Clumped isotope analysis of lacustrine endogenic carbonates and implications for paleo-temperature reconstruction:A case study from Dali Lake

作     者：Jiaojiao YUE Jule XIAO Xu WANG Jiawei FAN Ben QIN Jiaojiao YUE;Jule XIAO;Xu WANG;Jiawei FAN;Ben QIN

作者机构：Key Laboratory of Cenozoic Geology and EnvironmentInstitute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Life and PaleoenvironmentBeijing 100044China State Key Laboratory of Earthquake DynamicsInstitute of GeologyChina Earthquake AdministrationBeijing 100029China School of Earth SciencesZhejiang UniversityHangzhou 310027China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2021年第64卷第2期

页      面：294-306页

核心收录：

学科分类：070902[理学-地球化学] 070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 

基　　金：supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grants Nos.XDA19050104 and XDB26000000) the National Key R&D Program of China(Grant No.2017YFA0603400) the National Natural Science Foundation of China(Grants Nos.41931181&41672166) the Key Research Program of the Institute of Geology&Geophysics,CAS(Grant No.IGGCAS-201905) 

主　　题：Lacustrine endogenic carbonate Clumped isotope Paleo-temperature reconstruction Hydrogen peroxide treatment Isobaric interference 

摘      要：Carbonate clumped isotope(Δ47)is a new and reliable *** carbonates in lake sediments are good archives to reconstruct lake water temperature using clumped isotope ***,applications of carbonate clumped isotope thermometry to lacustrine carbonates are still scarce because the existed organic and/or sulfur contaminants in such samples interfere with clumped isotope analysis and cause notable temperature ***,exploring an effective way to remove contamination is a prerequisite to widely applying carbonate clumped isotope thermometry to lake *** pretreating fine-grained endogenic carbonates from Dali lake sediments with hydrogen peroxide of different concentrations for different lengths of time,we conducted a series of conditional experiments to seek the optimal pretreatment condition for clumped isotope analysis.Δ47,Δ48 offset and 49 parameter were obtained from clumped isotope measurements to assess the effect of contamination *** showed that untreated samples(0%-0)had a very high 49 *** the treatment with hydrogen peroxide,the 49 parameter was significantly reduced while theΔ48 offset evidently ***Δ47,Δ48 offset and 49 parameter of samples pretreated under different conditions showed significant variability,even though the measuredΔ47 temperatures changed within a relatively narrow range(i.e.,from 17.0±1.3 to 22.8±1.6°C).Among various treated samples,the sample3%-8yielded a smallerΔ48 offset and 49 parameter,and lowerΔ47 temperature of 17.0±1.3°***,reacting with 3%hydrogen peroxide for 8 hwas suggested to be the optimal condition for removing contaminants from lacustrine endogenic carbonates prior to clumped isotope *** the time when the pretreatment condition was too intense(i.e.,H2O2 concentration3%and/or reaction time8 h),secondary contaminants might have been generated in the closed reaction system,whose ultimately transformed state may interfere wit