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Mineralogical evolution of a weathering profile in the Tagaung Taung Ni laterite deposit: significance of smectite in the formation of high-grade Ni ore in Myanmar
Title: | Mineralogical evolution of a weathering profile in the Tagaung Taung Ni laterite deposit: significance of smectite in the formation of high-grade Ni ore in Myanmar |
Authors: | Murofushi, Ayaka Browse this author | Otake, Tsubasa Browse this author →KAKEN DB | Sanematsu, Kenzo Browse this author | Ya, Kyaw Zay Browse this author | Ito, Akane Browse this author →KAKEN DB | Kikuchi, Ryosuke Browse this author →KAKEN DB | Sato, Tsutomu Browse this author →KAKEN DB |
Keywords: | Chemical weathering | Harzburgite | Pyroxene | Nickel | Smectite | Laterite | Myanmar |
Issue Date: | Oct-2022 |
Publisher: | Springer |
Journal Title: | Mineralium Deposita |
Volume: | 57 |
Issue: | 7 |
Start Page: | 1107 |
End Page: | 1122 |
Publisher DOI: | 10.1007/s00126-021-01089-6 |
Abstract: | Myanmar has a drier sub-tropical climate than countries that typically contain Ni laterite deposits, but hosts a Ni laterite deposit at Tagaung Taung. Given that Ni enrichment processes in the Tagaung Taung deposit are poorly understood, we investigated the geochemical and mineralogical evolution of two weathering profiles developed on different bedrocks in the central part of Myanmar: a partly serpentinized harzburgite at Tagaung and an almost completely serpentinized peridotite at Budaung. The whole-rock geochemical data indicate that Si was retained relative to Fe and Al in the weathering profiles. Nickel has been enriched to contents as high as 4.89 wt.% NiO in the saprolite layers at Tagaung, whereas the saprolite layers at Budaung contain <= 1.55 wt.% NiO. Smectite is the main mineral that formed in the saprolite layers at Tagaung, whereas secondary serpentine dominates the saprolite layers at Budaung. Microscopic observations indicate that Ni-smectite (> 10 wt.% NiO), which is only observed at Tagaung, formed as a replacement product of orthopyroxene. In addition to the high Ni fixation capacity of smectite relative to secondary serpentine, Ni-rich pore water derived from the dissolution of olivine likely contributed to the high Ni contents of smectite. Our results imply that high-grade Ni laterite deposits may develop on unaltered or partly serpentinized harzburgite under the climatic conditions typical of Myanmar. |
Rights: | This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s00126-021-01089-6 |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/87633 |
Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 大竹 翼
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