Formation Mechanism of Underpressured Reservoir in Huatugou Oilfield of Qaidam Basin

Underpressured reservoirs are widespread in the Huatugou(花土沟) oilfield of the western uplift in Qaidam basin,western China.At depths between 462 and 1 248 m,the pressure of Neogene reservoirs in the Huatugou oilfield is only about 40% to 80% of hydrostatic pressure.Based on a study of the geological characteristics of these underpressured reservoirs,this work used fluid inclusion analysis and numerical simulation to investigate the mechanism creating these abnormal pressures and to evaluate the characterist...     

Application of Sampling Methods to Geological Survey

There are two kinds of research methods in geological ob-servation study.One is the remote-sensing observation.Theother is the partial sampling method extensively used in everystage of the geological work,for example,in arranging thelines and points of geologic survey,and in arranging the ex-ploration engineering.Three problems may occur in practicalapplication of the sampling method:(1 ) Though we use thepartial sampling method in geological work,we must makeuse of many labor powers,materials…     

XRF Determination of 17 Trace Elements in Geological Samples Using an Extended Compton Scattering Correction Procedure

This work is intended to explore a fast and effective apoproach to the determination of various trace elements in geological samples throuth improvement and simplification of the method developed by Reynolds (1963,1967),Absorption correction was made for the Fe content to eliminate the effect caused by inconsistency in mass absorption coefficients among the samples.A computer-aid regression analysis was performed on a number of standards of various compositions,which resulted in a set of calibration equations for directly converting X-ray intensities to concentrations.An analytical error of 10-30% was involved in the analyses of most elements.     

Accessing Multi-Source Geological Data through Network in MORPAS Software System

MORPAS is a special GIS (geographic information system) software system, based on the MAPGIS platform whose aim is to prospect and evaluate mineral resources quantificationally by synthesizing geological, geophysical, geochemical and remote sensing data. It overlays geological database management, geological background and geological abnormality analysis, image processing of remote sensing and comprehensive abnormality analysis, etc.. It puts forward and integrative solution for the application of GIS in basic-level units and the construction of information engineering in the geological field. As the polularization of computer networks and the request of data sharing, it is necessary to extend its funictions in data management so that all its data files can be accessed in the network server. The paper utilizes some MAPGIS functions for the second development and ADO (access data object) technique to qccess multi-source geological data in SQL Server databases. Then remote visiting and congruous management will be realized in the MORPAS system.     

吉林陨石中有机色素和卟啉化合物的初步研究

This paper discribes the extraction of porphyrin compounds and related pigments from Jilin meteorite with 9:1 (v/v) benzene and methanol mixture. After removal of sulfur and asphalts the hexane solution of the extract is eluted through a silica jel chromatographic column with hexane, benzene, and acetone successively.Nickel porphyrin, vanadium porphyrin and chlorins are found in the benzene eluate and their content are estimated to be 0.008 ppm, 0.006 ppm and 0.002 ppm respectively.The aliphatie hydrocarbons in the meteorite are estimated to be approximately 74pp.The results are summarized and discussed.     

LA-ICP-MS Zircon U-Pb Age of Newly Discovered Hatu Tectonic Mélange in the West Junggar, Xinjiang, NW China

正Objective The West Junggar, situated in the southwestern segment of the Central Asian Orogenic Belt, is considered to be an important area for Phanerozoic crustal growth owing to the excellent exposures of diverse rock types and multiple generations of structures and magmatic rocks. Recently, a new tectonic mélange has been identified in the southern West Junggar during geological mapping at a scale of 50000. This work presents new geochronological data for     

~(207)Pb/~(206)Pb Zircon Dating of the Huangtuling Hypersthene-Garnet-Biotite Gneiss from the Dabie Mountains, Luotian County, Hubei Province, China: New Evidence for Early Precambrian Evolution

The Huangtuling hypersthene-garnet-biotite gneiss at Luotian County, Hubei Provine, is a typicalgranulite-facies rock of the Dabie Group Complex in the Dabie orogenic belt. Investigations on the morphology andoccurrence of zircons and their internal structures shown in the thin sections lead to the recognition of three types ofzircons, which are in good agreement with the types identified on the basis of morphology, colour and external fea-tures from the related zircon concentrates. The observation of zircons in the rock reveals that part of type 1 zirconsshow signs of a double-layered structure. The interval part existed in the protolith prior to the granulite-facies meta-morphism. Type 2, the prismatic zircons which mainly occur in garnet and hypersthene are metamorphic minerals ofthe granulite-facies metamorphism. Type 3, the round multifaceted zircons in felsic minerals and biotite, are proba-bly attributed to a later geological event related to migmatization. The ~(207)Pb/~(206)Pb zircon dating by direct evaporationon (thermal evaporation ion mass spectrometer) yields ages ranging from 2814 Ma to 1992 Ma. The age discrepancyamong these different zircon types is conspicuous. The yellow-brown(type 1) zircons give ages of 2814±29 Ma to2527±6 Ma, the prismatic euhedral zircons (type 2), 2456±7 Ma to 2254±4 Ma, and the round multifaceted zircons(type 3), 1992±10 Ma. The results are geologically interpreted in consideration of the complicated behaviours of zir-cons during Precambrian geological evolution of the Dabie area. (1) If the protolith of the gneiss is a sedimentaryrock, then type 1 zircons are clastic ones and the ages 2814±29 Ma and 2811±27 Ma may reflect the minimum age ofthe rocks of its source region. also the first geological event in the area. Sedimentation of the protolith occurred be-tween 2814 Ma and 2527 Ma, probably close to 2814 Ma. If the protolith is a volcanic rock, then the formation age ofthe supracrustal rocks of the Dabie Group Complex is around 2814 Ma. The age 2456±7 Ma reflects the time whenthe granulite-facies metamorphism took place. The later migmatization event is dated at aboat 1992±10 Ma, and isprobably the latest early Precambrian event in the area. The present work provides geochronological evidence for the existence of the Dabie Archaean craton, whichhad probably experienced 3 or 4 geological events during its early Precambrian evolution.     

Major Advances in the Study of the Precambrian Geology and Metallogenesis of the North China Craton: A Review

The North China Craton(NCC) is one of the most ancient cratons in the world and records a complex geological evolution since the early Precambrian. In addition to recording major geological events similar to those of other cratons, the NCC also exhibits some unique features such as multistage cratonization(late Archaean and Palaeoproterozoic) and long-term rifting during the Meso–Neoproterozoic. The NCC thus provides one of the best examples to address secular changes in geological history and metallogenic epochs in the evolving Earth. We summarize the major geological events and metallogenic systems of the NCC, so that the evolutionary patterns of the NCC can provide a better understanding of the Precambrian NCC and facilitate comparison of the NCC with other ancient continental blocks globally. The NCC experienced three major tectonic cycles during the Precambrian:(1) Neoarchaean crustal growth and stabilization;(2) Palaeoproterozoic rifting–subduction–accretion–collision with imprints of the Great Oxidation Event and(3) Meso–Neoproterozoic multi-stage rifting. A transition from primitive- to modern-style plate tectonics occurred during the early Precambrian to late Proterozoic and is evidenced by the major geological events. Accompanying these major geological events, three major metallogenic systems are identified:(1) the Archaean banded iron formation system;(2) Palaeoproterozoic Cu–Pb–Zn and Mg–B systems and(3) a Mesoproterozoic rare earth element–Fe–Pb–Zn system. The ore-deposit types in each of these metallogenic systems show distinct characteristics and tectonic affinities.     

THM Coupled Modeling in Near Field of an Assumed HLW Deep Geological Disposal Repository

One of the most suitable ways under study for the disposal of high-level radioactive waste (HLW) is isolation in deep geological repositories. It is very important to research the thermo-hydromechanical (THM) coupled processes associated with an HLW disposal repository. Non-linear coupled equations, which are used to describe the THM coupled process and are suited to saturated-unsaturated porous media, are presented in this paper. A numerical method to solve these equations is put forward, and a finite element code is developed. This code is suited to the plane strain or axis-symmetry problem. Then this code is used to simulate the THM coupled process in the near field of an ideal disposal repository. The temperature vs. time, hydraulic head vs. time and stress vs. time results show that, in this assumed condition, the impact of temperature is very long (over 10 000 a) and the impact of the water head is short (about 90 d). Since the stress is induced by temperature and hydraulic head in this condition, the impact time of stress is the same as that of temperature. The results show that THM coupled processes are very important in the safety analysis of an HLW deep geological disposal repository.     

Statistical Prediction of Endogenetic Gold Deposit in East Junggar,Xinjiang

The system of mineral deposit statistical prediction methods, based on the similarity-analogy theory, searching anomaly theory and the theory of ore-controlling by quantitative assemblage of metallotects, can he summarized into the following aspects: (1)concluding main ore-controlling conditions and ore-hunting indicators from typical deposits; (2)establishing geological concept model of deposits; (3)selecting geological variable and dividing study units and granting specific value for each variable; (4)by the use of geological and mathematical geology method, building predication model , delineating prospective area for exploration and estimating the total resources; (5)evaluating the prospecting work . It is good practice to use this system for metallogenic prognosis and regional prospecting of gold deposit in East Junggar, Xinjiang and has achieved great success . As a result, we discovered the Kubusu gold mineralized belt , delineated prospective area , estimated total resources of gold in the belt a     

Numerical Modeling of Basin-Range Tectonics Related to Continent-Continent Collision

Continent-continent collision is the most important driving mechanism for the occurrence of various geological processes in the continental lithosphere. How to recognize and determine continent-continent collision,especially its four-dimensional temporal-spatial evolution, is a subject that geological communities have long been concerned about and studied. Continent-continent collision is mainly manifested by strong underthrnsting (subduction) of the underlying block along an intracontinental subduction zone and continuous obduction (thrusting propagation) of the overlying block along the intracontinental subduction zone, the occurrence of a basin-range tectonic framework in a direction perpendicular to the subduction zone and the flexure and disruption of the Moho. On the basis of numerical modeling, the authors discuss in detail the couplings between various amounts and rates of displacement caused by basin subsidence, mountain uplift and Moho updoming and downflexure during obduction (thrusting propagation) and subduction and the migration pattern of basin centers. They are probably indications or criteria for judgment or determination of continent-continent collision.     

New Progress in High-Precision and High-Resolution Seismic Exploration Technique in Coal Industry of China

In the past twenty years, the proportion of coal in primary-energy consumption in China is generally between 71.3% and 76.5%. The output of coal was 1.374 billion tons in 19%, and 1.21 tons in 1998, which ranked first in the world. Now coal is mined mainly with mechanization in China, which is planned to reach 80% in major State-owned coal mines in 2000 according to the planning of the government (Li et al., 1998; Tang Dejin, 1998).Compared with the USA and Australia, China has more complex coal geological structures. Based on high-resolution seismic technique in coal exploration, a new seismic technique with high-precision and high-resolution (2-D and 3-D) has been developed for the purpose of detecting small geological structures in coal mine construction and production to meet the needs of large-scale popularization of mechanized coal mining in China. The technique is low in cost and requires a relatively short period of exploration, with high precision and wide-range applications. In the middle of t     

Features of Geophysical Fields and Geodynamics of the China Sea

During 1960—1990, an extensive geological-geophysical investigation was carried out in the marine areas of China. According to the materials obtained, the "Geological—Geophysical Serial Maps of the China Seas and the Adjacent Areas (1:2,000,000)" was compiled. In fact, it is a systematic summary of the geological and geophysical work of the China Seas in the past 30 years.In this paper, the author explains the guiding thought and methodology of the compilation of the serial maps, and then briefly discusses the characteristics of geophysical fields and geodynamics, stratigraphy, tectonics and magmatism.     

Selection and Basic Properties of the Buffer Material for High-Level Radioactive Waste Repository in China

Radioactive wastes arising from a wide range of human activities are in many different physical and chemical forms, contaminated with varying radioactivity. Their common features are the potential hazard associated with their radioactivity and the need to manage them in such a way as to protect the human environment. The geological disposal is regarded as the most reasonable and effective way to safely disposing high-level radioactive wastes in the world. The conceptual model of geological disposal in China is based on a multi-barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the main engineered barriers for HLW repository. It is expected to maintain its low water permeability, self-sealing property, radio nuclides adsorption and retardation properties, thermal conductivity, chemical buffering property, canister supporting property, and stress buffering property over a long period of time. Bentonite is selected as the main content of buffer material that can satisfy the above requirements. The Gaomiaozi deposit is selected as the candidate supplier for China＇s buffer material of high level radioactive waste repository. This paper presents the geological features of the GMZ deposit and basic properties of the GMZ Na-bentonite. It is a super-large deposit with a high content of montmorillonite （about 75 %）, and GMZ-1, which is Na-bentonite produced from GMZ deposit is selected as the reference material for China＇s buffer material study.     

Modeling the effect of wetting on the mechanical behavior of crushable granular materials

It is well known that the compressibility of crushable granular materials increases with the moisture content,due to the decrease of particle strength in a humid environment.An existing approach to take into account the effect of grain breakage in constitutive modeling consists in linking the evolution of the grain size distribution to the plastic work.But how the material humidity can affect this relationship is not clear,and experimental evidence is quite scarce.Based on compression tests on dry and saturated crushable sand recently reported by the present authors,a new non-linear relationship is proposed between the amount of particle breakage and the plastic work.The expression contains two parameters:(1)a material constant dependent on the grain characteristics and(2)a constant depending on the wetting condition(in this study,dry or saturated).A key finding is that the relationship does not depend on the stress path and,for a given wetting condition,only one set of parameters is necessary to reproduce the results of isotropic,oedometric,and triaxial compression tests.The relationship has been introduced into an elastoplastic constitutive model based on the critical state concept with a double yield surface for plastic sliding and compression.The breakage ratio is introduced into the expression of the elastic stiffness,the critical state line and the hardening compression pressure.Incremental stress-strain computations with the model allow the plastic work to be calculated and,therefore,the evolution of particle crushing can be predicted through the proposed non-linear relationship and reintroduced into the constitutive equations.Accurate predictions of the experimental results in terms of both stress-strain relationships and breakage ratio were obtained.     

A Method for Evaluating the Suitability of CO2 Geological Storage in Deep Saline Aquifers

This work established an evaluation index system based on a comprehensive analysis of those factors affecting the suitability of CO2 geological storage. This evaluation index system includes three evaluation index layers of geological safety, storage scale and social economy, nine evaluation index sub-layers, and 28 evaluation index factors, and adopts the analytic hierarchy process (AHP) and index overlay methods. Taking the Xining Basin in northwest China as an example, we conducted comprehensive analysis of geological conditions and performed quantitative evaluation based on this evaluation index system, which indicates that the Shuangshu depression of the Xining Basin is comparatively suitable for CO2 geological storage. It is suggested that this evaluation index system and the evaluation method proposed in this study are suitable for most continental sedimentary basins in China and should be widely applied.     

Development of Geological Data Warehouse

Data warehouse (DW), a new technology invented in 1990s, is more useful for integrating and analyzing massive data than traditional database. Its application in geology field can be divided into 3 phrases: 1992-1996, commercial data warehouse (CDW) appeared; 1996-1999, geological data warehouse (GDW) appeared and the geologists or geographers realized the importance of DW and began the studies on it, but the practical DW still followed the framework of DB; 2000 to present, geological data warehouse grows, and the theory of geo-spatial data warehouse (GSDW) has been developed but the research in geological area is still deficient except that in geography. Although some developments of GDW have been made, its core still follows the CDW-organizing data by time and brings about 3 problems: difficult to integrate the geological data, for the data feature more space than time; hard to store the massive data in fifferent levels due to the same reason; hardly support the spatial analysis if the data are organized by time as CDW does. So the GDW should be redesigned by organizing data by scale in order to store mass data in different levels and synthesize the data in different granularities, and choosing space control points to replace the former time control points so as to integrate different types of data by the method of storing one type data as one layer and then to superpose the layers. In addition, data cube, a wide used technology in CDW, will be no use in GDW, for the causality among the geological data is not so obvious as commercial data, as the data are the mixed result of many complex rules, and their analysis needs the special geological methods and software; on the other hand, data cube for mass and complex geo-data will devour too much store space to be practical. On this point, the main purpose of GDW may be fit for data integration unlike CDW for data analysis.     

AN OUTLINE OF THE GEOLOGICAL STRUCTURE OF SHANSI

INTRODUCTION The author began his work in Shansi since 1919. The main aim of his work, as was the instruetiou of Dr. V K. Ting, director of The Geological Survey, was to survey a geological map on the scale of one to one million and examine the coal and iron resources which were known as exceptionally     

华北陆台上一个大型沉积盆地古生界油气的形成与演化

Based on the studies of geological history during the Paleozoic time. depoaitional esvironment, the evolution of organisms, the content of organic substances and the distribution of oil-generatlng strata, various indicators concerning oil generation are discussed and. compared in terms of Organic substance composition, the alkane and isopronoid in saturated hydrocarbon, characteristic functional group of the aromatic hydrocarbon and its structure, element composition and free radical concentration in asphaltene as well as carbon isotopes. The following conclusions can be drawn: (1) During the Later Paleozoic, the mud stone of the two oil-generating depressions of the Ponhsi Group on the western part of the basin was the most important reservoir and the black mud stone and limestone were secondary in importance. (2) Both the Ordovicoan Machiakou limestone and the shale of grapholithic facies are main oil (gas) generating strata in the western part of the basin. The Changhsia Group of the middle Cambrian system may also be oil-generatlng but is of little consequence. (3) Oil and gas formation in the Upper and. Lower Paleozoic groups represent two. different evolutionary stages. In the Upper Paleozoic group the petroleum formed is a kind of light oil, and large quantities of natural gas had been formed from the coal-bearing Taiyuan and Shansi Groups as a result of metamorphism. In response to the action of temperature and. presses over the prolonged geological period, oil sad gas formation in the lower Paleozoie group corresponds to a more advanced evolutionary stage, during which the generation of natural gas is the dominant process in comparation with oil condensation. Therefore the lower Paleozoic group is believed to be more promising for gas prospecting.     

Mineral fibres and environmental monitoring:A comparison of different analytical strategies in New Caledonia

Covered by ultrabasic units for more than a third of its surface,the New Caledonia(South West Pacific)is one of the largest world producers of Ni-ore from lateritic deposits.Almost all outcrops of geological units and open mines contain serpentine and amphibole,also as asbestos varieties.In this geological context,in which weathering processes had a great contribution in the production and dispersion of mineral fibres into the environment,the development of a routinely analytical strategy,able to discriminate an asbestiform fibre from a non-harmful particle,is a pivotal requisite.However,the acquisition of all these parameters is necessary for determining the risk associated to fibres exposition.A multidisciplinary routinely approach,based on the use of complementary simply-to-use but reliable analytical methods is the only possible strategy.In addition,the instrumental apparatus must be easily transportable on the field,directly on the mining site.The employment of specialized tools such as Polarized Light Microscopy associated to Dispersion Staining method(PLM/DS)and portable Raman spectroscopy for identification of environmental asbestos,are proved extremely effective in the improvement of the performance and rapidity of data acquisition and interpretation.Both PLM/DS and handheld Raman devices confirmed to be discriminant in the detection and characterization of asbestos fibres for both serpentine and amphibole.Furthermore,these techniques proved extremely effective even in the presence of strongly fibrous and altered samples.