云南北衙表生金矿形成与保存探讨   总被引：7，自引：3，他引：4  

肖骑彬  蔡新平  徐兴旺 《矿床地质》2003,22(4):401-407

通过对云南北衙地区表生金矿形成的地质背景、矿床特征等的研究,重点探讨了其特殊的形成与保存条件。认为北衙地区的表生金矿是“古砂矿”,它的巨大蕴藏量主要得益于其特殊的形成与保存条件：丰富的原生金矿为其提供充足的成矿物质,特别发育的古喀斯特洞穴为“古砂矿”提供了特殊的储存空间,强烈的气液爆破作用形成的热水角砾盖层为其提供了良好的保存条件。  相似文献   

Cephalopods of the “Falang Formation” (Triassic) from Guanling and Zhenfeng Counties, Guizhou Province, China     

HAO Weicheng  SUN Yuanlin  JIANG Dayong  YANG Shouren  WANG Xinping Geological Museum  Peking University  Beijing 《《地质学报》英文版》2003,77(4)

The "Falang Formation" of western Guizhou was previously called the "Halobia Bed" and considered to be I .adinian in age. It was subdivided upward into the Zhuganpo, Laishike and Longchang members based on ammonites and the Trachyceras multitubertulatum Zone of the Longchang Member was put in the Lower Carnian. Here in the present paper, 4 genera and 9 species of ammonites and 1 nautiloid genus and species collected from the upper part of the "Falang Formation" (i.e. the Wayao Formation used in this paper, equivalent to the Laishike Member from Guanling and Zhenfeng counties are described. The geological and geographical distribution of these cephalopods, as well as the co-existing conodonts, put the Wayao Formation to the late early Carnmian.  相似文献   

Ecohydrological change mechanism of a rainfed revegetation ecosystem at southeastern edge of Tengger desert,Northwest China   总被引：1，自引：0，他引：1  

Honglang Xiao  Guodong Cheng  Xinrong Li  Yaoxuan Song  Xinping Wang 《中国科学D辑(英文版)》2004,47(1):71-77

Study is made on a 45 km-long artificial ecosystem without irrigation in Tengger desert on the basis of long-term ecological monitoring and ecohydrological fundamentals. Changes in water allocation, utilization, cycle and balance patterns in more than 40-year evolution of the soil-plant system are analyzed. The formation of a drought horizon in shrub rhizosphere and its effect, ecohydrological function of the crust and its effect on the soil-plant system change are discussed. Driven by water self-regulation and water stress, the soil-plant system is going to develop towards the steppe desert to ensure more effective use and optimum collocation of water resource.  相似文献   

Variations of δ^18 O in Precipitation along Vapor Transport Paths   总被引：3，自引：3，他引：3  

章新平刘晶淼  田立德何元庆 姚檀栋 《大气科学进展》2004,21(4):562-572

Three sampling cross sections along the south path starting from the Tropics through the vapor passage in the Yunnan-Guizhou Plateau to the middle-low reaches of the Yangtze River, the north path from West China, via North China, to Japan under the westerlies, and the plateau path from South Asia over the Himalayas to the northern Tibetan Plateau, are set up, based on the IAEA (International Atomic Energy Agency)/WMO global survey network and sampling sites on the Tibetan Plateau. The variations, and the relationship with precipitation and temperature, of the δ^18 O in precipitation along the three cross sections are analyzed and compared. Along the south path, the seasonal differences of mean δ^18 O in precipitation are small at the stations located in the Tropics, but increase markedly from Bangkok towards the north, with the 51so in the rainy season smaller than inthe dry season. The δ^18 O sovalues in precipitation fluctuate on the whole, which shows that there are different vapor sources. Along the north path, the seasonal differences of the mean δ^18 O in precipitation for the stations in the west of Zhengzhou are all greater than in the east of Zhengzhou. During the cold half of the year, the mean δ^18 O in precipitation reaches its minimum at Uriimqi with the lowest temperature due to the wide, cold high pressure over Mongolia, then increases gradually with longitude, and remains at roughly the same level at the stations eastward from Zhengzhou. During the warm half of the year, the δ^18 O values in precipitation are lower in the east than in the west, markedly influenced by the summer monsoon over East Asia. Along the plateau path, the mean δ^18 O values in precipitation in the rainy season are correspondingly high in the southern parts of the Indian subcontinent, and then decrease gradually with latitude. A sharp depletion of the stable isotopic compositions in precipitation takes place due to the very strong rainout of the stable isotopic compositions in vapor in the process of lifting over the southern slope of the Himalayas. The low level of the δ^18 O in precipitation is from Nyalam to the Tanggula Mountains during the rainy season,but δ^18 O increases persistently with increasing latitude from the Tanggula Mountains to the northern Tibetan Plateau because of the replenishment of vapor with relatively heavy stable isotopic compositions originating from the inner plateau. During the dry season, the mean δ^18 O values in precipitation basically decrease along the path from the south to the north. Generally, the mean δ^18 O in precipitation during the rainy season is lower than in the dry season for the regions controlled by the monsoons over South Asia or the plateau, and opposite for the regions without a monsoon or with a weak monsoon.  相似文献   

Variations of δ18O in Precipitation along Vapor Transport Paths     

ZHANG Xinping  LIU Jingmiao  TIAN Lide  HE Yuanqing  YAO Tandong 《大气科学进展》2004,21(4):562-572

Three sampling cross sections along the south path starting from the Tropics through the vapor passage in the Yunnan-Guizhou Plateau to the middle-low reaches of the Yangtze River, the north path from West China, via North China, to Japan under the westerlies, and the plateau path from South Asia over the Himalayas to the northern Tibetan Plateau, are set up, based on the IAEA (International Atomic Energy Agency)/WMO global survey network and sampling sites on the Tibetan Plateau. The variations, and the relationship with precipitation and temperature, of the δ18O in precipitation along the three cross sections are analyzed and compared. Along the south path, the seasonal differences of mean δ18O in precipitation are small at the stations located in the Tropics, but increase markedly from Bangkok towards the north, with the δ18O in the rainy season smaller than inthe dry season. The δ18O values in precipitation fluctuate on the whole, which shows that there are different vapor sources. Along the north path, the seasonal differences of the mean δ18O in precipitation for the stations in the west of Zhengzhou are all greater than in the east of Zhengzhou. During the cold half of the year, the mean δ18O in precipitation reaches its minimum at Urumqi with the lowest temperature due to the wide, cold high pressure over Mongolia, then increases gradually with longitude, and remains at roughly the same level at the stations eastward from Zhengzhou. During the warm half of the year, the δ18O values in precipitation are lower in the east than in the west, markedly influenced by the summer monsoon over East Asia. Along the plateau path, the mean δ18O values in precipitation in the rainy season are correspondingly high in the southern parts of the Indian subcontinent, and then decrease gradually with latitude. A sharp depletion of the stable isotopic compositions in precipitation takes place due to the very strong rainout of the stable isotopic compositions in vapor in the process of lifting over the southern slope of the Himalayas. The low level of the δ18O in precipitation is from Nyalam to the Tanggula Mountains during the rainy season,but δ18O increases persistently with increasing latitude from the Tanggula Mountains to the northern Tibetan Plateau because of the replenishment of vapor with relatively heavy stable isotopic compositions originating from the inner plateau. During the dry season, the mean δ18O values in precipitation basically decrease along the path from the south to the north. Generally, the mean δ18O in precipitation during the rainy season is lower than in the dry season for the regions controlled by the monsoons over South Asia or the plateau, and opposite for the regions without a monsoon or with a weak monsoon.  相似文献   

Reinforcing a Dangerous Rock Mass Using the Flexible Network Method     

Yang Wendong Xie Quanmin Xia Yuanyou Li Xinping 《中国地质大学学报(英文版)》2005,16(4):354-358

Because the main failure type of a dangerous rock mass is collapse, the treatment of such a mass should focus on controlling collapse failure. When treating dangerous rock masses, disturbing the mass （e. g. by blasting） needs to be avoided, as this new damage could cause collapse. So the self-bearing capacity of the mountain mass must be used to treat the dangerous rock mass. This article is based on a practical example of the control of a dangerous rock mass at Banyan Mountain, Huangshi, Hubei Province. On the basis of an analysis of damage mechanism and the stability of the dangerous rock mass, a flexible network reinforcement method was designed to prevent the collapse of the rock mass. The deformations of section Ⅱ w of the dangerous rock mass before and after the flexible network reinforcement were calculated using the two-dimensional finite element method. The results show that the maximum deformation reduced by 55 % after the application of the flexible network reinforcement, from 45.99 to 20.75 ram, which demonstrates that the flexible network method is effective, and can provide some scientific basis for the treatment of dangerous rock masses.  相似文献   

MATHEMATICAL MODELING OF VARIATIONS ON STABLE ISOTOPIC RATIOS IN FALLING RAINDROPS   总被引：13，自引：0，他引：13  

章新平  谢自楚  姚檀栋 《Acta Meteorologica Sinica》1998,(2)

The variations of stable isotopic contents in falling raindrops are not only influenced by thehumidity conditions, but also by the stable isotopic contents in atmospheric vapor to a certainextent. If there is a difference between the isotopic contents in the vapor of the surrounding air andat the surface of the raindrops, the move of the isotopic contents from high to low values will beproduced. Usually. influenced by the evaporation process, the stable isotopic ratios in raindropsare constantly increased in the unsaturated atmosphere. The less the atmospheric humidity, themore obvious the increased range. As the enrichment rate of stable isotopes in raindrops is equal tothe outward isotopic move rate. the "pseudo-equilibrium state" appears. The influence ofevaporation on stable isotopic contents disappears in the saturated atmosphere, so that themagnitude of isotopic ratio in raindrops is dependent on the isotopic exchange between theraindrops and the surrounding atmosphere.  相似文献   

冀东金厂峪特大型金矿床的地质地球化学特征和矿床成因   总被引：6，自引：0，他引：6  

秦大军  蔡新平 《地质与勘探》1997,33(5):4-9

金厂峪金矿产于八道河群王厂组，矿体受刘村寨－双沟峪复式向斜控制，成矿与中生代构造作用及岩浆活动有密切关系矿床的形成经历了复式向斜构造的形成，与岩浆活动有关的成矿热液沿构造薄弱带运移；热液蚀变及矿质沉淀。硫，氧，碳，铅同位素数据表明成矿物质来源于深部，与矿床围岩具有不同的属性。  相似文献   

运城震群序列特征     

刘巍  赵新平 《地震研究》1988,(4)

1986年11月至1987年1月在山西运城发一次较大震群活动。本文着重讨论了这次震群活动的序列特征和衰减特征  相似文献   

山西地震带震群与地震序列活动特征          下载免费PDF全文

刘巍  赵新平 《地震工程学报》1988,10(4):62-68

本文利用文献[1]、[2]和1)所采用的方法,对邢台地震后在山西地震带发生的震群和地震序列的U值、h值和k值进行了计算。结果表明,在山西地震带中,如果出现U≥0.6、K≥0.8或h>1的震群活动,在大华北东部都有中强地震发生。本文还讨论了山西震群与地震序列活动和大华北中强地震的关系。认为在1966—1976年大华北地震活动幕里,山西地震带的地震活动受其东部河北平原地震带的影响和控制。  相似文献