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1.
The hydroxyl in phyllosilicate minerals is the most common occurrence of water in primitive meteorites. Direct hydrogen isotopic analysis of this water component using an ion microprobe has been made in some glassy or phyllosilicate spherules from the Al Rais (CR) and Orgueil (CI) chondrites. The spherules from Al Rais show large deuterium excesses (δD = +200 -+800‰) relative to terrestrial standards, whereas deuterium-enrichments in the spherules from Orgueil are much smaller (δD = +40 - +130‰). The phyllosilicate spherules are products of  相似文献   

2.
《岩土力学》2006,27(1):172
GeoTnechanics and Geoengineering（GMGE）是由一批海内外知名专家学者筹备主办，并由国际著名出版社Taylor and Francis（英国）发行的英文国际学报。该学报将于2006年初创刊并向全世界发行。  相似文献   

3.
This study investigates the convergence of well-being between Sub Saharan Africa (SSA) and Organization for Economic Cooperation and Development (OECD) member countries during the period 1980–2014. The gap in living standard was examined from a steady state represented by the average income of OECD countries. Applying the unit root estimation technique to test for convergence with and without structural breaks, the result shows that; among a total of 43 countries studied, about 14 % are converging towards the average of OECD average. When the shock caused by the economic crisis of 2008 was factored into the analysis, the gains of about five countries out of the six converging disappeared. These results are disturbing owing to the fact that countries in the Asian region that started almost at the same level with SSA have converged to form a convergence club. Therefore, a lot more effort is needed from the government and stake holders in most countries in SSA to improve on the determinants of growth like good health care, quality institutions, better education and commitments to pursue developmental programmes which will boost the income of an average African to acquire better life.  相似文献   

4.
The peculiarities of catastrophic earthquakes that occurred in the Northwest Pacific region on January 13, 2007, and January 15, 2007, east of the Kuril Islands and the Tohoku megaearthquake of March 11, 2011, east of Japan are considered and analyzed. It is revealed that these earthquakes, apart from the fact that they occurred in the transition zone from the Pacific to island arcs and the Eurasian continent, have common features and similar characteristics. The seismotectonic slip in the source of the chronologically first event, the 2006 Kuril earthquake, was a gentle thrust, while that of the second event of January 13, 2007, was a downthrow beneath the Kuril deep trench.  相似文献   

5.
The Lower Cretaceous volcanic formations of Copiapó (Chile) host major stratiform, disseminated, vein, and stockwork mineral deposits. Among these are the Punta del Cobre district (Cu-Fe) and the neighbouring, large Candelaria deposit (Cu-Fe-Au). These deposits are likely to have formed during a major extensional event that was accompanied by granitoid emplacement that triggered important contact metamorphism, metasomatic activity and mineralization processes. We suggest here that alteration-mineralization processes developed within the upper-plate domain of a NNE-trending, ESE-dipping extensional system, while granitoids were accomodated within the lower-plate. If this model prove to be right, `Candelaria-type' deposits may be hidden beneath the present, higher structural position of the Punta del Cobre district. Received: 13 May 1999 / Accepted: 2 August 1999  相似文献   

6.
Please refer to the attachment(s) for more details.  相似文献   

7.
Earth-reservoirs are increasingly exploited today with the extraction of resources, such as heat and hydrocarbons, and the large-scale emplacement of waste, such as CO2 sequestration. The characterization, site investigation, predictive modeling and long-term monitoring are dependent on the processes being investigated and modeled. In most cases complex coupled processes have to be addressed in a geologically complex rock mass system. In this paper we present a conceptual holistic framework known as geomechanical facies linking all the scales of investigation, characterization and reservoir development methods. We demonstrate this concept on the work undertaken during the design and development of the enhanced geothermal systems (EGS) systems at the forefront of European Hot-Dry-Rock (HDR) technology, Soultz-sous-Forêts (France) and Spa Urach (Germany). Soultz-sous-Forêts is situated within granitic rocks and an active tectonic graben system in the central part of the Rhine Graben. It presents conditions of lithology, temperature, stress, hydraulics and geochemistry that are very different from those at Spa Urach, located in a very dense gneiss formation in the South German crystalline complex. Spa Urach exhibits more elastic behavior and is set tectonically within an almost inactive strike-slip stress field described in more detail in Sects. “Drill core analysis” and “Hydraulic stimulation at Spa Urach”. This paper compares the exploration and field development methods used at these two sites against the back drop of the geomechanical facies concept. Issues addressed include the key parameters for flow and heat transport properties, coupled hydro-mechanical process identification, the success of the HDR reservoir as a heat exchanger and exploration techniques applicable to the different facies. Identification of the key geomechanical facies gives an indication as to which technologies will prove more efficient in the application of HDR technology. The results of this study will hopefully help in developing heat recovery schemes for the long-term economical operation of future HDR plants and EGS as well as assist in the understanding of engineered geosystems.  相似文献   

8.
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9.
The F–(Ba–Pb–Zn) ore deposits of the Zaghouan District, located in NE Tunisia, occur as open space fillings or stratabound orebodies, hosted in Jurassic, Cretaceous and Tertiary layers. The chondrite-normalized rare earth element (REE) patterns may be split into three groups: (i) “Normal marine” patterns characterizing the wallrock carbonates; (ii) light REE (LREE) enriched (slide-shaped) patterns with respect to heavy REE (HREE), with small negative Ce and Eu anomalies, characteristic of the early ore stages; (iii) Bell-shaped REE patterns displaying LREE depletion, as well as weak negative Ce and Eu anomalies, characterizing residual fluids of subsequent stages. The 87Sr/86Sr ratios (0.707654–0.708127 ± 8), show that the Sr of the epigenetic carbonates (dolomite, calcite) and ore minerals (fluorite, celestite) are more radiogenic than those of the country (Triassic, Jurassic, Cretaceous, lower Miocene) sedimentary rocks. The uniformity of this ratio, throughout the District, provides evidence for the isotopic homogeneity and, consequently, the identity of the source of the mineralizing fluids. This signature strongly suggests that the radiogenic Sr is carried by Upper Paleozoic basinal fluids.The δ34S values of barite, associated to mineralizations, are close to those of the Triassic sea water (17‰). The δ34S values of sulfide minerals range from − 13.6‰ to + 11.4‰, suggesting two sulfur-reduced end members (BSR/TSR) with a dominant BSR process.Taking account of the homogeneity in the Pb-isotope composition of galenas (18.833–18.954 ± 0.001, 15.679–15.700 ± 0.001 and 38.690–38.880 ± 0.004, for the 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios respectively), a single upper crustal source for base-metals is accepted. The Late Paleozoic basement seems to be the more plausible source for F–Pb–Zn concentrated in the deposits. The genesis of the Zaghouan District ore deposits is considered as the result of the Zaghouan Fault reactivation during the Late Miocene period.  相似文献   

10.
Platinum-group elements （PGE） in PGE-rich porphyry copper （gold） deposits are mainly Pt and Pd, whereas the concentrations of other PGE （Ru, Rh, Os, Ir） are significantly low. Moreover, Pt and Pd mainly exist in sulfides in the forms of crystal lattice or tiny platinum-group mineral （PGM） inclusions. The present data show that there is a positive relationship between Pt and Pd concentrations and Cu （Au） in porphyry copper （gold） deposits. The comparison of chondrite-normalized PGE distribution patterns between the ore-bearing porphyry intrusions and ore-barren porphyry intrusions in arc setting, 187^Os/188^Os, 87^Sr/86^Sr and S isotopes for porphyry copper （gold） deposits shows that PGEs were mainly derived from the mantle, and fluids from subduction zones devoted trivial PGE to the magma. The porphyry copper （gold） deposits associated with subducted events are most probably enriched in PGE, whereas those related to crustal thickening, lithospheric delamination or underplating rarely concentrate PGE. The osmium isotopic compositions in porphyry copper （gold） deposits reveal that （187^Os/188^Os）i values are highly variable and not lower than those of primitive upper mantle （PUM） and mantle peridotite, however, osmium concentrations are commonly lower than mantle peridotite, suggesting that parental magmas of some porphyry intrusions had experienced crustal contamination during magma evolution. Experimental investigations have proved that PGE exist in the forms of Cl^- and HS^- complexes during transportation and migration of the oreforming fluids. This paper summarizes previous studies including crucial controlling factors and mechanisms for PGE enrichment, and points out that the mantle-derived magmas parental to porphyry intrusions are the prerequisite for PGE enrichment in porphyry copper （gold） deposits. Favorable physical and chemical conditions （including salinity, temperature, pressure, pH, and oxygen fugacity） in hydrothermal fluids crucially control the  相似文献   

11.
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12.
ＱＵＡＮＴＩＴＡＴＩＶＥＤＹＮＡＭＩＣＳＴＲＡＴＩＧＲＡＰＨＹ（ＱＤＳ）Ｄｕｒｉｎｇｔｈｅｐａｓｔｆｅｗｄｅｃａｄｅｓｉｎｄｅｐｅｎｄｅｎｔｓｔｕｄｉｅｓｏｆｓｅｄｉ－ｍｅｎｔａｒｙｂａｓｉｎｓｗｅｒｅｃａｒｒｉｅｄｏｕｔａｌｏｎｇｄｉｆｅｒｅｎｔａ...  相似文献   

13.
The Lisan Peninsula is located within the Dead Sea basin which represents the plate boundary between African and Arabian plates. This basin constitutes a good example of a pull-apart basin because of its large dimensions, its structural simplicity and its active subsidence . The gravity data reveal that the Dead Sea basin can be divided into segments, each of them about 30 km long in N-S direction , where the Lisan Peninsula represents the deepest one (9 km thick Pleistocene sediments ), overlying about 6 km thick Mesozoic sediments . In addition , 20 km of extension was predicted along the Dead Sea basin, which indicates that the Dead Sea basin should be about 3.3 Ma in age . Furthermore, the Precambrian basement under the Lisan area is characterized by high susceptibility contrast that is related to continuous tectonic activity in the region.  相似文献   

14.
The biogeochemical migration of iodine in soil and its effect factors were studied by the isotope tracer (125I) and experiments of leaching and absorption by Chinese cabbage to iodine under simulated condition. The results show that the quantities of tran…  相似文献   

15.
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16.
ＰＯＳＩＮＧＴＨＥＰＲＯＢＬＥＭ“ＣｏｍｐｌｅｘｉｔｙａｎｄＳｅｌｆ－ＯｒｇａｎｉｚｅｄＣｒｉｔｉｃａｌｉｔｙｏｆＳｏｌｉｄＥａｒｔｈＳｙｓｔｅｍ”ｉｓａｎｅｗｐｒｏｂｌｅｍａｓｗｅｌａｓａｎｅｗｐｒｏｐｏｓｉｔｉｏｎ．Ｔｈｅａｕｔｈｏｒｐｕｔｓｆｏ...  相似文献   

17.
No.1 Chemical separation and isotopic variations of Cu and Zn from five geological reference materials Chapman J.B., Mason T.F.D., Weiss D.J., Coles B.J., Wilkinson J.J.(5 -16)…………………………………………………………………………Trace element analysis of fused whole-rock glasses by laser ablation-ICP-MS and PIXEKurosawa M., Shima K., Ishii S., Sasa K.(17 -30)……………………………………………………………………………………………………………………Determination of Ti, K, Sm and …  相似文献   

18.
The central domain of the Pan-African Belt in Cameroon is characterized by abundant porphyritic granitoids, which were emplaced synkinematically and variably orthogneissified in relation with ENE-striking steeply dipping transcurrent shear zones. These plutonic rocks have intermediate to felsic compositions and constitute a high-K calk-alkaline series. Conventional UPb zircon dating yields an age of 618 Ma for this syntectonic Pan-African magmatism in the Tonga area. The country rocks are made of metabasites (garnet amphibolites) and tonalitic to trondhjemitic gneisses, which suffered two distinct orogenic cycles: the first one is the Palaeoproterozoic Eburnean–Transamazonian cycle at 2.1 Ga and the second one is the Pan-African orogenesis. These new ages confirm the existence of an extensive Palaeoproterozoic crust in Cameroon and question the areal extent of the Congo–São Francisco craton towards the north. To cite this article: E.L. Tanko Njiosseu et al., C. R. Geoscience 337 (2005).  相似文献   

19.
Ernst Weinschenk was an excellent teacher at the High School of Technology from 1897 till his death 1921, and at the university in Munich from 1900. His studies of the mineralogy of meteorites and the contact-metamorphic mineralization in the eastern and western Alps and southern Tyrol made him widely known early-on. He successfully determined many new minerals with the aid of the polarizing microscope and the use of mineral and thin rock sections. He attributed the genesis of the sulfidic ore deposit Silberberg at Bodenmais (northern Bavarian Forest) and the graphite deposits near Passau (Lower Bavaria) to the exhalative output of sulphur and carbon during the granite orogenesis (Weinschenk 1914).  相似文献   

20.
The Pinios River is the third longest river of Greece. It drains the entire drainage basin of Thessaly (eastern part of Central Greece), part of which is the largest plain of the country. In this research the hydrological, geomorphological and geological characteristics of the riverine area of Pinios were studied. Classification and grouping of these characteristics were then carried out, which led to the segmentation of the Pinios River into seven sections, each one with its own set of thematic data. These sets assign separate functions and evolutions of the river system during the Quaternary. Specifically, the basin of the present Pinios River, before its evolution into a river basin, comprised three separate and independent systems. The present Pinios River emerged as a river system from the merging of the lacustrine paleoenvironments along with the major tributaries that drained large parts of the present hydrological basin and as soon as the karstic openings of the central hill valley and the Tempi valley took place during the Quaternary. The followed methodology for the segmentation of the river can be used for the study of heterogeneous river systems.  相似文献   

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