Hydrothermal sedimentation characteristics of the Dajiangping superlarge pyrite deposit, Yunfu, Guangdong

The Dajiangping pyrite deposit is hosted in a carbonate-clastic rock series which is characterized by a bioreef-chert suite in its middle part. Conformable lenses of various sizes constitute the orebodies which often branch transitionally into the surroundings. Syngenetic deformation fabrics can be observed in orebody No. 3. Orebody No. 4 is composed almost entirely of massive pyrite, with conspicuous hydrothermal sedimentation and bacterium-alga features. The hydrothermal sedimentation origin is also reflected by simple chemistry of the ore (predominated by quartz and pyrite), the presence of U and Th, and the REE compositions of pyrite and ankerite. The ores are rich in organic matter and the difference in organic content between the banded ores and the massive ores is mainly owing to the difference in the clastic components they contain rather than to the subsequent processes of reworking. Go/Ni ratios in the ore may reflect the temperature pattern during hydrothermal sedimentation.[PUBLICATION ABSTRACT]