共查询到20条相似文献，搜索用时 78 毫秒
1.
Xu Xiangzhen Yang Jingsui Chen Songyong Fang Qingsong Bai Wenji Ba Dengzhu 《中国地质大学学报(英文版)》2009,20(2)
A wide variety of unusual mantle has been reported from podiform chromitite orebodies Cr-31 and Cr-74 in the Luobusa (罗布莎) ophiolite, Tibet. A detailed investigation of chromitite ore-body Cr-11, located in the Kangjinla (康金拉) district at the eastern end of the ophiolite, has revealed many of the same minerals, including diamond, moissanite, and some native elements, alloys, oxides, sulphides, silicates, carbonates, and tungstates. This orebody is particularly rich in diamonds, with over 1 000 grains recovered from about 1 100 kg sample of chromitite. More detailed studies and experi-ments are needed to understand the origin and significance of these unusual minerals because they have not been found in situ. It is a great breakthrough in mineralogical research that we have picked up more than 40 kinds of minerals from the Kangjinla chromite deposit in Luobusa. It is notable that a large amount of diamonds were firstly discovered from the Kangjinla chromite deposit as well as many other unusual minerals, such as moissanites, rutiles, native irons, and metal alloys. Especially, that diamond was found again in different chromitites In the same ophiolite belt provided new key evidence for discussing the origin of the diamond and the hosted ehromitite and ophiolite. The mantle mineral group in Tibet has great significance in mineralogy and geodynamics. 相似文献
2.
WU Weiwei YANG Jingsui MA Changqian MILUSHI Ibrahim LIAN Dongyang TIAN Yazhou 《《地质学报》英文版》2017,91(3):882-897
In recent years diamonds and other unusual minerals(carbides,nitrides,metal alloys and native elements) have been recovered from mantle peridotites and chromitites(both high-Cr chromitites and high-Al chromitites) from a number of ophiolites of different ages and tectonic settings.Here we report a similar assemblage of minerals from the Skenderbeu massif of the Mirdita zone ophiolite,west Albania.So far,more than 20 grains of microdiamonds and 30 grains of moissanites(SiC) have been separated from the podiform chromitite.The diamonds are mostly light yellow,transparent,euhedral crystals,200~300 μm across,with a range of morphologies;some are octahedral and cuboctahedron and others are elongate and irregular.Secondary electron images show that some grains have well-developed striatums.All the diamond grains have been analyzed and yielded typical Raman spectra with a shift at ~1325 cm~(-1).The moissanite grains recovered from the Skenderbeu chromitites are mainly light blue to dark blue,but some are yellow to light yeUow.All the analyzed grains have typical Raman spectra with shifts at 766 cm~(-1),787 cm~(-1),and 967 cm~(-1).The energy spectrums of the moissanites confirm that the grains are composed entirely of silicon and carbon.This investigation expands the occurrence of diamonds and moissanites to Mesozoic ophiolites in the Neo-Tethys.Our new findings suggest that diamonds and moissanites are present,and probably ubiquitous in the oceanic mantle and can provide new perspectives and avenues for research on the origin of ophiolites and podiform chromitites. 相似文献
3.
Xieyan Song 《地学前缘(英文版)》2012,3(6):944
Magmatic sulfide deposits are significantly valuable because more than 60%of the nickel and 99%of the platinum-group elements in the world are produced from these deposits,although Ni-laterite deposits are also an important type of nickel resource.The magmatic sulfide deposits are grouped into sulfide-rich Ni-Cu-(PGE) deposits and sulfide-poor PGE deposits.Although the research on the 相似文献
4.
SONG Huanbin HE Mingqin ZHANG Shangzhong YI Fenghuang 《中国地球化学学报》2008,27(1):104-108
The Jingbaoshan platinum-palladium deposit is China＇s largest independent PGM （platinum-group metals） deposit so far discovered. There are eleven kinds of useful components in the ore： Pt, Pd, Os, Ir, Ru, Rh, Au, Ag, Cu, Ni, and Co. The platinum-group elements, gold and silver occur in the form of minerals in ores. twenty-five kinds of precious metal minerals have been found, of which twenty one belong to the platinum-group minerals. The minerals are very small in grain size. Copper occurs mainly as copper sulfide with a small amount of free copper oxide, and the beneficiated copper accounts for 95.21%. Nickel occurs mainly as nickel sulfide, and some nickel silicate and nickel oxide occur in the ore. The beneficiated nickel accounts for 72.03%. Cobalt occurs mainly as cobalt sulfide, and there are some cobalt oxide and other kinds of cobalt. The beneficiated cobalt accounts for 77.58%. 相似文献
5.
An extractive process is established for platinum metals by reduction roasting,flotation, magnetic separation, heavy liquid eentrifugation, and other experiments. Six alloys (Os-Fe-Cr-Ni, Os-Cn-Fe-Ni-Pt, Rh-Cr, Ti-Cu-Ni-Fe-Pt, Cu-Fe-Ni-Pt, and Os-Cu-Fe-Ni-Pt) have been identified in the Ieached residue. This resuIt indicates that most of the platinum metals in the leached residue tend to form alloys eith base metals. In many eases these alloys are enclosed by iron hydroxide and mative sulfur.Therefore, it is necessary to dissociate the alloys as well as their enclosing material in order to extract the platinum group. The experiments also demonstrate the mobility of Os, Pt, and Rh during the process of ore dressing and smelting. 相似文献
6.
Some soft and mud samples have been determined for eadmiun, lead, copper,nickel and cobalt by atomic absorption speetrophotometry with a high-temperature graphite tube, after their extraction with sodium diethylthiocarbonate into methy lisolutyl ketone. The tests of the effects of acidity on extraction and interference have been also carried out and the optimum conditions have been obtained. In addition, experiments on recoveries by this procedure have been performed for the elements in ppb amount. The recovery of the metals added to soil samples is made in the same manner and the precision values are given in this paper. This method is considered as to be applicable to the determination of soil and mud samples for the above-mentioned elements, of which the concentration is higher than 1 ppb. 相似文献
7.
Based on the analytical results for 101 samples from 50 survey spots,this paper describes the changes in rations of various components in calcium carbonate from the sea area at the Pearl River mouth with pH.Relations of ∑CO2 with salinity,and Ca concentration with salinity in different parts of the river mouth have been established.The annual throughput of Ca from the Pearl River and the saturation degrees of calcite and aragonite have been calculated. 相似文献
8.
Chemical variations, geochemical behaviors and other problems such as element assemblages and relative abundances of elements during and after various geologic processes (magmatism, assimilation, hydrothermal alteration as well as tectonic movements) have been discussed for a nickel-bearing ultrabasic intrnsion. Particular emphasis is placed on aspects concerning the geochemical behavior of nickel. Conclusions have been reached about the environment and possible mechanism for the emplacement of this massive and for the origin of Ni sulfides. A “assimilation-immiscibility“ hypothesis is proposed for formation of copper-nickel sulfide deposits in ultrabasic intrnsives. 相似文献
9.
Holocene Floral and Faunal Remains Revealed Concealed Neotectonic Disturbance (Saria Tal, Kumaun Himalaya, India) 总被引：1，自引：1，他引：0
Asha GUPTA 《《地质学报》英文版》2010,84(1):69-76
Palynological and paleontological investigations supported by the radiocarbon dates of the lacustrine sediments of two profiles from the temperate lake Saria Tal, in Naini Tal District, Kumaun Himalaya, have revealed the presence of a concealed fold at the region. The profile from bore cores represents the upper part of the Late Holocene and the profile from exposed sections from the Middle Holocene to the over middle part of the Late Holocene. The data generated from different investigations have uniformly indicated that the former profile represents normal superposition, while the latter represents the reverse order. The contemporary pollen as well as molluscan zones of both profiles are situated at different elevations but consist of similar bioremains – indicating continuation of the same strata in two profiles. The presence of reverse order of superposition, continuation of the same strata in two profiles at different elevations, and the orientation of biozones, have indicated that the revealed folding is of syncline type. The present study has also given an idea about the origin of this lake. 相似文献
10.
The knowledge of Martian salts has gone through substantial changes during the past decades. In the 70th of last century, Viking landers have noticed the existence of salts on Mars. Several salt species have been suggested from then on, such as sulfates and chlorides. However, their origin was a mystery due to the lack of observations. The recent explorations and related studies at the beginning of this century revealed that the crustal composition of Mars is similar to that of Earth, and it was hypothesized that almost one third of Martian surface was covered by oceans and lakes in the early stage of Mars. The huge water bodies may have dissolved a large quantity of ions from Martian primary rocks during the whole Noachian and Hesperian epoch. After the enormous drought event happened during the late Hesperian and the early Amazonian, these dissolved ions have formed huge salts deposits and most of them were preserved on Mars until today. To date, carbonates, sulfates, chlorides have all been detected by orbital remote sensing and by landers and rovers. However, the salt mineral assemblages on Mars seems to have some differences from those on Earth, e.g., rich in sulfates and lack of massive carbonates. To explain this difference, we propose that most of the surface carbonates precipitated from the ancient oceans may have been dissolved by the later ubiquitous acidic fluids originated from the global volcanism in the Hesperian era, and formed the enormous sulfate deposits as detected, and this hypothesis seems to be supported by the evidence that most of the sulfate deposits distribute around the Tharsis volcanic province while the survived carbonates located far from it. This process can release most of the carbon on Mars to the atmosphere in the form of CO2 and then be erased by the late heavy bombardments, which might have profound influence on the climate change happened in the Hesperian age. The positive correlation between the GRS results of the potassium distributions and the distribution of chlorides on Mars, together with the high Br concentration measured from the evaporate sediments at two Mars exploration rover landing sites, indicate that the brines in the regions where the chlorides deposited may have reached the stage for potassium salts deposition, thus we propose for the first time that potassium salts deposits might be prevalent in these regions. 相似文献
11.
Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
12.
Inter-regional correlation of transgressions and regressions in the Cretaceous period 总被引：1，自引：0，他引：1
T. Matsumoto 《Cretaceous Research》1980,1(4):359-373
Well investigated platforms have been selected in each continent, and the history of Cretaceous transgressions and regressions there is concisely reviewed from the available evidence. The factual records have been summarized into a diagram and the timing of the events correlated between distant as well as adjoining areas.On a global scale, major transgressions were stepwise enlarged in space and time from the Neocomian, via Aptian-Albian, to the Late Cretaceous, and the post-Cretaceous regression was very remarkable. Minor cycles of transgression-regression were not always synchronous between different areas. Some of them were, however, nearly synchronous between the areas facing the same ocean.Tectono-eustasy may have been the main cause of the phenomena of transgression-regression, but certain kinds of other tectonic movements which affected even the so-called stable platforms were also responsible for the phenomena. The combined effects of various causes may have been unusual in the Cretaceous, since it was a period of global tectonic activity. The slowing down of this activity followed by readjustments may have been the cause of the global regression at the end of the Cretaceous. 相似文献
13.
The Afyon stratovolcano exhibits lamprophyric rocks, emplaced as hydrovolcanic products, aphanitic lava flows and dyke intrusions, during the final stages of volcanic activity. Most of the Afyon volcanics belong to the silica-saturated alkaline suite, as potassic trachyandesites and trachytes, while the products of the latest activity are lamproitic lamprophyres (jumillite, orendite, verite, fitztroyite) and alkaline lamprophyres (campto-sannaite, sannaite, hyalo-monchiquite, analcime–monchiquite). Afyon lamprophyres exhibit LILE and Zr enrichments, related to mantle metasomatism. 相似文献
14.
正20140751 Guo Xincheng(Geological Party,BGMRED of Xinjiang,Changji 831100,China);Zheng Yuzhuang Determination and Geological Significance of the Mesoarchean Craton in Western Kunlun Mountains,Xinjiang,China(Geological Review,ISSN0371-5736,CN11-1952/P,59(3),2013,p.401-412,8 相似文献
15.
正20141058 Chen Ling(Key Laboratory of Mathematical Geology of Sichuan Province,Chengdu University of Technology,Chengdu610059,China);Guo Ke Study of Geochemical Ore-Forming Anomaly Identification Based on the Theory of Blind Source Separation(Geosci- 相似文献
16.
正20141334 Chen Kun(Institute of Geophysics,China Earthquake Administration,Beijing100081,China);Yu Yanxiang Shakemap of Peak Ground Acceleration with Bias Correction for the Lushan,Sichuan Earthquake on April20,2013(Seismology and Geology,ISSN0253-4967,CN11-2192/P,35(3),2013,p.627-633,2 illus.,1 table,9 refs.)Key words:great earthquakes,Sichuan Province 相似文献
17.
正20141624 Cai Xiongfei(Key Laboratory of Geobiology and Environmental Geology,Ministry of Education,China University of Geosciences,Wuhan 430074,China);Yang Jie A Restudy of the Upper Sinian Zhengmuguan and Tuerkeng Formations in the Helan Mountains(Journal of Stratigraphy,ISSN0253-4959CN32-1187/P,37(3),2013,p.377-386,5 illus.,2 tables,10 refs.) 相似文献
18.
正20142263Lü Shaojun(Geological Survey of Jiangxi Province,Nanchang 330030,China)Early-Middle Permian Biostratigraphical Characteristics in Qiangduo Area,Tibet(Resources SurveyEnvironment,ISSN1671-4814,CN32-1640/N,34(4),2013,p.221-227,2illus.,2tables,22refs.)Key words:biostratigraphy,Lower Permian,Middle Permian,Tibet 相似文献
19.
正20142560Hu Hongxia(Regional Geological and Mineral Resources Survey of Jilin Province,Changchun 130022,China);Dai Lixia Application of GIS Map Projection Transformation in Geological Work(Jilin Geology,ISSN1001-2427,CN22-1099/P,32(4),2013,p.160-163,4illus.,2refs.) 相似文献
20.
正20140692 Duo Tianhui(No.402 Geological Team,Exploration of Geology and Mineral Resources of Sichuan Authority,Chengdu611730,China);Wang Yongli Computer Simulation of Neptunium Existing Forms in the Groundwater(Computing Techniques for Geophysical and Geochemical Exploration,ISSN1001-1749,CN51-1242/P,35(3), 相似文献