Quantitative estimation of crustal thickness based on Bayesian method
The continental crust has played an important role in recording the Earth's evolution over the past four billion years.The geochemical characteristics of magmatic rocks formed by the modern plate convergence boundary are highly correlated with the crust thickness during magmatic activity,so a series of geochemical indicators can be used as excellent tracers of crust thickness.However,due to the complexity of the geochemical composition of magmatic rocks,accurately quantifying crustal thickness in past geological periods has been a challenging task.Based on large geochemical databases,a Bayesian model for the quantitative estimation of crustal thickness using various geochemical indices(CaO,K2O,MnO,Dy,Ho,Lu,Y,Sr/Y,Ce/Y,La/Yb,Sm/Yb,Dy/Yb)is established in this paper.Validation results using global data since the Miocene(＜15 Ma)show that the Bayesian model provides a more accurate estimate of present-day crustal thickness than traditional single-indicator methods.This model is used to reconstruct the crustal thickness changes of the Lhasa block in the Cenozoic.The reconstruction results show that the Lhasa block experienced multiple stages of crustal thickening from 50 Ma to 30 Ma,and finally formed today's extremely thick crust.
国家科技期刊平台
NSTL
万方数据
