共查询到20条相似文献，搜索用时 59 毫秒
1.
Petrography and mineral chemistry of ninety-eight ordinary chondrites from Grove Mountains (GRV), Antarctica, were presented and their.weathering effect, shock metamorphism and type distribution patterns were discussed in this study. Among them, six are unequilibrated ordinary chondrites, including 3 H3 and 3 L3; and 92 meteorites are equilibrated ordinary chondrites, including 24 H-group (13 H4, 10 H5, 1 H6), 64 L-group (2 L4, 44 L5, 18 L6) and 4 LL-group (3 LL4, 1 LL5). Most GRV chondrites (>90%) displayed minor weathering effect (W1 and W2). About half of the meteorites experienced severe shock metamorphism. They commonly contain shock-induced melt veins and pockets. These heavily shocked meteorites provide us with natural samples for study of high-pressure polymorphs of minerals. In addition, the Grove Mountains collection seems to have more abundant unequilibrated and L group ordinary chondrites compared to the US Antarctic meteorite collection which were mainly found along the Transantarctic Mountains. 相似文献
2.
Thirty-two meteorites were collected in Grove Mountains area, Antarctica, by the 15th and 16th Chinese Antarctic Research Expeditions (CHINARE). Petrography and mineral chemistry of these meteorites are reviewed, among which there are one Martian lherzolite, one eucrite, one ungrouped iron meteorite, and six unequili-brated and twenty-three equilibrated ordinary chondrites. An equilibrated ordinary chondrite GRV 98004 ( H5 ) has an unusually low cosmic-ray exposure age. Meteorite concentrating processes in Grove Mountains area are discussed. In addition, future studies on Grove Mountains (GRV) meteorites are proposed. 相似文献
3.
Petrography and mineral chemistry of four carbonaceous chondrites (GRV 020017, GRV 020025, GRV 021579, GRV 022459) collected from the Grove Mountains (GRV), Antarctica, were reported here. All four chondrites are unequilibrated, as indicated by well shaped chondrules and the chemical variations of olivine and low-Ca pyroxene. The modal abundance ratio of matrix/chondrule are 2(GRV 020017), 2.8(GRV 020025), 1.2(GRV 021579), 1(GRV 022459). GRV 022459 has the largest chondrules(0.6-2.0mm). A total of 30 Ca-Al-rich inclusions were found in the four meteorites. Most inclusions were highly altered, with abundant phyllosilicates in the inclusions of GRV 020017 and GRV 020025. On the base of petrography and mineral chemistry, these chondrites are classified as CM2 (GRV 020017 and 020025), CO3 (GRV 021579) and CV3 (GRV 022459). 相似文献
4.
Ureilites are a common group of achondrites with a high abundance of carbon. They probably have a genetic relationship with chondrites, hence provide an insight into origin and evolution of terrestrial planets. A new meteorite-rich region, Grove Mountains (GRV), was found by the Chinese Antarctic Research Expedition, with discovery of 9834 meteorites. Of 2433 meteorites classified, 9 ureilites have been identified. In this paper, we report petrography of 6 of these ureilites. Four ureilites contain graphite and exhibit triangle conjunction and common reduced margins of olivine. GRV 052382 probably experienced heavy shock metamorphism followed by fast cooling, as indicated by mosaic texture or fine-grained granular texture of olivine. GRV 022931 was highly reduced of these ureilites, with olivine as isolated grains in abundant carbonaceous matrix. All 9 ureilites are monomict, and are classified into subtype II (with medium FeO content, Fa15-18) and subtype I (with high FeO content, Fa>18) based on compositions of the cores of olivine. The diverse mineral compositions and petrography of these ureilites suggest that they are not paired and reveal a multi-event history of the parent body. Partial melting of the parent body produced carbon-rich magma, followed by crystallization of graphite and silicates. Later, graphite was partially inverted to diamond by shock events. Reburial of the shocked debris experienced various degree of thermal metamorphism. Finally, these rocks were excavated from the parent asteroid and ejected into Earth-cross orbit by another impact event. 相似文献
5.
Shock effects of 93 Grove Mountains (GRV) ordinary chondrites were studied in this work, including fracture, various types of extinction, and recrystallization of silicates observed under optical microscopy. Shock-induced veins and pockets show various microtextures, decomposition and phase transformation of minerals. The confirmed high-pressure polymorphs of silicates are ringwoodite, majorite, pyroxene glass and maskelynite. Based on the shock effects and assemblages of high-pressure minerals, shock stages of all of 93 GRV chondrites were classified. In comparison with literature, the Grove Mountains meteorites have a higher fraction (23 out of 93) of heavily shocked samples (S4-S5). Most of the heavily shocked meteorites are L group (22 out of 23), except for one H chondrite. The distinct shock metamorphism between H and L groups may indicate different surface properties of their parent bodies. In addition, there is relationship between petrologic types and shock stages, with most heavily shocked samples observed in equilibrated ordinary chondrites (especially Type 5 and 6). 相似文献
6.
GRV 90027 is a Martian lherzolitic shergottites (L-S) containing poikilitic, non-poikilitic, and melted pocket components. GRV 99027 is mainly composed of olive (55 vol%) and pyroxene (37.5 vol%), with minor maskelynite (6 vol%) and chromite (1.5 vol%), and trace whitelockite and troilite, ect. In this paper, the mineralogy and petrology of GRV 99027 are reported; in addition, the geochemical characteristics of the REEs and H isotopes in the GRV 99027 are also further investigated. The ΣREE in GRV 99027 is relatively low; HREEs are enriched in olivine and pyroxene grains; LREEs are enriched in plagioclase with a high positive Eu anomaly. High ΣREE value is found in rare mineral whitlockite (less than 0.2 vol%), LREE≈HREE, and whitlockite has a negative Eu anomaly. The REE distribution patterns of the whole -rock of GRV 99027 is similar to but different from that of other L-S Martian meteorites, indicating that they came from different location of Mars. GRV 99027 has a high δD value. Different water-bearing minerals give different contribution for δD value. The δD of phosphates generally does not correlate with water content, and δD has a weak negative correlation with water content. GRV 99027 can be classified as an L-S Martian meteorite based on mineralogical assemblage patterns, REE distribution patterns, and hydrogen isotope. The isotope data of Sr, Nd, Pb, Os and REE from other L-S Martian meteorites were collected to discuss the formation history of the GRV 99027. Similar to other L-S Martian meteorites, GRV 99027 originated from part of Mar's mantle; during one strong impact event about 4M years ago, the meteorites were ejected from deep mantle into space, and traveled for a different duration in space (indicated by different cosmic exposure time), and captured by the Earth later in different time, ultimately falling on the Antarctica as L-S Martian meteorites. 相似文献
7.
Meteorites are the extraterrestrial rocks, which provide insights into the origin and evolution of the solar system. During the past half century, a great number of meteorites has been discovered on the Antarctic Ice Sheet, confirming that the Antarctica is the most important meteorite concentration area on the earth. Since the first four Antarctic meteorites were found in Grove Mountains in 1998, a total of 9834 meteorites have been collected by four subsequent expeditions. It opens a new field of meteorite study in China, and also accumulates a great deal of scientific samples for China. Recently, classification of Grove Mountains meteorites has been carried out for 6 years, and made following progresses: (1) 2433 meteorites, which include many special meteorites, e.g. Martian meteorites, ureilites and carbonaceous chondrites, have been classified. (2) the Antarctic meteorite curation and the sample sharing system are set up preliminarily. (3) the classification procedure, the management of meteorite samples, and the application procedure for the Antarctic meteorites are completed after the systematic classification during these years. (4) young generation researchers on meteorite are trained through the cooperation of many universities and institutes on meteorite classification. 相似文献
8.
The GRV 024516 and GRV 024517 meteorite samples collected from Grove Montains,Antactica are ureilite and H5 ordinary chondrite,respectively.Based on the study of mineralogy-petrology,the cosmic-ray exposure ages and gas retention ages of these two meteorites were determinated and calculated.Their cosmic-ray exposure ages are 33.3 Ma,51.7 Ma,and gas retention ages are 1936.8 Ma and 3720 Ma,respectively.The ureilite contains diamond,graphite and amorphous C,which are mainly carrier of noble gases indicating obviously shock metamorphism effects,which induced 40Ar partial loss.The H5 chondrite indicates thermal metamorphism of parent body,its gas retention age fall the range between 3220 Ma and 4510 Ma of the least shocked H5 chondrites 相似文献
9.
Grove Mountains (GRV) 051523 is a newly identified eucrite, consisting mainly of coarse-grained pyroxene (62.9 vol%) and plagioclase (34.2 vol%), with less abundant opaque minerals (2.7 vol%), minor silica and tiny FeO-rich olivine (Fa75). Coarse-grained pyroxenes show exsolution of augite lamellae in pigeonite or vice versa. Width of most exsolution lamellae in pyroxenes is 1-3 μm. Opaque minerals are mainly chromite, ilmenite and sulfides. The meteorite was heavily shocked, as indicated by breccias and melt veins. Coarse-grained pyroxenes commonly contain abundant tiny or needle-like chromite inclusions with orientation, probably due to heavy shock events. Pyroxenes in various petrographic occurrences exhibit highly homogeneous compositions, indicating that GRV 051523 experienced intense thermal metamorphism in the parent asteroid 4 Vesta. GRV 051523 is classified as Type 5-6. This new eucrite will have additional constraints on chemical composition, magmatic differentiation, multi-stage shock and thermal history of Vesta. 相似文献
10.
Progress in study of Chinese Antarctic Meteorites 总被引：1，自引：0，他引：1
This paper reviews and summarizes the Chinese Antarctica meteorite search, classification and research. During the past four antarctic explorations, a total of 9834 meteorites were collected in the Grove Mountains region. Among them, 2431 meteorites were classified by the end of 2008. So far, 684 meteorites have been officially published in the Meteoritical Bulletin, Meteoritical Society, including 2 martian meteorites, 2 eucrites, 6 ureilites, 5 mesosiderites, 1 pallasite, 1 iron and 10 carbonaceous chondrites. Comprehensive studies were carried out on a number of these rare type meteorites. In addition, we propose to continue the meteorite searching project in Grove Mountains and other regions in Antarctica. We also suggest several key topics of the future researches on the Chinese Antarctic meteorites. 相似文献
11.
Concentrations of Cr, Co, Ni, Cu, Ga, Ge, As, Sb, W, Re, Ir, Pt and Au of two ungrouped iron meteorites, Grove Mountains （GRV） 98003 from Antarctica and Ujimqin, were measured using instrumental neutron activation analysis. According to the bulk chemistry, GRV 98003 is classified as a member of ⅠAB group, and Ujimqin as a unique one of ⅠAB iron meteorite complex. The elemental abundance pattern and correlation between elements （e. g. Ni-Au, Co-Au, As-Au, W- Au, Cu-Au, Sb-Au） of GRV 98003 are similar with those of NAW 468 （ⅠAB）, but significantly depleted in refractory siderophile elements （ Re, It） and moderate volatile elements （Ca, Ge） relative to the latter. In addition, we reclassify Nantan （ⅢCD） as a member of ⅠAB main group （MG） and Yongning （ⅠA） as a unique iron meteorite related with IAB iron meteorite complex. 相似文献
12.
The colorful satellite image maps with the scale of 1∶100 000 were made by processing the parameters-on-satellite under the condition of no data of field surveying. The purpose is to ensure the smooth performance of the choice of expedition route, navigation and research task before the Chinese National Antarctic Research Expedition (CHINARE) first made researches on the Grove Mountains. Moreover, on the basis of the visual interpretation of the satellite image, we preliminarily analyze and discuss the relief and landform, blue ice and meteorite distribution characteristics in the Grove Mountains.
Key words Grove Mountains, parameters-on-satellite, satellite image, digital mapping, blue ice, meteorites distribution. 相似文献
13.
The serum thyroid hormone and plasma catecholamine were examined in 18 male and 2 female members of the Chinese Antarctic Expedition (who spent the 2000 or 2001 austral winter at the Great Wall Station) . The changes of serum thyroid hormone i. e. total thyroxine (TT4) and free T4 (FT4) , total triodothyronine (TT3) and freeT3 ( FT3 ) , thyroid stimulating hormone ( TSH ) and plasma catecholamine, including norepinephrine (NE) , epinephrine ( E) and dopamine ( DA ) , were investigated by Chemoluminescence Immunoassay (CLIA) and High Performance Liquid Chromatography with electrochemical detection (HPLC-ECD) . Samples were taken at different time; (1)1 day before departure to Antarctica (16th expedition 1999/12/ 09; 17th expedition 2000/12/06). (2) 1 day after returned to China after living 54 weeks in Antarctica ( 16th expedition 2000/12/25 ; 17th expedition 2001/12/25 ). Comparing the data of before departure and returned, results showed that there was a significant decrease in the contents of TT4 (P < 相似文献
14.
随机微分方程的Euler数值解法 总被引：1，自引：0，他引：1
胡建成 《成都信息工程学院学报》2007,22(3):388-393
基于常微分方程(ODEs)的Euler数值解法,提出了求解一类随机常微分方程(ODEs)的3种Euler格式:显Euler格式,半隐Euler格式和隐Euler格式.讨论了3种Euler格式的T-稳定条件,并给出了部分数值实验结果. 相似文献
15.
利用Bedmap2数据与中国第29次南极科学考察期间获取的冰雷达数据,在中山站至Dome A断面的Gamburtsev山脉地区首次构建11.3 km×11.5 km南极局部冰盖三维模型。着重介绍三维模型建立过程中的数据处理,其中冰雷达数据采集首次采用中国自主研发的冰雷达系统。详细阐述了冰雷达数据的处理流程,包括数据预处理、常规图像修正技术以及冰下地形获取,得到冰下基岩埋深和冰盖内部等时层埋深,插值得到100 m分辨率的冰下基岩DEM（海拔1 729 m~2 718 m）和等时层DEM（海拔2 601 m~2 950 m）,利用南极Bedmap2冰表面栅格影像得到100 m分辨率的冰盖表面DEM（海拔3 679 m~3 745 m）。结合冰盖内外部数据处理结果,构建包含冰盖表面、冰盖内部等时层和冰下基岩地形特征的三维模型,并对模型进行检验,对冰盖内外部地形特征进行初步分析。 相似文献
16.
1997年降落在山东省鄄城县的陨石雨,是橄榄石-古铜辉石球粒陨石。该陨石中的金属矿物主要为铁纹石和陨硫铁,其次为镍纹石,金属矿物呈填隙状分布于以橄榄石和古铜辉石为主的硅酸盐矿物粒间及球粒周围。陨石中可见由铁纹石和镍纹石组成的显微蠕虫状连晶,是陨石中金属矿物在降温冷却过程中发生固溶体分离作用而成。陨石中金属矿物的分布特征... 相似文献
17.
国际南极大地参考框架的构建与进展 总被引：10，自引：2，他引：8
回顾了南极大地参考框架发展的历史,总结了由国际南极研究科学委员会(SCAR)组织的历次南极地区大地测量观测活动的成果,并结合2007~2008第四次国际极地年(IPY)对南极大地参考框架的前景进行了展望,其中重点介绍了我国对构建南极大地参考框架的贡献。 相似文献
18.
Cheng Shaohua Zhang Xia Zhu Jiangang Zhao Weiquan Ling Xiaoliang Li Shenggui Fang Binxian Zhao Huili 《极地研究(英文版)》2000,11(1)
Based on the general framework of ADDS (Antarctic Data Directory System) established by SCAR-COMNAP ad hoc Planning Group on Antarctic data management, the CN—ADDS (Chinese Antarctic Data Directory System ) project is going on, of which the research and activity keeps to the available method and technique in ADDS development and allows for the Chinese specific status in Antarctic data management as well. At present, authoring and submitting timely Antarctic data directory in China is one of the key issues that is to be dealt with necessarily. This paper aims at studying the technical procedure in collecting, processing, examining and submitting data directory. In additional, it also discusses the efficient collection of data directory, which needs the effort of administrative and technical support 相似文献
19.
Snow samples collected from a 50 m firn core and two snow pits along the route of the 1996/1997 Chinese First Antarctic Inland Traverse Expedition in Princess Elizabeth Land, East Antarctica, have been analyzed for chemical composition and oxygen isotope ratio. Analyzing the relationship between the concentration and flux of major ions and accumulation rate can draw the following conclusions. 1 ) The concentrations of major ions in the atmosphere in the study region is big enough so that the concentrations of the ions do not vary with snow accumulation rate, that is to say, the concentrations of major chemical species are independent of snow accumulation rate. 2) The results of analyzing the depositional styles of major chemical species suggest that wet deposition dominates the major ions flux. In addition, there is no apparent correlation between nssSO2-4 fluctuations and isotope profile. This would indicate the short-term climatic effect of volcanism is not evident in the region. 相似文献
20.
Antarctic krill (Euphasia superba Dana) is a key organism of the Antarctic marine ecosystem and a potential fishery resoure. Its ecology was the major biological
project in the First Chinese Antarctic Expedition (1985). Acoustic observations and IKMT tows were madecin waters north and
west of Antarctic Peninsula. Environmental factors were also observed. Analyses of the population structure, i.e. the sex
percentage distribution and other data obtained show that among the 3,640 individuals of determinable sex, only 38.1% were
males and that the larger the body length the smaller the percentage of males, for example, male percentage dropped to 8.3%
for size group >55 mm. The population's relations to environmental factors are also discussed.
Contribution No. 1711 from the Institute of Oceanology, Academia Sinica. 相似文献