Tile super-Luge Tongciiang porpliyry Cu deposit in Dexin, liangxi province.characterized by dissenxinated ore, occurs in the two sides of contact zone btween the granodiorite porphry and the low grade met:smorphie talf of Sutanqiaoshan Formation, Middle Proterozoic era.A fairly systematic oxygen (hydrogen) isotope study was madc on diffcrcnt stagcs of orc-forming fluids and altered rocks in the deposit It is known that for the main ore-fornung stage of quartz veins,δ18O=1.9‰to -2.5‰ δD and δD=-54‰ to -62‰,and that for hydrothermal solution of the late stage of quartz vine, δ18O=-3.4‰ and δD=-57‰.Systematic planar sampling and oxygen isotope analysis were performed in the openpit working of the deposit, and the results reveal that the variations of oxygen isotope compositions for altered rocks from about δ18O=6‰ to 13‰and show that There are at lcast 5 water-rock interaction low 18O centers indicated. On the oxygen isotope contour map,the extent of 5 water-rock interaction renters are quite coincident with the localites of superhuge copper orebogies.The δD of al tered rocks(whole rock) and ore-forming fluid are about-85‰ and -60‰,respectively,showing an cquilibrated fractionation between altered minerals and mincralization tluids. The water content in altered rock is higher than 2% in Tongchang Cu deposit but lower than 2% in the other deposits such as Yinshan, Lengshuikeng tunic near by the Tongehang mine in which,appear H isotope kineLie fractionation in water-rock interaction system. Studies,how that the higher H2O content in Tongchang is related to the superimposed water-rock interactions.The effective W/R ratio and temperature for the Tongchang porphyry type Cu(Mo)depusits at the hydrothermal fluid reservoir forming period is 0.5 to 1.0 and 300℃,bat it is higher than 10.0 and lower than 250℃ diaring the of water-rock interacaions mineralization deposition. In addition, the minimum etffective H2O weight in water-rock system in super-faint copper district is about 1.9×1010tons.We conclude that the super-huge Tongchang Cu(Mo)deposit was formed at peculia water-rock system.
Zhang Ligang,Liu Jingxiu,Chen Zhensheng et al. HYDROGEN AND OXYGEN EVOLUTION FOR WATER-ROCK SYSTEM IN SUPER-HUGE TONG CHANG COPPER DEPOSIT, JIANGXI PROVINCE[J]. Chinese Journal of Geology, 1996, (3): 250-263.