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Peter J. ISAACSON Amit BASU SARBADHIKARI Carlé M. PIETERS Rachel L. KLIMA Takahiro HIROI Yang LIU Lawrence A. TAYLOR 《Meteoritics & planetary science》2011,46(2):228-251
The lunar rock and mineral characterization consortium (LRMCC) has conducted coordinated mineralogy/petrography/spectroscopy analyses of a suite of pristine lunar basalts. Four basalt slabs (two low‐Ti, two high‐Ti) and paired thin sections were analyzed. Thin sections were analyzed for mineralogy/petrography, while the slabs were used to prepare particulate separates of major mineral phases and bulk samples. Mineral separates and particulate bulk samples were crushed to controlled grain sizes and their reflectance spectra measured in the NASA RELAB at Brown University. The resulting data set provides an essential foundation for spectral mixing models, offers valuable endmember constraints for space weathering analyses, and represents critical new ground truth results for lunar science and exploration efforts. 相似文献
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Cretaceous high-temperature rapid loading and unloading in the Abukuma metamorphic terrane, Japan 总被引：7，自引：0，他引：7
The Cretaceous Abukuma metamorphic terrane consists of the oceanic Gosaisyo Series overthrust onto the terrigenous Takanuki Series. Although the dominant mineralogy defines one of the classic areas of andalusite–sillimanite type progressive metamorphism, there are several lines of evidence suggesting an earlier higher-pressure (up to c . 12 kbar) history of the Takanuki Series and the nearby Gosaisyo Series. These are: (1) the occurrence of rare although widespread relic kyanite in sillimanite+K-feldspar zone-grade pelitic rocks; (2) the high grossular content of garnet interiors (up to c . 30 mol %) overgrown by Ca-poor rims ( c . 2 mol % grossular) in pelitic rocks containing Al2 SiO5 minerals (sillimanite±relic kyanite±retrograde andalusite), plagioclase and quartz; (3) the occurrence of rutile as inclusions in garnet in pelitic rocks; and (4) the occurrence of relic corundum+almandine association in silica-poor and Al–Fe-rich rocks. Garnet in the Takanuki Series pelitic rocks commonly shows textural sector zoning and preserves growth zoning despite the high metamorphic grade, suggesting rapid changes in P–T conditions and a relatively short duration of high-temperature conditions. Combined with radiometric dating, these observations suggest that the Abukuma sillimanite+K-feldspar zone-grade rocks underwent a clockwise P–T path with very fast (>4 mm y−1 ) average burial and exhumation rates. 相似文献
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JANICE L. BISHOP CARL M. PIETERS TAKAHIRO HIROI JOHN F. MUSTARD 《Meteoritics & planetary science》1998,33(4):699-707
Abstract— Spectroscopic measurement and analysis of Martian meteorites provide important information about the mineralogy of Mars, as well as necessary ground-truths for deconvolving remote sensing spectra of the Martian surface rocks. The spectroscopic properties of particulate ALH 84001 from 0.3 to 25 μm correctly identify low-Ca pyroxene as the dominant mineralogy. Absorption bands due to electronic transitions of ferrous iron are observed at 0.94 and 1.97 μm that are typical for low-Ca pyroxene. A strong, broad water band is observed near 3 μm that is characteristic of the water band typically associated with pyroxenes. Weaker features near 4.8, 5.2 and 6.2 μm are characteristic of particulate low-Ca pyroxene and can be distinguished readily from the features due to high-Ca pyroxene and other silicate minerals. The reflectance minimum occurs near 8.6 μm for the ALH 84001 powder, which is more consistent with high-Ca pyroxene and augite than low-Ca pyroxene. The dominant mid-infrared (IR) spectral features for the ALH 84001 powder are observed near 9 and 19.5 μm; however, there are multiple features in this region. These mid-IR features are generally characteristic of low-Ca pyroxene but cannot be explained by low-Ca pyroxene alone. Spectral features from 2.5–5 μm are typically associated with water, organics and carbonates and have been studied in spectra of the ALH 84001, split 92 powder and ALH 84001, splits 92 and 271 chip surfaces. Weak features have been identified near 3.5 and 4 μm that are assigned to organic material and carbonates. Another feature is observed at 4.27 μm in many surface spots and in the powder but has not yet been uniquely identified. Spectroscopic identification of minor organic and carbonate components in this probable piece of Mars suggests that detection of small amounts of organics and carbonates in the Martian surface regolith would also be possible using visible-infrared hyperspectral analyses. Laboratory spectroscopic analysis of Martian meteorites provides a unique opportunity to identify the spectral features of minerals and other components while they are embedded in their natural medium. 相似文献
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MICHIO TAGIRI DANIEL J. DUNKLEY TATSURO ADACHI YOSHIKUNI HIROI C. MARK FANNING 《Island Arc》2011,20(2):259-279
Ion microprobe dating of zircon from meta‐igneous samples of the Hitachi metamorphic terrane of eastern Japan yields Cambrian magmatic ages. Tuffaceous schist from the Nishidohira Formation contains ca 510 Ma zircon, overlapping in age with hornblende gneiss from the Tamadare Formation (ca 507 Ma), and meta‐andesite (ca 507 Ma) and metaporphyry (ca 505 Ma) from the Akazawa Formation. The latter is unconformably overlain by the Carboniferous Daioin Formation, in which a granite boulder from metaconglomerate yields a magmatic age of ca 500 Ma. This date overlaps a previous estimate for granite that intrudes the Akazawa Formation. Intrusive, volcanic, and volcaniclastic lithologies are products of a Cambrian volcanic arc associated with a continental shelf, as demonstrated by the presence of arkose and conglomerate in the lowermost Nishidohira Formation. Granitic magmatism of Cambrian age is unknown elsewhere in Japan, except for a single locality in far western Japan with a similar geological context. Such magmatism is also unknown on the adjacent Asian continental margin, with the exception of the Khanka block in far northeastern China. A ‘great hiatus’ in the Paleozoic stratigraphy of the Sino–Korean block also exists in the Hitachi terrane between Cambrian volcanic arc rocks and Early Carboniferous conglomerate, and may indicate a common paleogeographic provenance. 相似文献
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It has been previously suggested that the high-pressure metamorphic rock complex of Motalafjclla, central-western Spitsbergen, is older than Lower Silurian. An unconformity has been discovered at the base of a limestone which contains fossils similar to those reported as Lower Silurian from the same massif. This proves that the high-pressure metamorphics represent an older rock complex. The unconformity surface is inverted in the area, and large recumbent folds involving the Silurian Bulltinden Formation have been mapped. These folds are considered to be pre-Carboniferous. 相似文献
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JANICE L. BISHOP JOHN F. MUSTARD CARL M. PIETERS TAKAHIRO HIROI 《Meteoritics & planetary science》1998,33(4):693-698
Abstract— Reflectance spectra of splits 92 and 271 from the Martian meteorite Allan Hills (ALH) 84001 are presented and analyzed in this paper. Although the visible and infrared spectra of both chips show that the dominant mineralogy is low-Ca pyroxene, the focus here is on identification of the minor constituents. Infrared spectra measured at multiple spots along the surface of chips 92 and 271 show subtle spectroscopic variations due to changes in the low-Ca pyroxene texture and composition and to the presence of secondary minerals. Absorption bands observed near 0.93 and 1.95 μm are characteristic of low-Ca pyroxene. Strong mid-infrared reststrahlen bands are observed near 9 and 19.5 μm in all surface spectra, and additional bands near 7, 10.5, 11.4, 17.8, 20.5 and 23 μm are variable depending on the low-Ca pyroxene texture and the presence of secondary minerals. Selected spectra exhibit carbonate features near 4, 6.4–7.1 and 11.3 μm. Detailed analysis of these carbonate features indicates the presence of Mg-Fe carbonate, which is consistent with petrographic studies. Many of these spectra with strong carbonate features exhibit a magnetite feature near 17.9 μm and a shoulder near 20.5 μm that cannot be uniquely ascribed to one mineral. Spectroscopic identification of the minor carbonate and magnetite minerals in this probable piece of Mars indicates that detection of small amounts of these minerals of possible biological significance will be possible using infrared hyperspectral analyses of the Martian surface. Also of importance for remote sensing on Mars is the result that Mg, Fe and Mg-Fe carbonates in a low-Ca pyroxene matrix should be distinguishable from one another in the spectral region measured by the thermal emmitance spectrometer (TES). 相似文献
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