微量碳酸盐团簇同位素Δ_(47)分析方法及其应用——以浮游有孔虫和腕足动物壳体为例  

ANALYTICAL METHOD AND APPLICATION OF CLUMPED ISOTOPEΔ_(47) IN TRACE CARBONATE——EXAMPLES OF PLANKTONIC FORAMINIFERA AND BRACHIOPOD SHELL

作　　者：席海斌 陈延龙 王珮瑶 张志飞[1] XI Haibin;CHEN Yanlong;WANG Peiyao;ZHANG Zhifei(State Key Laboratory of Continental Evolution and Early Life,Department of Geology,Northwest University,Xi’an 710069)

机构地区：[1]大陆演化与早期生命全国重点实验室,西北大学地质学系,西安710069

出　　处：《微体古生物学报(中英文)》2025年第1期84-98,共15页Acta Micropalaeontologica Sinica

基　　金：国家自然科学基金项目(批准号:42172013,42072013,41720104002,41890844,41890843,41930319,41572002)资助。

摘　　要：碳酸盐团簇同位素是近年来开发的用于重建地质历史时期温度变化与气候条件的新型指标。然而目前大部分研究中都要求较多的碳酸盐样品量(>10 mg),这限制了微体古生物研究中一些质量有限的样品材料(如有孔虫)的应用。本文以浮游有孔虫、底栖腕足动物壳体和国际碳酸盐标准物质的测试和分析过程为例,建立了微量碳酸盐团簇同位素Δ_(47)分析方法,所需碳酸盐样品量最低仅3−4 mg,测试结果可达到同传统大用量测试方法近似的精度表现(SE<0.02‰)。腕足动物壳体同心纹层的Δ_(47)测试结果为0.693±0.007‰−0.708±0.009‰,经校正公式转换后代表了12.31−16.98℃的壳体形成温度,这与20 m深度记录的海水年平均温度基本接近。浮游有孔虫壳体的团簇同位素组成为0.643±0.01‰,经有孔虫Δ_(47)-T校正公式转换后指示壳体钙化温度为29.53℃,与同层位同属种的有孔虫Mg/Ca温度计衍生得到的温度值29.19℃十分相近。本研究为质量有限的生物样品进行团簇同位素分析测试提供了参考方法,微量样品Δ_(47)分析方法的建立提高了运用生物化石(如腕足动物、有孔虫和陆生腹足动物)重建古气候的可行性。Carbonate clumped isotope is a new proxy developed in recent years for the reconstruction of temperature changes and climate conditions in geological history.However,most recent studies require a good deal of carbonate samples(>10 mg),which limits its application when only small quality of materials are available(such as foraminifers)in micropaleontological studies.In this paper,a method for the analysis of clumped isotopeΔ_(47) with trace carbonate was established based on the measurements and analyses process of planktonic foraminifera,brachiopod shell and international carbonate standard materials.The minimum amount of carbonate required is only 3−4 mg.The test results can achieve the same accuracy as the traditional method(SE<0.02‰).TheΔ_(47) test results of the concentric layers of the brachiopod shell range from 0.693±0.007‰to 0.708±0.009‰,and the transformation of the correction formula represents the shell formation temperature of 12.31−16.98℃,which is basically close to the annual average temperature of seawater recorded at a depth of 20 m.The clumped isotopic composition of planktonic foraminiferal shell is 0.643±0.01‰,and the calcification temperature of the shell is 29.53℃after transformation by the correction formula of foraminiferaΔ_(47)-T,which is very similar to the temperature of 29.19℃derived from the Mg/Ca thermometer of foraminifera in the same position and species.This study provides a reference method for clumped isotope analysis of biological samples with limited quality.The establishment of trace sample method improves the feasibility of using biological fossils(such as brachiopods,foraminifers and terrestrial gastropods)to reconstruct paleoclimate.

关 键 词：微量碳酸盐 团簇同位素 有孔虫 腕足动物 分析方法 古海洋温度 

分 类 号：P597[天文地球—地球化学]