The Relationships between Uranium Mineralization and Organic Matter in 373 Uranium Deposit

The 373 deposit,as a typical carbonanceous-siliceous-pelitic rock type uranium deposit,is rich in organic matter and pyrite.Close relationships exist between organic matter and uranium mineralization in a lot of uranium deposits. But few people have studied the relationship between uranium mineralization and organic matter of carbonanceous-siliceous-pelitic rock type uranium deposit.The organic matter type of 373 uranium deposit is type-II2.The sources of organic matter are mainly marine plankton,microbial and terrestrial plant. The organic maturity is relatively low,at the immature-low mature stage.Compared with the surrounding rock ,the ore has gone through higher paletemperature on account of hydrothermal and fault. The type and the maturity of organic matter result in the generation of large amount of humic acid during thermal evolution that could be preserved in strata. The contents of chloroform bitumen “A” of organic matter in the mineralized layer are 0.47—10.42ug/g .Asphaltene is the main component of chloroform bitumen “A”.The correlation between chloroform bitumen “A” and uranium content is high,as well as the correlation between the content of asphaltene and uranium content. Study shows that the functions of organic matter in 373 uranium deposit are mainly adsorption,complexation and reduction.

Restite-melt and mafic-felsic magma mixing and mingling in an S-type dacite, Cerro del Hoyazo, southeastern Spain

ABSTRACTApproximately 10-15 vol% of the Neogene Hoyazo dacite consists of Al-rich restite rock inclusions (A12O3 = 20–45%) and monocrystal inclusions derived therefrom. Restite material and dacitic melt were formed syngenetically from a (semi-)pelitic rock sequence by means of anatexis. Restite rock fragments and dacite show similar high δ18O values (13–16‰) corresponding to those found for sedimentary material. Striking monocrystal restite inclusions in the dacite rock are graphite crystals measuring a few hundred μm, 0.5–10 mm blue cordierite crystals and 2–10 mm ruby red crystals of almandine-rich garnet (1.1 ± 0.2 vol%). Although the almandine crystals are perfectly euhedral, they are identical in every respect to the crystals found in the Al-rich restite rock inclusions and cannot be crystallisation products of the magmatic melt. The dacite also contains many inclusions of quartz gabbroic and basaltoid material which contains inclusions identical to the restite material found in the dacitic glass base. Many basaltoid inclusions show well-developed chilled borders. These inclusions may represent a more mafic magma of deeper origin which mixed with some dacite magma before mingling into it.