Geochemistry and tectonic setting of the Paleoproterozoic metavolcanic rocks from the Chirano Gold District, Sefwi belt, Ghana

Senyah, Gloria Awo A; Dampare, Samuel B.; Asiedu, Daniel K.

doi:10.1016/j.jafrearsci.2015.07.022

Cited by 18 publications

(16 citation statements)

References 35 publications

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“…Whilst most research works have been focused on the Birimian metavolcanics (e.g., Dampare et al, ; Dampare, Shibata, Asiedu, Osae, & Banoeng‐Yakubo, ; Gallip, Klemd, & Hirdes, ; Senyah, Dampare, & Asiedu, ), the Palaeoproterozoic sedimentary rocks of the WAC have received little attention, and therefore, remain the subject of continuous debate. For example, a school of thought suggesting that the sediments were derived from the WAC was disputed by Leube and Hirdes (1986) who used geochemical evidence (based on negative and low positive Eu anomalies) of the sediments to show that the bulk of the sediments could only be of volcanic source of predominantly dacitic composition.…”

Section: Introductionmentioning

confidence: 99%

Geochemical and Sm–Nd isotopic evidence for the composition of the Palaeoproterozoic crust of the West African Craton in Ghana

Sakyi

Manu

et al. 2018

Geological Journal

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The metasedimentary rocks of the Sefwi and Lawra volcanic belts in Ghana respectively were analysed for their major and trace elements and Sr‐Nd isotopic compositions to constrain the provenance, palaeo‐weathering conditions, and tectonic setting of the rocks. Geochemical characteristics of the metasedimentary rocks show low to moderate chemical weathering in their source regions and the rocks are interpreted to have been derived from mixture of mafic and felsic rock components. The LREE show much enrichment in relation to the HREE (LaN/LuN, 4.67‐11.66). The εNd (2.1 Ga) values of −0.12 to +3.72 strongly suggest that the source of the sedimentary rocks was derived from a depleted mantle source and that they were most likely produced in an almost entirely oceanic environment with minor influence from the continental crust. The Nd model ages ranging from +2.05 to 2.41 Ga suggest possible contributions of a pre‐Birimian crustal material (or Archaean?) in the source material of the volcanic rocks. The rock types that contributed as detritus to the Birimian metasedimentary rocks were mainly pyroclastics and basalts, and their REE patterns suggest that the contribution to the phyllites can be modelled after 20% basalt, 13% andesite, and 67% dacite. Similarly, the schists can be modelled as a mixture of 16% basalt, 34% andesite, and 50% dacite. The Nd isotopic modeling implies that the bulk of the sedimentary detritus was supplied by the Palaeoproterozoic volcanic arc with contributions of less than 10% from the pre‐Birimian crust (Archaean?).

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Section: Introductionmentioning

confidence: 99%

Geochemical and Sm–Nd isotopic evidence for the composition of the Palaeoproterozoic crust of the West African Craton in Ghana

Sakyi

Manu

et al. 2018

Geological Journal

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“…The low Nb/Y values of the Bhukia albitites together with low to moderate SiO 2 values mimic the typical characteristics of basic to intermediate rocks (Senyah, Dampare, & Asiedu, ; Table ). The rocks of crust or mantle origin have been distinguished using Y/Nb ratio for a long time now.…”

Section: Resultsmentioning

confidence: 55%

Geochemical characterization of mineralized albitite from Paleoproterozoic Bhukia IOCG‐IOA deposit of Aravalli‐Delhi Fold Belt, Rajasthan, western India: Genetic linkage to the gold (±Cu ± U) mineralization

2019

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Paleoproterozoic Bhukia gold deposit is located within the Debari Group of Aravalli Supergroup, Rajasthan, northwestern India. The major lithounits that are associated with gold-graphite (±Cu ± U) mineralization exposed in Bhukia are albitite, carbonates, and quartzite which have undergone upper greenschist to amphibolite facies metamorphism. Ore mineralization viz. pyrrhotite, arsenopyrite, chalcopyrite, pyrite, graphite, magnetite, and goethite in the study area are associated with NNW-SSE trending shear zone. Nuggets of gold are identified in the thick gossan zones that occurs parallel to the shear zone. The gold-sulfide lodes of the Bhukia deposits are largely confined either to marble or albitized marble and pure monomineralic albitite.The mineralization that is associated with the albitite, follows the boundaries of albite grains which confirms the role of these weak zones for the mobilization of mineralizing fluid and concentration of metal ions. Hence, geochemical studies of albitite would help to evaluate the petrogenesis, likely magmatic affinity, tectonic setting, controls of the mineralizing fluid, source, and their linkage to the gold (±Cu ± U) metallogeny. Bhukia albitite is characterized by Na-Al-rich and K-poor compositions along with metaluminous nature. Geochemical analysis of various key elements suggests that albitite is the product of low-K calc-alkaline magma series with variation in Nb/Ta ratio indicating their fractionation during the melt-rock interaction within the shear zone. Geochemical signatures suggest the role of upper continental crust in channelizing the mineralized fluids that generated albitite with felsic to intermediate composition in and around Bhukia deciphered from their low Nb/Y ratios. Lower concentration of compatible elements (Ni and Cr) and higher concentration of incompatible elements (Th, La, and Nd) with SiO 2 suggest that evolution of albitite rock is related to the fractional crystallization process. Zr/Hf ratios of 9-35 with the average of 18 suggest that albitite formed under magmatic-hydrothermal transitional environment. Rare Earth Elements (REE) patterns of albitite samples are moderately fractionated showing Light Rare Earth Elements (LREE)-enrichment with a rather steep slope and exhibit distinct negative Eu anomalies (0.42-0.71, average 0.57). The enrichment of LREE in comparison to the Heavy Rare Earth Elements (HREE) suggests a more evolved source, i.e., process of melting at shallow environments. Tectonic setting of albitite samples suggest their origin in a volcanic arc region that underwent rifting. Detailed geochemical characterization unravelled complex evolutionary history of albitite in the Bhukia area, which attests derivation of the parental melt possibly from an enriched SCLM (Sub-continental lithospheric mantle) source similar to most of the IOCG-IOA deposits worldwide.

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“…Volcanic rocks of the Birimian Supergroup range in composition from basalt to rhyolite, displaying tholeiitic to calc-alkaline affinities (e.g. Baratoux, et al, 2011;Hirdes, et al, 1993;Senyah, et al, 2016;Sylvester & Attoh, 1992), with subordinate intercalations of volcanoclastic or immature sedimentary rocks. Volcano-sedimentary domains comprise deformed sequences of greywacke, shale, argillite, volcanoclastic rocks (pyroclastic and epiclastic) and calc-alkaline volcanic sequences (Hirdes, et al, 1993;Leube, et al, 1990).…”

Section: Paleoproterozoic Geology Of West Africamentioning

confidence: 99%

Onset of the supercontinent cycle: Evidence for multiple oceanic arc accretion events in the Paleoproterozoic Sefwi Greenstone Belt of the West African Craton

McFarlane

Thébaud

Parra‐Avila

et al. 2019

Precambrian Research

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Geochemistry and tectonic setting of the Paleoproterozoic metavolcanic rocks from the Chirano Gold District, Sefwi belt, Ghana

Cited by 18 publications

References 35 publications

Geochemical and Sm–Nd isotopic evidence for the composition of the Palaeoproterozoic crust of the West African Craton in Ghana

Geochemical and Sm–Nd isotopic evidence for the composition of the Palaeoproterozoic crust of the West African Craton in Ghana

Geochemical characterization of mineralized albitite from Paleoproterozoic Bhukia IOCG‐IOA deposit of Aravalli‐Delhi Fold Belt, Rajasthan, western India: Genetic linkage to the gold (±Cu ± U) mineralization

Onset of the supercontinent cycle: Evidence for multiple oceanic arc accretion events in the Paleoproterozoic Sefwi Greenstone Belt of the West African Craton

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