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1.
The results of potassium‐argon measurements are reported. Three samples from the southern end of the New England bathylith confirm its Permian age (240–245 m.y.). Two samples of the “pre‐Permian” granites are not younger than Lower Permian (Hillgrove, 270 m.y.; Barrington Tops, 260 m.y.). A sample of the analcite basalt from Spring Mountain gave an Oligocene age (34 m.y.) by measurements on two separate minerals.  相似文献   

2.
3.
Luobusaite: A New Mineral   总被引:6,自引:0,他引:6  
A group of mantle minerals including about 70-80 subtypes of minerals are discovered from a podiform chromitite in Tibet, China. Recovered minerals include diamond, coesite, moissanite, wustite, Fe-silides and a new mineral, luobusaite. All of these minerals were hand-picked from heavymineral separates of the podiform chromitite in the mantle peridotite of an ophiolite. The grains of luobusaite are as host mineral with inclusions of native silicon or as an intergrowth with native silicon and Fe-Si phase. Luobusaite occurs as irregular grains, with 0.1-0.2 mm in size, consisting of very finegrained aggregates. The mineral is steel-grey in color, metallic luster, and opaque. The empirical formula (based on 2 for Si) is Fe0.83Si2, according to the chemical compositions of luobusaite. X-ray powder-diffraction data: orthorhombic system, space group Cmca, a = 9.874 (14) A, b = 7.784 (5) A, c= 7.829(7) A, Z=16.  相似文献   

4.
In 1974 the author preliminarily reported two new platinum group minerals-daomanite and hongshiite. The two minerals were accepted by the Commission on New Minerals and Minerals Names of the International Mineralogical Association in 1976 and 1982 respectively. Because of the conditions at that time, the work was preliminary, for example, there were only reflectance values of four wave bands. Recently the author again made measurements of reflectances, corrected cell parameters by the four-circle diffractometer and electron diffraction and supplemented their new occurrences and nomenclature.  相似文献   

5.
Pelagic manganese nodules from the East Pacific Ocean have been studied using polarizing,scanning electron and transmission electron microscopes. It has been revealed that the manganesenodules are composed of cores and stromatolite coatings. The structures and textures of thesenodules are peculiar to oncolite. Consequently, the pelagic manganese nodules are manganeseoncolites. Based on the stromatolites in the coatings, the manganese oncolites from the East Paci-fic Ocean can be divided into two types. One is smooth on surface and dense inside. Its coatingsare composed mainly of Minima. The other has a knobby surface and is loose internally. Itscoatings consist mainly of Admirabilis. The TEM investigation has also revealed that the con-structors of the manganese oncolites are ultra-microbes. The Minima is constructed byMiniactinomyces chinensis sp. nov. and the Admirabilis is built by Spirisosphaerospora pacifica sp.nov.  相似文献   

6.
正Objective The Cambrian fossil embryos of radial animals are represented by taxa of Olivooides, Pseudooides, Carinachites, hexangulaconulariids (including Hexaconularia and Arthrochites) and Quadrapyrgites. Liu Yunhuan established a new genus: Qinscyphus Liu 2017 and reconstructed the general morphology of its hatched stages in 2017; this genus has only one species Qinscyphus necopinus. It was interpreted to be a member of Olivooidae Steiner 2014, and was placed besides crown  相似文献   

7.
A New Zealand Landslide Database has been developed to hold all of New Zealand’s landslide data and provide factual data for use in landslide hazard and risk assessment, including a probabilistic landslide hazard model for New Zealand, which is currently being developed by GNS Science. Design of a national Landslide Database for New Zealand required consideration of existing landslide data stored in a variety of digital formats and future data yet to be collected. Pre-existing landslide datasets were developed and populated with data reflecting the needs of the landslide or hazard project, and the database structures of the time. Bringing these data into a single database required a new structure capable of containing landslide information at a variety of scales and accuracy, with many different attributes. A unified data model was developed to enable the landslide database to be a repository for New Zealand landslides, irrespective of scale and method of capture. Along with landslide locations, the database may contain information on the timing of landslide events, the type of landslide, the triggering event, volume and area data, and impacts (consequences) for each landslide when this information is available. Information from contributing datasets include a variety of sources including aerial photograph interpretation, field reconnaissance and media accounts. There are currently 22,575 landslide records in the database that include point locations, polygons of landslide source and deposit areas, and linear landslide features. Access to all landslide data is provided with a web application accessible via the Internet. This web application has been developed in-house and is based on open-source software such as the underlying relational database (PostGIS) and the map generating Web Map Server (GeoServer). Future work is to develop automated data-upload routines and mobile applications to allow people to report landslides, adopting a consistent framework.  相似文献   

8.
New Insco铜矿床是一个太古代火山型块状硫化物矿体.矿石产在薄层枕状角砾玄武岩底部附近,玄武岩覆盖在流纹质火山碎屑岩之上.矿体建造与下伏的块状流纹岩被闪长岩侵入体分隔开,与一系列上覆的枕状玄武岩之间被断层分隔开.矿体为富含磁黄铁矿的块状硫化物透镜体,其中有浸染状黄铜矿与黄铁矿的整合条带,并还有含黄铁矿—黄铜矿的硅质矿石透镜体夹层.原生矿物为磁黄铁矿,在区域变质作用中,它又重结晶,形成多角形粒状结构,附生在黄铁矿晶体上.继更新世冰川作用后,黄铁矿,白铁矿,铁的氧化物,碳酸盐和氢氧化物广泛取代了磁黄铁矿.  相似文献   

9.
Chengdeite occurs in chromite orebodies in dunite as well as in placers in their neighbourhood. The mineral occurs as granular aggregates in association with inaglyite and in some cases occurs as graphic intergrowths with native iridium. It is opaque with a metallic lustre, colour steel-black, streak black,HM = 5.2, VHN50=452 kg/mm2, cleavage not observed, fracture not observed, strongly magnetic. Its reflection colour is bright white with a yellowish tint. It has no internal reflection, bireflectance or pleochrism, and shows isotropism.Thirteen chemical analyses were carried out by means of the electron microprobe. The mean percentages of the data obtained in the 13 analyses ares S 0.001, Fe 7.9, Ni 0.03, Co 0.03, Cu 0.83, As 0.02, Rh 0.19, Pd 0.00, Os 0.06, Ir 88.5, Ft 2.2 and Pb 0.00. The simplified formula is Ir3Fe, which requires Ir 91.17 and Fe 8.83, the total being 100.00 (% ).Five strongest lines of X-ray powder diffraction (hkl, d, I)are: 111, 2.18 (80);200, 1.89 (60); 220, 1.34 (70);311, 1.142  相似文献   

10.
A new superstructure was found in bafertisite [(Ba0.98Na0.02)1.00(Fe1.71Mn0.26Mg0.01)1.98 TiO[(Si1.82Ti0.04Al0.03Cr0.01)1.90O7](OH1.40F0.53Cl0.03)1.96] from Donghai County, Jiangsu Province, China. The occurrence of the superstructure reflections were observed by single crystal diffraction using a SMAR APEX CCD. The a*, b*and c* axis directions revealed extra weak reflection spots of the superstructure. The apparent 2a, 2b and 2c superstructure is monoclinic with unit cell a=10.6502(15)?, b=13.7233(19)?, c=21.6897(3)?, α=90o, β=94.698(3)o, γ=90o,space group Cm,Z=16. If c* extra weak reflections are ignored, the secondary supercell gave a cell a=10.6548(15)?, b=13.7284(19)?, c=11.6900(17)?, α=90o, β=112.322(28)o, γ=90o,space group Cm,Z=8. The basic subcell was obtained by ignoring all extra weak reflection spots and gave: a=5.3249(17)?, b=6.8669(22)?, c=10.8709(36)?, α=90o, β=94.740(62)o, γ=90o,space P21/m,Z=2. The superstructure has been refined to R = 0.063 for 7805 [R(int) = 0.0266] unique reflections I>2δ(I). The structure consists of an octahedra (O) sheet sandwiched between two heteropolyhedral (H) sheets. These sheets consist of Ti–octahedra and twin tetrahedral disilicate groups [Si2O7]. The O sheet comprises (Fe,Mg)O4 octahedra. The large Ba cation is located in the interlayer area. The refined structure shows Fe, Mg are partly ordered. The shifting of the TiO6 octahedron and SiO4 tetrahedron sites in the sheet may be a consequence of the superstructure.  相似文献   

11.
A geothermometer equation \(T = \frac{{1531}} {{\ln K_d + 0.883}}\), where \(K_{\dot d} = \frac{{X_{Zr}^S X_{Hf}^m }} {{X_{Zr}^m X_{Hf}^s }}\) [X j i is the concentration (in ppm) of component i in phase j] is the Zr and Hf distribution coefficient between melt and zircon, and T is temperature in K, was derived by thermodynamic processing of literature experimental data on Zr and Hf distribution between acid melts (m) and zircon (s) and on the solubility of zircon and hafnon in the melts with variable silica content. In calculations with this equations, we assumed the Zr concentration in zircon to be constant: 480000 ppm. It is shown that the commonly observed increase in Hf concentration from the cores to margins of magmatic zircon crystals is caused by the fractional crystallization of zircon. For differentiated acid magmatic series, the initial crystallization temperature of zircon in the least silicic cumulates should be evaluated using the cores of large zircon grains with the highest Zr/Hf ratio. Application of the geothermometer for mafic and intermediate rocks may be hampered due to simultaneous crystallization of zircon with some other ore and mafic minerals relatively enriched in Zr and Hf. The newly derived geothermometer has some advantages over other indicators of the crystallization temperature of magmatic zircon based on the zircon saturation index (Watson and Harrison, 1983; Boehnke et al., 2013) and on Ti concentration in this mineral (Ferry and Watson, 2007) as it does not depend on the major-oxide melt composition and on the accuracy of the estimated SiO2 and TiO2 activities in the melts. Calculations of the Zr and Hf fractionation trends in the course of zircon crystallization in granitoid melts allow one to evaluate the temperature at which more evolved melt portions were segregated.  相似文献   

12.
New Material of Silurian Rugose Corals from Yunnan   总被引:2,自引:0,他引:2  
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13.
M. Peñaloza  A. Marcos 《GeoJournal》1995,35(4):471-479
On the basis of modern works of a Spanish paleographer, a North American geographer and, a historian-sailor, also North American, respectively, we have reexamined some controversial aspects of the cosmographic ideas ascribed to the Columbus brothers (Christopher and Bartholomew), regarding the preparation of their first transoceanic voyage. First, we present a discussion of two versions of the translation and explanation of a part or phrase of one of the marginal notes or postils, written supposedly by one of them or both in Latin in their IMAGO MUNDI (d'Ailly, Pierre. Tract of Geography of century XV) copy that seriously questions the credibility of the Columbus brothers' knowledge of the cartography of that time. Secondly, we have analized three hypotheses attempting to explain the methods they could have used, to measure the length of a terrestrial degree either on the equator or on a meridian. We will show that these hypotheses are unacceptable due to the manipulation of the information by its authors and, because there is not enough historical evidence to demonstrate that Christopher Columbus or his brother made such geodesical measurements.  相似文献   

14.
New Early Cambrian Chordates from Haikou, Kunming   总被引:8,自引:0,他引:8  
Two new chordates, Cathaymyrus haikouensis Luo et Hu sp. nov. and Zhongxiniscus intermedius Luo et Hu gen. et sp. nov. are studied in this paper. Both display numerous S-shaped myomeres on their trunk. C. haikouensis shows a long and slim body similar to that of Cathaymyrus diadexus Shu et al., Zhongxiniscus approaches to Myllokunmingia and Haikouichthys in the dorsal fin, but differs in the myomeres. Zhongxiniscus may be the intermediate form between Cathaymyrus and Myllokunmingia and Haikouichthys.  相似文献   

15.
Bismuthoan galena is a variety of galena, resulting from the replacement of Bi for some Pb in galena.This mineral occurs in the No.11 orebody of the Lamo skarn-type Zn-Cu deposit in the Dachang ore field ,but only the No,11 orebody of the Lamo deposit is developed such bismuthoan galena.This is closely related to such a geochemical background that the No.11 orebody contains high Bi and Bi-sulfosalt minerals are well developed there.Eight electron microprobe analyses of five samples give 60.17-70.20%Pb(66.94% on average),10.00-16.06%Bi (12.47%),4.83-8.97%Ag(6.39%)and 13.25-13.98% S(13.65%).Its molecular formula is Pb0.76,Bi0.14,Ag0.13,1.03S.No galena so high in Bi has been reported in the literature and this is the first report in China.  相似文献   

16.
Chevkinite specimen from a rare-earth mineral deposit in Sichuan,southwest ofChina have been studied in detail by means of transmission electron microscope(TEM).The selected area electron diffraction(SAED)and convergent beam electron diffraction(CBED)patterns,obtained from different crystal zone axis direction,proved coineidently that the space group of chevkinite is C2/m.Fringe lattice image obser-vation showed the mineral crystal is structurally uniform in microscale,and it is anideal specimen for electron diffraction analysis.The mineral studied here is similar to theone from Bayan Obo,Inner Mongolia,China,in chemical composition and REE distri-bution.The chemical formula of the crystal is(Ce,La,…,Ca)_4 Fe~2-(Fe,Ti,Nb)_2O_8 (Si_2O_7)_2 .From our study,we come to the conclusion that the space group of the natu-ral chevkinite is C2/m,instead of P2_1/a as synthetic one.Up to now,chevkinitecompositionally similar to the synthetic one,in which the complete replacements of Ce,La by Nd and Fe by Mg or Co o  相似文献   

17.
The metamorphic belt of northern New Caledonia represents one of the best-exposed example of fossil Pacific-type subduction zone and a worldwide reference for high-pressure (HP) metamorphism and metamorphic mineral isograds, marked by a gradual evolution from very low-grade lawsonite-bearing to high-grade epidote-bearing eclogite assemblages. Despite the general agreement on the progressive increase in metamorphism, open debates hinge on the tectonic meaning of such mineral isograds, either interpreted as fossilized continuous metamorphic gradients or as major tectonic discontinuities. We present a new and extensive metamorphic dataset acquired by means of Raman spectroscopy of carbonaceous material and pseudosection modeling. Additional PT estimates were also obtained via traditional thermobarometry. Our dataset indicates the occurrence of two tectonometamorphic domains characterized by distinct patterns and significantly modifies the past tectonic interpretation of the HP terranes. The first domain, rich in metasediments, shows a continuous metamorphic gradient starting at ~300 °C and ~0.8 GPa and reaching the blueschist-eclogite transition at 500–520 °C and ~1.8 GPa and is only locally cut by minor tectonic breaks. The second one, rich in metaophiolites, shows a rather constant metamorphism at 520–550 °C and ~2.4 GPa. The two terranes are separated by a conspicuous pressure gap (0.6 GPa, or ~20 km), but no temperature gap exists. We therefore interpret the metamorphic mineral isograds in the blueschist, metasediment-rich unit as a continuous prograde metamorphic gradient corresponding to ~35 km of accreted material (in a cold subduction zone favoring lawsonite stability) later affected by a factor of two decompressional thinning. Only the epidote isograd, which localized strain as a result of fluid release during decompression, reflects regional reequilibrations. Importantly, no significant tectonic break affects the regional distribution of the classical mineral isograds, and the most significant metamorphic break is best depicted by a lithological contrast (metasediment-rich vs. metamafic/ultramafic-rich domains). Comparable patterns are observed in Tethyan-type orogens like the Western Alps or Corsica. This contribution provides useful insights into the mechanisms of exhumation and stacking of HP terrains and mountain building of both Pacific and Tethyan orogenic belts.  相似文献   

18.
Chemical compositions and geochronological data utilising the laser ablation ICP-MS technique are presented for zircon megacrysts found in alluvial gem corundum deposits associated with Upper Cretaceous–Cenozoic alkali basalts in the Inverell district-New England field, New South Wales, eastern Australia. Three localities, Kings Plains, Swan Brook and Mary Anne Gully, produce gem-quality transparent dark brown and yellow zircon megacrysts, mostly under 10 mm in size. Although brown zircon shows relative enrichment in Hf and REE, there are no differences in relative transition metal concentrations between the colours. Chemical homogeneity within a single crystal indicates stable crystallisation conditions. The 206Pb/238U age of zircon megacrysts from these three localities define older and younger groups of 216–174 Ma and 45–37.7 Ma, respectively. The ?Hf values of zircon megacrysts from Kings Plains show +7.51±0.34 in the older group and +10.72±0.31 in the younger group. Swan Brook zircons give +11.54±0.47 and +8.32±0.58, and Mary Anne Gully zircons are +13.67±0.63 and +8.50±0.48, respectively. These zircons from New England alluvial gem deposits have two main formational events around Upper TriassicLower Jurassic and Eocene episodes. Most originated from lithospheric mantle and all were brought-up by later host basaltic magmas.  相似文献   

19.
Argentian mercurian gold,golden-yellow in colour,is a variety of native gold containing Ag and Hg,coccurring as hexagonal and tetragonal crystals in hairy,milk-droplet or irregular forms.Its microhardness Hv=91kg/mm^2,equivalent to 3.04on Mons‘scale,and the reflectance is 70.35%(589nm).Chemical analysis gave:Au 56.05-67.33,Ag18.29-31.06 and Hg 10-14.82%,as well as minor Cu.In a few samples Bi or Fe was also detected.The simplified formula is (Au0.52Ag0.36Hg0.09Cu0.02)0.99.X-ray analysis suggests the mineral is of isometric system,with space group=Oh^5-Fm3m,a0=0.40803nm,V=0.06739nm^3,and Z=4.Argentian mercurian gold occurs in a Ag-multimetal deposit at Xiacun,Baiyu County,Sichuan Province,As observed in the mining district,the mineral is distributed along the fissures of the main metallic minerals pyrite,tetrahedrite,chalcopyrite,arsenopyrite,galena,sphalerite,etc.,or in the sulfide veinlets developed in the.fissures of these minerals.Also found in the mineral deposit are native gold,argentite,sulvanite,bournonite,boulangrite,etc.  相似文献   

20.
LI Xin  ZHANG Xiang 《地质学报》2014,88(Z2):443-444
Please refer to the attachment(s) for more details.  相似文献   

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