Geochemical characteristics of the karst-type bauxites: an example from the Kanirash deposit, NW Iran
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ORIGINAL PAPER
Geochemical characteristics of the karst-type bauxites: an example from the Kanirash deposit, NW Iran Ali Abedini 1 & Masoud Habibi Mehr 1 & Maryam Khosravi 2 & Ali Asghar Calagari 3 Received: 8 January 2019 / Accepted: 2 July 2019 # Saudi Society for Geosciences 2019
Abstract The Kanirash bauxite deposit belongs to the Iran-Himalayan karst-type bauxite belt, which is situated about 30 km southeast of Mahabad city, northwestern Iran. The bauxite ores are embedded by the Late Permian carbonate rocks intercalated with shale of the Ruteh Formation and occurred as layer and lens-shaped patches. The bauxite ores contain diaspore, clinochlore, hematite, pyrophyllite, illite, rutile, and lesser amounts of zircon, pyrite, and barite. This mineral assemblage indicates that this deposit was formed in a transitional zone between the vadose and the phreatic environments. The presence of pyrite in the bauxite ores demonstrates that organic matters were present in the uppermost parts of the profile and the depositional diagenetic/epigenetic environment was reducing. Ti and Fe together with a suite of trace elements, including Ni, Cr, Co, Ga, Ta, and V, were leached from the upper parts of the weathered profile and concentrated in the bottom parts with respect to Hf, chosen as the least mobile element. Some factors, such as pH variations in weathering solutions, buffering nature of the carbonate bedrock, mineral control, the existence of organic materials, and fluctuations of groundwater table played important roles in distribution of trace and rare earth elements. Keywords Kanirash bauxite deposit . Mass change . Fluctuations of groundwater level . Iran
Introduction Bauxite, though generally exploited as an Al ore, is also a major source of several trace elements, notably the high field strength elements (HFSEs) Ti, Nb, P, and Zr, as well as Ni, Au, Ga, Co, V, Cr, and rare earth elements (REEs). These elements may be hosted by authigenic as well as detrital minerals, such as zircon, tourmaline, and rutile (Liu et al. 2010; Wang et al. 2010, 2012; Gamaletsos et al. 2017; Abedini and Calagari 2014; Ling et al. 2013, 2015, 2017, 2018), which are stable in the supergene environment (Nesbitt 1979; Gamaletsos et al. Editorial handling: Maurizio Barbieri * Ali Abedini [email protected]; [email protected] 1
Department of Geology, Faculty of Sciences, Urmia University, Urmia 5756151818, Iran
2
Department of Earth Sciences, Faculty of Sciences, Shiraz University, Shiraz 7146713565, Iran
3
Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz 5166616471, Iran
2017). Bauxites are the weathered deposits that are developed from intense chemical weathering of aluminosilicate-rich parent rocks under humid, tropical to subtropical climate conditions (Bárdossy 1982) and are restricted to a belt between 30° north latitude and 30° south latitude (Tardy et al. 1991). In turn, bauxitization is a result of a good drainage under humid, tropical climate and moderate relief (Marker and Oli
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