地磁场解释的数学方法(续)

磁场分解为分量场。我们对总的地磁场的统计性质作了分析之后,随之而来的便是将地磁场分解为分量场。在全球范围内研究总磁场时,需要划分出正常场;在研究区域磁场时,则需要把异常分成不同级次。     

太古代和元古代科马提岩的野外地质特征和岩石学

引言虽然现在已知有些早已描述过的超基性岩是喷出成因的(例如,Naldrett & Mason, 1968),但对超基性熔岩的认识和首先作明确描述的应归功于Viljoen & Viljoen(1969),他们认为南非巴伯顿山地绿岩带中的许多超基性岩单位是火山成因的。他们建议把包括这些超基性熔岩以及有关的基性火山岩和超基性岩墙和岩床的一套岩石称为科马提岩(Komatiite)。作为喷出证据,他们描述了冷却的岩流顶部构造、     

硫化物饱和的和硫化物未饱合的科马提岩熔融体的化学和热力模拟

科马提岩熔融体的化学的和热力的模拟试验进行了我们对卡姆巴尔达型镍矿床成因的认识。化学模拟的价值明显地受工程使用资料的质量的限制。现有的模式是以Rajamani和Naldrett(1978)提出的镍分配系数的实验测定为根据的。这些系数是在1200℃和1300℃间温度的玄武岩熔融体在未知S及O逸度条件下测定的。如果把这些资料用于模拟科马提熔融体的分馏,就可外推更多超镁铁质成分和超过1500℃温度条件下的结果。     

原始地核:离子探针为西格陵兰和恩德比地(南极洲)太古宙地区大约4000Ma地壳物质提供的证据

对古老岩区的典型花岗片麻岩中提取单—锆石颗粒内一些直径为15μm的点,用离子探针测量了~(207)pb/~(206)pb的比值表明,这些地方保存一个~(207)pb/~(206)pb比值范围。在含有较高铀含量的锆石内一般可测得~(207)pb/~(206)pb的最低比值,计算的~(207)pb/~(206)pb年龄,一般与反映它们形成后各岩层经受的比较主要地质事件可以对比。似乎可能的是,在年轻事件期间,由于遭受锆石粒高铀区放射性的破坏,使这些地带的放射性铅损失了。在含     

元古代及早古生代的微古植物化石

当前,在许多国家和地区古生物工作者十分重视研究古老的微植物化石,特别对于晚元古代及早古生代的微古植物化石的研究,取得了显著成绩。根据外貌特征,微古植物可以分成六个主要群落:球状藻(Sphaeromorphida),棱状藻(Scaphomorphida),多面藻(Edromorphida),刺球藻(Sphaerohystrichomorphida),卵形藻(Ooidomorphida)及椭状藻(Ellipasoidomorphida)。并包括几个亚群落和很多     

Fossil Vertebrates from Kuangyuan, N. Szechuan, China

正 During the late spring of 1941, Messrs. M. N. Bien, T. H. Mi and the present writer were fortunate enough to discover several localities of vertebrate fossils. The geological condition will be reported in another paper' and need not be repeated there. Most of the fossils were derived from the hill     

SUBDIVISIONS OF THE JURASSIC, CRETACEOUS AND TERTIARY COAL-BEARING STRATA OF RUSSIAN MARITIME AND AMUR PROVINCES, AND OF SAKHALIN ISLAND

As is well known, the first information on the coal-bearing strata of the Russian Far East and their characteristic fossil flora was given by the acadeinician Prof. Schmidt (2), and his fellow-traveller Glehn (13), to Lopatin, Bogoluibsky (9), A. Koeppen (26) and others. However the     

A PLIOCENE FLORA FROM SHANSI PROVINCE

A small collection of fossil plants was made in 1930 by Dr.GeorgeB. Barbour,of Yenching University,in the course of his study of the sedimen-tary deposits near Taiku,Shansi Province (See text figure 1).My acknow-ledgement is due to Dr. Barbour,and to Dr.     

A PRELIMINARY REPORT OF ARCHAEOLOGICAL INVESTIGATIONS ON THE SINO-TIBETAN BORDER OF SZECHWAN§

INTRODUCTION During the year 1930-31, while holding a schularship from the Harvard-Yenching Institute, I received permission from the Institute to engage in ethnological and anthropological research on behalf of the University Museum