【摘 要】
:
Oxygen isotopic compositions of zircons from pyroxenite (~145 Ma) of Daoshichong, Dabieshan have been measured by an ion microprobe. Both within the single grain
【机 构】
:
Department of Earth and Space Sciences,CRPG-CNRS
论文部分内容阅读
Oxygen isotopic compositions of zircons from pyroxenite (~145 Ma) of Daoshichong, Dabieshan have been measured by an ion microprobe. Both within the single grain and among different grains, oxygen isotopic ratios are homogeneous, δ 18O = (7.66‰±0.46)‰ (1 SD, 1 σ = 0.10, n = 22). High δ 18O values indicate that the mantle-derived parent magma of Daoshichong pyroxenite have undergone interaction with crustal materials. Combing with other geochemical constraints, the way of crust-mantle interaction is suggested to be source mixing other than crustal contamination. The time interval between crust-mantle interaction and formation of the parent magma of Daoshichong pyroxenite is less than several million years. The crustal component involving in crust-mantle interaction is mafic lower crust, and the parent magma of pyroxenite possibly contain large proportion (>37%) of such lower crust.
其他文献
免疫学是研究机体免疫系统结构和功能的一门学科.免疫系统由早期的天然免疫和后期的获得性免疫所组成.免疫系统的任务是通过天然免疫和获得性免疫, 其中包括长效的免疫记忆反
通过对数字图书馆研究领域的重要参考期刊D-lib Magazine的考察,从栏目设置、主要内容及其特色等方面对其进行评述,旨在通过对该杂志的评述,为从事数字图书馆研究的学者介绍
短期电价预测的准确性和稳定性对电力竞价决策具有重要作用。针对目前短期电价预测方法的局限性,提出并建立了一种基于多智能体的智能化短期电价预测方法。按照智能预测和组
Evidence for the "8.2 ka cold event" has been provided mostly from the circum-North Atlantic area. However, whether this cold event occurred in other places is
On July 20~21, 1998, a torrential rain with 24-hour rainfall of 286 mm occurred in Wuhan, Hubei Province of China. In this study, a three-dimensional variational
根据武汉1951~2000年50年暴雨日数资料,应用Mann-Kendall统计方法对暴雨序列进行年际突变检验.揭示出武汉暴雨在1979年发生突变,20世纪80年代后暴雨出现频数明显上升,强度增大
The Quaternary Tailan River fault has been found in the Tianshan foothills area, the Xinjiang Uygur Autonomous Region. It is the recent boundary fault of the Ta
From the first finding in 1970s, the findings of foraminiferal fossil assemblages in inland basins have been reported from time to time, especially in recent ye
This paper studies the effect of photochemistry on the gravity wave instability in summer polar mesopause region. The calculation method of the effects of eddy
Lower Cretaceous red sedimentary rocks from the depositional basin of East Qilian fold belt have been collected for a paleomagnetic study. Stepwise thermal dema