Re-Os Age of Cu-Ni Ores from the Huangshandong Cu-Ni Sulfide Deposit in the East Tianshan Mountains and Its Implication for Geodynamic Processes

An isochron age of 282±20 (95% conf. limit) Ma of the sulfide ores in the Huangshandong Cu-Ni sulfide deposit, the East Tianshan Mountains has been obtained through Re-Os isotopic measurement. The age implies that the Cu-Ni sulfide deposit and other related deposits in the same area occurred in a Permian extensional environment of post-collision instead of Devonian-Early Carboniferous ophiolite-related oceanic or island arc environments inferred before. It shares the same ages with the orogenic and epithermal gold deposit systems in the same area. An initial 187Os/188Os ratio of 0.25±0.04 (1σ) and a γos value of 99 on average display the participation of large quantities of crustal components into the rock-forming and ore-forming system during mineralization and magmatic emplacement.     

大洋多金属结核研究概况

从多金属结核的分布及富集规律、物质成分、内部结构、形成机制等方面论述了目前国内外的一些研究动态,对目前在这一研究领域提出的一些新概念、新方法作了一定的介绍.在分析和总结前人研究成果的基础上,指出了在这一研究领域还存在的一些问题及今后研究的方向.     

洛阳市水资源可利用量研究

以洛阳市为对象，对区域水资源的可利用量进行了研究。区域水资源量包括地表水实际可利用量和地下水实际可利用量。将地表径流中基流部分按比例划出，与河道汛期弃水量加在一起作为河道的生态需水量，从地表水资源量中扣除生态需水量后可得地表水的实际可利用量。将难以利用的地下水量从地下水资源量中扣除后可得地下水实际可利用量。     

玛尼7.9级地震对昆仑山口西8.1级地震的触发作用及动力背景初探

根据库仑静应力变化的概念，对青藏块体中部地区1997年11月8日玛尼7．9级地震及2001年11月14日昆仑山口西8．1级地震的应力触发作用进行了初步研究。不同震源机制解计算结果表明，玛尼地震造成了昆仑地震断层面上10^-3MPa量级的库仑应力增量，该变化仅使得昆仑地震的发生提前了最长10年左右，表明当前地壳应变能水平可能并不很低。对照20世纪初以来全球7级以上强震频度和强度演化特征与地球自转变化的关系，认为地球自转幅度衰减、变化频率升高是近期强震活动的重要控制因素。昆仑山口西8．1级地震的发生，可能是地球自转持续加速阶段后期，青藏块体内部区域应力场逐渐强化，及玛尼地震应力触发的结果。     

2002年四川仁寿双流4.6级地震震害调查

2002年5月31日在四川省仁寿县与双流县交界地区发生一次ML4．6地震，震中烈度Ⅵ度。宏观震中大致在仁寿县高家镇以西一带，地震使部分民房遭到破坏，造成直接经济损失约545万元。     

Study of Triggering Action Between the Mani （Ms7.9） and the West Kunlun Mountains Pass （ Ms 8.1 ） Great Earthquakes and Their Dynamic Background

Based on Coulomb static stress variation, the stress trigging action of the Mani ( Ms7.9, Nov.1997) earthquake on the West Kuulun Mountains Pass (MsS.1, Nov. 2001 ) earthquake is researched. Results of different source mechanism resolutions show that a 10_3 MPa Coulomb stress due to the Mani earthquake was added to the fracture fault of the Kunlun earthquake, and this may shift the broken date to about 10 years earlier, and infer that the stress level in the crust is not low. Comparing the relationship between strong earthquake strength and frequency and earth rotation change, it is shown that the strength‘s decrease and the variation period‘ s shortening of earth rotation are important controlling factors on strong earthquake activity. This great event with Ms = 8.1 took place probably due to a gradual strengthening background of regional stress field within the Qinghai-Xizang block in the period of acceleration of change of day‘s length and stress triggering from the Mani earthquake.     

Aseismic negative dislocation model and deformation analysis of crustal horizontal movement during 1999——2001 in the northeast margin of Qinghai-Xizang block

Through numerical simulation for GPS data, aseism/c negative dislocation model for crustal horizontal movement during 1999-2001 in the northeast margin of Qinghai-Xizang block is presented, combined with the spatial distri-bution of apparent strain field in this area, the characteristics of motion and deformation of active blocks and their boundary faults, together with the place and intensity of strain accumulation are analyzed. It is shown that: a) 9 active blocks appeared totally clockwise motion from eastward by north to eastward by south. Obvious sinistral strike-slip and NE-NEE relative compressive motion between the blocks separated by Qilianshan-Haiyuan fault zone was discovered; b) 20 fault segments (most of them showed compression) locked the relative motion between blocks to varying degrees, among the total, the mid-east segment of Qilianshan fault (containing the place where it meets Riyueshan-Lajishan fault) and the place where it meets Haiyuan fault and Zhuanglanghe fault, more favored accumulation of strain. Moreover, the region where Riyueshan-Lajishan fault meets north boundary of Qaidam block may have strain accumulation to some degree, c) Obtained magnitude of block velocities and locking of their boundaries were less than relevant results for observation in the period of 1993-1999.     

Gravity variation before Kunlun mountain pass western Ms=8.1 earthquake

The relation between the gravity variation features and Ms=8.1 earthquake in Qinghai-Xizang monitoring area is analyzed preliminarily,by using spatial dynamic variation results of regional gravity field from absolute gravity and relative gravity observation in 1998 and 2000.The results show that:1)Ms\8.1 earthquake in Kulun mountain pass westem occurred in the gravity variation high gradient near gravity‘s high negative variation;2)The Main tectonic deformation and emnergy accumulation before MS=8.1 earthquake are distributed at south side of the epicenter;3)The range of gravity‘s high negative variation at east of the MS=8.1 earthquake epicenter relatively coincides with that rupture region according to field geology investigation;4)Gravity variation distribution in high negative value region is just consistent with the second shear strain‘s high value region of strain field obtained from GPS observation.     

特定基准下的异常位移诊断

针对地壳运动和变形研究中存在的位移资料的参考基准、异常位移等问题，主要讨论了位移资料特定基准的转换和异常位移诊断的数学模型——特定基准转换模型为七参数相似变换模型，转换保持了变形体内部相对位置关系不变，并使转换后的位移矢量更能体现区域内的相对运动信息；异常位移诊断采用拟准检定法(QUAD)，在选定拟准观测的情况下，使得位移真误差具有明显的分群性；模拟算例结果显示，本文采用的线性变换模型、粗差拟准检定法都表现出很好的效果。     

利用GPS位移和主应力方向观测资料进行川滇地区边界力的联合反演研究

在简要介绍了川滇地区的构造格局和构造运动特征的基础上，讨论了不同观测数据同时用于反演的合理性和物理意义，利用1998～2000年观测的9个测点位移数据和1986年以前所测的10个主应力方向数据，将边界力和相对权比λ作为待反演参数，并考虑了主要活动断裂运动特性，进行了弹性有限元数值反演计算。计算结果表明，现今川滇地区的构造活动主要力源仍来源于印度板块与欧亚大陆的碰撞，菲律宾海板块的挤压作用也不可忽略，这一结论说明了该地区现今构造运动的继承性活动特征。