Garnierite mineralization from a serpentinite-derived lateritic regolith, Sulawesi Island, Indonesia: Mineralogy, geochemistry and link to hydrologic flow regime

Wei Fu, Yinmeng Zhang, Chongjin Pang, Xiangwei Zeng, Xiaorong Huang, Mengli Yang, Ya Shao, Hangsheng Lin

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

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 Fe–Mn oxides pipes as well as Fe–Mn 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.

Original languageEnglish (US)
Pages (from-to)240-256
Number of pages17
JournalJournal of Geochemical Exploration
Volume188
DOIs
StatePublished - May 1 2018

Fingerprint

Geochemistry
Mineralogy
serpentinite
regolith
lizardite
Talc
Minerals
saprolite
mineralogy
geochemistry
preferential flow
talc
mineralization
Weathering
Biological materials
Oxides
mineral
weathering
oxide
organic matter

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Economic Geology

Cite this

Fu, Wei ; Zhang, Yinmeng ; Pang, Chongjin ; Zeng, Xiangwei ; Huang, Xiaorong ; Yang, Mengli ; Shao, Ya ; Lin, Hangsheng. / Garnierite mineralization from a serpentinite-derived lateritic regolith, Sulawesi Island, Indonesia : Mineralogy, geochemistry and link to hydrologic flow regime. In: Journal of Geochemical Exploration. 2018 ; Vol. 188. pp. 240-256.
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title = "Garnierite mineralization from a serpentinite-derived lateritic regolith, Sulawesi Island, Indonesia: Mineralogy, geochemistry and link to hydrologic flow regime",
abstract = "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-N{\'e}pouite) 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 N{\'e}pouite (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 Fe–Mn oxides pipes as well as Fe–Mn 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.",
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Garnierite mineralization from a serpentinite-derived lateritic regolith, Sulawesi Island, Indonesia : Mineralogy, geochemistry and link to hydrologic flow regime. / Fu, Wei; Zhang, Yinmeng; Pang, Chongjin; Zeng, Xiangwei; Huang, Xiaorong; Yang, Mengli; Shao, Ya; Lin, Hangsheng.

In: Journal of Geochemical Exploration, Vol. 188, 01.05.2018, p. 240-256.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Garnierite mineralization from a serpentinite-derived lateritic regolith, Sulawesi Island, Indonesia

T2 - Mineralogy, geochemistry and link to hydrologic flow regime

AU - Fu, Wei

AU - Zhang, Yinmeng

AU - Pang, Chongjin

AU - Zeng, Xiangwei

AU - Huang, Xiaorong

AU - Yang, Mengli

AU - Shao, Ya

AU - Lin, Hangsheng

PY - 2018/5/1

Y1 - 2018/5/1

N2 - 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 Fe–Mn oxides pipes as well as Fe–Mn 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.

AB - 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 Fe–Mn oxides pipes as well as Fe–Mn 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.

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