Geochemical features of nickel-laterite deposits from the Balkan Peninsula and Gordes,Turkey: The genetic and environmental significance of arsenic |
| |
| Institution: | 1. Department of Mining Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran;2. College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK;3. Department of Geology, Payame Noor University, PO Box 19395-3697, Tehran, Iran;4. Department of Geology, North Tehran Branch, Islamic Azad University, Tehran, Iran;1. Dipartimento Scienze della Terra Università di Napoli “Federico II” Complesso Universitario di Monte S. Angelo, Via Cintia 26 80126, Napoli, Italy;2. Metals X Limited, L5/197 St Georges Terrace, Perth, WA, 6000, Australia;3. Centre for Exploration Targeting, The University of Western Australia, 35, Stirling Highway, Crawley, WA 6009, Australia;1. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China;2. CAS Key Laboratory of Crust–Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;3. University of Chinese Academy of Sciences, Beijing 100049, China |
| |
| Abstract: | Iron–nickel-laterite deposits in the Balkan Peninsula and Turkey, located in the Mirdita–Sub-Pelagonian and Pelagonian geotectonic zones, extending into the Anatolides zone are a major source of nickel. Repeated marine transgression and regression, and the multistage development of allochthonous laterite deposits by re-working and re-deposition in a shallow sea environment are demonstrated by the alternation of Fe–Ni-laterite layers within marine sequences.Geochemical study of these Fe–Ni laterite deposits shows that arsenic contents are generally low, ranging from less than 2 to a few tens of ppm. However, in the Aghios Ioannis deposit, Lokris, Central Greece As varies significantly and attains values up to 0.26 wt.% As and in the Gordes deposit of W. Turkey, the As content ranges from 0.004 to 1.07 wt.% As (average 0.34), reaching values up to 1.94 in the hematite zone. Investigation of the mineral chemistry (SEM-EDS) shows that goethite is the main host of As, ranging between 0.5 and 1.2 wt.% As2O3 in the Aghios Ioannis deposit, and between 1.2 to 6.9 wt.% As2O3 in the Gordes deposit, whereas, in co-existing calcite As was not detectable. Goethite occurs in fine-grained porous and concretionary, concentric textures. As values are higher in concretionary goethite. Positive correlation (r > 0.74) between As and Al2O3, TiO2 and ∑ REE contents in the laterite deposits of Greece, coupled with the As-enrichment only in certain laterite deposits points to post depositional As-enrichment.Assuming that high pH facilitates the adsorption of As by goethite, due to its high surface area and low values of the activation energy of adsorption (literature data) As-adsorption by goethite is considered to play an important role in its retention. Elevated As-contents in goethite (Fe-oxides) in Fe–Ni-laterites of Greece and Turkey, due to its absorption capacity, are considered to be of particular significance in the remediation of aquifer and soil contamination rather than being a source of environmental risk. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
