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Obvious differences in mineralization characteristics exist between the southern and northern parts of the eastern part of the Jiangnan Uplift in northern Jiangxi Province and southern Anhui Province. The regional metallogeny is discussed, and the ore-forming fluid systems are classified in this article. It is proposed that the fluid ore-forming activities in the Jiangnan Uplift both in northern Jiangxi and southern Anhui have close relationships with the crust-mantle interaction and magmatic-tectonic activities. The types and scales of the mineralization on the both sides of the eastern Jiangnan Uplift were determined by fluid ore-forming systems and geological backgrounds.

Based upon fluid effects, retrograde metamorphism of eclogites in the Dabie region can be divided into the fluid-poor, fluid-bearing and fluid-rich stages. The fluid-poor stage is marked by polymorphic inversion, recrystallization and exsolution of solid solutions, and is thought to represent eclogite-facies retrograde environments. The fluid-bearing stage is likely to have occurred at the late stage of ecologite-facies diaphthorosis and is represented by kyanite porphyroblasts, rutile, and sodic pyroxene in association with high-pressure hydrous minerals such as phengite and zoisite (clinozoisite) without significant amount of hydrous minerals such as amphibole, epidote and biotite. The fluid-rich stage might have commenced concomitantly with lower amphibolite-facies diaphthoresis and persisted all the way towards the near-surface environment. The product of this stage is characterized by plentiful hydrous and volatile-bearing phases. The dissemination-type rutile mineralizations in eclogites might have formed by preferential shearing-induced pressure solution of gangue minerals at the fluid-bearing stage. The accompanying vein rutile was precipitated from fluids of this stage after local transport and concentration, and may hence represent proximal mobilization of titanium from the eclogite. Therefore, rutile veins can be used as an exploration indicator for dissemination-type rutile deposits.

Four samples of plagioclase and biotite from the Shaxi porphyry in the lower part of the Yangtze metallogenic belt were analyzed for age determination with the 40Ar/39 Ar method. The results yield reproducible ages of 126 Ma to 135 Ma with a high level of confidence according to the agreement between isochron and plateau ages. The four Ar-Ar ages are relatively consistent within the analytical error. These ages are also consistent with, but more precise than, previous K-Ar and Rb-Sr ages and thus provide better constraints on the time of porphyry formation and associated Cu-Au mineralization along the middle to lower part of the Yangtze metallogenic belt. The ages of 126 to 135 Ma are interpreted to represent the intrusive time of the Shaxi porphyry, so that the Cu-Au mineralization should have occurred later due to the post-magmatic hydrothermal event.

The origins of gases in springs, pools and wells from the Wudalianchi (WDLC) volcanic area are discussed based upon molecular and isotope compositions of the gases. Nine gas and water samples were collected from bubbles and water of the springs and pools in the WDLC volcanic area, Northeastern China, in August 1997. The molecular components were measured with a MAT-271 mass spectrometer (MS), helium isotope ratios with a VG-5400 MS, and δ13C with a MAT-251 MS in the Lanzhou Institute of Geology. The gases are enriched in CO2 , and most of the CO2 concentrations are over 80% (V). The helium and methane concentrations have relatively wide ranges of 0.7 to 380 ×10-6 and 4 to 180×10-6, respectively. The 3He/4He ratios are between 1.05 Ra and 3.1 Ra(Ra = 1.4×10-6); the 4He/20Ne values are between 0.45 and 1011, larger than the atmospheric value (0.32). The δ13C (PDB) values of carbon dioxide range from -9.6 to -4.2‰. These geochemical data demonstrate that the spring water is from aquifers at different depths, and that helium and carbon dioxide are derived from the mantle, and are contaminated by crust gases during deep fluid migration. Also, there are larger fluxes of deep-earth matter and energy in the WDLC volcanic area.