澳大利亚造山型金矿和侵入岩有关金矿系统流体包裹体资料和矿化过程的比较

We have examined the fluid inclusion data and fluid chemistry of Australian orogenic and intrusion-related gold deposits to determine if similar mineralization processes apply to both styles of deposits.The fluid inclusion data from the Yilgarn craton,the western subprovince of the Lachlan orogen,the Tanami,Tennant Creek and Pine Creek regions,and the Telfer gold mine show that mineralization involved fluids with broadly similar major chemical components(i.e.H_2O NaCl CO_2±CH_4±N_2).These deposits formed over a wide range of temperature-pressure conditions(<200 to>500℃,<100～400MPa).Low salinity, CO_2-bearing inclusions and low salinity aqueous inclusions occur in both systems but the main difference between these two types of deposits is that most intrusion-related gold deposits also contain at least one population of high-salinity aqueous brine.Oxygen and hydrogen isotope data for both styles of deposit usually cannot distinguish between a magmatic or metamorphic source for the ore-bearing fluids.However,sulfur and lead isotope data for the intrusion-related gold deposits generally indicate either a magmatic source or mixing between magmatic and sedimentary sources of fluid.The metamorphic geothermal gradients associated with intrusion-related gold deposits are characterized by low pressure,high temperature metamorphism and high crustal geothermal gradients of>30/km.Where amphibole breakdown occurs in a granite source region,the spatially related deposits are more commonly associated with Cu-Au deposits rather than Au-only deposits that are associated with lower temperature granites.The dominant processes thought to cause gold precipitation in both types of deposits are fluid-rock interaction(e.g.desulfidation)or phase separation.Consideration of the physical and chemical properties of the H_2O-NaCl-CO_2 system on the nature of gold precipitation mechanisms at different crustal levels infers different roles of chemical(fluid-rock interaction)versus rheological(phase separation and/or fluid mixing)host-rock controls on gold deposition.This also implies that at the site of deposition,similar precipitation mechanisms operate at similar crustal levels for both orogenic and intrusion-related gold deposits.     

正压大气中根据天气和同化资料制作统计-动力预报

1.前言从一些离散的观测站采样而得某一气象变量的主观分析多半会和它的真实情况不同。如果这种不确定的分析用作数值预报的初始状态,那么所作预报也将会有误差。格利森1961年发展的一种统计-动力理论对这种初始状态的误差及其随时间增长作了定量处理。在这种理论模式中用调整物理模式的动力项将初始误差的正态分布转为预报误差的正态分布。从最终的分布求得预报量处于其真实数值的某一允许偏差范围内的理论概率。实际上这样也就作出了对预报     

地震的震级频度分布与古登堡—里克特关系式的偏离:大震之前前兆异常的检测

本文介绍了表示地震的震级频度分布与古登堡-里克特(GR)关系式偏离的一种量度。以前曾认为震级频度分布遵从古登堡-里克特关系式,然而,实际分布常常与这一关系式偏离相当大。令n_i、N、M_0和b分别是震级为M_i～M_i+△M的事件数目、地震的总数目、震级的下限以及古登堡-里克特关系式的b值。这样,用Kullback-Leibler平均信息就可给出偏离的量度:式中,p(X_i)=n_i/N,q(X_i)= b ln 10 exp(-b ln 10 X_i),函数q(X_i)代表古登堡-里克特分布,因此这个量度给出了震级分布与古登堡-里克特关系式的偏离程度。如果地震的震级分布与古登堡-里克特关系式符合得越好,那么‘C’值将越小;而如果分布精确地遵从古登堡-里克特关系式时,‘C’为零。相反,如果分布与古登堡-里克特关系式偏离很大,‘C’指标给出的值也很大。我们研究了日本的大地震和震群前后‘C’值随时间的变化,结果显示出大震前后‘C’值的变化是不可忽视的。在大震之前,‘C’值变小,这说明震级分布与古登堡-里克特关系式吻合得较好,主震之后,‘C’急剧变化。在震群活动期间,‘C’值的变化也相当大,但是,震群的‘C’值比一般地震的‘C’值小些。在某些震群中,‘C’指标在最大活动时刻达到极大值。这个量度是很有用的工具,用它可观测地震活动的典型特征并且或许可用来作为检验大震的前兆现象。     

区域断裂对韩国东南部地区现今应力状态的影响

利用朝鲜半岛东南部地区浅层地应力数据,给出区域现今应力状态的分布特征及其与断层分布的关系.地应力数据表明,区域最大主压应力呈ENE-WSW到NE-SW向,这与地震震源机制解及欧亚板块东部构造应力方向的一阶模式一致.或许是受到断层的影响,现今应力张量在大小和方向上表现出不均匀性.区域水平主应力变化较为一致,而垂向则变化较...     

ALKALINE INTRUSIVES OF LUTINGSHAN AND CH''IAOSHAN IN S.SHANSI

In recent years several localities of highly alkaline rocks have been dis-covered in Shansi by the National Geological Survey of China and the Sino-Swedish Research Institute.The results of investigation in this line up to 1927are embodied in the paper:"S     

On Tectonic History in Regions East of the Tibetan Plateau from Kansu to Yunnan

正 With 2 Plates During the recent five years I have joined several field parties in the carrying out of geological reconnaissances in regions between the valley of the Huangho and of the Yangtze and in the Sino-Tibetan borderland. This vast territory can be divided into six major geological units, e     

Note on the Liangshanophyllum,a new Subgenus of Waagenophyllum from Permian of China

The material of this short paper includes four species, one is a new form of Waagenophyllum, and the three others belong to a new subgenus named Liangshanophyllum. The specimens of the latter were collected by Y. H. Lu in 1942 from Liangshan, S Shensi, in a grayish black massive limestone, which is considered as the upper-most part of the Permian limestone at that region wish very abundant fossil corals of fasciculate cylindrical form. The new species of Waagenophyllum was collected in     

非洲荒漠草原地理简介

非洲荒漠草原是介于撒哈拉沙漠和南部热带稀树草原之间的地带。因有一个短暂的雨季和一个漫长严酷的干季,故在气候上以强烈的季节性为其特征。非洲荒漠草原的界限较难确定。本地带的环境从南向北随着降雨量的不同而发生明显的变化,而且又因降雨量有长期和短期的变化,同一地区在不同时期的情况又不尽相同。尽管其环境十分恶劣,但仍有可用之处,许多非洲古代王国曾都于此。     

第二届阿帕拉契地理学代表会议

第二届阿帕拉契地理学代表会议于1983年10月21—22日在西弗吉尼亚的派普斯特姆州立公园召开。会议参加者有47人。他们分別来自肯塔基、北卡罗来纳、田纳西以及西弗吉尼亚。他们当中有大学的教师、大学生、应用及地理学工作者及其它热心阿帕拉契地区地理学研究的同行们。向这次代表会议提交的论文有11篇。     

Cepheus C的C^18O（J=1—0）分子辐射的观测—多核结构

利用日本名古屋大学天体物理系的毫米波射电望远镜对ＣｅｐｈｅｕｓＣ的Ｃ＾１８Ｏ（Ｊ＝１－０）分子辐射首次进行了观测，得到了强度分布图。从强度分布图上，我们发现Ｃ＾１８Ｏ（Ｊ＝１－０）分子的分布呈现三个核。通过计算得到了三个核的物理参数。