广东乳源大峡谷老虎头组沉积特征研究及其地质意义  

Sedimentary Characteristics and Geological Significance of Laohutou Formation in Ruyuan Grand Canyon,Guangdong Province

作　　者：宁萌萌 杨豫川 陈斌[1] 刘明[1] 袁茂珂 许竞超 NING Mengmeng;YANG Yuchuan;CHEN Bin;LIU Ming;YUAN Maoke;XU Jingchao(Regional Geological Survey Team,BGEEMRSP,Chengdu 610213;The 7th Geological Team of Sichuan,Leshan 614000)

机构地区：[1]四川省地质矿产勘查开发局区域地质调查队,成都610213 [2]四川省第七地质大队,四川乐山614000

出　　处：《四川地质学报》2024年第3期408-415,共8页Acta Geologica Sichuan

基　　金：2021年度广东省生态林业建设省级财政专项资金项目(编号:006939916)资助。

摘　　要：为探究广东乳源大峡谷内泥盆系老虎头组沉积特征,选择区内游溪林场典型剖面开展详细的测量和研究工作。通过野外调查、薄片鉴定和粒度分析以及沉积相标志研究,认为乳源大峡谷地区老虎头组为一套辫状河-潮控三角洲-潮坪相沉积,垂向上为一套下粗上细的海侵沉积序列。其中,河流沉积从下至上依次为河床滞留相、心滩与天然堤三个微相;潮控三角洲主要为三角洲前缘沉积,可识别出水下分流河道、水下分流间湾和河口砂坝;潮坪沉积可识别出潮下带与潮间带两个亚相,砂坪与潮道旋回、混合坪与潮道旋回依次出现,最上部为泥坪。本次研究为老虎头组建立了一套由陆相向海相过渡的完整沉积模式,为乳源地区泥盆系沉积相和岩相古地理研究提供了理论支撑。In order to explore the sedimentary characteristics of the Devonian Laohutou Formation in Ruyuan Grand Canyon,Guangdong Province,the typical section of Youxi forest farm in the area was selected.Based on field investigation,thin section identification,grain size analysis and sedimentary facies markers,the Laohutou Formation in the Ruyuan Grand Canyon area is considered to be a set of braided river-tide-controlled delta-tide-flat facies deposits,and a set of transgression sedimentary sequence with coarse bottom and fine top.The river deposits are three microfacies from bottom to top:bed retention phase,diara and natural embankment.Tidal deltas are mainly delta front deposits,which can identify underwater distributary channels,interdistributary bays and estuarine sand bars.Two subphases of tidal flat deposit can be identified:subtidal zone and intertidal zone,sand flat and tidal channel cycle,mixed flat and tidal channel cycle,the upper part of which is mud flat.This study establishes a complete sedimentary model for the transition from continental to Marine facies,and provides theoretical support for the study of Devonian sedimentary facies and lithofacies paleogeography in Ruyuan area.

关 键 词：沉积特征 沉积相 老虎头组 广东乳源 

分 类 号：P535[天文地球—古生物学与地层学]