This paper gives a description of high-temperatUre contact metamorphism at the contact of some Alpine-type ultrabasic intrusions in the Mian-Luee region of the southern Qiuling Range. At the contact, because of the me...This paper gives a description of high-temperatUre contact metamorphism at the contact of some Alpine-type ultrabasic intrusions in the Mian-Luee region of the southern Qiuling Range. At the contact, because of the metamorphism, volcanic rocks and turfs have changed into amphibolites and pyroxene hornfelses; pelitic phyllites into bfotite-cordierite hornfelses; and limestones into marbles. Hornblende shows a variation in colour from green in the outer aureole to brown at the contact. The original hlgh-temperature contact effects have been obscured by later retrogressive metamorphism and tectonic deformation. In combination with some other experimental data on high-temperature and highpressure diagenesis, the author has come to the conclusion that Alpine-type uitrabasie intrusions in the Mian-Luee region are high-temperature intrusions of liquid magmas.展开更多
Two conclsions may be drawn on the calculation of Cr2O3 parameters from eight ultrabasic intrusions in northwestern China: (1) To a first approximation, a normal distribution of chromium can he established for chromit...Two conclsions may be drawn on the calculation of Cr2O3 parameters from eight ultrabasic intrusions in northwestern China: (1) To a first approximation, a normal distribution of chromium can he established for chromite-free intrusions, while positive skewness is observed in chromite-bearing masses. (2) The greater the “metallogenetic coefficient” value (ρCr) of the ultrahasic intrusions the greater the potential of chromite deposits.展开更多
文摘This paper gives a description of high-temperatUre contact metamorphism at the contact of some Alpine-type ultrabasic intrusions in the Mian-Luee region of the southern Qiuling Range. At the contact, because of the metamorphism, volcanic rocks and turfs have changed into amphibolites and pyroxene hornfelses; pelitic phyllites into bfotite-cordierite hornfelses; and limestones into marbles. Hornblende shows a variation in colour from green in the outer aureole to brown at the contact. The original hlgh-temperature contact effects have been obscured by later retrogressive metamorphism and tectonic deformation. In combination with some other experimental data on high-temperature and highpressure diagenesis, the author has come to the conclusion that Alpine-type uitrabasie intrusions in the Mian-Luee region are high-temperature intrusions of liquid magmas.
文摘Two conclsions may be drawn on the calculation of Cr2O3 parameters from eight ultrabasic intrusions in northwestern China: (1) To a first approximation, a normal distribution of chromium can he established for chromite-free intrusions, while positive skewness is observed in chromite-bearing masses. (2) The greater the “metallogenetic coefficient” value (ρCr) of the ultrahasic intrusions the greater the potential of chromite deposits.
