Geological characteristics and metallogenesis of the shilu Fe-ore deposit in Hainan Province, South China

Geological characteristics and age of the Dahongliutan Fe-ore deposit in the Western Kunlun orogenic belt, Xinjiang, northwestern China

“…The Neoproterozoic or temporally similar hematite-rich BIF-type deposits in China have been reported in the Jingtieshan, Gansu Province of North China (Sun et al, 1998) and in the western Hainan Province of south China (Xu et al, 2013(Xu et al, , 2014. The Jingtieshan deposit in North China, which is hosted by a suite of rift-type marine sediments of the Neoproterozoic Jingtieshan Formation comprising fine-grained clastic sedimentary rocks, carbonate rocks with a small amount of andesitic basalts, is characterized by the upper Fe orebodies dominated by specularite and jasper with lesser amounts of magnetite, hematite, siderite, and barite, and the lower Cu orebodies composed of pyrite and chalcopyrite occurring as disseminated and stockwork mineralization (Sun et al, 1998;Xu et al, 2014).…”

“…In addition, the Neoproterozoic Jingtieshan-type iron deposit (in Gansu province) in China is considered as a Superior-type BIF (Sun et al, 1998). Xu et al (2013Xu et al ( , 2014 Klein and Ladeira, 2004;Halverson et al, 2011) or glaciated rift environment (Young, 2002). Rapitantype BIFs have been widely reported to be related to the prominent Neoproterozoic glacial events (Sturian: 718-660 Ma; Marinoan: 651-635 Ma), such as those in the Rapitan in Canada, Urucum in Brazil, the Adelaide Geosyncline in South Australia, Damara in South Africa, southern Paraguay Belt in Brazil and Jiangnan paleocontinent in South China Block (Tang et al, 1987;Klein and Beukes, 1993;Lottermoser and Ashley, 2000;Klein and Ladeira, 2004;Ilyin, 2009;Babinski et al, 2013;Cox et al, 2013;Li et al, 2014).…”

“…If they did form very early, then the precursor phase probably was a form of ferric oxyhydroxide, such as ferrihydrite (Bekker et al, 2014). The local preservation of blastopsammitic and microcrystalline Fe ores also provide good support for a sedimentary origin (Xu et al, 2013). (6) Greenschist facies regional metamorphism is conspicuous, mineral orientations (Fig.…”

“…However, the Jingtieshan deposit contains typical banded jasper-barite-iron formation and stratabound Cu mineralization beneath the iron formation, which do not occur in the Dahongliutan BIF. The Neoproterozoic Shilu iron formation in South China, which is hosted within a suit of submarine siliciclastic and carbonate sedimentary succession subjected to greenschistfacies metamorphism, consists of Fe-rich ores dominated by hematite ( 85%), locally with minor magnetite (61%), quartz ( 14%), anhydrite and barite ( 1%), Fe-poor ores (or amphibolitic itabirites) comprising hematite (20-40%), magnetite (20-45%), garnet (20-25%), quartz ( 19%), feldspar( 5%), diopside and actinolite ( 4%) and barite ( 1%), as well as minor titanite and biotite, and Co-Cu ores including cobaltiferous pyrite, cobaltiferous pyrrhotite, chalcopyrite, quartz sericite, dolomite and calcite (Xu et al, 2009(Xu et al, , 2013(Xu et al, , 2014. Xu et al (2013Xu et al ( , 2014 proposed that the Shilu Fe-ore deposit, which formed under anoxic but Fe 2+ -rich conditions, belongs to Lake Superior-type BIF and Fe and Cu-Co orebodies precipitated possibly from sea floor hydrothermal fluids which likely were associated with the break-up of the Rodinian supercontinent due to mantle superplume activity in South China.…”

“…Hofmann et al (2003) suggested that surface weathering gives rise to a gossaneous appearance and obliterates primary structural feature. Xu et al (2009Xu et al ( , 2013 also proposed the formation of Fe-rich ores in the Shilu hematite-rich ore deposit are due to the interaction meteoric fluids and the original BIF during the oxidation-leaching stage. The existence of micro-platy hematite replacement of euhedral siderite, and the occurrence of recently formed limonite as the main constituent of gossan in the Dahongliutan Fe deposit, possibly suggests that supergene oxidation and leaching by meteoric fluids were responsible for the ore upgrade.…”