REE abundances in sulfides from the Huize Zn-Pb ore field were determined with the ICPMS after preconcentration. The REE abundances in 26 sulfide samples （including pyrite, galena and sphalerite） are very low, with the ~REE ranging from 1.6×10^-9 to 166.8×10^-9. Their LREE/HREE ratios range from 7.6 to 98, showing LREE enrichment relatively. The JEu values are below 1, indicating that they were deposited from an Eu-depleted and reducing fluid-system. Similar to the ore-hosting carbonate strata, calcite separates from carbonate veinlets filling in the fractures or faults crosscutting the carbonate strata also show clear Eu-depletion. This indicates that the carbonate veinlets and their parent fluid was possibly sourced from the strata and inherited the REE geochemical features of the strata. Therefore, REE-geochemical characteristics of both the sulfides and calcites, which were deposited from an ore-forming hydrothermal system, are similar to those of carbonate strata, and strongly suggest that the ore metals were mainly sourced from carbonate strata.
The Longgouhe and Ershiyizhan intrusions of the Late Jurassic, located in the Upper Heilongjiang Basin of the northern Great Hinggan Range, are closely related to porphyry Cu-Au mineralizations. In lithology the intrusions are quartz diorite, quartz monzodiorite and granodiorite of high-K caIc-alkaline series, with minor aspects of shoshonite series. Their SiO2 and A1203 contents range from 61.37% to 66.59% and 15.35% to 17.06%, respectively. The MgO content ranges from 2.02 % to 3.47 %, with Mg# indices of 44-59. The （La/Yb）N and Eu/Eu＊ values range from 16.85 to 81.73 and 0.68 to 0.93, respectively, showing strong differentiation rare earth element （REE） patterns similar to those of adakites. The rocks are enriched in Ba, Sr and light REE （LREE）, obviously depleted in Nb and Ta, slightly depleted in Rb and Ti, and poor in Yb and Y, with Yb and Y contents of 0.31-1.32 ppm and 4.32-12.07 ppm, respectively. As indicated by Sr/Y ratios of 67.74-220.60, the rocks are characterized by low-Y and high-Sr contents, which characterize the adakites in the world. Holistically, geochemical tracers suggest that the interested intrusions are adakitic rocks. Given that the Paleo- Asian Ocean and Mongol-Okhotsk Ocean were closed in the Late Paleozoic and Permian-Middle Jurassic, respectively, the interested intrusions should be formed by partial melting of delaminated crust, which had been thickened during collisional orogeny between the Siberian and Mongolian- Sinokorean continents.
The Jinlongshan gold ore belt in southern Shaanxi Province contains a number of Carlin-type gold deposits in the Qinling collisional orogenic belt. Their fluid inclusions are of the Na-Cl- type. From the main metallogenic stage to later stages, the total quantity of anions and cations, temperature and deoxidation parameter (R) for fluid inclusions all gradually decreased, suggesting the gradual intensification of fluid oxidation, the reduction of metallogenic depth and the input of meteoric water and organic components. The deposits were formed during crustal uplifting and hence had similar tectonic settings to orogenic gold deposits. The CO-2 contents and CO-2/H-2O values of the ore fluid increased from early to late stages, and the wall-rock alteration is represented by decarbonation, which is inconsistent with the characteristics of orogenic gold deposits. It is also discovered that Na, K, SO{2-}-4, Cl- and the total amounts of anions and cations in the inclusions in quartz are higher than those in the coexisting calcite. The H, O and C isotope ratios indicate that the ore fluid was sourced from meteoric water and metamorphic devolatilisation of the sedimentary rocks that host the ores. The high background {δ{}{18}O} and {δ{}{13}C} values of wall rocks resulted in high {δ{}{18}O} and {δ{}{13}C} values of ore fluid and also high {δ{}{18}O} and {δ{}{13}C} values of hydrothermal minerals such as quartz and carbonate. The carbon in ore fluid stemmed largely from the hosting strata. The {δ{}{18}O} and {δ{}{13}C} values of Fe-calcite and the δD values of fluid inclusions are lower than those of calcite and quartz. In terms of the theory of coordination chemistry, all these differences can be ascribed to water-rock interaction in the same fluid system, instead, to the multi-source of ore fluid.
