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![Fig. 5. Drill core from the Karakaene-Ndi and Goto deposits. A. Angular inclusions of altered microdiorite (secondary garnet and clinopyroxene) in semimassive magnetite (Karakaene-Ndi, sample KADD24). B. Irregular, strongly corroded inclusions of altered microdiorite (secondary clinopyroxene and biotite) in semimassive magnetite (Karakaene-Ndi, sample KA96-14). C. Magnetite-clinopyroxene-biotite skarn with weakly indicated tectonic banding (Karakaene-Ndi, sample KA96-14). D. Serpentinized clinopyroxene-magnetite skarn (Goto, sample Got11).]()
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![Fig. 9. Plots of Cr2O3, MnO, TiO2, and V2O5 concentrations of magnetite in skarn, granodiorite, and andesite from the Falémé district. The magnetite in skarn has low Cr2O3 and V2O5 concentrations compared to magnetite in granodiorite and andesite. The low MnO/(V2O5 + TiO2) ratios of magnetite in skarn are more typical of skarn associated with gabbro and diorite than in skarn associated with granite. A. Plot of V2O5 vs. TiO2 in magnetite from the Karakaene-Ndi endoskarn, Goto exoskarn, Boboti granodiorite, and Guebouria andesite. B. Plot of V2O5 vs. Cr2O3 in magnetite from the Karakaene-Ndi endoskarn, Goto exoskarn, Boboti granodiorite, and Guebouria andesite. C. Plot of MnO vs. TiO2 in magnetite from the Karakaene-Ndi endoskarn, Goto exoskarn, Boboti granodiorite, and Guebouria andesite. D. Plot of V2O5 vs. TiO2-MnO in magnetite from the Karakaene-Ndi endoskarn and Goto exoskarn; the compositional fields for magnetite in skarn deposits associated with various igneous rocks from China (Zhao et al., 1990, inXu and Zhang, 1998) is shown for comparison. Open circles = Karakaene-Ndi endoskarn, open squares = Goto exoskarn, filled circles = Boboti granodiorite, crosses = Guebouria andesite.]()
![Fig. 6. Mineral associations and paragenesis of the Karakaene-Ndi and Goto iron deposits.]()
![Histograms showing δ13C data from (A) ankerite and dolomite in auriferous hydrothermal veins, barren hydrothermal veins, and carbonate country rocks from the Loulo-Gounkoto complex, including the Gara, Yalea, and Gounkoto mines (data from Fouillac et al., 1993; Lawrence et al., 2013b; Lambert-Smith et al., 2016b); (B) ankerite and dolomite in auriferous and barren hydrothermal veins from the Bambadji exploration targets, Gefa, Boboti, Kabe West, Kolya, and Baqata; (C) calcite from late hydrothermal veins at the Karakaene Ndi iron skarn deposit. Fields of typical C isotope characteristics of Precambrian marine carbonates and organic carbon are indicated (Schidlowski et al., 1975; Eichmann and Schidlowski, 1975). Histograms showing δ18O data from (D) ankerite and dolomite in auriferous hydrothermal veins, barren hydrothermal veins, and carbonate country rocks from the Loulo-Gounkoto complex; (E) ankerite and dolomite in auriferous and barren hydrothermal veins from the Bambadji exploration targets, Gefa, Boboti, Kabe West, Kolya, and Baqata; (F) calcite from late hydrothermal veins at the Karakaene Ndi iron skarn deposit. Number of samples and key is equivalent to (A), (B) and (C).]()
![Histograms showing δ34S data from pyrite at (A) the Loulo Au deposits (Fouillac et al., 1993; Lawrence et al., 2013b; Lambert-Smith, 2014; Lambert-Smith et al., 2016b) and diagenetic pyrite from the Kofi series dolostones; (B) the Kabe West, Kolya, Baqata, and Bobotie exploration targets; (C) the Karakaene Ndi skarn deposit, with paragenetic breakdown between sulfides disseminated in the iron ore and those hosted in crosscutting veins (inset).]()
![Fig. 16. A. Temperature vs. XCO2 of decarbonation reactions at 0.5 kbar. The reactions 1, 2, 4, 6, and 8 may have been important during the formation of the Karakaene-Ndi endoskarn and the Goto exoskarn. The reactions involving hematite, forsterite, and wollastonite (3, 5, 7, 9, 10, and 11) are shown for comparison. B. Corresponding temperature vs. relative oxygen fugacity (▵log ƒO2), defined as the calculated log fO2 minus that of the pyrrhotite-pyrite-magnetite (PPM) buffer, for decarbonation equilibria at XCO2 = 0.05 and various oxygen-fugacity buffers at 0.5 kbar. The shaded area indicates the depositional conditions for the Goto exoskarn, which has graphite and abundant pyrrhotite. The hatched area indicates the depositional conditions for the Karakaene-Ndi endoskarn, which has very little pyrrhotite but iss. The data for the minimum oxygen fugacity derived from the sulfur fugacity for the iss-forming reaction in the presence of magnetite is taken from Sugaki et al. (1975) and Kojima and Sugaki (1985). The decarbonation reactions are calculated with the SUPCRT92 program (Johnson et al., 1992) and AX (activity concentration) program of T. Holland and R. Powell (©2000; Holland and Powell, 1990, 1998), using the CO2-H2O equation of state of Kerrick and Jacobs (1981). The oxygen-fugacity buffers are calculated with the SUPCRT92 program (Johnson et al., 1992). (1) Di + 2CO2 = Do + 2Qu, (2) 10Di60Hed40 + Py + 16CO2 = 4Ca + 6Do + 20Qu + 2Po + Mt, (3) 5Di60Hed40 + 2Hm + 8CO2 = 2Ca + 3Do + 10Qu + 2Mt, (4) Se + 48Ca + 14CO2 = 17Di + 31Do + 31H2O, (5) And + 3CO2 = 3Ca + Hm + 3Qu, (6) 4And + 2Po + 12CO2 = 12Ca + 12Qu + 3Mt + Py, (7) 9And56Grs44 + 20CO2 + 1.75H2O = 3.5Ep71Cz29 + 20Ca + 16.5Qu + 3.75Hm, (8) 9And56Grs44 + 1.875 Po + 20CO2 + 1.75H2O = 3.5Ep71Cz29 + 20Ca + 16.5Qu + 0.938Py + 2.813Mt, (9) 34Fo + 20Ca + 20CO2 + 31H2O = Se + 20Do, (10) 2Fo + 4Ca + 2CO2 = Di + 3Do, and (11) Wo + CO2 = Qu + Ca. Abbreviations: And = andradite, Ca = calcite, Cp = chalcopyrite, Cz = clinozoisite, Di = diopside, Do = dolomite, Fo = forsterite, Ep = epidote, Gr = graphite, Grs = grossular, Hed = hedenbergite, Hm = hematite, iss = Cu-Fe-S intermediate solid solution, Mt = magnetite, Po = pyrrhotite, Py = pyrite, Qu = quartz, Se = serpentine (antigorite), Wo = wollastonite.]()
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1-9 OF 9 RESULTS FOR
Karakaene Deposit
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Journal Article
Stable C, O, and S Isotope Record of Magmatic-Hydrothermal Interactions Between the Falémé Fe Skarn and the Loulo Au Systems in Western Mali
Journal: Economic Geology
Publisher: Society of Economic Geologists
Published: 01 November 2020
Economic Geology (2020) 115 (7): 1537–1558.
... and Kofi series opens the possibility that the Fe skarns and Au deposits are part of the same mineral system. In this paper, we combine new δ 13 C, δ 18 O, and δ 34 S data from the Karakaene Ndi skarn, Au occurrences along the western margin of the Kofi series, and zircons within plutonic rocks...
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Includes: Supplemental Content
Image
F ig . 5. Drill core from the Karakaene-Ndi and Goto deposits. A. Angular i...
Published: 01 August 2004
F ig . 5. Drill core from the Karakaene-Ndi and Goto deposits. A. Angular inclusions of altered microdiorite (secondary garnet and clinopyroxene) in semimassive magnetite (Karakaene-Ndi, sample KADD24). B. Irregular, strongly corroded inclusions of altered microdiorite (secondary clinopyroxene
Journal Article
The Falémé Iron District, Senegal
Journal: Economic Geology
Publisher: Society of Economic Geologists
Published: 01 August 2004
Economic Geology (2004) 99 (5): 917–939.
...F ig . 5. Drill core from the Karakaene-Ndi and Goto deposits. A. Angular inclusions of altered microdiorite (secondary garnet and clinopyroxene) in semimassive magnetite (Karakaene-Ndi, sample KADD24). B. Irregular, strongly corroded inclusions of altered microdiorite (secondary clinopyroxene...
FIGURES
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Image
F ig . 9. Plots of Cr 2 O 3 , MnO, TiO 2 , and V 2 O 5 concentrations of m...
Published: 01 August 2004
endoskarn and Goto exoskarn; the compositional fields for magnetite in skarn deposits associated with various igneous rocks from China (Zhao et al., 1990, in Xu and Zhang, 1998 ) is shown for comparison. Open circles = Karakaene-Ndi endoskarn, open squares = Goto exoskarn, filled circles = Boboti
Image
F ig . 6. Mineral associations and paragenesis of the Karakaene-Ndi and Got...
Published: 01 August 2004
F ig . 6. Mineral associations and paragenesis of the Karakaene-Ndi and Goto iron deposits.
Image
Histograms showing δ 13 C data from (A) ankerite and dolomite in aurifero...
in Stable C, O, and S Isotope Record of Magmatic-Hydrothermal Interactions Between the Falémé Fe Skarn and the Loulo Au Systems in Western Mali
> Economic Geology
Published: 01 November 2020
., 2013b ; Lambert-Smith et al., 2016b ); (B) ankerite and dolomite in auriferous and barren hydrothermal veins from the Bambadji exploration targets, Gefa, Boboti, Kabe West, Kolya, and Baqata; (C) calcite from late hydrothermal veins at the Karakaene Ndi iron skarn deposit. Fields of typical C isotope
Image
Histograms showing δ 34 S data from pyrite at (A) the Loulo Au deposits (...
in Stable C, O, and S Isotope Record of Magmatic-Hydrothermal Interactions Between the Falémé Fe Skarn and the Loulo Au Systems in Western Mali
> Economic Geology
Published: 01 November 2020
exploration targets; (C) the Karakaene Ndi skarn deposit, with paragenetic breakdown between sulfides disseminated in the iron ore and those hosted in crosscutting veins (inset).
Image
F ig . 16. A. Temperature vs. X CO 2 of decarbonation reactions at 0.5 kb...
Published: 01 August 2004
indicates the depositional conditions for the Goto exoskarn, which has graphite and abundant pyrrhotite. The hatched area indicates the depositional conditions for the Karakaene-Ndi endoskarn, which has very little pyrrhotite but iss. The data for the minimum oxygen fugacity derived from the sulfur fugacity
Journal Article
The Alamoutala Carbonate-Hosted Gold Deposit, Kédougou-Kénieba Inlier, West Africa
Journal: Economic Geology
Publisher: Society of Economic Geologists
Published: 01 January 2017
Economic Geology (2017) 112 (1): 49–72.
...Quentin Masurel; Nicolas Thébaud; John Miller; Stanislav Ulrich; Malcolm Peter Roberts; Didier Béziat Abstract The Alamoutala gold deposit is located in the Kédougou-Kénieba inlier, a window of Paleoproterozoic rocks that crop out in eastern Senegal and western Mali. The deposit is part of the ~3...
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