后期地质扰动对岩石钕同位素参数计算的影响  

Influence of Late Geological Disturbance on Nd Isotopic Parameter Calculation

作　　者：万渝生[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037

出　　处：《矿物岩石地球化学通报》2000年第1期22-24,共3页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金!项目成果之一(49473172)

摘　　要：根据推导的误差公式，本文对岩石遭受后期强烈改造于其εＮｄ（ｔ０）计算的影响问题进行了讨论。指出应用εＮｄ（ｔ０） 讨论太古宙早期岩石成因及地壳演化需持特别谨慎的态度。Neodymium isotope data from the oldest preserved rocks can provide evidence for early large scale depletion of the mantle. However, the samariun neodymium system may be strongly disturbed in late geological events. This paper has worked out a formula to show the influence of late geological disturbance on the ε Nd ( t 0) calculation of the rocks. δε Nd ( t 0)= Q ( t 0-t 1)( f 0-f 1)+Δε Nd ( t 1), where δε Nd ( t 0) is the calculation error, t 0 and t 1 are the formation time and disturbing time of the rock respectively, f 0 and f 1 are the f values of the rock at the time t 0 and t 1 respectively, Δε Nd ( t 1)is the Nd isotopic change of the rock caused by geological disturbance at t 1.It is indicated that most of the early Archaean rocks, especially, the 3.8 Ga rocks in the Anshan area, have strongly undergone late metamorphism and deformation, it may be one of the important reasons why they show in different degrees but generally obviously positive deviation of ε Nd ( t 0).

关 键 词：钕同位素 太古宙 地壳演化 地质 岩石成因 误差公式 扰动 后期 影响 早期 

分 类 号：P597[天文地球—地球化学]