摘要
文章以柴达木盆地察汗斯拉图、昆特依和一里坪盐湖共计6个中更新统—全新统含盐地层剖面为研究对象,通过铀系测年和光释光测年测定其成盐年代,利用X射线衍射分析测定其盐类矿物种类。察汗斯拉图D19剖面芒硝和石盐层的铀系年代为(231.5±19.5)~(239.5±40.4)ka BP,对应于深海氧同位素阶段(MIS)7早期;昆特依KP4剖面芒硝和石盐层的铀系年代为(76.8±19.7)~(53.7±6.5)ka BP,其中,芒硝沉积的年代可以对应于末次冰期早冰阶MIS 4;察汗斯拉图D13剖面钾盐和石盐地层的光释光年代为(6.6±1.0)~(2.6±0.4)ka BP,对应于MIS 1;一里坪YP3剖面石盐地层的铀系年代为(6.2±2.7)~(2.7±1.1)ka BP,对应于MIS 1,但测年误差较大。一里坪YP2剖面和昆特依KP2剖面未能得到有效的测年数据,测年失败的主要原因是剖面样品受到卤水开采和输卤的影响。研究表明,柴达木盆地西部盐湖存在MIS 7早期和MIS 4的芒硝和石盐层,而在MIS 1有固体钾镁盐沉积。盆地西部盐湖在MIS 8、MIS 6、MIS 4和MIS 2有芒硝沉积,芒硝沉积期与冰期有对应关系。结合前人的晚第四纪成盐年代数据,作者对柴达木盆地晚第四纪成盐期与冰期对比方案进行改进,并将已研究至MIS 6的对比方案扩展到MIS 8。因此,晚第四纪冰期环境有利于柴达木盆地以芒硝为主的盐沉积。
Six middle Pleistocene-Holocene evaporite-bearing profiles in saline lakes(namely Chahansilatu, Kunteyi and Yiliping) of the western Qaidam Basin were taken as study objects. The U-series dating and optically stimulated luminescence(OSL) dating were applied to obtain the evaporite depositional age, and X-ray diffraction was applied to identify the evaporite minerals. Based on the geochronology and evaporite mineralogy data, this paper discussed the relationship between evaporite deposition period and glacial period in the Qaidam Basin.The U-series age of mirabilite and halite layer in D19 profile of Chahansilatu is(231.5±19.5)~(239.5±40.4) ka BP, corresponding to marine oxygen isotope stage(MIS) 7. The U-series age of mirabilite and halite layer in KP4 profile of Kunteyi is(76.8 ± 19.7)~(53.7 ± 6.5) ka BP, in which the deposition age of mirabilite correspond to the early stage of the last glaciation MIS 4. The OSL age of potash and halite strata in D13 profile of Chahansilatu is(6.6±1.0)~(2.6±0.4) ka BP, corresponding to MIS 1. The age of U-series in YP3 profile of Yiliping is(6.2±2.7)~(2.7±1.1) ka BP, corresponding to MIS 1, but with large dating error. The age dating work of YP2 profile in the Yiliping and KP2 profile in the Kunteyi were failed. The main reason for the failure was that the samples of the profile were affected by brine mining and brine transportation. This study indicates there were mirabilite-dominated evaporite deposits during MIS 7 and MIS 4, while in the MIS 1, there were potash deposit. There are mirabilite deposits during MIS 8, MIS 6, MIS 4 and MIS 2 in saline lakes of the western Qaidam Basin, and there is correlation between mirabilite-deposition period and glacial period. Combined with the previously reported data of the saline lake in the late Quaternary, the correlation scheme between the evaporite-deposition period and glacial period of the saline lake in Qaidam Basin was improved, and the correlation scheme since MIS 6 was extended to MIS 8. The Late Quaternary glacial environment is conducive to the mirabilite-dominated evaporite deposition in the Qaidam Basin.
作者
陈安东
顾佳妮
王学锋
韩光
李洪普
袁文虎
CHEN AnDong;GU JiaNi;WANG XueFeng;HAN Guang;LI HongPu;YUAN WenHu(MNR Key Laboratory of Saline Lake Resources and Environments,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Key laboratory of Cenozoic Geology and Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Qinghai Provincial Key Laboratory of Exploration and Research of Salt Lake Resources in Qaidam Basin,Qaidam Integrated Geological Exploration Institute of Qinghai Province,Golmud 816000,Qinghai,China)
出处
《矿床地质》
CAS
CSCD
北大核心
2022年第2期426-439,共14页
Mineral Deposits
基金
国家自然科学基金资助项目(编号:41902190)
中国地质科学院矿产资源所基本科研业务费专项经费(编号:KK1923)
青海学者专项(编号:QHS201802)
中国地质调查局地质调查项目(编号:DD20190172、DD20221913)联合资助。
关键词
地质学
盐湖
成盐期
第四纪冰期
铀系测年
柴达木盆地
geology
saline lake
evaporite-deposition period
Quaternary glaciation period
U-series dating
Qaidam Basin
