K-Ar isotopic geochronology of Lianhuashan tungsten mining district,Guangdong Province     

Yuzhen Bai  Fasheng Man  Shoubin Ni  Tong Li 《中国地球化学学报》1985,4(1):33-40

Reported in this paper are K-Ar ages of volcanic rocks, biotite-granite and greisen from the Lianhuashan tungsten mine in Guangdong Province. The isotopic dilution method was adopted in this work. Whole-rock isochron ages of the volcanic rocks are in the range 120.4±12.1 m.y. The petrogenetic age of biotite-granite and the minero genetic age of tungsten ore are close to those of the volcanic rocks. The apparent ages of various types of rock in the mining district generally bias towards younger values, which may be attributed to the effects of late thermal events which took place in the circum-Pacific metallogenetic belt.  相似文献   

甘肃天水地区1654年罗家堡7(1)/(2)级地震构造背景的初步分析          下载免费PDF全文

白启圣  王之佩 《地震工程学报》1984,6(1):65-71

本文从分析天水地区区域地质构造背景出发着重指出,1654年罗家堡7(1/2)级地震发生在天礼盆地中北东向构造与北北西向活动构造交汇所形成的新生代以来沉陷最深的部位。并对1936年天水镇6级地震发生的构造条件以及天礼盆地的成因进行了初步探讨。  相似文献   

On the conditions of formation of Gushan iron ore deposit     

Chuanxian Lin  Zheru Zhang  Zhengua Bai 《中国地球化学学报》1984,3(1):45-55

On the basis of its geological characteristics, the Gushan iron deposit should be assigned to volcano-hydrothermal type with hematite-quartz as its principal mineral assemblage. Iron concentration of the ore solution has been estimated from the ratio of hematite to quartz in the ore. By using experimental and thermodynamic data, the solubility of ferro-minerals at elevated temperatures and pressures have been calculated in the system FeO?Fe₂O₃?NaCl?HCl?H₂O. The effects ofT, P, pH,f _{O 2} and total Cl concentration on the solubility of ferrominerals are discussed. Thermodynamic calculations based on presumed physico-chemical conditions for the ore solution are in good agreement with geological observations. The calculation shows that ferro-minerals were deposited at logf _{O 2}=?21～?25, log(m_HCl+m_H+)=?2.5～?3,P=1?0.75 (or 0.5) kb, andT=400°?350°C. It is believed that the original solution was an acid NaCl-bearing solution of magmatic derivation. However, iron in the solution was enriched with falling temperatures by dissolving pre-existing ferro-minerals in consolidated rocks rather than extracting directly from the magma. Either temperature (below 400°C) or pressure decrease may result in the precipitation of ferro-minerals from the solution, but the Fe/Si ratio in the ore is dependent mainly upon pH. The widespread siliceous veins of later stages are a reflection of decreasing acidity of the solution. An increase inf _{O 2} will also favor the deposition of ferro-minerals. The hypabyssal occurrence and the existence of the Huangmaqing sandy shale have contributed greatly to the formation of hematite.  相似文献   

渤海湾西部海陆风的空间结构   总被引：12，自引：1，他引：12  

于恩洪  陈彬  白玉荣 《气象学报》1987,45(3):379-381

海陆风虽然只是距海岸线两侧几十公里的一种中尺度现象,但它对沿海一带的天气有很大的影响。它不仅对大范围的空气运动有作用,而且可以改变局地气候。 研究海陆风,对进一步开发利用沿海风能资源,弄清空气污染规律和中小尺度天气的物理机制,提高短时天气预报准确率都有重要意义。 作者在1983年—1984年间的春、秋、夏、冬分别进行了有关海陆风观测。观测站的分布见图1。  相似文献   

机载热红外扫描在岩溶水文地质中的应用     

茹锦文  白桂云  黄瑞照 《中国岩溶》1986,(Z1):33-41

<正> 由地面资料评价一个地区地下水的排泄地段,已经有了一套比较成功的方法。然而,地面方法相对来说所需要的时间长,花钱多,尤其是在那些交通不便,人们难以到达的地区。四十年代以来,随着航空地质工作的发展,借助于航空摄影所提供的地形、植被类型、地层产状以及破裂等资料来分析地下水的补给和排泄关系。  相似文献   

当代造山带研究中值得重视的若干前沿问题   总被引：18，自引：4，他引：18  

肖庆辉  李晓波 《地学前缘》1995,2(1):43-50

当代造山带研究正从以往以阐明板块运动历史和板块边界相互作用为主，转向并进入到了阐明造山带岩石圈及其之下地幔系统中各层圈相互作用过程和动力学的新阶段，大陆动力学正成为造山带研究的主要指导思想。在这种形势下，造山带研究正围绕着下列前沿问题展开工作：（１）碰撞后的造山过程：拆沉作用、伸展垮塌和深变质岩剥露；（２）造山带之下地幔的结构和演化；（３）壳内软层的性质和动力学作用；（４）造山带地壳的精细构造和演化；（５）巨量花岗岩的成因和侵位动力学；（６）沉积作用与造山过程：根据沉积特征对造山过程、造山事件的恢复再造；（７）新元古代超大陆。  相似文献   

A CASE OF MESOSCALE CONVECTIVE COMPLEX EVOLVING INTO A VORTEX   总被引：1，自引：0，他引：1       下载免费PDF全文

陶祖钰  王洪庆  白洁  朱文琴  石定朴  杨红梅 《Acta Meteorologica Sinica》1995,(2)

A case of mesoscale convective complex(MCC)which evolved into a vortex is documented in this paper.As theMCC entered into the dissipating phase,a well-defined spirally banded structure became visible in the satellite image.The blackbody temperature(TBB)of the residual cold-cloud-shield indicates the vortex existed in the layer from 400 to250 hPa.According to the upper air analysis,the upper level vortex was an anticyclone.The MCC-generated vortex wasvisualized in the satellite images because it was located in the subtropical high where the wind field was very weak.  相似文献   

A DIAGNOSTIC EXPERIMENTAL STUDY OF EFFECTS OF CO_2 ENRICHMENT ON COTTON GROWTH,DEVELOPMENT AND YIELD          下载免费PDF全文

王春乙  白月明  温民 《Acta Meteorologica Sinica》1995,(4)

A series of experiments were conducted about the effects of different CO_2 concentrations andventilating time on cotton using OPT-1 open top chambers.The results show that.for all theventilating treatments,the development stages of cotton were advanced,plant height increased,thebiomass of root and stalk increased when CO_2 concentration increased: the number of bolls formed insummer was more than 85% of the total for the treatment of 700 ppm CO_2 concentration; single bollweight,the number of bolls per plant,ginned and unginned cotton weights,and stalk weightincreased obviously when CO_2 concentration increased,but the influences of CO_2 enrichment on theratio of ginned weight to the total weight of ginned and unginned cotton,fibre length and ginnedweight of 100-seed were small.  相似文献   

A CASE OF MESOSCALE CONVECTIVE COMPLEX EVOLVING INTO A VORTEX^*          下载免费PDF全文

Tao Zuyu  Wang Hongqing  Bai Jie  Zhu Wenqin  Shi Dingpu  Yang Hongmei 《Acta Meteorologica Sinica》1995,9(2):184-189

A case of mesoscale convective complex(MCC) which evolved into a vortex is documented in this paper.As the MCC entered into the dissipating phase,a well-defined spirally banded structure became visible in the satellite image.The blackbody temperature(TBB) of the residual cold-cloud-shield indicates the vortex existed in the layer from 400 to 250 hPa.According to the upper air analysis,the upper level vortex was an anticyclone.The MCC-generated vortex was visualized in the satellite images because it was located in the subtropical high where the wind field was very weak.  相似文献   

500毫巴湿位势倾向诊断分析和应用     

吴正华  支德先  石林平  白玉荣 《气象学报》1983,41(2):129-137

本文用湿位势倾向方程进行诊断分析,表明,湿大气中差动潜热能平流对500毫巴湿位势倾向有重要影响。日常业务中计算500毫巴层位势倾向,在判断未来低值系统的移动和暴雨落区中,有一定指示意义。  相似文献