摘要
华南早中生代构造体制转换对粤南地区古气候演化产生了深远影响,但对其内在联系的研究尚有不足.本文以粤南地区上三叠统‒下、中侏罗统小坪组、金鸡组、桥源组为研究对象,采集各组泥岩样品进行了X⁃射线荧光光谱主量元素和ICP⁃MS微量、稀土元素测试,并开展了沉积特征和古生物特征综合分析.测试表明,小坪组凤岗段泥岩样品CIA(75.7~81.3)、Sr/Cu(0.83~21.3)、Rb/Sr(2.32~12.8)、Mg/Ca(0.57~2.50)和Sr/Ba(0.04~0.19)均指示该区晚三叠世早期为温湿气候,δCe(0.93~0.95)指示弱氧化环境,间接反映该时期为温湿气候;小坪组马安段泥岩样品CIA(77.5~82.2)、Sr/Cu(8.41~13.3)、Rb/Sr(2.08~5.83)、Mg/Ca(0.79~3.10)和Sr/Ba(0.06~0.26)指示该区晚三叠世晚期为干热气候,δCe(1.04~1.05)指示还原环境,间接反映该时期为干热气候;金鸡组、桥源组泥岩样品CIA(77.1~82.3)、Sr/Cu(1.51~4.38)、Rb/Sr(2.16~12.1)、Mg/Ca(0.84~2.94)和Sr/Ba(0.04~0.24)指示该区早侏罗世‒早、中侏罗世以温湿气候为主,短暂出现干热气候,δCe(0.92~1.00)指示弱还原‒弱氧化环境,间接反映该时期气候以温湿为主,短暂出现干热.将研究区与周缘地区古气候进行对比,晚三叠世‒早、中侏罗世粤南及其围区古气候都经历了由温湿(晚三叠世早期)‒干热(晚三叠世晚期)‒温湿为主,短暂出现干热(早侏罗世‒早、中侏罗世)的转变,这一具有相同演化趋势的古气候转变,正是对该时期华南经历了由特提斯构造域向古太平洋构造域转换的响应.
The Early Mesozoic tectonic regime transition in South China had a profound impact on the paleoclimate evolution in southern Guangdong,but the study of its internal relationship is still insufficient.In order to understand the response relationship,the mudstone samples collected from Xiaoping Formation,Jinji Formation and Qiaoyuan Formation in South Guangdong in Upper Triassic⁃Lower⁃Middle Jurassic were used for the main element analyses by X⁃ray fluorescence spectrometry,ICP⁃MS trace and rare earth element tests,combined with the comprehensive analysis of sedimentary and paleontological characteristics.According to the tests,the CIA(75.7-81.3),Sr/Cu(0.83-21.30),Rb/Sr(2.32-12.80),Mg/Ca(0.57-2.50)and Sr/Ba(0.04-0.19)of mudstone samples from Xiaoping Formation in Fenggang indicate that it was in a warm and humid climate in the Early Triassic,and the redox indexδCe(0.93-0.95)indicates a weak oxidation environment,indirectly reflecting the warm and humid climate;The CIA(77.5-82.2),Sr/Cu(8.41-13.30),Rb/Sr(2.08-5.83),Mg/Ca(0.79-3.10)and Sr/Ba(0.06-0.26)of mudstone samples from Xiaoping Formation in Ma’an indicate that it was in a hot and dry climate in the Late Triassic,and the redox indexδCe(1.04-1.05)indicates a reduction environment,indirectly reflecting the dry and hot climate;The CIA(77.1-82.3),Sr/Cu(1.51-4.38),Rb/Sr(2.16-12.10),Mg/Ca(0.84-2.94)and Sr/Ba(0.04-0.24)of mudstone samples from Jinji and Qiaoyuan formations indicate that the paleoclimate of Early Jurassic⁃Early⁃Middle Jurassic was mainly warm and humid,with a brief time of hot and dry climate.And the redox indexδCe(0.92-1.00)indicates a weak reduction⁃weak oxidation environment,indirectly reflecting the paleoclimate was mainly warm and humid,with a brief time of hot and dry climate.Compared with other areas in South China continental margin,the paleoclimate underwent the same change of warm and humid(the early of Late⁃Triassic)⁃dry and heat(the late of Late⁃Triassic)⁃mainly warm and humid,dry and hot for a brief time(Early Jur
作者
陈森然
许中杰
孔锦涛
程日辉
王嘹亮
Chen Senran;Xu Zhongjie;Kong Jintao;Cheng Rihui;Wang Liaoliang(College of Earth Sciences,Jilin University,Changchun 130061,China;Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Natural Resources,Changchun 130061,China;Guangzhou Marine Geological Survey,Guangzhou 510075,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2021年第9期3290-3306,共17页
Earth Science
基金
国家自然科学基金项目(Nos.41872101,41402087)
自然资源部东北亚矿产资源评价重点实验室开放课题基金项目(No.DBY⁃ZZ⁃18⁃13).
关键词
粤南
华南陆缘
早中生代
古气候
构造体制
响应
地球化学
South Guangdong
South China continental margin
Early Mesozoic
paleoclimate
tectonic regime
response
geochemistry
