Sapphirine granulites occur in the Daqingshan and Jining areas in the Palaeoproterozoic Khondalite belt, which divides the Western Block of the North China Craton into the Yinshan block to the north and the Ordos block to the south. The sapphirine granulites in the Daqingshan area are always in contact with meta-gabbronorite dykes, implying a causal relationship. The sapphirine-bearing rocks are divided into spinel-garnet-sillimanite-biotite-plagioclase-sapphirine gneiss, UHT sapphirine granulite, and spinel-garnet granulite. The sapphirine granulite contains up to 30% sapphirine, garnet (30-50%), spinel (5-15%), sillimanite (5-15%), biotite (10-20%) and plagioclase (10-20%) with minor cordierite, rutile and ilmenite, but without quartz and orthopyroxene. Bulk chemical compositions show that the sapphirine granulites have very low SiO2 contents (39wt.%), high Al contents, and low XMg. Biotite contains very high TiO2 contents up to 7.6wt.%. Detailed petrographic examination of the sapphirine granulites reveals five mineral assemblages (M0-M4): (1) an assemblage (M0) of mineral inclusions within garnet cores, (2) a matrix (peak) assemblage (M1) represented by coarse-grained garnet, sapphirine, spinel, sillimanite, biotite and plagioclase, (3) sapphirine + plagioclase symplectite (M2), (4) spinel + plagioclase symplectite (M3), and (5) retrogressive biotite (M4). The P-T stability field in the pseudosection of the NCKFMASH system indicates that the temperature of the peak UHT metamorphism of the Daqingshan sapphirine granulites is in the range 910-980 ° C (this compares with the peak regional metamorphic temperature of the khondalites of 700-820 ° C). The P-T path inferred from the P-T stability fields of the mineral assemblages (M1 -M4) suggests that the peak UHT metamorphism (M1) was followed by nearly isothermal decompression (M2 and M3) and later cooling (M4). Field relations and geochrono-logical data suggest that the high-heat flow necessary for the UHT metamorphism of the sapphirine granulites from the Daqingshan area was provided by coeval ~1.93-1.92 Ga gabbronorite intrusions that were most probably generated by ridge subduction, which was also responsible for abundant garnet-rich granites by crust melting the area.

This volume was edited by Russell I. Hemley in preparation for a short course by the same title, organized together with Ho-kwang Mao and sponsored by the Mineralogical Society of America, December 4-6, 1998 on the campus of the University of California at Davis. This is number 37 in the Reviews in Mineralogy series, begun in 1974 and continuing with vigor, at least into the near future, with volumes on "Uranium Mineralogy and Geochemistry," on "Sulfate Mineralogy," and on "Natural Zeolites" planned for 1999 and 2000. Volume 36 (1056 pagesl), "Planetary Materials," edited by 1.1. Papike, appeared earlier this year, and it is certainly not unrelated to the subject of this volume on the physics and chemistry of the deep interior of one of the planets. Rus Hemley has highlighted Reviews in Mineralogy Volumes 14, 18, 20 and 29 as particularly relevant to the subject matter of "Ultrahigh-Pressure Mineralogy."

Вскрытие невидимого золота: использование наноразмеров для оценки содержания золота, микроэлементов и изотопов серы в пирите из золоторудных месторождений типа Карлин

One-hundred-nm-resolution secondary ionizing mass spectrometry (nanoSIMS) was used to determine the distribution of Au, Cu, As, Sb, and S, and stable isotopes of S (34S/32S) in gold-bearing pyrite from two refractory Carlin-type gold deposits: West Banshee, northern Carlin Trend, and Turquoise Ridge, Getchell Trend, located in northern Nevada. NanoSIMS maps reveal that gold occurs in two discrete episodes in each deposit. Elevated gold concentrations correlate with elevated concentrations of As, Sb, Cu ± Te, and lower 34S/32S ratios, compared to periods when gold was not deposited. Precipitation of elevated gold and trace elements at West Banshee was followed by precipitation of pyrite with lower gold concentrations, whereas at Turquoise Ridge precipitation of trace element-rich pyrite was followed by precipitation of late ore-stage minerals. These NanoSIMS results are consistent with formation of the deposits by the episodic incursion of gold-rich fluids into hydrothermal systems otherwise dominated by gold-poor fluids. Such gold-rich fluid pulses may be related to incursions of magmatic fluid, which have been shown to have high concentrations of gold, arsenic, and copper in porphyry and high-sulfidation epithermal systems.

This book provides a systematic description of the theories, key technologies, and main types of unconventional petroleum geology after analyzing the development trends in the petroleum industry along with the theories, technologies, development prospects, and strategic considerations related to unconventional petroleum.