项目名称: 金伯利岩中碳同位素分馏的量子化学计算研究
项目编号: No.41303047
项目类型: 青年科学基金项目
立项/批准年度: 2014
项目学科: 天文学、地球科学
项目作者: 原杰
作者单位: 中国科学院地质与地球物理研究所
项目金额: 25万元
中文摘要: 金伯利岩是克拉通内部形成的主要深成岩之一。前人主要通过实验观测来研究野外金伯利岩样品中碳同位素在矿物及岩体内的分布,少量高温高压实验研究给出了实验条件下金伯利岩可能包括的含碳矿物组合和碳同位素特征;但是,这些工作没有从机理上研究压力对碳同位素分馏的影响。针对压力对金伯利岩中碳同位素分馏影响机理这一科学问题,本项目拟用量子化学计算手段和Urey模型,研究高温压条件下原始金伯利岩岩浆、金伯利岩主要含碳矿物(方解石、文石、白云石、金刚石等)中及之间的碳同位素分馏系数。达到应用这些参数揭示或反推金伯利岩形成过程所经历的关键温压条件的目标。这些数据是克拉通演化、深部碳循环等重大课题研究过程中需要的基本数据,也是基础地质学研究中的必须数据,有重大科学意义。
中文关键词: 碳同位素;13C-18O Clumped同位素温度计;量子化学计算;复平面内约化配分函数;U-Pb定年法
英文摘要: The kimberlite is one kind of plutons formed in the inner Craton. Previous publications mainly focused on the carbon isotopes in the kimberlite smaples from the field, and few of them aimed to research on the groups of minerals which include the carbon element at the high T and high P conditions in the lab. However, those works did not consider the influence of pressure on the carbon isotopes at the mechanical level. To solve this problem, this foundation will study the carbon isotope fractionation in and/or between the original kimberlite melts and the minrerals, including calcite, aragonite, dolomite, and diamond in it by using the Urey model and the ab initio calculatons and molecular dynamic simulations.This will furher help understanding the key T and P condition that the kimberlite experienced, and the results here are the basis for and play significant roles in Craton evolution, Deep Carbon Cycling and other important geological research.
英文关键词: Carbon isotope;13C-18O Clumped thermometer;Quantum chemistry calculation;Reduced partition function ratio in complex plane;U-Pb dating method