粒级的高含量有别于半岛南北两侧的河源物质。