کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8866007 1620869 2018 17 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Garnierite mineralization from a serpentinite-derived lateritic regolith, Sulawesi Island, Indonesia: Mineralogy, geochemistry and link to hydrologic flow regime
ترجمه فارسی عنوان
کانی سازی گارنیریت از یک رگولیت لندیته حاصل از سرپنتینیت، جزیره سولاوسی، اندونزی: کانی شناسی، ژئوشیمی و ارتباط آن با رژیم جریان هیدرولوژیکی
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی اقتصادی
چکیده انگلیسی
Garnierite represents a significant nickel ore in many lateritic Ni deposits worldwide. To gain a better understanding of its nature and origin, a well-developed garnierite-hosting transect from the Kolonodale area of East Sulawesi, Indonesia, has been investigated using field geology, mineralogy and geochemical data. Garnierite occurs mainly in veins in the lower saprolite of a serpentinite-derived regolith. Mineralogically, it can be determined as an intimate mixture of Ni-rich serpentine-like (lizardite-Népouite) and talc-like (kerolite-pimelite) phases. Results of EMP analyses indicate that Ni is preferentially enriched in the talc-like phases rather than the serpentine-like phases. A sequential precipitation of mineral phases progressively enriched in Ni and Si to form garnierite during weathering is suggested. The Ni-lizardite (2.63-8.49 wt% Ni) with elevated Fe (4.02-6.44 wt%) may have been inherited from saprolite in a first instance and enriched in Ni by cation exchange processes. Newly precipitated minerals are kerolite-pimelite (7.84-23.54 wt% Ni) and then followed by Ni-free quartz. Minor amount of Népouite (23.47-28.51 wt% Ni) occur in laths along shrinkage cracks of previously formed minerals, indicating a late stage paragenetic sequence. With emphasis on a hydrologic consideration, indicators of a preferential flow regime are identified in the garnierite-hosting regolith, including: (i) non-uniform pattern of the garnierite field occurrence, (ii) syn-weathering active nature of the garnierite-hosting structures, (iii) close relationship between the garnierite occurrence and vertical FeMn oxides pipes as well as FeMn oxides patched areas, and (iv) specific physico-chemical property of the garnierite location with higher organic matter concentrations but lower pH values compared to surroundings. It is proposed that the origin of garnierite is closely linked to a preferential flow of oversaturated solutions through accessible conduits in the regolith. Garnierite features as colloidal nature, high organic matter and low pH are key-parameters in metal transport and deposition.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Geochemical Exploration - Volume 188, May 2018, Pages 240-256
نویسندگان
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