Hiroharu Matsueda

Multiphase Melt Inclusions in the Jinchuan Complex, China: Implications for Petrogenic and Metallogenic Physico-Chemical Conditions

Three types of melt inclusions were identified in pyroxenes, olivine, and chromite from the Jinchuan intrusion–sulfide inclusions (I), crystallized polyphase inclusions (II), and fluid inclusions (III). Sulfide inclusions in chromite are spherical and occur parallel to chromite growth planes. Polyphase inclusions are found in olivine and consist of olivine, orthopyroxene, chrome-spinel, amphibole, and sulfide daughter minerals. Primary fluid inclusions are usually found in olivine and pyroxene with spherical to tubular shapes. Laser Raman analyses were used to identify daughter minerals and fluid phases in the inclusions. The result shows that fluids consist mainly of CO2, with minor amounts of SO2, H2S, and CH4. This indicates that the parental magma of the Jinchuan intrusion contains abundant volatiles. Microthermometry shows that Type-II inclusions in dunite and sulfide-rich lherzolite have higher trapping temperatures (1000° to 1050°C), whereas trapping temperatures in sulfide-poor lherzolite are lowe...

Petrography and geochemistry of Cretaceous (?) red beds in Hong Kong

Abstract A preliminary investigation was carried out on the petrography and geochemistry of Cretaceous red beds in Hong Kong. The supply of iron minerals from the basement volcanic rocks in the source area to the depositional sites, and a palaeoclimatic condition favourable for the preservation of iron in the ferric state are necessary in causing the colouration of the beds. Red colouration of the sediments was chiefly accomplished before deposition, and was partly supplemented by following transformation of minerals after deposition.