Meteoritics最新文献

{"title":"Noble gases in presolar diamonds II: Component abundances reflect thermal processing","authors":"G. Huss, R. Lewis","doi":"10.1111/J.1945-5100.1994.TB01095.X","DOIUrl":"https://doi.org/10.1111/J.1945-5100.1994.TB01095.X","url":null,"abstract":"— Using the isotopic compositions derived in Huss and Lewis, 1994a (Paper I), abundances of the P3, HL, and P6 noble-gas components were determined for 15 diamond separates from primitive chondrites of 8 chondrite classes. Within a meteorite class, the relative abundances of these components correlate with the petrologic subtype of the host meteorite, indicating that metamorphism is primarily responsible for the variations. Relative abundances of P3, HL, and P6 among diamond samples can be understood in terms of thermal processing of a single mixture of diamonds like those now found in CI and CM2 chondrites. With relatively gentle heating, primitive diamonds first lose their low-temperature P3 gases and a “labile” fraction of the HL component. Mass loss associated with release of these components produces an increase in the HL and P6 content of the remaining diamond relative to unprocessed diamond. Higher temperatures initiate destruction of the main HL carrier, while the HL content of the surviving diamonds remains essentially constant. At the same time, the P6 carrier begins to preferentially lose light noble gases. Meteorites that have experienced metamorphic temperatures ≳650 °C have lost essentially all of their presolar diamond through chemical reactions with surrounding minerals. \u0000 \u0000 \u0000 \u0000The P3 abundance seems to be a function only of the maximum temperature experienced by the diamonds and thus is independent of the nature of the surrounding environment. If all classes inherited the same mixture of primitive diamonds, then P3 abundances would tie together the metamorphic scales in different meteorite classes. However, if the P3 abundance indicates a higher temperature than do other thermometers applicable to the host meteorite, then the P3 abundance may contain information about heating prior to accretion. Diamonds in the least metamorphosed EH, CV, and CO chondrites seem to carry a record of pre-accretionary thermal processing.","PeriodicalId":81993,"journal":{"name":"Meteoritics","volume":"29 1","pages":"811-829"},"PeriodicalIF":0.0,"publicationDate":"1994-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/J.1945-5100.1994.TB01095.X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63672704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Meteoritical Bulletin, No. 77, 1994 November*","authors":"F. Wlotzka","doi":"10.1111/J.1945-5100.1994.TB01104.X","DOIUrl":"https://doi.org/10.1111/J.1945-5100.1994.TB01104.X","url":null,"abstract":"— This Meteoritical Bulletin is again dominated by meteorite finds from hot and cold deserts: 99 from the Nullarbor, 12 from the Sahara, and 35 from Antarctica. Besides 161 ordinary chondrites, it lists 5 irons (Cotton, Hidden Valley, Miles, Tagounite, Tres Castillos), 2 ureilites (FRO90168, Hughes 009), 1 howardite (ALH 88135), 1 CV3 (Axtell), 1 CK4 (Sleeper Camp 006), and 2 enstatite chondrites (ALH 88070, Forrest 033). Three of the meteorites are falls.","PeriodicalId":81993,"journal":{"name":"Meteoritics","volume":"29 1","pages":"891-897"},"PeriodicalIF":0.0,"publicationDate":"1994-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/J.1945-5100.1994.TB01104.X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63672959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Infrared diffuse reflectance spectra of carbonaceous chondrites: Amount of hydrous minerals","authors":"M. Miyamoto, M. Zolensky","doi":"10.1111/J.1945-5100.1994.TB01098.X","DOIUrl":"https://doi.org/10.1111/J.1945-5100.1994.TB01098.X","url":null,"abstract":"Infrared diffuse reflectance spectra (2.53-25 microns) of some carbonaceous (C) chondrites were measured. The integrated intensity of the absorption bands near 3 microns caused by hydrous minerals were compared with the modal content of hydrous minerals for the meteorites. The CM and CI chondrites show larger values of the intergated intensity than those of the unique C chondrites Y82162, Y86720 and B7904, suggesting that the amount of hydrous minerals in the CM and CI chondrites is larger, which supports the contention that hydrous minerals were dehydrated by thermal metamorphism in the unique chondrites. Orgueil (CI) has the largest value of the integrated intensity among the C chondrites we measured and shows a sharp absorption band at 3685/cm (2.71 microns) that is not seen in the spectra of the CM chondrites. There is an excellent correlation between the observed hydrogen content in C chondrites and the integrated intensity. The CM chondrites show a wide variation in the strength of absorption bands at 1470/cm (6.8 microns), despite the similarity in absorption features near 3 micron for all CM chondites. The 1470/cm band could be due to the presence of some hydrocarbons but may also be a result of terrestrial alteration processes.","PeriodicalId":81993,"journal":{"name":"Meteoritics","volume":"29 1","pages":"849-853"},"PeriodicalIF":0.0,"publicationDate":"1994-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/J.1945-5100.1994.TB01098.X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63672643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Authentication controversies and impactite petrography of the New Quebec Crater","authors":"U. Marvin, D. Kring","doi":"10.1111/J.1945-5100.1992.TB01081.X","DOIUrl":"https://doi.org/10.1111/J.1945-5100.1992.TB01081.X","url":null,"abstract":"— A meteoritic origin was proposed for the New Quebec Crater in 1949 on the basis of an aerial photograph showing its unique circularity and raised rim amid Precambrian gneisses of the Canadian Shield. At that time, only those few craters associated with meteorites were generally accepted as of impact origin. When the earliest field expeditions failed to find meteorites or impact products, two leading meteoriticists, Frederick C. Leonard and Lincoln LaPaz, cited the “Chubb” Crater as a flagrant example for which claims of meteoritic origin were advanced without valid proof. They also listed the Lake Bosumtwi Crater in Ashanti (now Ghana) among crater-like features, clearly of non-meteoritic origin, misidentified as meteorite craters. Controversy over the origin these two craters continued for decades. \u0000 \u0000 \u0000 \u0000In Part I of this paper, we trace the investigations that led to the current acceptance of New Quebec as an authentic impact crater. We note that, for reasons that are not entirely clear, a meteoritic origin for the New Quebec Crater achieved wider acceptance at an earlier date than for the Lake Bosumtwi Crater, where petrographic and chemical evidence is more abundant and compelling. \u0000 \u0000 \u0000 \u0000In Part II, we describe the petrography of two impact melt samples from the New Quebec Crater and present new evidence on the degrees of shock metamorphism affecting the accessory minerals: apatite, sphene, magnetite and zircon. Zircon, in particular, shows a range from euhedral grains with no signs of alteration to those decomposed to baddeleyite plus silica.","PeriodicalId":81993,"journal":{"name":"Meteoritics","volume":"43 1","pages":"585-595"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/J.1945-5100.1992.TB01081.X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63664194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aberrations and Angels","authors":"D. Sears","doi":"10.1111/J.1945-5100.1992.TB01070.X","DOIUrl":"https://doi.org/10.1111/J.1945-5100.1992.TB01070.X","url":null,"abstract":"","PeriodicalId":81993,"journal":{"name":"Meteoritics","volume":"27 1","pages":"487-488"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/J.1945-5100.1992.TB01070.X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63663443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineralogy, petrology and geochemistry of carbonaceous chondritic clasts in the LEW 85300 polymict eucrite","authors":"M. Zolensky, R. Hewins, D. Mittlefehldt, M. Lindstrom, X. Xiao, M. Lipschutz","doi":"10.1111/J.1945-5100.1992.TB01082.X","DOIUrl":"https://doi.org/10.1111/J.1945-5100.1992.TB01082.X","url":null,"abstract":"— We have performed a detailed petrologic and mineralogic study of two chondritic clasts from the polymict eucrite Lewis Cliff (LEW) 85300, and performed chemical analyses by INAA and RNAA on one of these. Petrologically, the clasts are identical and are composed of dispersed aggregates, chondrules and chondrule fragments supported by matrix. The aggregates and chondrules are composed of olivine (Fo100–45), orthopyroxene (Wo1–2En98–60), plus some diopside. The matrix consists of fine-grained olivine (Fo60–53), and lesser orthopyroxene and augite. Fine-grained saponite is common in the matrix. The bulk major element composition of the matrix is identical in both clasts and similar to that of CM, CO and CV chondrites. The bulk composition of the clast studied by INAA and RNAA shows unusual abundance patterns for lithophile, siderophile and chalcophile elements but is basically chondritic. The INAA/RNAA data preclude assignment of the LEW 85300,15 clast to any commonly accepted group of carbonaceous chondrite. The unusual rare earth element abundance pattern may, in part, be due to terrestrial alteration.","PeriodicalId":81993,"journal":{"name":"Meteoritics","volume":"27 1","pages":"596-604"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/J.1945-5100.1992.TB01082.X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63664274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large meteorite impacts and planetary evolution, 1992 August 31, -September 2, Sudbury, Canada","authors":"R. Grieve","doi":"10.1111/J.1945-5100.1992.TB01072.X","DOIUrl":"https://doi.org/10.1111/J.1945-5100.1992.TB01072.X","url":null,"abstract":"","PeriodicalId":81993,"journal":{"name":"Meteoritics","volume":"24 1","pages":"489-489"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/J.1945-5100.1992.TB01072.X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63663666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An analysis of differential impact melt‐crater scaling and implications for the terrestrial impact record","authors":"R. Grieve, M. Cintala","doi":"10.1111/J.1945-5100.1992.TB01074.X","DOIUrl":"https://doi.org/10.1111/J.1945-5100.1992.TB01074.X","url":null,"abstract":"— It has been known for some time that the volume of impact melt (Vm) relative to that of the transient cavity (Vtc) increases with the magnitude of the impact event. This paper investigates the influence that this phenomenon has on the nature of terrestrial impact craters. A model of impact melting is used to estimate the volume of melt produced during the impact of chondritic projectiles into granite targets at velocities of 15, 25, and 50 km S−1. The dimensions of transient cavities formed under the same impact conditions are calculated from current crater-scaling relationships, which are derived from dimensional analysis of data from cratering experiments. Observed melt volumes at terrestrial craters are collated from the literature and are paired with the transient-cavity diameters (Dtc) of their respective craters; these diameters were determined through an established empirical relationship. The model and observed melt volumes have very similar trends with increasing transient-cavity diameter. This Vm-Dtc relationship is then used to make predictions regarding the nature of the terrestrial cratering record. In particular, with increasing size of the impact event, the depth of melting approaches the depth of the transient cavity. As a consequence, the base of the cavity, which ultimately would appear as an uplifted central structure in a complex crater, will record shock stresses that will increase up to a maximum of partial melting. Examination of the terrestrial record indicates a general trend for higher recorded shock levels in central structures at larger diameters; impact structures in the 100-km size range record partially melted and vesiculated parautochthonous target rocks in their centers. In addition, as the depth of melting approaches a depth equivalent to that attained by the base of the transient cavity, the floor of the transient cavity will have progressively less strength, with the result that cavity modification and uplift will not produce topographic central peaks. Again, the observed terrestrial record is not inconsistent with this prediction, and we offer differential melt scaling as a possible mechanism for the transition from central topographic peaks to rings with increasing crater diameter. Among other implications is the likelihood that impact basins in the 1000-km size range on the early Earth would not have the same multi-ring form as observed on the moon.","PeriodicalId":81993,"journal":{"name":"Meteoritics","volume":"27 1","pages":"526-538"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/J.1945-5100.1992.TB01074.X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63663803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Memorial for Howard James Axon (1924–1992)","authors":"A. Bevan, N. Ridley, D. Sears","doi":"10.1111/J.1945-5100.1992.TB01085.X","DOIUrl":"https://doi.org/10.1111/J.1945-5100.1992.TB01085.X","url":null,"abstract":"","PeriodicalId":81993,"journal":{"name":"Meteoritics","volume":"27 1","pages":"611-612"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/J.1945-5100.1992.TB01085.X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63664187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"40Ar-39Ar Dating of the H3 Chondrite Sainte Rose","authors":"T. Stephan, E. Jessberger","doi":"10.1111/J.1945-5100.1992.TB01080.X","DOIUrl":"https://doi.org/10.1111/J.1945-5100.1992.TB01080.X","url":null,"abstract":"— A whole rock sample from the H3 chondrite Sainte Rose, which was discovered in 1983, was dated with the 40Ar-39Ar technique. From the K/Ca spectrum and from an analysis of the 39Ar recoil effect we conclude that this meteorite has at least two distinguishable K-carriers: a low temperature, high-K/Ca, fine-grained carrier with a typical grain size of about 2 μm and a high temperature, low-K/Ca, more coarse-grained carrier. The K-Ar clocks of both were started 4.40 ± 0.01 Ga ago.","PeriodicalId":81993,"journal":{"name":"Meteoritics","volume":"27 1","pages":"580-584"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/J.1945-5100.1992.TB01080.X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63664093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}