当前位置: X-MOL 学术ACS Earth Space Chem. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Technical Note: Developments and Applications in Triple Oxygen Isotope Analysis of Carbonates
ACS Earth and Space Chemistry ( IF 2.9 ) Pub Date : 2020-03-31 , DOI: 10.1021/acsearthspacechem.9b00330
Benjamin R. Fosu 1 , Rachana Subba 1 , Rahul Peethambaran 1 , S. K. Bhattacharya 1 , Prosenjit Ghosh 1, 2
Affiliation  

Triple oxygen isotope systematics has evolved as a powerful tool in understanding various earth system processes. It has proven reliable in assessing paleoenvironmental conditions from natural archives (e.g., waters, ice cores, biota, sediments, etc.) owing to recent advances in high-precision mass spectrometric analysis. Toward the standardization of triple oxygen isotope analyses in carbonates, we describe a procedure of high-precision Δ′17O analysis of carbonates by a two-step protocol: acid digestion of carbonates to evolve CO2 followed by the catalytic CO2–O2 exchange method. The Δ′17O values of a suite of carbonate reference materials and several carbonates of different origins have been determined with good precision (∼0.007‰). The accuracy of sample Δ′17O values is dependent on the accuracy of Δ′17O composition of the reference CO2 used in determining the effective fractionation (θs) in the experimental setup. The obtained Δ′17O values (λ = 0.528, versus VSMOW) for NBS18-CO2 (−0.119‰) and NBS19-CO2 (−0.169‰) show a difference of 0.050‰, similar to that obtained elsewhere via complete fluorination. The analyzed carbonates mostly conform to equilibrium mass-dependent fractionation laws, but we encountered a suite of samples from cold seeps, caves, and metasomatic environments that have Δ′17O values indicative of disequilibrium fractionation. We show that a combination of clumped isotope composition (Δ47) that provides estimates of formation temperature and triple oxygen isotope ratios in carbonates can help in reconstructing past environments, where paired carbonate data (δ13C−δ18O−Δ47–Δ′17O) and parent water data (δ17O−δ18O−Δ′17O) are particularly useful.

中文翻译:

技术说明:碳酸盐三重氧同位素分析的开发和应用

三重氧同位素系统学已发展成为了解各种地球系统过程的有力工具。由于高精度质谱分析的最新进展,它已被证明可可靠地评估自然档案(例如水,冰芯,生物群,沉积物等)的古环境条件。朝向三重氧同位素的标准化在碳酸盐分析中,我们描述的高精度Δ'的过程17的碳酸盐的O分析由两步协议:碳酸酯的酸消化进化CO 2,随后通过催化CO 2 -O 2交换方法。该Δ' 17已确定一组碳酸盐参考物质和几种不同来源的碳酸盐的O值,精度很高(〜0.007‰)。样本Δ的准确度“ 17个O值是依赖于Δ的准确度” 17参考CO的O-组合物2在确定有效分馏(θ用于小号)中的实验装置。将所得到的Δ' 17个O值(λ= 0.528,与VSMOW)为NBS18-CO 2(-0.119‰)和NBS19-CO 2(-0.169‰)的差异为0.050‰,与其他地方通过完全氟化获得的相近。该分析碳酸盐大多符合平衡质量相关分馏法,但我们遇到了一套样品从冷泉,洞穴,并交代环境有Δ“ 17个O值指示不平衡分馏。我们表明,结块同位素组成的组合(Δ 47),其提供形成温度和三氧同位素比率在碳酸酯可以在重建过去的环境中,其中,成对的碳酸盐数据(δ帮助的估计13 C-δ 18 O型Δ 47 -Δ ' 17 O)和父水数据(δ 17 O形δ 18O型Δ' 17 O)是特别有用的。
更新日期:2020-03-31
down
wechat
bug