Proterozoic carbonate-hosted Morro Agudo sulfide Pb-Zn district, Brazil: Mineralogical and geochemical evidence of fluid mixing during the ore stage

Aldis, Colin; Olivo, Gema R.; Arruda, Jessica A.A.C.; Cevik, Ilkay S.

doi:10.1016/j.oregeorev.2021.104592

Cited by 2 publications

(1 citation statement)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Morro Agudo zinc-lead sulphide deposit comprises several stratabound lenses hosted by dolostone interbedded with shaley dolostone, that is interpreted as a cycle boundary where carbonates are overlain by mudstones, located in the hangingwall of a complex fault zone (Misi et al, 2005). The host rock includes oolitic and stromatolitic dolostone overlying dolostone breccia (Aldis et al, 2022). A number of other sulphide zinc-lead deposits, as well as the Vazante willemite (zinc silicate) deposit, occur in the same stratigraphic position, in a sequence interpreted to lie above a Neoproterozoic glacial diamictite.…”

Section: Other Deposits and Districtsmentioning

confidence: 99%

Global Irish – Diversity of the diaspora

Reynolds,

Allen,

Muhling

et al. 2023

Irish-Type Zn-Pb Deposits Around the World

View full text Add to dashboard Cite

The spectrum of zinc-lead deposits formed in basinal mineral systems encompasses VMS (volcanogenic massive sulphide), SHMS (shale-hosted massive sulphide), Irish-type and MVT (Mississippi valley Type) deposits. The platform carbonate-hosted part of that spectrum, the Irish-type and MVT deposits, has created the greatest challenges to pigeonholing approaches and the Irish Midland deposits have been variably considered as unique, “SedEx” variants, or MVT variants. In fact, the Irish-type spectrum of deposits can be considered as a global diaspora of diverse deposits that, nonetheless, show a number of distinct and economically significant characteristics in style and setting. For this reason, they warrant consideration as a discrete deposit type, though not in a neat pigeonhole, that is best considered in a mineralizing system context. The distinguishing features of Irish-type mineral systems can be considered in terms of source, trigger, pathway, trap, and preservation. The key features that distinguish Irish-type from ‘typical’ MVT and SHMS deposits are related to basin type and setting, timing of the mineralization event, mineralization style and chemistry, and deposit geometry. Empirically, these characteristic basin to deposit scale features overlap both MVT and SHMS but, together, are unique to Irish-type systems. This gives rise to criteria that can be applied to determine prospectivity of basins for Irish-type deposits and to target deposits within these basins. It is important to distinguish Irish-type from MVT systems because their economic characteristics are different. However, it is also important to recognise that there is great variability within the broad basinal carbonate-hosted zinc-lead deposit family and that each basin, and indeed each trend and deposit, are to some extent unique. It is therefore extremely important to avoid model-driven exploration and to develop a targeting understanding that acknowledges the model framework but is based on actual observations and data. To understand this diversity and targeting context, it is pertinent to consider the wide range of carbonate-hosted deposits that do not fit into the published MVT pigeonhole, including the Irish Midlands deposits; the Alpine deposits; deposits in the Basque-Cantabria Basin; deposits on the Gondwana margin including a number of deposits in North African,, southeast Turkey, Iran, and Duddar in Pakistan; the Early Cretaceous deposits on the Atlantic margin in Gabon; the Ordovician of the Sibumasu terrane (Tibet to Southeast Asia); Polaris in the Franklinian Basin; Nanisivik in the Borden Basin; and the Devonian Lennard Shelf deposits of Western Australia. All of these deposits occur in rift-sag basins with carbonate platforms, in some cases with multiple rift-sag cycles or with successor basins and, where constrained, the mineralization event is syn-basinal and typically related to early extension or inversion events. The deposits are stratabound and mostly tabular and continuous, often show strong direct control by extensional structures, are typically dominated by replacement, and commonly have significantly higher grades than ‘typical’ MVT deposits such as those in the mid-continent US, Silesia (Poland) and Pine Point (Canada).

show abstract

Section: Other Deposits and Districtsmentioning

confidence: 99%

Global Irish – Diversity of the diaspora

Reynolds,

Allen,

Muhling

et al. 2023

Irish-Type Zn-Pb Deposits Around the World

View full text Add to dashboard Cite

show abstract

LA-ICP-MS Trace Element Composition of Sphalerite and Galena of the Proterozoic Carbonate-Hosted Morro Agudo Zn-Pb Sulfide District, Brazil: Insights into Ore Genesis

2022

View full text Add to dashboard Cite

The metal-rich Vazante-Paracatu Mineral Belt, in central Brazil, hosts the Zn-Pb sulfide Morro Agudo District in the Mesoproterozoic (1.3–1.1 Ga) upper carbonate sequence of the Vazante Group. The Morro Agudo district is comprised of the Morro Agudo deposit and the Bento Carmelo, Sucuri, and Morro do Capão occurrences. This carbonate sequence also hosts the Fagundes, Ambrósia and Bonsucesso Zn-Pb sulfide deposits (northern part) and the zinc silicate Vazante and North Extension deposits (southern part). The structurally controlled, stratabound and stratiform styles of mineralization in the Morro Agudo orebodies have been variably classified as sedimentary exhalative, Irish-type and Mississippi Valley-type. In this study, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) spot analyses of sphalerite and galena from the Morro Agudo district revealed that red sphalerite (interpreted as the last stage) has higher Fe and Mn and lower Bi, Co, Cu, Ge, Hg, Tl compared to the other types of sphalerite, whereas the first generation of galena (Gn-I) is enriched in Ag, Cd, and Se and depleted in Cu and Mn relative to later galena (Gn-II). Mineral paragenesis and principal component analysis (PCA) of ore mineral composition suggest that the Morro Agudo, Sucuri and Morro do Capão mineralized zones formed by similar processes involving Zn-Pb mineralizing fluids with various compositions, comprising two main elemental associations: (1) Fe, As, In, Mn, Sb, Ag; and (2) Cd, Bi, Co, Ga, and Se. Bento Carmelo is distinguished in PCA by its unique dolomite-hosted sphalerite composition with elevated concentrations of Cu, Ge, Hg and likely formed from distinct fluids or processes. Temperatures of the mineralizing fluids for the Morro Agudo district range from 82 to 320 °C, calculated based on the trace element composition of sphalerite. The styles of mineralization and ore compositions are consistent with MVT deposits; however, fluid temperatures are hotter than typical MVT mineralizing fluids and may reflect a higher geothermal gradient or active advective fluid flow during the Brasiliano orogeny.

show abstract

Proterozoic carbonate-hosted Morro Agudo sulfide Pb-Zn district, Brazil: Mineralogical and geochemical evidence of fluid mixing during the ore stage

Cited by 2 publications

References 22 publications

Global Irish – Diversity of the diaspora

Global Irish – Diversity of the diaspora

LA-ICP-MS Trace Element Composition of Sphalerite and Galena of the Proterozoic Carbonate-Hosted Morro Agudo Zn-Pb Sulfide District, Brazil: Insights into Ore Genesis

Contact Info

Product

Resources

About