Mineralogy, petrography, geochemistry and genesis of the Paleoproterozoic Birimian manganese-formation of Nsuta/Ghana

Chemostratigraphy of Paleoproterozoic carbonate successions of the Wyoming Craton: tectonic forcing of biogeochemical change?

“…Controls on ocean anoxia remain conjectural. On the one hand, high hydrothermal and volcanic inputs of reduced elements to seawater (as recorded in mantle-dominated 87 Sr/ 86 Sr values in seawater proxies; cf. Asmerom et al, 1991) and the atmosphere would scrub out photosynthetically produced oxygen, but the balance of these two fluxes is unconstrained.…”

An integrated approach to environmental risk assessment of cumulatively impacted drainage basin from mining activities in southwestern Ghana

“…pyrite ? chalcopyrite and occurs commonly in phyllite, quartz veins rich in (Kleinschrot et al 1994;Mücke et al 1999;Nyame 1998). Carbonates, dominated by rhodochrosite, kutnahorite and subordinate calcite, dolomite, and siderite, are more abundant in the carbonate ore and transition ore zones (up 70% volume), followed by the phyllite unit which hosts the ore (up 40%) and less abundant in the associated greenstones (less 40%).…”

Petrography and geochemistry of intraclastic manganese–carbonates from the ∼2.2Ga Nsuta deposit of Ghana: Significance for manganese sedimentation in the Palaeoproterozoic of West Africa

“…Milesi et al (1989) and Ledru (1988) identified slump structures in what they described as sandstone and conglomerate within the succession of the Nsuta manganese deposit which they interpreted as ''mass flow'' type turbidites deposited at the foot of an old talus slope. Intraclastic structures within the manganesestone or immediate host rocks at Nsuta have, however, either not been reported or studied in detail in all published work on the deposit (Kleinschrot et al, 1994;Mucke et al, 1999). The stratigraphic occurrence, petrography, and geochemistry of the ''intraclastic facies'' in relation to the manganesestone shed considerable light on the environmental conditions and processes during and/or soon after sedimentation of the manganesestone.…”

“…The geology, structure, and aspects of the geochemistry of the Nsuta deposit have been given in Service (1943), Kesse (1976), Kleinschrot et al (1994), Nyame (1998), Mucke et al (1999), andYeh et al (1995). The general stratigraphy of the Nsuta deposit as reported by Kesse (1976) comprises a basal greenstone unit followed successively upwards by argillaceous rocks and tuffs, manganese-carbonates, argillaceous rocks and tuffs, and greenstone.…”