Features of the Formation of Mineral Deposits at the Initial Stages of Formation of the Earth’s Mantle and Crust

The Purpose of the Work: The modern mantle and crust have a complex structure and, in addition, contain both thermal and material heterogeneities, as evidenced by the results of seismic and electromagnetic studies. Changes are also reflected by the change in the mineralogical and chemical composition of the matter. This structure was formed for the long geological history of the planet’s development and the process continues at the present time. The system remains unsteady. To understand the evolution of such dynamic structures, information is needed about the initial state of the system, in our case, about the state of the Earth at the final stage of its formation. It can be obtained only by the results of numerical modeling based on the results of the investigation of the evolution of isotope systems. Therefore, the purpose of the work is to identify the features of the formation of mineral deposits in the early crust and mantle. For this, it is necessary to obtain variants of the numerical solution of the problem of the formation of the planet. Solution Methods: An algorithm for solving a non-linear system of differential equations for solving a 3D boundary dynamic problem in the sphere of an increasing radius is developed. The numerical method of “through account” is used in the work. Results: Based on methods for solving boundary value problems for a system of differential equations with the use of new results of mineralogical and isotope studies of the oldest material samples, quantitative variants of the thermal evolution of the Earth, directly determining the formation of early metallogeny, are constructed. It is shown that the random distribution of particles and bodies of a protoplanetary cloud during the accumulation of the planet causes the formation of a random material and temperature composition of the growing crust and mantle, which ensured a special metallogeny of the cratons and their framing, which no longer repeated in the geological history of the planet. A special role in it was played by changes in the gravitational field during the growth of the planet and the angular velocity of the Earth’s rotation. Further Research: It is proposed to extend the results obtained to the conditions for taking into account the dynamics of the double Earth-Moon system.

Stony Brook’s Collaborations with Czech Scientists

For the past half-century, I have been fortunate in maintaining collaborations with Czech scientists in the Czech Republic [formerly Czechoslovakia] from the Geofyzikální ústav-GFU [Institute of Geophysics] of the ?eskoslovenská Akademie Věd-?SAV [Czechoslovak Academy of Sciences]. These collaborations have included exchange visits by me to Prague [Praha] and convening international workshops in 1976, 1986 and 1996 in castles used by the ?SAV as well as visits by Czech colleagues to Stony Brook University. The objective of this report is to relate this history. This paper is dedicated to the memory of Vladislav Babu?ka.

My Research Collaborations with Chinese Scientists over the Past Three Decades

For more than three decades, I have been fortunate in working with Chinese graduate students and postdoctoral research scientists in our High-Pressure Laboratory at Stony Brook University. These colleagues have conducted a wide variety of experiments at high pressures and temperatures in collaboration with our other students and researchers. These studies utilized transmission electron microscopy, ultrasonic interferometry, X-ray powder diffraction and synchrotron X-radiation to investigate phase transitions, thermal equations of state, sound velocities, atomic diffusion, dislocation dissociation and deviatoric stress in high-pressure apparatus. During this period, I have also visited high-pressure laboratories in the mainland of China and Taiwan on several occasions. The objective of this paper is to relate this history.

自转速率快速变化引起的全球位移场和应力场

该文建立了百万网格的分层PREM地球模型,利用并行有限元方法计算了自转速率快速变化所引起的全球附加的位移场和应力场。计算模型中不仅考虑了地球的径向分层,同时还考虑椭率和地形的影响。利用数值试验的方法,系统分析了地球自转速率变化为Δω/ω=2×10-10时所引起的全球应力分布特征,研究表明椭率对地表各个应力分量的影响在千分之几,而地形的影响则表现为径向应力与地形正相关,且相同高度的地形在低纬度影响较大,纬向和经向的应力大小分别与地形在SN向和EW向的地形梯度直接相关。

地球内部结构及物性研究的进展及问题

本文对近几年中国地球物理学家在地球内部结构和物质性质方面的研究工作进行总结.从地球内部结构的地震波速度成像,地幔介质的各向异性,地幔间断面及地幔介质物性进行了综述,指出在一些原有的研究领域,工作更加深入,方法更加先进,而且进行了广泛的国际合作,合作的范围也逐渐扩大,方式多样,并开拓了一些新的研究方向.在肯定我们近几年取得的一些新的进展的同时,也提出了地球内部结构研究中应进一步研究的问题.

中国东部地壳与上地幔速度不均匀性和各向异性的初步研究(英文)

本文利用763式地震仪记录的地震瑞利面波资料,用双台法计算出瑞利面波的频散曲线,从而得到相速度.将我国东部地区(99.8°—123.8°E,20°—44°N)分成4°×4°大小的方格,利用代数重建法得出该地区上地幔与地壳的横向不均匀性.对同一地区再进行一次分块,块的大小为8°×8°,考虑到各向异性对面波相速度的影响,利用周期为60 s 的面波相速度资料,反演出我国东部的横向不均匀和各异向性的特征。