The Characteristics of Spinels in Mantle-derivedXenoliths in Cenozoic Basalts from Eastern Chinaand Their Thermal States

The colours and chemical composition variations of 160 spinels in peridotite and pyroxenite xenoliths from Cenozoic basalts in eastern China and their petrogeneses have been studied in detail. The relationships between major elements of spinels are discussed. The equilibrium temperatures, pressures and oxygen fugacities of spinels and their coexisting olivines, orthopyroxenes and clinopyroxenes have been determined using the Brey-kohler' s T-P calculation methods (1990) and Ballhaus' fo2 calculation method (1991). The relationships betweenthe composition and the equilibrium temperatures, pressures or oxygen fugacities of spinels in peridotite xenoliths from the basalts and the stable field of the spinels in the upper mantle have been shown.     

A New Idea of Sinian Doushantuo''an Metaphyte Fossils from Xiuning, Anhui Province

This paper gives a summary of the fossil data from the Sinian Doushantuo' an Lantian Formation in the Xiuning area, Anhui Province, China, and reports the genital butt structure comparable to that of some modern advanced algae and the fossil structure comparable to the dehiscence of sporangia as well as the ontogenetic phenomenon occurring possibly from the formation of embryos by zygote germination to the production of sessile benthonic algal adults. This phenomenon furnishes a useful clue to the further study of the life history of alternate generations in advanced algae and provides megafossil evidence for the sex differentiation of metaphytic algae.     

Borate Deposits in Liaoning and Jilin Provinces, NE China: A Guide to Identifying Paleoproterozoic Collision Settings

１．ＩｎｔｒｏｄｕｃｔｉｏｎＦｉｇ．１．　ＲｅｇｉｏｎａｌｇｅｏｌｏｇｙｏｆｔｈｅｅａｓｔｅｒｎＬｉａｏｎｉｎｇＳｏｕｔｈｅｒｎＪｉｌｉｎａｒｅａ（ＡｆｔｅｒＺｈａｎｇ,１９８４）　　ＴｈｅＰａｌｅｏｐｒｏｔｅｒｏｚｏｉｃｖｏｌｃａｎｉｃｓｅｄｉｍｅｎｔａｒｙｓｅｑｕｅｎｃｅ,ｉ．ｅ．,ｔｈｅＳｏｕｔｈＬｉａｏｈｅＧｒｏｕｐａｎｄＮｏｒｔｈＬｉａｏｈｅＧｒｏｕｐ,ｅｘｔｅｎｄｓｂｅｔｗｅｅｎｔｗｏＡｒｃｈａｅａｎｃｒａｔｏｎｓ（Ｆｉｇ．１）．Ａｂｕｎｄａｎｔｍｉｎｅｒａｌｒｅｓｏｕｒｃｅｓ…