广西南丹铁陨石雨的发现

The distribution and exterior characters of each individual meteorite are presented for the iron meteorite shower in Nantan County, Kwangsi Chuang Autonomous Regiou,China. Nineteen iron meteorites have been found up to date, umounting approximately to 9,500 kg in total weight and spreading over an area of about 30 square kilometers. As compared with other iron meteorites known in China, they are much larger in size and contuin much more mineral species. It is also interesting to note that a complete sample of various parts of a primitive meteorite can be expected. The discovery of this meteorite shower is considered to be of significant value in science.     

几块铁陨石的火花源质谱分析

Iron meteorites from Nandan, Guangxi ; Wushike, Xinjiang; Shangdu, Hebei and Huangling, Hubei are investigated with a spark souree mass speetrometer for their Cr, Ni, Co, Cu, Zn, Ga, Ge, As, Mo, Ru, Rh, Pd, Os and Ir contents. The accuracy of the results and the factors affecting it are discussed. It is preliminarily concluded,while textural evidences of these meteorites are also taken into account, that the Nandan, Wushike and Shangdu meteorites belong to IA, Ⅲ .4 and ⅢE groups respectively. The Ni, Ga and Ge contents in the Huangling iron meteorite come close to that of mesosiderites.     

我国古代陨石的研究

Preliminary results of our study an ancient meteorite records by the end of the Ching dynasty are presented in the present paper. Early in 645 B.C. there were formal records on meteorite falls and cosmoganesis of meteorites. The utinization of iron meteorites for making weapons alloyed with bronze has a history of more than 3000 years (in the Shang and Zhou dynasties). By the time of 1064 (in the Sung dynasty) iron meteorites were well doeum anted. The geographical distribution and falling time of meteorites are also mentioned. The maximum number of meteorite falls was recorded in May and June against the minimum number in December in a year.33 serious calamities caused by meteorite f alls themselves, and several interesting records on meteorite falls are also described in this paper.     

宁波铁陨石宇宙成因核的测定

The Ningbo iron meteorite fell near Ningbo, Chekiang province, on October 4,1975. 103 days later, γ-ray spectrum of the meteorite, was undestructively measured by a low-level γ-ray spectrometer. It is shown that the specific activity of Mn^34 present in the Ningbo iron meteorite is ap proximately close to that of Mn^34 in the Bogou and Aroos meteorites, while the specific activity of Co^37 seems to be higher in the Bogou and Aroos than in the Ningbo.     

西乌珠穆沁陨石和渑池陨石的初步研究

The Xi Ujumqin meteorite fell in Aug. 1980 at Xi Ujumqin County, Nei Monggol, China.This chondrite can be classified as L6 type based on the bulk chemical analysis (6wt% metal iron, 24% total iron, olivine Fa-26) and the textural feature of complete intergrowth of the chondrules with the matrix, The Mianchi meteorite is a type Hs chondrite that fell in Sep, 1980 at Mianchi County,Henan, China. Apart from porphyritic, barred, radial, cryptocrystanine chondrules, many intermediate-type or mixed-type chondrules are observed in the Mianchi meteorite under the microscope. It is suggested that the origin of chondrules showing different textures depend on the primeval compositions and cooling rates,     

Analysis of platinum-group elements in drill core samples from the Meishan Permian-Triassic boundary section,China

There is a long-standing controversy of what triggered the extinction at the Permian-Triassic boundary, the most severe mass extinction in the geologic record, including flood basaltic volcanism and/or bolide impact hypothesis. In order to clarify various pieces of evidence for the mass extinction event at the Permian-Triassic boundary, some researchers from some laboratories throughout the world have made a comprehensive study on a group of samples from the Meishan area of China. Some fresh core samples from the Permian-Triassic boundary in the Meishan area were analyzed in this study. The results showed that there is no Ir anomaly, Moreover, the PGEs patterns of those samples show obvious differentiation characteristics, that is different from the case encountered in meteorites. So no evidence supports the hypothesis of extraterrestrial impact. In contrast, the PGEs patterns are similar to those of Siberian and Emeishan basalts, which indicates that those PGEs are derived mainly from the basalts, lending a support to the correlation between mass extinction at the Permian-Triassic boundary and flood basaltic volcanism. This study has also confirmed the results for samples from section C prior to the analysis of the samples.     

Noble gases,nitrogen and cosmic ray exposure age of the Sulagiri chondrite

The Sulagiri meteorite fell in India on 12 September 2008,LL6 chondrite class is the largest among all the Indian meteorites.Isotopic compositions of noble gases(He,Ne,Ar,Kr and Xe) and nitrogen in the Sulagiri meteorite and cosmic ray exposure history are discussed.Low cosmogenic(~(22)Ne/~(21)Ne)_c ratio is consistent with irradiation in a large body.Cosmogenic noble gases indicate that Sulagiri has a 4πcosmic-ray exposure(CRE) age of 27.9 ± 3.4 Ma and is a member of the peak of CRE age distribution of IX chondrites.Radiogenic ~4He and ~(40)Ar concentrations in Sulagiri yields the radiogenic ages as 2.29 and4.56 Ca,indicating the loss of He from the meteorite.Xenon and krypton are mixture of Q and spallogenic components.     

吉林陨石雨样品中宇宙成因核素Mn^54、Co^57和K^40的深度变化

Cosmogenic radioactive nuclides, particularly K^40, Mn^54 and Co^57 are measured in meteorites Nos. Ⅰ,Ⅱ and Ⅴ from the Kirin meteorite shower which is very seldom to be met with in world history in the sense of its scale. Brief accounts are given of the distribution of cosmogenic nuclides with depth, the characteristics of cosmicray induced reactions and that of target nuclides, the energy region of bombarding particles, and the relative positions of meteorites Ⅰ,Ⅱ and Ⅴ with respect to the original meteoroid. The variations in Mn^54, Co^57 and K^40 with depth in No. I Kirin meteorite provides an excellent example for studies in this field.     

月岩（70017—291）的X光电子能谱（XPS）初步研究

Using X-ray photoemission spectroscopy (XPS), the Preliminary results on the lunar basalt sample (70017-291)are shown in the paper. Major elements (O, Si,Al, Fe, Ca, Mg, Ti, etc.) of the lunar sample are similar to that of the Jilin meteorite and the Allende meteorite. The valence of iron in the sample has also been studied in detail. The authors suggest that Fe^ may be differentiated from Fe^ in the XPS spectra in terms of the satellite lines of Fe(2p3/2).     

Heavy metal retention by soil mineral phases during a potential soil contamination by sewage sludge

The immobilization conditions of heavy metals （Ni, Cu, Zn, Pb） potentially released from sewage sludge to soils were examined. Competitive adsorption experiments, sequential extraction and analytical electron microscopic studies were performed on soils with different compositional characteristics to gain information about the interaction and association of metals with soil minerals. The results showed that Cu and Pb can be characterized by a preferred adsorption in contrast to Zn and Ni independent of initial metal concentrations, ratios, and soil composition. Precipitation is the dominating retardation process in the sample containing carbonates, but it is also characteristic of metals with inhibited adsorption in samples free of carbonate. Both Cu and Pb show high affinity towards organic matter. Differences in metal affinities towards different clay minerals show the immobilization of Cu rather by specific adsorption and that of Pb rather by ion exchange. According to the sequential extraction studies the role of ion exchange is the most important process for the retardation of Zn, and in the sample containing montmorillonite. The specific adsorption is significant mostly for Cu and Pb, and primarily in samples rich in organic matter and containing vermiculite. The co-precipitation of metals with Fe-Mn oxides is significant primarily for Cu, but in some cases Pb and Zn can be also found in this fraction. In general, the strength of immobilization for the studied metals is as follows： Cu〉Pb〉Zn〉Ni. Significantly higher metal adsorption was found by the phases in the sample containing carbonates, as well as in samples characterized by the close association of clay minerals and iron oxides. Smectite and vermiculite are the most important adsorbents in soils for all of the metals. Additionally, iron-oxides immboilize significant amounts of Cu and Zn, too.     

Sodium-rich volcanic rocks and their relationships with iron deposits in the Aqishan-Yamansu belt of Eastern Tianshan,NW China

The volcanic rocks hosting the iron deposits in the Aqishan–Yamansu metallogenic belt are sodium-rich.The geochronology,petrography,and geochemistry of minerals and sodium-rich rocks as well as the relationship between these rocks and the iron deposits are studied.Geochemically,the ore-hosting volcanic rocks are sodiumrich(the averages of Na2O and Na2O/K2O are 4.31 wt.%and 8.56,respectively)and belong to the calc-alkaline series.They are enriched in LREEs and LILEs(Ba,U,K,and Sr),but depleted in HFSEs(Nb,Ta,and Ti).SHRIMP zircon U–Pb dating of the crystal tuff in the Aqishan Formation and the dacite in the Tugutu Bulak Formation yields ages of 337.5
2.3 Ma(n?15,MSWD?0.85)and 313.0
3.3 Ma(n?13,MSWD?0.74),respectively,indicating that the sodium-rich volcanic rocks formed from the early–late Carboniferous.Electron microprobe data from plagioclases demonstrate that albites and/or oligoclases were formed in the basic–intermediate–acid volcanic rocks.Two stages of albitization are identified,and the latter is likely attributed to the dissolution of iron in the Aqishan–Yamansu belt.The sodium-rich volcanic rocks probably formed by the interaction between volcanic lava and seawater after volcanoes erupted on the seafloor;meanwhile,the albites formed by element substitution in a low-metamorphic environment.The spatiotemporal coupling relationship between sodium-rich volcanic rocks and iron deposits in the Aqishan–Yamansu belt is favorable.Iron dissolved from the dark minerals of basic–intermediate volcanic rocks through sodium metasomatism is one of the material sources for the iron deposits.     

A New Martian Meteorite from Antarctica:Grove Mountains (GRV) 020090

Reported in this paper are the petrology and mineral chemistry of GRV 020090, the second Martian meteorite collected from the Grove Mountains, Antarctica. This meteorite, with a mass of 7.54 g, is completely covered by a black and glazy fusion crust. It has two distinct textural regions. The interstitial region is composed of euhedral grains of olivine, pigeonite, and anhedral interstitial maskelynite, with minor chromite, augite, phosphates and troilite. The poikilitic region consists of three clasts of pyroxenes, each of which has a pigeonite core and an augite rim. A few grains of subhedral to rounded olivine and euhedral chromite are enclosed in the pyroxene oikocrysts. GRV 020090 is classified as a new member of lherzolitic shergottites based on the modal composition and mineral chemistry. This work will shed light on the composition of Martian crust and magmatism on the Mars.     

Discovery of Cosmic Spherules from the Mesoproterozoic Strata and its Significance—in Case of the Ming Tombs Area, Beijing

This study covers cosmic spherules derived from the Mesoproterozoic Dahongyu Formation in the Ming Tombs area, Beijing. The cosmic spherules include iron oxide cosmic spherules, carbonaceous chondrites, and atomic iron “steely bead”-shaped cosmic spherules. The mineral assemblage of silicon carbide, forsterite, zircon, and glass spherules and fragments were picked from melt-silicified carbonate of the Mesoproterozoic Dahongyu Formation (ca. 1625 Ma). Cosmic spherule assemblages are solely discovered from sedimentary rocks in China. Platinum group elements (PGE) were determined for the first time in cosmic spherules and associated minerals. PGE comparative observation between meteorite and cosmic spherules is presented in this study. It is recognized that an extraterrestrial meteorite impact event might have occurred in the Dahongyu Stage. The main evidence is a large number of iron cosmic spherules in silicified oncolitic limestone, and associated cosmic silicon carbide, glass spherules, and fragments, as well as the presence of forsterite. The impact-volcanic crater is characteristic of a big black shale block dropped into the bended silicified limestone.     

Burial Records of Reactive Iron in Cretaceous Black Shales and Oceanic Red Beds from Southern Tibet

One of the new directions in the field of Cretaceous research is to elucidate the mechanism of the sedimentary transition from the Cretaceous black shales to oceanic red beds. A chemical sequential extraction method was applied to these two types of rocks from southern Tibet to investigate the burial records of reactive iron. Results indicate that carbonate-associated iron and pyrite are relatively enriched in the black shales, but depleted or absent in red beds. The main feature of the reactive iron in the red beds is relative enrichment of iron oxides （largely hematite）, which occurred during syn-depostion or early diagenesis. The ratio between iron oxides and the total iron indicates an oxygen-enriched environment for red bed deposition. A comparison between the reactive iron burial records and proxies of paleo-productivity suggests that paleo-productivity decreases when the ratio between iron oxides and the total iron increases in the red beds. This phenomenon could imply that the relationship between marine redox and productivity might be one of the reasons for the sedimentary transition from Cretaceous black shale to oceanic red bed deposition.     

Methods for Calculation of Geogenetic Depth

Some current methods for the calculation of the geogenetic depth are based on the hydrostatic model, it is induced that the depth in certain underground place is equal to the pressure divided by the specific weight of rock, on the assumption that the rock is hydrostatic and overlain by no other force but gravity. However, most of rock is in a deformation environment and non-hydrostatic state, especially in an orogenic belt, so that the calculated depth may be exaggerated in comparison with the actual depth according to the hydrostatic formula. In the finite slight deformation and elastic model, the relative actual depth value from the 3-axis strain data was obtained with the measurement of strain including that of superimposed tectonic forces but excluding that of time factor for the strain. If some data on the strain speed are obtained, the depth would be more realistically calculated according to the rheologicai model because the geological body often experiences long-term creep strains.     

The production of iron oxide during peridotite serpentinization: Influence of pyroxene

Serpentinization produces molecular hydrogen(H2)that can support communities of microorganisms in hydrothermal fields;H2 results from the oxidation of ferrous iron in olivine and pyroxene into ferric iron,and consequently iron oxide(magnetite or hematite)forms.However,the mechanisms that control H2 and iron oxide formation are poorly constrained.In this study,we performed serpentinization experiments at 311℃ and 3.0 kbar on olivine(with 5% pyroxene),orthopyroxene,and peridotite.The results show that serpentine and iron oxide formed when olivine and orthopyroxene individually reacted with a saline starting solution.Olivine-derived serpentine had a significantly lower FeO content(6.57±1.30 wt.%)than primary olivine(9.86 wt.%),whereas orthopyroxene-derived serpentine had a comparable FeO content(6.26±0.58 wt.%)to that of primary orthopyroxene(6.24 wt.%).In experiments on peridotite,olivine was replaced by serpentine and iron oxide.However,pyroxene transformed solely to serpentine.After 20 days,olivine-derived serpentine had a FeO content of 8.18±1.56 wt.%,which was significantly higher than that of serpentine produced in olivine-only experiments.By contrast,serpentine after orthopyroxene had a slightly higher FeO content(6.53±1.01 wt.%)than primary orthopyroxene.Clinopyroxene-derived serpentine contained a significantly higher FeO content than its parent mineral.After 120 days,the FeO content of olivine-derived serpentine decreased significantly(5.71±0.35 wt.%),whereas the FeO content of orthopyroxene-derived serpentine increased(6.85±0.63 wt.%)over the same period.This suggests that iron oxide preferentially formed after olivine serpentinization.Pyroxene in peridotite gained some Fe from olivine during the serpentinization process,which may have led to a decrease in iron oxide production.The correlation between FeO content and SiO_2 or AI_2 O_3 content in olivine-and orthopyroxene-derived serpentine indicates that aluminum and silica greatly control the production of iron oxide.Based on our results and data from natural serpentinites reported by other workers,we propose that aluminum may be more influential at the early stages of peridotite serpentinization when the production of iron oxide is very low,whereas silica may have a greater control on iron oxide production during the late stages instead.     

Chemical Forms of Heavy Metals in Carbonate—Derived Laterite and Enrichment of Its Iron Oxide Minerals

In this paper the seven-step continuous extracting method was employed in the study of chemical forms of the six heavy metals Co,Zn,Pb,Cu,Cr and Mn,The result shows that the etals in the laterite are present in the chemical form of crystalline iron oxides and residues,and they are transformed towared organic and exchangeable forms in the surface soil.Linear regression analysis indicates that the above heavy metals have a positive correlation with the crystalline iron oxide minerals.The crystalline iron oxide minerals have a very important role to play in the enrichment of heavy metals,especially the solid components in the laterite.     

Temporal and Spatial Distribution of Elements in a Small Catchment, and Buffer Function of Wetland in Longgan Lake, China

Wetland is the conjunction of lake and terrene where human activities are concentrated. From the viewpoints of material transport and cycling in the terrene-lake system, wetland is the buffer where sand and mud, heavy metals, pollutants and nutrients are tarried. In this paper, we provide a case study based on the temporal and spatial distribution of elements in the Wangling River catchment, a small sub-catchment of Longgan Lake in the middle reaches of the Yangtze River. We have found that wetland can buffer major heavy metals such as Cr, Cu, etc.significantly, but has a little buffer function to some active elements such as Fe and Mn, which are always transported as solutions. Human activities not only influence the distribution of elements, but also weaken the buffer function of wetland. Intensive human activities in the Longgan Lake area in the past 70 years have been recorded in stream, wetland and lake sediments, especially the human activity events such as deforesting and reclaiming on a large scale in 1958 and the 1980‘s. Human activities caused the increase of sedimentation rates since the 1950‘ s, as well as the increase of elements‘ concentrations. The extensive use of fertilizers and pesticides since the 1960‘ s have led to the increase of total P concentrations. Increasing SO2 emission accelerate the process of cation exchange in soil, and enhance the leaching of Mn out of soils. Permanent storing of water causes the soil gleyification that also intensifies the leaching of Mn.These are two major reasons for the obvious increase of manganese concentrations in recent 20 years in Longgan Lake. Intensive human activities since the 1950s‘ have intensified the population in this region and thus destroyed the buffer function of wetland.     

包裹体研究与石碌铁矿成因的探讨

Shilu iron deposit is one of the highly economically important rich iron deposits in China. Based upon the research results on its ore composition and fluid inclusions, it can be reasonably explained that the genesis of this iron deposit is such that marine voleanic sediments there suffered later regional metmnorphism and hydrothermal reformation. The temperature of regional metamorphism ranges from 465 to 536℃,while that of hydrothermal reformation from 344 to 396℃. The latter seems to be related to the migmatization of Zhan Xian stock near Shilu iron deposit, Due to the hydrothermal reformation, the ore-forming materials were mobilized and transfered from the marine sedimentary rocks, subsequently redepositing and concentrating as a rich iron deposit in the present site.     

M1 site splitting due to Next Nearest Neighbor effects and ferric iron in tetrahedral site in clinopyroxene megacrysts

It is well known that in pyroxene structure,there are two metal sites,M1 and M2.Generally speaking,Ferrous iron in each of these sites would normally be expected to give rise to a doublet,However,anomalies have been found in the relative areas of the peaks in the room temperature spectra of some clinopyroxene(CPX)when the above assignment is followed.According to the calculation of Next Nearest Neighbor configurations of divalent cations in M1,we found that the four configurations of M1 can be divided into two groups.One group is 3Ca configuration that increases with the content of Ca(p.f.u);the other group is made up of three No-3Ca configurations that decrease with the content of Ca.The two groups contribute to the spectrum structure of M1.so in this study we fit two doublets for ferrous iron in M1.Though there were several reports on Fe^3 in tetrahedral site previously,it was not sure that Fe^3 occupies the T site is a universal fact in CPX,despite of the content of Al.We found that the Fe^3 in the T site fitted by Moessbauer spectroscopy is negatively correlated to the Si content in the T site and positively correlated to the Fe^3 in the T site estimated on the supposition that Fe^3 and Al occupy the T site randomly.If it is true.it is important in the modeling of ion exchange geobarometries and geothermomeries.