The Early Proterozoic Matachewan Large Igneous Province: Geochemistry, Petrogenesis, and Implications for Earth Evolution

Ciborowski, T. Jake R.; Kerr, Andrew C.; Ernst, Richard E.; McDonald, Iain; Minifie, Matthew J.; Harlan, Stephen S.; Millar, Ian L.

doi:10.1093/petrology/egv038

Cited by 35 publications

(22 citation statements)

References 154 publications

(245 reference statements)

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“…On the basis of coeval magmatism, Bleeker and Ernst (2006) suggested that the Fennoscandian Shield was situated along the southern margin of the Superior Craton at the end of the Archean. The tectonic setting as well as the mantle source of magmatism remain under debate, but most researchers prefer a rift-related mantle plume melting model followed by large-scale contamination with older felsic crustal rocks to explain the trace element and isotopic signature of the igneous rocks (Amelin et al, 1995;Barnes et al, 2001;Ciborowski et al, 2015;Hanski et al, 2001b;Puchtel et al, 1997;Yang et al, 2016).…”

Section: Geological Settingmentioning

confidence: 99%

Critical Controls on the Formation of Contact-Style PGE-Ni-Cu Mineralization: Evidence from the Paleoproterozoic Monchegorsk Complex, Kola Region, Russia

et al. 2018

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The Paleoproterozoic Monchegorsk Complex, located in the Russian part of the Fennoscandian Shield, constitutes one of the largest mafic-ultramafic layered intrusions in Europe. The complex hosts extensive contact-style PGE-Ni-Cu sulfide mineralization along its margin, irrespective of the host lithology, which ranges from peridotite to pyroxenite and gabbronorite. The mineralized intervals reach up to 3 ppm Pt + Pd and attain a thickness of up to 50 m in the central portions of the intrusion, thinning towards the periphery. Our study shows that the key process controlling the size and grade of a contactstyle deposit in the Monchegorsk Complex, was the efficiency of sulfide collection in distinct zones of the intrusion. Strongly mineralized basal contacts are always associated with intense brecciation and the presence of large amounts of felsic pegmatite, suggesting a multi-stage emplacement of the mafic-ultramafic succession. Thermal modeling demonstrates that multiple episodes of magma influx are required to allow for significant partial melting of the basement. Moreover, the interaction between magma and basement led to the local addition of water and potentially carbon dioxide to the magma, resulting in partial melting of cumulus phases and a reduction in viscosity of the interstitial melt. This increased the porosity of the mush in the vicinity of the lower intrusion contact, which promoted preferential sulfide liquid accumulation at the base, while the local decrease in magma viscosity facilitated gravitational settling of sulfide droplets. These factors led to an efficient collection of sulfide liquid, especially in the center of the complex, where permeability was maintained the longest due to slower cooling relative to more peripheral parts.

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Section: Geological Settingmentioning

confidence: 99%

Critical Controls on the Formation of Contact-Style PGE-Ni-Cu Mineralization: Evidence from the Paleoproterozoic Monchegorsk Complex, Kola Region, Russia

et al. 2018

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“…Geochemistry, Geophysics, Geosystems intrusions in the Superior and Wyoming Cratons, are thought to be part of one the oldest large igneous provinces on Earth (Ciborowski et al, 2015;Heaman, 1997).…”

Section: 1029/2018gc007548mentioning

confidence: 99%

Investigating Complex Isochron Data Using Mixture Models

Davies

Sheldrake

Reimink

et al. 2018

Geochem Geophys Geosyst

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The isochron technique for dating geological events is widely used in many fields of isotope geochemistry. However, data sets can be complex, and many samples may not behave as closed systems, resulting in excess scatter around a regression line. In certain data sets, however, excess scatter may result when geological samples are partially reset or when samples are comprised of multiple components recording different geological processes separated in time and/or initial isotope composition. Here we introduce a new approach for investigating evidence of such multicomponent mixtures within isochron space. We provide a mathematical framework to resolve the number of mixture components, without requiring any prior knowledge of this number. Crucially, the model reports the proportion of each individual sample that belongs to each mixture component, allowing the user to return to the samples and independently test model outputs with other techniques. It is important to distinguish accurate and meaningful ages and initial daughter isotope compositions from the meaningless values that are caused by mismatch between geological processes and the models that we use to describe them. First, we demonstrate our new model on a synthetic data set to show that it can successfully separate distinct isochrons in a complex mixture. We further validate our approach with a previously published data set using the 187Re‐187Os system in bitumen and 147Sm/144Nd system in magmatic rocks. We identify discrete components in these data sets and using complementary geological observations discuss the implications of treating these scattered data as recording multiple geological processes.

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“…On the basis of coeval magmatism, it was suggested that the Fennoscandian Shield was situated along the southern margin of the Superior craton at the end of the Archean [14]. The tectonic setting, as well as the mantle source of magmatism, remain under debate, but most researchers prefer a rift-related mantle plume melting model followed by large-scale contamination with older felsic crustal rocks to explain the trace element and isotopic signature of the igneous rocks [15][16][17][18][19][20].…”

Section: Geologic Settingmentioning

confidence: 99%

Low-Sulfide Platinum–Palladium Deposits of the Paleoproterozoic Fedorova–Pana Layered Complex, Kola Region, Russia

Groshev

Rundkvist

Karykowski³

et al. 2019

Minerals

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Several deposits of low-sulfide Pt–Pd ores have been discovered in recent decades in the Paleoproterozoic Fedorova–Pana Layered Complex located in the Kola Region (Murmansk Oblast) of Russia. The deposits are divided into two types: reef-style, associated with the layered central portions of intrusions, and contact-style, localized in the lower parts of intrusions near the contact with the Archean basement. The Kievey and the North Kamennik deposits represent the first ore type and are confined to the North PGE Reef located 600–800 m above the base of the West Pana Intrusion. The reef is associated with a horizon of cyclically interlayered orthopyroxenite, gabbronorite and anorthosite. The average contents of Au, Pt and Pd in the Kievey ore are 0.15, 0.53 and 3.32 ppm, respectively. The North Kamennik deposit has similar contents of noble metals. The Fedorova Tundra deposit belongs to the second ore type and has been explored in two sites in the lower part of the Fedorova intrusion. Mineralization is mainly associated mainly with taxitic or varied-textured gabbronorites, forming a matrix of intrusive breccia with fragments of barren orthopyroxenite. The ores contain an average of 0.08 ppm Au, 0.29 ppm Pt and 1.20 ppm Pd. In terms of PGE resources, the Fedorova Tundra is the largest deposit in Europe, hosting more than 300 tons of noble metals.

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The Early Proterozoic Matachewan Large Igneous Province: Geochemistry, Petrogenesis, and Implications for Earth Evolution

Abstract: 32 33The Matachewan Large Igneous Province (LIP) is interpreted to have formed during the early

Cited by 35 publications

References 154 publications

Critical Controls on the Formation of Contact-Style PGE-Ni-Cu Mineralization: Evidence from the Paleoproterozoic Monchegorsk Complex, Kola Region, Russia

Critical Controls on the Formation of Contact-Style PGE-Ni-Cu Mineralization: Evidence from the Paleoproterozoic Monchegorsk Complex, Kola Region, Russia

Investigating Complex Isochron Data Using Mixture Models

Low-Sulfide Platinum–Palladium Deposits of the Paleoproterozoic Fedorova–Pana Layered Complex, Kola Region, Russia

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