聚类分析法在地质样品分类中的应用研究

概述聚类分析及原理,通过题示内容的研究,包括测试样品,标准化数据,分类,获得适宜的样品聚类分析方法及建立了方法软件。该研究实验表明,采用聚类分析法对地质样品进行分类,效果较好。为开展Ｘ荧光定量分析及建立模式识别专家系统奠定了基础。     

辽宁阜新排山楼金矿地质和成矿作用

排山楼大型金矿床产于辽酉高级变质太古宙花岗岩－绿岩带中，受绿岩中、上部层位的基性－中酸性火山岩系和东西向韧性剪切带控制。容矿岩石主要是变安山质－英安质火山岩类。金矿围岩蚀变强烈。蚀变作用具分带性，从外带到内带可分为绿泥石化带、碳酸盐化带和黄铁矿－绢云母化带，各带之间没有明显界线。矿体与黄铁矿－绢云母化带关系密切。金矿石为矿化糜棱岩，主要金属矿物为黄铁矿和磁黄铁矿，金矿物为自然金。中深层次的韧性剪切作用为主要成矿作用，控制了矿体的就位空间和时间。     

无机盐类对干酪根生烃过程的影响

利用岩石热解评价仪（Rock-Eval）和热解气相色谱仪（Py-GC)，对采自东营凹陷和松辽盆地的烃源岩干酪根进行了热模拟实验，探讨了地层水中所存在的无机盐类对生烃过程的影响，求得了不同盐类作用下的反应动力学参数。结果表明，无机盐类对干酪根的热解生烃过程具有不同的影响。其中，氯化盐类具有一定程度的反催化作用，其他盐类表现出正的催化作用。这种催化作用是通过降低热解反应的表观活化能或提高反应的频率因子而表现出来的。最后，对无机盐类的催化作用机制进行了初步探讨，认为电子诱导效应理论可以初步解释无机盐类的催化作用。     

鄂尔多斯盆地延长组致密油成藏控制因素

鄂尔多斯盆地延长组发育我国典型的低渗透和特低渗透油气资源,其油藏呈现出储层致密、储集砂体预测难度大、成藏机理复杂等特征.目前,根据勘探开发实践,长庆油田成功实现对渗透率大于0.3×10^-3μm²油藏的开发,目前正在开展渗透率为(0.1~0.3)×10^-3 μm²致密砂岩储层的技术攻关.笔者结合国外最新致密油气资源研究成果和鄂尔多斯盆地延长组低渗透油藏的特征,从延长组致密油分布、致密油流体特征、赋存状态、储集体和致密油形成的控制因素入手,对鄂尔多斯盆地延长组致密油形成与分布规律进行了探讨.确定了延长组致密油形成的控制因素:①长7优质烃源岩分布范围广,生烃强度大,为致密油形成提供了充足的油源供给和资源基础;②大面积广泛展布的复合叠加的碎屑岩储集体,为致密油藏形成提供了储集空间;③油页岩与致密砂岩互层共生,形成了近源成藏的有利配置关系;④成藏期生烃增压,致密储层石油充注程度高,为致密油形成提供了运移动力.     

中国海相碳酸盐岩油气储层基本特征

中国在碳酸盐岩油气勘探中相继发现了陕中气田、轮南—塔河油田、塔中油气田、川东北大气区等大型油气田。这些发现揭示了非均质性强的碳酸盐岩储层,主要有4种类型:台缘生物礁(滩)、岩溶风化壳、白云岩和台内颗粒滩四大类储层。中国的台缘礁滩储层主要有两类,一类是面积小的孤立状的塔礁(川东和川东北),另一类是连片分布似层状的台缘礁滩复合体。岩溶风化壳储层依岩溶成熟度和构造型式有三种,即克拉通内岩溶老年期的低幅度地貌层状白云岩储层,岩溶壮年期的高幅度地貌非均质裂缝-洞穴单元储层,以及断块掀斜翘倾的岩溶青年期独立岩溶储层。有油气前景的白云岩储层主要为三类:与蒸发台地相关的准同生白云岩,埋藏成岩作用白云岩和生物成因白云岩。台内颗粒滩主要有两类:即白云石化颗粒滩和裂缝性颗粒滩储层。中国的碳酸盐岩分布广,达300km2,四大类储层发育良好,除已发现油气的四大盆地外,相信不久的将来在中国南方和羌塘地区古特提斯域碳酸盐岩沉积区将取得大的突破。     

辐照条件下绿柱石通道中顺磁配合物的ESR行为

四川平武贫铁富碱型无色绿柱石通道中主要存在碱氢化物（NaH)、[Fe2(OH)4]^2 多聚合离子及OH自由基，在电子辐照作用下，通道中顺磁配合物的结构、带电性质及化学键易发生转型、裂解和变价，并形成自旋浓度不等的[H^0]i心（裂距为500G,g值分别为2．175，1．8774的二重超精细结构线）、[Fe^3 ]OH(g=2.0031)和[Fe4^3 ]s(g=4.3172)等辐照损伤心。[Fe^3 ]OH心属一种有效的电子陷阱，其热稳定性大于[Fe4^3 ]s心。绿柱石杂质铁离子的占位方式，与成矿物理、化学条件及成矿流体的pH值密切相关。由电子辐照作用而导致杂质离子价态的转变，属一种可逆的动态平衡过程。     

CHIM-geoelectrochemical method in search of concealed mineralisation in China and Australia

A version of the geoelectrochemical prospecting technique developed in China was demonstrated in China and Australia to test its suitability under both Chinese and Australian conditions. This paper briefly describes the mechanism and effectiveness of the technique applied to search of concealed mineralisation through regolith cover, based on both experimental and field tests. This paer deals with three main aspects of the method： a） how metallic ions are released from orebodies by electrochemical dissolution; b） how these ions migrate to the collector and are deposited as elements by electrochemical extraction in the presence of an electric field; and c） the effectiveness of the method illustrated by some case studies.     

Geochemical evidence for the variation of historical seabird population on Dongdao Island of the South China Sea

From a rare freshwater lake characteristic of alkalescence, named “Cattle Pond”, on the Dongdao Island of South China Sea (16°39′–16°41′ N, 112°43′–112°45′ E), we collected two undisturbed sediment cores that contain seabird droppings. In this paper, we determined the concentration-versus-depth profiles of the geochemical elements in the ornithogenic sediment layers of the two cores, analyzed these profiles by various statistical methods, and studied their geochemical characteristics. The concentration profiles of As, Cd, Cu, Se, Zn, P and S are significantly correlated with each other and with loss on ignition (LOI) at 550°C, the measure for the abundance of organic matter. Similar geochemical characteristics, however, were not observed in the upper sediment layer of the Cattle Pond notably affected by cattle excrements, as well as in the bottom sediment layer compositionally dominated by coral sand and gravel. This shows that these “bio-elements” are mainly derived from seabird feces and their geochemical composition is an important geochemical characteristic of the lacustrine ornithogenic sediments. By Q-mode factor analysis (QFA) on the concentration profiles of these bio-elements, we reconstructed the historical seabird population on Dongdao Island between 1350 and 350 year B.P., and observed significant fluctuations in the calculated population. The fluctuations seem to be related to the change of sea surface temperature (SST) in the Southern China Sea. This study provides new paleoenvironmental information of past seabird population changes in low latitude areas using an indirect geochemical method.     

Spatial pattern and compositive structure of forests in Guizhou

Remote-sensing and field data of Guizhou forest resources in 2000 are processed using ArcGIS, with the production of forest resource distribution map, forest age class structure map, and forest canopy distribution map. Analysis of these data shows that: (1) though there are multiple types of forest resources, forest coverage is low (only 25.27%, excluding sparse woodland, shrub and underage-forest); (2) the geographical distribution of forests is quite uneven, mainly in the southeast of the province and in Zunyi prefecture; (3) the zonal evergreen broad-leaved forests have been seriously destroyed, with striking secondary features, i.e., coniferous forest and shrubbery account for the greatest proportion of Guizhou forests; (4) the timber-forest is much larger in area than shelter-forest and economic forest; (5) young-and-middle aged forests are more widely distributed than near-and-over matured forest; and (6) the forest of Guizhou is not enough to effectively protect the environment of karst mountain areas of the province.     

Study on Environmental and Hydrological Effects of Thermokarst Lakes in Permafrost Regions of the Qinghai-Tibet Plateau

Thermokarst lake is the most visible morphologic landscape developing during the process of permafrost degradation, and it is still an international hot topic in permafrost research. The climate warming, and the consequent degradation of the permafrost on the Qinghai-Tibet Plateau aggravate thermokarst lake development. The permafrost is normally considered as an aquiclude, and the permafrost degradation, especially when the permafrost is completely thawed by a thermokarst lake, might influence regional ground water. Therefore, a research program focusing on environmental and hydrological effects of thermokarst lakes in permafrost regions of the Qinghai-Tibet Plateau was started and supported by the National Natural Science Foundation of China. The work proposed by the application includes: To analysis the spatial and temporal distribution rule of thermokarst lakes in the Qinghai-Tibet Engineering Corridor (QTEC) under the climate change and engineering activities, and to evaluate the ecological environment effects through remote sensing and field investigation; to reveal the main factors influencing a typical thermokarst lake and its hydrothermal condition, and to elucidate the conversion relationship between the thermokarst lake and the groundwater with hydrological and isotope tracer tests; to make an analysis of the influences of different lake stage and size on regional permafrost, hydrological conditions and ecological environment through numerical simulation and statistical modelling, considering the relationships between the thermokarst lake and the ground water level. The research results will help to accurately assess regional permafrost ecological environment evolution and trend prediction, and to reasonably understand the impact factors of the permafrost hydrological evolution and its response mechanism to the ecological environment in the river source regions of the Qinghai-Tibet Plateau. In this paper, the research status analysis, the main research contents, research objectives and prospects were introduced so as to provide some references for related researchers and engineers.