青海省镍矿资源开发利用现状浅析

世界上镍工业资源主要为红土型、硫化镍及海底含镍锰结核3种,我国镍资源储量占全球第九,主要以硫化镍矿为主,而西部地区,尤其是西北地区是我国最主要硫化镍矿产资源地.近年来,随着青海省夏日哈木超大型铜镍硫化物矿床的发现,青海省加大了硫化镍矿资源的找寻力度,发现了一批成矿潜力较大的矿床（点）,省内铜镍资源有望进一步得到拓展.本文通过分析青海省内镍矿资源分布、勘探开发及目前全球镍资源供需变化等,为我国镍矿业的投资、开发、管理提供参考依据.     

塔中地区良里塔格组碳酸盐岩储层特征及成岩作用

塔中地区良里塔格组发育巨厚的礁滩相碳酸盐岩,为碳酸盐岩储层的形成提供了有利条件。通过对钻井岩心和薄片分析,系统研究了研究区良里塔格组碳酸盐岩的储层岩石学、成岩作用类型和特征,总结了各类成岩作用的识别标志、发育规律及对储集体形成的影响。研究区碳酸盐岩储层的成岩作用包括泥晶化作用、白云石化作用、方解石胶结作用、溶蚀作用、硅化和硅质充填作用,以及压实、压溶作用、破裂作用和自生黄铁矿作用。在此基础上,总结了良里塔格组碳酸盐岩成岩序列及储层孔隙演化规律,认为早期强烈的方解石胶结作用和压实压溶作用降低了储层的孔隙度和渗透率,而溶蚀作用和构造破裂作用对良里塔格组礁滩相碳酸盐岩优质储层的形成具有明显控制作用。     

RESEARCH ON NEOGENE-QUATERNARY STRATIGRAPHIC STRUCTURE AND SHALLOW TECTONIC FEATURES IN THE NORTH SECTION OF DAXING FAULT ZONE BASED ON SHALLOW SEISMIC REFLECTION PROFILING

The Daxing Fault is an important buried fault in the Beijing sub-plain, which is also the boundary fault of the structural unit between Langgu sub-sag and Daxing sub-uplift. So far, there is a lack of data on the shallow tectonic features of the Daxing Fault, especially for the key structural part of its northern section where it joins with the Xiadian Fault. In this paper, the fine stratigraphic classifications and shallow tectonic features of the northern section in the main Daxing Fault are explored by using three NW-trending shallow seismic reflection profiles. These profiles pass through the Daxing earthquake(M6¾)area in 1057AD and the northern section of the main Daxing Fault. The results show that seven strong reflection layers(T₀₁—T₀₃, T_Q and T₁₁—T₁₃)are recognized in the strata of Neogene and Quaternary beneath the investigated area. The largest depth of strong reflection layer(T₁₃)is about 550~850ms, which is interpreted as an important surface of unconformity between Neogene and Paleogene or basement rock. The remaining reflection layers, such as T₀₁ and T_Q, are interpreted as internal interfaces in Neogene to Quaternary strata. There are different rupture surfaces and slip as well as obviously different structural features of the Daxing Fault revealed in three shallow seismic reflection profiles. The two profiles(2-7 and 2-8)show obvious rupture surfaces, which are the expression of Daxing Fault in shallow strata. Along the profile(2-6), which is located at the end of the Daxing fault structure, a triangle deformation zone or bending fracture can be identified, implying that the Daxing Fault is manifested as bending deformation instead of rupture surfaces at its end section. This unique structural feature can be explained by a shearing motion at the end of extensional normal fault. Therefore, the Daxing Fault exhibits obviously different tectonic features of deformation or displacement at different structural locations. The attitude and displacement of the fault at the shallow part are also different to some extent. From the southwest section to the northeast section of the fault, the dip angle gradually becomes gentler(80°~60°), the upper breakpoint becomes deeper(160~600m), and the fault displacement in Neogene to Quaternary strata decreases(80~0m). Three shallow seismic reflection profiles also reveal that the Daxing Fault is a normal fault during Neogene to early Quaternary, and the deformation or displacement caused by the activity of the fault reaches the reflection layer T₀₂. This depth is equivalent to the sedimentary strata of late Early-Pleistocene. Therefore, the geometry and morphology of the Daxing Fault also reveal that the early normal fault activity has continued into the Early Pleistocene, but the evidence of activity is not obvious since the late Pleistocene. The earthquakes occurring along the Daxing Fault, such as Daxing earthquake(M6¾)in 1057AD, may not have much relation with this extensional normal fault, but with another new strike-slip fault. A series of focal mechanism solutions of modern earthquakes reveal that the seismic activity is closely related to the strike-slip fault. The Daxing Fault extends also downwards into the lower crust, and may be cut by the steeply dipping new Xiadian Fault on deep seismic reflection profile. The northern section of the Daxing Fault strikes NNE, with a length of about 23km, arranged in a right step pattern with the Xiadian Fault. Transrotational basins have been developed in the junction between the northern Daxing Fault and the southern Xiadian Fault. Such combined tectonic features of the Daxing Fault and Xiadian Fault evolute independently under the extensional structure background and control the development of the Langgu sub-sag and Dachang sub-sag, respectively.     

高含冰量冻土路基融化固结规律研究

为了研究高含冰量冻土路基的融化固结规律，在线性大变形融化固结理论的基础上引入非线性本构关系，并运用分段插值法实现了孔隙比与压缩模量之间的非线性关系，完善了三维大变形融化固结数值模拟方法。在此基础上结合青藏公路实测数据验证了其合理性。研究结果表明，采用非线性应力?应变关系的大变形融化固结理论能够显著提高高含冰量冻土路基的沉降计算精度，并能够进一步合理描述热学场和力学场的相互叠加影响。冻土融化固结度受有效融化固结时间以及特征排水长度等因素的影响呈现出完全不同于融土路基的发展规律，即在路基运营初期其融化固结度上升，随着时间发展，其固结度在达到峰值后持续降低，这主要是由于融化深度持续增大后所引起的特征排水长度的增加和有效融化固结时间的缩短所造成的。因此，在计算高含冰量冻土路基稳定性设计指标时，应采用非线性应力?应变关系来进一步提高融化深度、沉降以及固结度等指标的计算精度。     

Quantitative analysis on tectonic deformation of active rupture zones

Introduction The Global Position System (GPS) may provide information about the crust movement of high precision in a large area, which significantly improve the capability of monitoring crustal movement over the area. In the last decade, studies on the global plate movement, the large scale block motions, the high-resolution crust movement of related monitored regions and tectonic de-formation fields have become the hotspot of spatial geodesy (ZHU et al, 2003; Wang et al, 2001; HUANG et…     

利用GPS资料研究印尼8．7级地震对我国西部地震趋势的影响

利用我国西部20世纪90年代以来不同来源的GPS观测资料,结合地质构造和地震活动分析了区域现今地壳水平运动变形背景及其与地震活动的关系;根据印尼8.7级地震后川滇地区2005年1月GPS应急观测结果研究了本区水平运动变形对印尼大震的远场响应特征;初步分析探讨了印尼8.7级地震对我国西部地震活动趋势的影响。     

浅谈1∶5万水系沉积物测量在藏东资源大调查中的应用——以芒康盐井为例

芒康县盐井属于西藏东部昌都地区,地处著名的三江成矿区。由于三江地区地形切割强烈,水系发育,采用1:5万水系沉积物测量地球化学勘查方法,在藏东矿产资源预查中取得了新的突破,为进一步勘查工作提供了丰富的地球化学资料和可靠的依据。     

辽宁树基沟铜锌矿床成矿时代——来自斜长角闪片麻岩锆石U-Pb同位素的制约

树基沟铜锌矿是产于华北地台北缘东段花岗-绿岩带中与火山岩有关的块状硫化物矿床.本次运用LA-ICP-MS锆石U-Pb定年技术获得赋矿围岩斜长角闪片麻岩原岩结晶年龄为2564±2 Ma,可近似代表树基沟铜锌矿成矿时代.根据已发表的幔部锆石U-Pb年龄（2517~2529 Ma）,认为树基沟铜锌矿经后期鞍山运动发生变质变形活化迁移.结合赋矿围岩地球化学特征及演化过程,推测树基沟铜锌矿的成因是板块俯冲引起地幔部分熔融形成富含贱金属岩浆,岩浆向上运移、会聚、喷发、固结成岩,后经海水淋滤成矿元素向渗透性差的部位下渗富集,并沿着深渗透性的断裂构造喷出地表,热流体与海水相互作用成矿,而后经变质变形作用的产物.     

四川九龙中咀铜矿床地质特征及找矿前景

四川九龙中咀铜矿床为近年来新发现的一个产于江浪变质核杂岩中的富铜矿床。矿体呈似层状,受韧性剪切带控制,矿体在走向和倾向上延伸稳定。主要矿石类型为浸染状、网脉状、角砾状、块状铜锌矿石。矿石建造为FeCu-Zn建造。金属矿物由黄铜矿、磁黄铁矿、闪锌矿、方铅矿等组成。主要蚀变类型为石榴子石化、绢云母化、绿泥石化、黑云母化。矿体铜品位较高,平均品位为1.65%。目前该矿床仍在进行详查地质工作,矿区向东和向北西方向仍具有较好的找矿前景。该矿床的发现与评价,对于重新认识里伍铜矿床外围找矿潜力和进一步指导该区找矿工作具有重要意义。     

非饱和冻土水汽迁移与相变过程的光滑粒子法模拟

为了研究多年冻土表层的水热分布情况,在非饱和冻土的能量守恒方程和水分迁移的质量控制方程的基础上考虑冰水相变和水汽相变过程,并考虑水汽运移传热及温度势对水汽迁移的影响,建立了非饱和冻土的水-热-汽耦合模型。采用光滑粒子流体动力学(smoothed particle hydrodynamics,简称SPH)方法可方便地计算它们的演化过程。为此,在计算中先求解能量守恒方程的含冰量及气态水含量,再对未冻水含量和温度场进行求解,从而实现了温度场与水汽场的耦合。在此基础上,模拟计算了第1类热边界条件下半无限空间介质内非稳态温度场、体积含水率及水汽通量的分布情况,并将计算结果与未考虑耦合的解析解进行比较,结果显示水汽耦合的作用不容忽略。最后,针对处于季节性周期温度边界下路基的水热场的分布情况进行计算。研究表明,相比于水-热耦合模型,所建立的水-热-汽耦合模型得到的计算结果更为接近实际监测结果,可很好地揭示非饱和冻土中的水热汽迁移特征及其相变过程。