华南腹地茶永盆地白垩系古沙漠床沙构型定量重建与启示  

Quantitative reconstruction and implications of the Cretaceous aeolian bedform architecture in Chayong Basin,the hinterland of South China

作　　者：黄乐清 胡能勇 文春华 孟繁星 陈旭 向轲 曾广乾 焦鹏 王灵珏 HUANG Leqing;HU Nengyong;WEN Chunhua;MENG Fanxing;CHEN Xu;XIANG Ke;ZENG Guangqian;JIAO Peng;WANG Lingjue(Geological Survey Institute of Hunan Province,Changsha 410116,China;Institute of Geological Survey,China University of Geosciences,Wuhan 430074,China;Hubei Key Laboratory of Paleontology and Geological Environment Evolution,Wuhan 430205,China;Hunan Center of Natural Resources Affairs,Changsha 410004,China;Nuclear Geological Survey Institute of Hunan Province,Changsha 410007,China)

机构地区：[1]湖南省地质调查所,湖南长沙410116 [2]中国地质大学(武汉)地质调查研究院,湖北武汉430074 [3]古生物与地质环境演化湖北省重点实验室,湖北武汉430205 [4]湖南省自然资源事务中心,湖南长沙410004 [5]湖南省核地质调查所,湖南长沙410007

出　　处：《古地理学报》2024年第6期1372-1395,共24页Journal of Palaeogeography：Chinese Edition

基　　金：湖南省自然科学基金项目(编号:2021JJ30388);中国地质调查局古生物与地质环境演化湖北省重点实验室开放基金(编号:PEL-202203);湖南省地质院科研项目(编号:HNGSTP202322);湖南省创新型省份科普专题(编号:2022ZK4207)共同资助。

摘　　要：华南腹地茶永盆地白垩系发育古沙漠沉积,其沙丘构型特征多样,是构造活动、地下水文条件和古气候演变等多因素的综合结果,然而目前在该方面的研究却近乎空白,制约了对华南腹地古沙漠环境演变规律的认识。本研究将粒度端元分析(EMMA)新方法和沙丘构型分析传统方法相结合,开展古沙漠形态学研究及床沙构型定量重建工作。结果表明,华南腹地茶永盆地白垩纪沙漠沙丘规模较大,各项沙丘形态参数均远超全球典型断陷盆地的古沙丘均值,可以类比鄂尔多斯盆地白垩系古沙丘或塔克拉玛干沙漠的现代沙丘,指示茶永盆地的初始状态可能为一个大型干旱或沙漠盆地;通过粒度端元四组分识别出风成沙丘、沙席和潮湿丘间(泥滩)等沉积环境类型。基于沙丘构型重建,恢复古风向为N-NE向,受北半球西风带控制,且该沉积构型记录了复合新月形沙丘、复杂(爬升)横向沙丘等多种形态类型。茶永盆地南部风成序列为干燥—潮湿型丘间风成体系,表现为内部干旱—潮湿丘间沉积与小—中型新月形沙丘的叠置;盆地北部风成序列发育干燥型丘间风成体系,发育巨型(爬升)叠加复合沙丘。茶永盆地周缘地区的构造隆升与水系发育,为盆地带来大量沉积物源,并在风力作用下发生二次侵蚀、迁移和堆积;断—拗陷盆地基底下沉、潜水面的升降,为风成沉积物的累积和保存创造了可容纳空间。该研究从风成沉积地质记录分析出发,提出了茶永盆地白垩纪沙漠沙丘规模可能较大的新见解,加深了对华南腹地风成/水成沉积—盆地构造—古气候等多要素耦合过程的理解。The Cretaceous strata in the Chayong Basin,located in the hinterland of South China,are characterized by ancient desert sediments with diverse dune morphology.These features reflect a com-plex interplay of tectonic activity,hydrological conditions,and palaeoclimatic changes.Despite their sig-nificance,research on this topic remains limited,hindering our understanding of the evolution of the pa-leodesert environment.This study employs the innovative End-Member Modeling by Grain Size Analysis(EMMA)with traditional dune morphology analysis to investigate paleoaeolian morphologies and quantita-tively reconstruct bedform configurations.The results indicate that the Cretaceous dunes in the Chayong Ba-sin are exceptionally large,with morphological parameters surpassing global averages for typical fault ba-sins.This suggests an initial arid or desert basin state comparable to the Cretaceous dunes of the Ordos Basin's or the modern dunes of the Taklamagan Desert.EMMA identified four end-members that are indica-tive of aeolian dunes,sand sheets,and moist interdune areas.The reconstructed paleowind direction was predominantly north-northeast,influenced by the westerlies of the Northern Hemisphere.The sedimentary configurations exhibit a variety of forms,including compound crescentic and complex transverse dunes.The southern part of the basin is characterized by a dry-moist interdune system,presenting internal arid-moist interdunes and small-medium crescentic dunes.In contrast,the northern part develops a dry inter-dune aeolian system dominated by giant compound dunes.Tectonic uplift and fluvial development surround-ing the basin have provided abundant sediment sources,resulting in secondary erosion,migration,and deposition driven by wind action.The subsidence of the fault-basin basement and fluctuations in the groundwater table,has created accommodation space for the accumulation and preservation of aeolian sedi-ments.This study,based on aeolian sedimentary geological records,offers a new perspective on the large-scale dyna

关 键 词：沙漠 床沙构型 白垩系 茶永盆地 华南 

分 类 号：P512.21[天文地球—地质学]