Dual clumped isotope thermometry of carbonates: resolving the effects of temperature from kinetics and diagenesis for accurate reconstruction of Earth’s surface temperature

碳酸盐的双簇同位素测温：解决动力学和成岩作用中温度的影响，以准确重建地球表面温度

• 批准号: 451014668
• 负责人: Professor Dr. Jens Fiebig
• 金额: --
• 依托单位: Leibniz-Institut für Ostseeforschung Warnemünde (IOW)
• 依托单位国家: 德国
• 项目类别: Reinhart Koselleck Projects
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/451014668?language=en
• 关键词: Dual; clumped; isotope; thermometry; carbonates

How and why did our planet become habitable? Which boundary conditions triggered the evolution of life on Earth? How will climate evolve and how will it affect biodiversity? To find answers for these important questions it is essential to reconstruct the past interplay between atmospheric greenhouse gas abundances, Earth’s surface temperatures and biodiversity. Earth’s surface temperatures are reconstructed from chemical and isotopic proxy data from well-dated sedimentary archives. Yet, there is no proxy available that unambiguously records Earth’s surface temperature. Besides temperature, kinetic and diagenetic processes as well as the chemical and isotopic composition of the parent fluid exert control on the proxy composition of the sedimentary archive. Non-exclusive temperature control and secondary alteration of the original proxy composition introduce large uncertainties in reconstructed temperatures.My research group has most recently pioneered dual clumped isotope analysis of carbonates, i.e., the extremely challenging analysis of the abundance of rare molecules of 12C18O18O (Δ48) in CO2 evolved from phosphoric acid digestion of carbonates along with 13C18O16O (Δ47). Now, for the first time, dual clumped isotope thermometry, may allow us to resolve temperature from the kinetic and diagenetic information just from the analysis of a single carbonate phase, without requiring any further knowledge about the composition of the fluid from which the carbonate crystallized. It has the potential to become the method of choice for the reconstruction of accurate formation temperatures (unbiased by kinetics) with unprecedented precision (< ±2°C on the 95% confidence interval level).I request funding to systematically und comprehensively investigate the fundamental thermodynamic and kinetic systematics of carbonate (bio)mineralization in Δ47 vs. Δ48 space. This may allow us to reliably reconstruct the interplay between Earth’s surface temperature and greenhouse gas abundance for past high-pCO2 intervals. The provision of accurate paleo-latitudinal temperature gradients for epochs with pCO2 as high as predicted to be encountered in the near future is necessary to improve state-of-the-art models predicting future climate. Moreover, the exploration of fundamental thermodynamics and kinetics will provide information essential for further potential applications of the dual clumped isotope proxy. These include reconstructions of temperature-time paths of burial and uplift of rocks, the evolution of marine biological production, the response of carbonate biomineralization to anthropogenic CO2 forcing and the evolution of Earth’s surface temperature and habitability since the Archean.

为什么我们的星球变得可居住？和良好的沉积档案中的同位素代理。我的研究小组最近在碳酸盐的双重团块同位素分析中，即12C18O18O（Δ48）在碳酸盐中碳酸盐中的稀有分子（Δ48）在CO2中的碳酸酸胶合中，对碳酸盐的丰富性极具挑战性的挑战性，即对重建温度的原始不确定性。 13C18O16O（Δ47），这是第一次，双重的同位素温度计，可以使我们能够从单个碳酸盐的分析中从动力学和成岩化信息中解析有关碳酸盐晶体的进一步的知识。具有前所未有的精度（95％EL上的<±2°C）的温度（无动力学）。我要求系统地要求使用二级空间的基本热力学和动力学系统在过去的IGH-PCO2间隔中重建地球的表面温度和温室气体丰度。未来的气候和动力学将为埋葬的温度时间和隆起的双重同位素的潜在应用，海洋生物生产的演变，碳酸盐生物矿化的反应和地球演变的反应表面温度和宜居性。