The uplift of the Qinghai-Xizang (Tibet) Plateau happened in different crustal movements and different time from those of the collision of Asia continent with the allochthonous India crustobody, and the uplift occurred very long after the finish of the collision. According to its temporal evolution, the uplift happened in another active stage of the mantle creep flow after the active stage resulting in the collision and the interruption of the 140Ma’s quiet stage. On the basis of the dynamic analysis, the uplift resulted from the multiple compressing stresses in the reactivation stage after weakening of the colliding stress and the following compressing stress, and after the interruption of the stable stage dominating the vertical movements and represented by formation of the universal Qinghai-Xizang (Tibet) ancient platform. It was the production of another stress field existing in another crustobody evolution stage and growth age. In the light of the nature of the orogeny, the uplift was caused by the intracontinental Diwa (geodepression)-type orogeny after converging connection of the Central Asia Crustobody and the India crustbody which immediately became a part of the Asia continent, and hence after the substitution for the colliding stress and the following compressing stress by the platform-type crustal movements.
The Baiyin copper ore-field of Gansu Province is characteristic of a particular fold structure consisting of anticlines with volcanic rocks as their cores, so called volcanic-rock-core anticlines (VCA) by the authors. The styles of folding manifested by the volcanic and sedimentary rocks are differed from each other, and reveal that they have been subjected to different kinds of formation mechanisms in the processes of folding and flattening. The primary inclinations of volcanic domes and the harmonic deformation of different lithological layers both are the requirements for the location, deformation and development of VCA.
Mufu-Jiuling district is an important placer gold producing land since the ancient time. In recent years, some primary gold deposits and mineralizations, e. g., Huangjindong and Tulongshan gold deposits, have been found. But the metallogenic conditions and regularities as well as the ore-prospecting future remain to be recognized. Through the study on the metallogenic background and condition, the auriferous source bed and the mineralizing characteristics, three types of primary gold deposits are confirmed to be prospective in this district and some key problems about their prospecting and evaluating are put forward.
Variable IP method mainly measures the Percent Frequency Effect (PFE), and phase IP method mainly measures phase. They both aim at finding IP anomaly. However, only using PFE anomaly or single phase anomaly can’t distinguish IP body’s property. The authors put forward a new method—dual-frequency and multi-parameter IP method, which can not only find anomaly of PFE and phase, but also provide the property information of IP anomaly resource. The authors also have invented the dual-frequency and multi-parameter IP instrument. A lot of experiments and field work have been done. The results show that the instrument is valuable in distinguishing IP anomalies.
Induced Polarization (IP), with 100–200 m exploration depth currently, is an effective method for metal deposit survey. Since most shallow metal deposits have been discovered, the deep ones have to be searched for. So, deep IP must be studied. In this article, the following key problems relating to improving signal-to-noise ratio are discussed such as selection between time domain system and frequency domain one, powerful IP dual-frequency observation system, deep IP field configurations, removal of electromagnetic couple effect. The discussion is helpful to undertake research of deep IP.
Comparatively analyzing 47 REE distribution data of the Southern Hunan geosynclinal arkose-silicarenite and various period granitic rocks and the results of their partially melting experiment series in company with the occurence and petrogeochemical features of various period granitic rocks, the authors suggest that all of the above-mentioned salic rocks can be partially melt to produce granitic magma.
The authors first put forward the concept of metallogenic couplezone (MCZ) through the research on metallogenic zones in Zhejiang. Different features of the metal and non-metal MCZ in Zhejiang are studied. MCZ model which is related to geodome and Diwa series is established. The author thinks that MCZ dynamic characteristic is related with crustobody dynamics, and controlled by magmatic, volcanic and structural activity zoning.
This paper describes a series of plugging agents which have been developed these years by the authors. The features of these agents can bestated as: (1) Stopping losses without stopping driling; (2) High ratio of success; (3) Improving fluids properties; (4) Suiting to many types of losses, even large cracks and caves; (5) Perfect efficiency in different conditions of pollution such as calcium, salt pollution and high temperature; (6) Sufficient resources of raw materials, no-poison, no-harm, no pollution to the environment; (7) Convenience in use; (8) Lower cost. The properties, mechanisms and applications of these agents are also described in this paper.
The reason for bit slipping in extra-hard formations has been analysed, and a new type of anti-slipping bit for extra-hard formations have been recommended.
Even though the ophiolite sequence has been disturbed by tectonism and metamorphism, the ultramafic rocks, the gabbro, the diabase and the basalt of the Animaqen ophiolite have been proved to be respectively the metamorphic peridotite and the ultramafic cumulate, the mafic cumulate, the sheeted dike and the mafic extrusive rocks of the ophiolite suite based on the petrochemistry. The Animaqen ophiolite zone represents the location of the ancient plate suture line.
The H. O. S isotopic geochemical features and the REE geochemical parameters of some deposits in Xiong’ershan region are discussed, and the coherent various geological bodies are confirmed.
The vein-shaped lead-zinc deposit in Hengshanling-Shexingping has two characteristics ore veins formed before macro-fracturing: From the shallow part into the deep part, the strikes of veins shift from SN to EW.
New classification scheme about faulted rocks is proposed, according to the extent of grain reduction and growth and their sequence, and faulted rocks are classified as follows: (1) faulted rocks formed by the reduction action mainly include breccia series, cataclasite series, tectonobutchite series, mylonite series; (2) faulted rocks formed by growth action is mainly tectono-schist (gneiss) series; (3) blastomylonite series formed by grain reduction first and then growth; (4) mylonitic schist (gneiss) series formed by crystal growth first and then grain reduction. All series can be further classified according to matrix contents.
The geochemical characteristics of keratophyre-spilite series in Kunyang Rift Valley at Yunnan are studied, including main chemical composition, trace element, REE distribution, and alkalinity. The study shows that its geochemical characteristics have close relations with copper and iron deposit.
South Xinjian Cu-Au-Ag Metallogenic Belt is located near the boundary between Jiangnan Terrane and Cathysia Terrane. It has the cathysia type of crystalline basement, and experienced basin opening (rifting) for three times and the basin closing for three times since Proterozoic age. In correspondance with the structural evolution the belt has developed three sets of ore-forming rock series and happened reformed metallization for three times. The emplacement of large deposits has been controlled by the crossing of many different geological factors.
Based on the availabities of three ore-controlling factors, the authors put forword the locating mechanism of gold deposits. The model experiment indicates that the pressure-release effect occuring during the locating process marks the metallogenic nonlinear effect and causes the formation of deposits. In addition, the deposits involved in this paper can be divided into four kinds of locating mode.
An objection has been lodged against the traditional P/C boundary which were still upholded by International Subcommission on Permian Stratigraphy, International Commission on Stratigraphy, IUGS. And the rationality to take the base of theMontiparus Zone as the P/C boundary is comprehensively demonstrated.
The characteristics of the chemical composition of the rich-alkali granite porphyries are poor in SiO2, with mean content of 69.19%, but rich in alkali and high in potash. The mean content of (K2O+Na2O) is 9.85%. K2O is much greater than Na2O, mean value of K2O/Na2O is 2.10. As shown by the REE analysis, REE contents is lower. Compared with the granite of south China, the rich-alkali granite porphyry hase higher LREE, and no anomaly of europium (δEu=0.87). Its genetic type belongs to A type graritoid.
In this paper we put forward a new concept—the ore of associated gain element. It is thought that the theoretical index forecast of dressing and smelting should be the component part of contents of technological mineralogy study. The relative problems of the representativeness of ore sample, the handling of study sample and the choice of test means, and the examination of element existance form in the ore, etc., are discussed.
The Animaqen ophiolite belt, controlled by the south Kunlun fault zone, represents the location of the ancient plate suture line. Even though the ophiolite sequence has been disrupted by faulting, the ultramafic rocks, gabbro, diabase and basalt of the Animaqen ophiolite have been proved to be respectively the metamorphic peridotite and the ultramafic cumulate, the mafic cumulate, the sheeted dike and the mafic exrusive rocks of the typical ophiolite suite. The Animaqen ophiolite is a fragment of the Tethys oceanic crust.
Jingshan superlarge gold deposit is a typical deposit closely related to the ductile shear zone, developing the economic enrichment during the transition form the ductile deformation to the brittle deformation. The ore-forming process of Jingshan Au deposit can be described as the development of marine volcanic-turbidity current Au-bearing initial sedimentation → regional metamorphism and the first enrichment → strong transformation of dynamic metamorphism and deformation→ore-controlling and ore-holding of ductile shear structure→supperimposed transformation and enrichment of magma-hydrothermal solution. This process can be summarized as the “source-migration-accumulation” metallogenic-geochemical process of Au. The proved Au reserve of this deposit has exceeded 100 t and its prospect of searching for ore is considerable. So it is called the only super-large gold deposit in the south of the lower reach of the Yangtze River, China.
Geochemical characteristics of trace and minor elements in some strata of geosynclinal tectonic layer, platform tectonic layer, in granite of Diwa stage, altered rocks and wolframite in the Xiangdong Tungsten Mine are systematically studied. Enrichment of W, Sn and Cu in geosynclinal tectonic layer could be one part of mineralization. Different types of alteration might result in variance of distribution of the same trace or minor element.mNb/mTa andmMn/mFe ratios, contents of Nb and Ta in wolramite vary with vein groups’ location.
The authors discussed the metallogenic conditions of gold-bearing skarn deposits along the middle-lower Yangtze River reaches. Gold was enriched in mantle-originated magmas while copper was enriched in crust-originated magmas. So the enrichment of gold in skarn deposits was decided by the M/C ratios of the intrusive rocks. The distribution of these deposits was controlled not only by the localization of the intrusive rocks which were decided by Mesozoic Era-developed large-scaled and deep-seated faults, but also by the favorable stratigraphic horizons.
This paper discusses the seafloor thermalwater spout sedimentary activity in South Yongmei Depression according to the following evidences: the Yongmei region was in an extended tectonic environment of metaplateform and locally developed intracontinental rift aulacogen in company with the activity of rich alkali, high potassium volcanics of double-peak type. Several kinds of hydrothermal sedimentary rocks and the ore-bearing sedimentary formations of copper-polymetals, iron and manganese exist in this region with a zoning feature of the seafloor thermalwater spout sedimentation.
The alkali-rich porphyries formed in the structural relaxation epoch of the Himalayan Movement. The tectonic setting and crustal structure in which the rocks formed and the compositional regionization feature of the rocks indicate that the magma formed inside the crust, which is further proved by REE. Sr and Pb isotope data. Combined the aforesaid data with the result of REE inversion, it is suggested as a new opinion that the alkali-rich porphyries were the remelting product of the mixture of mantle rocks intrusing into the crust with crustal material.
The functions of lubricants in diamond drilling were discussed in this paper. The influences of lubricant on drilling efficiency and bit’s life were compared and analyzed with simulated drilling test and lubrication test apparatus. Lubricating mechanisms were also discussed.
Fission track analysis can provide important information of paleotemperatures and its temporal change, and is a very favourable method to solve geothermal problems in fine space-time scale. According to the determination of apatite fission track ages and length, the annealing characteristics of apatite fission track, geothermal evolution and prediction of petroleum source in studied area are discussed.
Deep crustal rocks of the Early Proterozoic orogenic belt (DCR) in Daqingshan area mainly included the synorogenic-metamorphic khondalite series and reworked Archean-basement granulites. During the early stage about 1900–1800 Ma, the DCR consisted of five huge slices which obducted over and stacked up along a series of high-temperature shear zone (HTSZ). and were subsequently uplifted from the deep crustal level to the middle one accompanied with granulite-amphibolite facies retrometamorphic reworking in HTSZ. From 1800 – 1700 Ma, some slices and HTSZ mentioned above were oveprinted by several low-temperature shear zone (LTSZ), of which the low-angle oblique thrusts caused these DCR to uplift again from the middle crustal level to the shallow one, and experienced retrometamorphic reworking of greenschist facies. These two stages of uplifting processes should be included in an entire Early Proterozoic orogenic cycle.
Four wear modes and four wear mechanisms of diamonds in saw blades are identified in a study of varied segments damaged in field operation of sawing hard stone. The four wear mechanisms are impact-shearing, fatiguing, pulling-out and thermal effects. Surface erosion is the result of thermal effects, while impact-shearing and fatiguing lead to macroand microfracture, and pulling-out results in wholesale dislodgement of diamonds provided the inequalityFn>M/(μλ-δ) is satisfied.
To solve the difficult scattering problem, Born approximation, the most prevalent method, is used to linearize the expression of the problem. However, for electromagnetic (EM) scattering problem, especially in many practical cases, it has poor effect. On the base of works done by other geophysicists, the authors suggest a new approximation approach that greatly surpasses Born approximation. It is illustrated by an example of 2-D crosswell electromagnetic imaging.
The mining geological work had been conducted in China since the ancient time. From 14 th to 18 th century, the output of iron mine reached to 6450 t annually. During 1763 to 1773, the annual output of copper in Yunnan Province was 9 200 t. In modern time, Chinese mining industry grew slowly. However, in 1950’s the mining geological organization were established in each administrative department and its affiliated mining companies. A set of regulations had also been established systematically. The mining geology has made the great contribution to reserve the mineral resources and to raise the economical benefit. Now resources have been found in many mine sites. The tasks facing us in future are to look for new deposits for old mine companies which are in shortage of resources and extend their service period; to involve in research for improving mining operational parameters and raise the economic benefit; to develop the technical market, and to provide service for development of mining industry reling on science and technology progress.