The Gangdise rockk belt is the northmost an4 petrochemically the most complex one of the three east-west striking intermedlate-acid rock belt in south Xizang. Rh-Sr whole rock isochronous dating was conducted on sampl...The Gangdise rockk belt is the northmost an4 petrochemically the most complex one of the three east-west striking intermedlate-acid rock belt in south Xizang. Rh-Sr whole rock isochronous dating was conducted on samples of different rocks collected aerossing this belt from Quxur throwgh Lhasa to Yangbajan, Results show that these rocks are not contemporaneous and can be roughly assigned to four periods: Indosinian (240±30 my), Early Yenshanian (160--180my), Late Yenshanian (80--100 my), and Himalayanian (20-40 my). Their initial ratios of Sr isotopes are relatively low (0.7033--0.7054). The relationship between Rb, Sr and the major components such as SiO2, K2Oand FeO are also investigated. It seems that, the formation and development of the Gangdise belt can be obviously related with the subduction and collision of the Indian plate with the Eurasian plate. The material that formed this rock belt probably originated from the upper marital or the partial molten products from oceanic crust.展开更多
More than 50 kinds of accessory minerals have been diseovered in 13 plutons along the Kangdese, Lhagoi Kangri and Himalaya petrographical belts. The features of zircon,apatite, radioactive minerals and sulphide minera...More than 50 kinds of accessory minerals have been diseovered in 13 plutons along the Kangdese, Lhagoi Kangri and Himalaya petrographical belts. The features of zircon,apatite, radioactive minerals and sulphide minerals are described in more detail. From early to late, the percentages of titanium, iron, calcium and zirconium minerals decrease,while those of niobium (tantalum), beryllium, uranium and tin minerals show an opposition. The accessory mineral associations from the Kangdese belt are rich in sphene, allanite, apatite and magnetite, whereas the associations from the Himalaya belt are rich in tourmaline, and the Lhagoi Kangri belt shows intermediate features.展开更多
文摘The Gangdise rockk belt is the northmost an4 petrochemically the most complex one of the three east-west striking intermedlate-acid rock belt in south Xizang. Rh-Sr whole rock isochronous dating was conducted on samples of different rocks collected aerossing this belt from Quxur throwgh Lhasa to Yangbajan, Results show that these rocks are not contemporaneous and can be roughly assigned to four periods: Indosinian (240±30 my), Early Yenshanian (160--180my), Late Yenshanian (80--100 my), and Himalayanian (20-40 my). Their initial ratios of Sr isotopes are relatively low (0.7033--0.7054). The relationship between Rb, Sr and the major components such as SiO2, K2Oand FeO are also investigated. It seems that, the formation and development of the Gangdise belt can be obviously related with the subduction and collision of the Indian plate with the Eurasian plate. The material that formed this rock belt probably originated from the upper marital or the partial molten products from oceanic crust.
文摘More than 50 kinds of accessory minerals have been diseovered in 13 plutons along the Kangdese, Lhagoi Kangri and Himalaya petrographical belts. The features of zircon,apatite, radioactive minerals and sulphide minerals are described in more detail. From early to late, the percentages of titanium, iron, calcium and zirconium minerals decrease,while those of niobium (tantalum), beryllium, uranium and tin minerals show an opposition. The accessory mineral associations from the Kangdese belt are rich in sphene, allanite, apatite and magnetite, whereas the associations from the Himalaya belt are rich in tourmaline, and the Lhagoi Kangri belt shows intermediate features.
