Mineral chemistry, bulk rock geochemistry, and S-isotope signature of lode-gold mineralization in the Bétaré Oya gold district, south-east Cameroon

Akumbom Vishiti, Cheo Emmanuel Suh, Bernd Lehmann, Elisha Mutum Shemang, Njumbe Lionel Junior Ngome, Nfor Jones Nshanji, Fonkwo Edmond Chinjo, Oben Yoland Mongwe, Ashu Jones Egbe, Sven Petersen

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Abstract

Lode-gold mineralization in the Bétaré Oya gold district is related to a series of quartz?sulphide veins that define a steeply dipping NNE?SSW-trending brittle?ductile shear zone. The veins transect metasedimentary sequences in the vicinity of small granitic intrusions. Quartz veins range from barren (massive quartz) to mineralized with textures that vary from foliated, sheared, vuggy, fractured, and sugary to brecciated with inclusions of altered wall rock. They contain gold, pyrite, and galena in addition to chalcopyrite and both hypogene and supergene haematite and covellite. Parameters that consistently define primary gold mineralization in the area include silicification, sulphidation, sericitization, K-feldspar alteration, haematitization, and carbonatization. Gold grains recovered from heavy mineral concentrate and grains that occur as inclusions in pyrite were characterized by microchemical methods. The gold grains are zoned and exhibit a simple internal structure of partly deformed and leached rims and high-purity intragranular veinlets. Gold is alloyed with Ag; gold fineness varies between 859 and 877 in the core and from 958 to 997 in the leached rims. Inclusions of gold in pyrite cluster between 875 and 900. Pyrite has up to 0.59 wt% Au, and other trace elements occur in low quantities but for Pb (0.13 wt%), Ag (1.36 wt%), and Sb (1.63 wt%). The bulk trace element signature of the veins is characterized by Au, Ag, As, Bi, Ba, Cr, Cu, Mn, Pb, Sb, Sr, V, W, Zn, and Zr. This depicts a geochemical association of Au ± Cu ± Bi ± As ± Pb. The occurrence of Au as well as elevated Pb and Zn could suggest a granitic source for the ore-bearing fluid. The auriferous quartz veins are characterized by a widespread in δ34S from 2.8 to 14.9? pointing to multiple sources of sulphur in the system, perhaps a mixture of sulphur from the metasedimentary and the granitic rocks.
Original languageEnglish
Pages (from-to)2579-2596
Number of pages18
JournalGeological Journal
Volume53
Issue number6
DOIs
Publication statusPublished - 2017

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gold
geochemistry
isotope
mineralization
mineral
rock
pyrite
quartz vein
sulfur
trace element
quartz
silicification
heavy mineral
wall rock
galena
chalcopyrite
hematite
shear zone
feldspar
transect

Cite this

Vishiti, Akumbom ; Suh, Cheo Emmanuel ; Lehmann, Bernd ; Shemang, Elisha Mutum ; Ngome, Njumbe Lionel Junior ; Nshanji, Nfor Jones ; Chinjo, Fonkwo Edmond ; Mongwe, Oben Yoland ; Egbe, Ashu Jones ; Petersen, Sven. / Mineral chemistry, bulk rock geochemistry, and S-isotope signature of lode-gold mineralization in the Bétaré Oya gold district, south-east Cameroon. In: Geological Journal. 2017 ; Vol. 53, No. 6. pp. 2579-2596.
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title = "Mineral chemistry, bulk rock geochemistry, and S-isotope signature of lode-gold mineralization in the B{\'e}tar{\'e} Oya gold district, south-east Cameroon",
abstract = "Lode-gold mineralization in the B{\'e}tar{\'e} Oya gold district is related to a series of quartz?sulphide veins that define a steeply dipping NNE?SSW-trending brittle?ductile shear zone. The veins transect metasedimentary sequences in the vicinity of small granitic intrusions. Quartz veins range from barren (massive quartz) to mineralized with textures that vary from foliated, sheared, vuggy, fractured, and sugary to brecciated with inclusions of altered wall rock. They contain gold, pyrite, and galena in addition to chalcopyrite and both hypogene and supergene haematite and covellite. Parameters that consistently define primary gold mineralization in the area include silicification, sulphidation, sericitization, K-feldspar alteration, haematitization, and carbonatization. Gold grains recovered from heavy mineral concentrate and grains that occur as inclusions in pyrite were characterized by microchemical methods. The gold grains are zoned and exhibit a simple internal structure of partly deformed and leached rims and high-purity intragranular veinlets. Gold is alloyed with Ag; gold fineness varies between 859 and 877 in the core and from 958 to 997 in the leached rims. Inclusions of gold in pyrite cluster between 875 and 900. Pyrite has up to 0.59 wt{\%} Au, and other trace elements occur in low quantities but for Pb (0.13 wt{\%}), Ag (1.36 wt{\%}), and Sb (1.63 wt{\%}). The bulk trace element signature of the veins is characterized by Au, Ag, As, Bi, Ba, Cr, Cu, Mn, Pb, Sb, Sr, V, W, Zn, and Zr. This depicts a geochemical association of Au ± Cu ± Bi ± As ± Pb. The occurrence of Au as well as elevated Pb and Zn could suggest a granitic source for the ore-bearing fluid. The auriferous quartz veins are characterized by a widespread in δ34S from 2.8 to 14.9? pointing to multiple sources of sulphur in the system, perhaps a mixture of sulphur from the metasedimentary and the granitic rocks.",
author = "Akumbom Vishiti and Suh, {Cheo Emmanuel} and Bernd Lehmann and Shemang, {Elisha Mutum} and Ngome, {Njumbe Lionel Junior} and Nshanji, {Nfor Jones} and Chinjo, {Fonkwo Edmond} and Mongwe, {Oben Yoland} and Egbe, {Ashu Jones} and Sven Petersen",
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Vishiti, A, Suh, CE, Lehmann, B, Shemang, EM, Ngome, NLJ, Nshanji, NJ, Chinjo, FE, Mongwe, OY, Egbe, AJ & Petersen, S 2017, 'Mineral chemistry, bulk rock geochemistry, and S-isotope signature of lode-gold mineralization in the Bétaré Oya gold district, south-east Cameroon', Geological Journal, vol. 53, no. 6, pp. 2579-2596. https://doi.org/10.1002/gj.3093

Mineral chemistry, bulk rock geochemistry, and S-isotope signature of lode-gold mineralization in the Bétaré Oya gold district, south-east Cameroon. / Vishiti, Akumbom; Suh, Cheo Emmanuel; Lehmann, Bernd; Shemang, Elisha Mutum; Ngome, Njumbe Lionel Junior; Nshanji, Nfor Jones; Chinjo, Fonkwo Edmond; Mongwe, Oben Yoland; Egbe, Ashu Jones; Petersen, Sven.

In: Geological Journal, Vol. 53, No. 6, 2017, p. 2579-2596.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Mineral chemistry, bulk rock geochemistry, and S-isotope signature of lode-gold mineralization in the Bétaré Oya gold district, south-east Cameroon

AU - Vishiti, Akumbom

AU - Suh, Cheo Emmanuel

AU - Lehmann, Bernd

AU - Shemang, Elisha Mutum

AU - Ngome, Njumbe Lionel Junior

AU - Nshanji, Nfor Jones

AU - Chinjo, Fonkwo Edmond

AU - Mongwe, Oben Yoland

AU - Egbe, Ashu Jones

AU - Petersen, Sven

N1 - doi: 10.1002/gj.3093

PY - 2017

Y1 - 2017

N2 - Lode-gold mineralization in the Bétaré Oya gold district is related to a series of quartz?sulphide veins that define a steeply dipping NNE?SSW-trending brittle?ductile shear zone. The veins transect metasedimentary sequences in the vicinity of small granitic intrusions. Quartz veins range from barren (massive quartz) to mineralized with textures that vary from foliated, sheared, vuggy, fractured, and sugary to brecciated with inclusions of altered wall rock. They contain gold, pyrite, and galena in addition to chalcopyrite and both hypogene and supergene haematite and covellite. Parameters that consistently define primary gold mineralization in the area include silicification, sulphidation, sericitization, K-feldspar alteration, haematitization, and carbonatization. Gold grains recovered from heavy mineral concentrate and grains that occur as inclusions in pyrite were characterized by microchemical methods. The gold grains are zoned and exhibit a simple internal structure of partly deformed and leached rims and high-purity intragranular veinlets. Gold is alloyed with Ag; gold fineness varies between 859 and 877 in the core and from 958 to 997 in the leached rims. Inclusions of gold in pyrite cluster between 875 and 900. Pyrite has up to 0.59 wt% Au, and other trace elements occur in low quantities but for Pb (0.13 wt%), Ag (1.36 wt%), and Sb (1.63 wt%). The bulk trace element signature of the veins is characterized by Au, Ag, As, Bi, Ba, Cr, Cu, Mn, Pb, Sb, Sr, V, W, Zn, and Zr. This depicts a geochemical association of Au ± Cu ± Bi ± As ± Pb. The occurrence of Au as well as elevated Pb and Zn could suggest a granitic source for the ore-bearing fluid. The auriferous quartz veins are characterized by a widespread in δ34S from 2.8 to 14.9? pointing to multiple sources of sulphur in the system, perhaps a mixture of sulphur from the metasedimentary and the granitic rocks.

AB - Lode-gold mineralization in the Bétaré Oya gold district is related to a series of quartz?sulphide veins that define a steeply dipping NNE?SSW-trending brittle?ductile shear zone. The veins transect metasedimentary sequences in the vicinity of small granitic intrusions. Quartz veins range from barren (massive quartz) to mineralized with textures that vary from foliated, sheared, vuggy, fractured, and sugary to brecciated with inclusions of altered wall rock. They contain gold, pyrite, and galena in addition to chalcopyrite and both hypogene and supergene haematite and covellite. Parameters that consistently define primary gold mineralization in the area include silicification, sulphidation, sericitization, K-feldspar alteration, haematitization, and carbonatization. Gold grains recovered from heavy mineral concentrate and grains that occur as inclusions in pyrite were characterized by microchemical methods. The gold grains are zoned and exhibit a simple internal structure of partly deformed and leached rims and high-purity intragranular veinlets. Gold is alloyed with Ag; gold fineness varies between 859 and 877 in the core and from 958 to 997 in the leached rims. Inclusions of gold in pyrite cluster between 875 and 900. Pyrite has up to 0.59 wt% Au, and other trace elements occur in low quantities but for Pb (0.13 wt%), Ag (1.36 wt%), and Sb (1.63 wt%). The bulk trace element signature of the veins is characterized by Au, Ag, As, Bi, Ba, Cr, Cu, Mn, Pb, Sb, Sr, V, W, Zn, and Zr. This depicts a geochemical association of Au ± Cu ± Bi ± As ± Pb. The occurrence of Au as well as elevated Pb and Zn could suggest a granitic source for the ore-bearing fluid. The auriferous quartz veins are characterized by a widespread in δ34S from 2.8 to 14.9? pointing to multiple sources of sulphur in the system, perhaps a mixture of sulphur from the metasedimentary and the granitic rocks.

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DO - 10.1002/gj.3093

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