江西省信江盆地上白垩统塘边组红色砂岩成土作用特征及地质意义  

Pedogenesis Characteristics and Geological Significance of the Red Sandstone in Upper Cretaceous Tangbian Formation,Xinjiang Basin,Jiangxi Province

作　　者：丛云燕 刘娜[1] 高福红[1] 张松旭 Cong Yunyan;Liu Na;Gao Fuhong;Zhang Songxu(College of Earth Sciences,Jilin University,Changchun 130061,China)

机构地区：[1]吉林大学地球科学学院,长春130061

出　　处：《吉林大学学报(地球科学版)》2025年第1期84-97,共14页Journal of Jilin University:Earth Science Edition

基　　金：国家自然科学基金项目(42272146)。

摘　　要：古土壤是研究古气候的重要载体。目前针对成土作用的研究主要围绕着成土过程中元素的迁移行为和成土演化过程等方面,但对成土作用表现形式的相关报道却很少。江西省信江盆地上白垩统塘边组以发育大型交错层理红色砂岩为特征,是华南白垩纪温室气候陆地沉积的典型代表。本文在详细的野外调查基础上,运用岩石学和地球化学方法对信江盆地白垩系塘边组的红色砂岩开展成土作用研究,探究晚白垩世信江盆地的古气候特征。研究区塘边组红色砂岩的岩石类型主要为中粒长石砂岩。塘边组沉积物普遍经历了成土作用,其主要识别特征包括发育于碎屑颗粒边部的黏土膜、微晶—亮晶碳酸盐胶结物和潜育作用。化学蚀变指数(CIA)分布在50.20~83.30之间(平均值58.08),反映该套红色砂岩处于弱化学风化水平。微量元素分析以及成土作用的识别,共同指示研究区砂岩形成于干旱—炎热的古气候,这种干旱—炎热的古气候可能与中国东部晚白垩世高大沿岸山系阻碍古太平洋湿润水汽向华东南内陆地区的流入有关。Paleosol is a significant carrier for studying paleoclimate.Presently,the research on pedogenesis principally focuses on the migratory behavior of elements and the evolutionary process of pedogenesis,with limited reports on the manifestations of pedogenesis.The Upper Cretaceous Tangbian Formation in Xinjiang basin is dominantly composed of red sandstone with large cross-beddings,which is a typical representative of Cretaceous greenhouse climate terrestrial deposits in South China.Based on detailed field investigation,petrological and geochemical methods were employed to study the pedogenesis of red sandstone during the Cretaceous Tangbian Formation and explore paleoclimate characteristics of the Xinjiang basin during the Upper Cretaceous.The red sandstone of Tangbian Formation in the study area is primarily medium-grained arkose.The sediments have universally experienced pedogenesis,the key identification features of red sandstone include clay films on the edge of the detrital grains,micritic-sparry carbonate cement and gleization.The CIA(Chemical Index of Alteration)ranges from 50.20 to 83.30(58.08 on average),indicating that the red sandstone is at a low level of chemical weathering.The analysis of microelement and the recognition of pedogenesis collectively indicate that the sandstone in the study area was formed in a hot and dry paleoclimate.This may be attributed to the high coastal mountain system that emerged during the Upper Cretaceous period in Eastern China,hindering the flow of moist water vapor from the Paleo-Pacific Ocean into the inland areas of Southeast China and forming a sedimentary paleogeographic environment dominated by aridity and torridity.

关 键 词：红色砂岩 成土作用 地球化学 古气候 信江盆地 塘边组 晚白垩世 

分 类 号：P581[天文地球—岩石学]