The Tarim Basin, China, a prospect for plume-related Zr(Hf)-Nb(Ta)-REY-Ga-U mineralization

Abstract

This study is based on published data from the Tarim and Emeishan Large Igneous Provinces (TLIP and ELIP, respectively). The data are interpreted in a comparative manner, using the well-studied ELIP’s mineralization as a reference. Some additional information on related U and REY-carbonate ores from Far Eastern Russia are also included in this comparison. The results show that the Tarim Basin has both positive and negative indicators for tuffaceous Zr(Hf)–Nb(Ta)–REY–Ga–U ores. Like in ELIP, the source of the mineralization in the Tarim Basin is likely to be the Permian volcaniclastic deposits. The volcaniclastic deposits in the Tarim are not well studied geochemically; however, since the composition of the parent magmatic rocks are similar between TLIP and ELIP, the volcaniclastic material is also thought to be similar. Positive indications are that the TLIP’s deposits are larger (volumetrically), more felsic than the ELIP’s volcaniclastics. In addition, the former are concentrated in an almost closed terrestrial basin (Tarim Basin), whereas the latter are disseminated throughout a wide continental margin. The Paleozoic strata of the Tarim Basin are deeply altered in and around fracture zones, which are widespread. The alteration is caused by acidic volcanic-related fluids that are a key factor in metal mobilization and redistribution. However, in contrast to the ELIP’s area, the Tarim Basin was under influence of semi-arid climate that probably resulted in a weak activity of meteoric waters and poorly developed vegetation during deposition of the Permian volcaniclastic strata, which have a relatively low content of organic matter (<5%, commonly <2%) and contain no coal seam. These may be considered negative indicators for tuffaceous Zr(Hf)–Nb(Ta)–REY–Ga–U ores because organic acids might play a significant role in the leaching, redistribution, and the finishing processes that concentrated Zr, Hf, Nb, Ta, REY, Ga, and U within rocks with clay alteration. Finally, the Permian tuffaceous mudstones located in and around deep faults of the Tarim Basin may be a likely target for geochemical prospecting for Zr(Hf)–Nb(Ta)–REY–Ga–U ores similar to those found in southwestern China. In addition, the fracture zones in the Tarim Basin are likely to contain REY-carbonate and U ores similar to those discovered in Primorye, the Far Eastern Russia.