Sulfide-Bearing Veinlets Throughout the Stratiform Mineralization of the Central African Copperbelt: Temporal and Genetic Implications

Sillitoe, Richard H.; Perelló, José; García, Alfredo Martín

doi:10.2113/econgeo.105.8.1361

Cited by 49 publications

(15 citation statements)

References 30 publications

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“…Several other deposits in the Central African Copperbelt contain pre-folding bedding-parallel veins with fibrous growth morphology (Mendelsohn, 1961b;Sweeney et al, 1986;Annels, 1989;Selley et al, 2005;McGowan et al, 2006;Sillitoe et al, 2010;Hitzman et al, 2012;Schuh et al, 2012;Torremans et al, 2013), although not all of these deposits reveal the exact same fine-grained carbonaceous argillite facies as in this study. Hence, if the pre-folding veins are present in these deposits, similar mechanisms could be at work.…”

Section: Enhanced Permeability Structures: Implications For Fluid Flosupporting

confidence: 51%

Mechanisms of flexural flow folding of competent single-layers as evidenced by folded fibrous dolomite veins

Torremans

Muchez

Sintubin

2014

Journal of Structural Geology

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a b s t r a c tFlexural flow is thought unlikely to occur in naturally deformed, competent isotropic single-layers. In this study we discuss a particular case of folded bedding-parallel fibrous dolomite veins in shale, in which the internal strain pattern and microstructural deformation features provide new insights in the mechanisms enabling flexural flow folding. Strain in the pre-folding veins is accommodated by two main mechanisms: intracrystalline deformation by bending and intergranular deformation with bookshelf rotation of dolomite fibres. The initially orthogonal dolomite fibres allowed a reconstruction of the strain distribution across the folded veins. This analysis shows that the planar mechanical anisotropy created by the fibres causes the veins to approximate flexural flow. During folding, synkinematic veins overgrow the pre-folding fibrous dolomite veins. Microstructures and dolomite growth morphologies reflect growth during progressive fold evolution, with evidence for flexural slip at fold lock-up. Homogeneous flattening, as evidenced by disjunctive axial-planar cleavage, subsequently modified these folds from class 1B to 1C folds. Our study shows that the internal vein fabric has a first-order influence on folding kinematics. Moreover, the fibrous dolomite veins show high viscosity contrasts with the shale matrix, essential in creating transient permeability for subsequent mineralising stages in the later synkinematic veins during progressive folding.

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Section: Enhanced Permeability Structures: Implications For Fluid Flosupporting

confidence: 51%

Mechanisms of flexural flow folding of competent single-layers as evidenced by folded fibrous dolomite veins

Torremans

Muchez

Sintubin

2014

Journal of Structural Geology

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“…Such a thickness of sediments would not appear to have been present until well into the Paleozoic, suggesting that the disseminated style of mineralization is late diagenetic. The absence of evidence for successive generations of mineralized veins and the similarity of the paragenetic sequences between the disseminated and the vein-hosted mineralization suggest that they may be related to the same mineralizing event [81]. Hence the disseminated style of mineralization was rapidly followed by the Late Carboniferous compression and the onset of the vein-style mineralization.…”

Section: Timing Of Mineralization and Genetic Processesmentioning

confidence: 98%

Geology and Metallogenesis of the Sediment-Hosted Cu-Ag Deposit of Tizert (Igherm Inlier, Anti-Atlas Copperbelt, Morocco)

et al. 2017

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The Tizert Cu-Ag deposit is the largest of a series of sediment-hosted copper deposits of the Anti-Atlas copper province in Morocco. Mineralized rocks in the deposit contain disseminated sulphides within a Late Ediacaran, dominantly siliciclastic sedimentary formation named the Basal Series. Isopach map of the Basal Series thickness shows that during the Late Ediacaran the area was composed of large subsiding zones separated by paleohighs. The ore-grade zones are well developed along basin margins adjacent to the basement paleohighs. These mineralized zones display a lateral sulphide zoning with central bornite-chalcocite zones grading outward to intermediate chalcopyrite and external pyrite zones. There is also a vertical sulphide zoning with evolution from bornite and chalcocite dominant mineralized rocks at the bottom to chalcopyrite and pyrite dominant mineralized rocks at the top of the lithostratigraphic succession. A second style of mineralization is represented by sulphide filled fractures and veins present in the Basal Series, as well as in the basement and the overlying dolomites. The similarity of the paragenetic sequences between the disseminated and the vein-hosted mineralization suggests that they may be related to the same mineralizing event, the disseminated style of mineralization being rapidly followed by the onset of the vein-style mineralization.

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“…This replacement of pyrite by chalcopyrite is followed by the replacement of chalcopyrite by bornite (El Desouky et al, 2010). Also Sillitoe et al (2010) focussed on the widely developed sulphide texture of bornite rims on chalcopyrite grains and chalcocite rims on bornite grains. Although we modelled the most permeable layer above the mineralised zone, the results are the same in the reverse configuration with layer 2 as footwall rocks.…”

Section: Discussionmentioning

confidence: 99%

“…However, this model is not yet generally accepted (e.g. Sillitoe et al, 2010). The early diagenetic phase is characterised by fine-grained anhedral dolomite followed by Cu-Co sulphides and authigenic quartz, low δ 34 S values of the sulphides (− 10.3 to −3.1‰ V-PDB) indicating bacterial sulphate reduction of sulphate for the origin of the sulphide, moderate saline (8.4-20.9 eq.…”

Section: Geological Setting and Ore-forming Processes In The Katanga mentioning

confidence: 99%

Factors controlling the precipitation of copper and cobalt minerals in sediment-hosted ore deposits: Advances and restrictions

Muchez

Corbella

2012

Journal of Geochemical Exploration

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Sulfide-Bearing Veinlets Throughout the Stratiform Mineralization of the Central African Copperbelt: Temporal and Genetic Implications

Cited by 49 publications

References 30 publications

Mechanisms of flexural flow folding of competent single-layers as evidenced by folded fibrous dolomite veins

Mechanisms of flexural flow folding of competent single-layers as evidenced by folded fibrous dolomite veins

Geology and Metallogenesis of the Sediment-Hosted Cu-Ag Deposit of Tizert (Igherm Inlier, Anti-Atlas Copperbelt, Morocco)

Factors controlling the precipitation of copper and cobalt minerals in sediment-hosted ore deposits: Advances and restrictions

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