A intrusão diamantífera Abel Régis (Carmo do Paranaíba, MG): kimberlito ou lamproíto?

Chaves, Mario Luiz de Sá Carneiro; Andrade, Kerley Wanderson; Moreira, Luiz Alberto

doi:10.1590/s0370-44672009000400004

Cited by 5 publications

(5 citation statements)

References 9 publications

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“…Crystallization temperatures of Alfeu-I lamproite were determined using the olivine-spinel Mg-Fe 2+ exchange geothermometer of O' Neill and Wall (1987) and Ballhaus et al (1991), who applied their geothermometer to peridotite xenoliths. We used chromites and olivines microcrysts analyses of Alfeu-I lamproite (Chaves et al 2014, Provenzano 2016; and this study -Table 3 and Suppl. data) from mineral separates, as the Alfeu-I pipe is unfortunately very altered and it was not possible to collect preserved samples.…”

Section: Geothermobarometry and Oxygen Barometry Resultsmentioning

confidence: 99%

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Mineral chemistry from the Alfeu-I lamproite (Southern Brazil) and its contribution to understand the mantle heterogeneity under South American Plate during the Gondwana breakup

Carniel,

Conceição,

Provenzano

et al. 2023

Braz. J. Geol.

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The Alfeu-I lamproite is one of the few alkaline rock occurrences in the South of Brazil that represents the alkaline event related to the South Atlantic opening and the enormous magmatic activity that formed the Paraná basalts. Alfeu-I lamproite is a diatreme facies and exhibits an inequigranular texture with macrocrysts of mica, spinel, garnet, and ilmenite and microcrysts of mica, pyroxene, and rare olivine, all immersed in a groundmass of pyroxene, spinel, perovskite, rutile, ilmenite, and, more rarely, olivine. Major element compositions of Alfeu-I pyroxene, garnet, ilmenite, mica, and olivine were determined by electron microprobe analyses, and trace element concentrations of clinopyroxene, garnet, ilmenite, and mica were measured using laser-ablation inductively coupled plasma mass spectrometry techniques. Temperature, pressure, and oxygen fugacity (fO 2 ) conditions during the crystallization of Alfeu-I lamproite were calculated with the geothermobarometers and olivine, spinel, garnet, and orthopyroxene. The resulting mean equilibrium temperature ranges from 1375°C at 4 GPa to 1395°C at 5 GPa, whereas the fO 2 points to ΔFMQ = +2.4 (at 4 GPa) and ΔFMQ = +2.2 (at 5 GPa). Rb-Sr and Sm-Nd isotopic data together with the trace element concentrations of minerals suggest that melting of a mantle source enriched in incompatible elements and volatiles due to previous subduction events occurred during the Gondwana breakup around 125 Ma ago. Fluids that may have originated from subducting slabs in the old subduction zone are probably the cause of the high fO 2 conditions in Alfeu-I lamproite.

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Section: Geothermobarometry and Oxygen Barometry Resultsmentioning

confidence: 99%

“…Olivine compositions are from this study. Chromite compositions from Chaves et al (2014). Olivines (Ol), chromites (Chr), ΔFMQ (fO 2 relative to FMQ buffer), and standard deviations (stdev) as last significant digits in brackets.…”

Section: Sr-nd Isotope Datamentioning

confidence: 99%

Mineral chemistry from the Alfeu-I lamproite (Southern Brazil) and its contribution to understand the mantle heterogeneity under South American Plate during the Gondwana breakup

Carniel,

Conceição,

Provenzano

et al. 2023

Braz. J. Geol.

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“…The occurrence of G5 and G9 garnets and low-MgO ilmenite in the lamproitic pipe Abel Régis (Chaves et al 2009), can be related to the mineral assembly found in the diamond deposit of Romaria, suggesting a lamproitic source, although primary rock was not found to characterize the representative faciologies of this type of diamond-bearing rock.…”

Section: General Implicationsmentioning

confidence: 91%

“…The volcanoclastic sequence of the Água Suja Mine (GAR-Mineração and surroundings) has been correlated to the Marília Dias 2017, Seer andMoraes 2017) or the Uberaba Formation (Gravina et al 2002, Gravina 2003. Chaves et al (2009) worked with the Abel Régis (Carmo do Paranaíba, Minas Gerais state, Brazil) lamproitic intrusion where there is a high concentration of garnets in the G5 and G9 fields of Grutter et al (2004) and MgO-poor ilmenites. Kaminsky and Belousova (2009) identified manganese ilmenite in kimberlitic pipes from to the Juina kimberlitic field (Mato Grosso state, Brazil).G5 garnets are interpreted by Grutter et al (2004) as indicative of a destroyed lithosphere and are also correlated to lamproitic rocks when associated with manganoan ilmenites and dravitic tourmalines (Fipke 1991, Presser 2019.…”

Section: General Implicationsmentioning

confidence: 99%

Occurrence of dravitic tourmaline in a diamond-bearing breccia: a possible lamproite deposit in the Alto Paranaíba Igneous Province

et al. 2022

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The mineral chemistry of diamond indicator minerals is used to trace mineralizations in primary rocks such as lamproites/kimberlites and in secondary deposits. Subcalcic garnets and magnesian ilmenites are both minerals associated with the diamond potential described in many deposits in the Alto Paranaíba Igneous Province where several kimberlitic pipes and alluvial deposits occur. Our study was conducted on the Romaria diamond deposit of (Brazil), where garnet, ilmenite and tourmaline grains were recovered from a diamon-bearing breccia were analyzed under electron microprobe. The garnet composition is compatible with G10, G9 and G5 types. Ilmenite grains are Mg-to Mn-rich. Nearly 80% of the tourmaline grains are dravite-type. This association of dravite tourmaline with diamond in rocks of lamproitic affinity may be common, as evidenced in the Argyle, Ellendale, Prairie Creek, Sask, Presidente Olegário and Ymi-1 pipes. We therefore suggest a possible lamproite origin for the studied diamond deposit.

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“…The grey areas in (a) and (b) represent the composition of the clinopyroxene of mantle xenoliths and concentrates of the kimberlites from Rondônia (196 analyses) and APIP (1322 analyses), respectively, from previous works. Data compilation from: Costa (1996), Carvalho (1997), Zolinger (2005), Chaves (2008a), Costa (2008), Silva (2008), Melluso et al (2008), Almeida (2009), Chaves et al (2009), Thomaz (2009), Hunt et al (2009), Nannini (2011), Andrade (2012), Guarino et al (2013), Nannini (2016) and Gervasoni et al (2022).…”

Section: Major Element Compositionmentioning

confidence: 99%

Composition and P-T conditions of the lithospheric mantle beneath the Azimuth 125º Lineament, Northern and Southeastern Brazil: constraints from peridotite xenoliths enclosed in diamond-bearing kimberlites

Almeida¹,

Rodrigues²,

Neto³

et al. 2022

JGSB

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We present new petrographic and chemical data together with calculated P-T equilibrium conditions of peridotite xenoliths enclosed in kimberlites from Rondônia, Northern Brazil (Cosmos-1 and Carolina-1) and Minas Gerais, Southeastern Brazil (Canastra-1) located in the Azimuth 125º Lineament. The composition of the mantle minerals is distinct in both areas, which can be related to the diversity of the lithospheric mantle beneath the southwestern portion of the Amazonian Craton and the Brasília Belt. New and compiled chemical data indicate that subcalcic G10 garnet occurs in samples from the Canastra-1 kimberlite and other occurrences of the Alto Paranaíba Igneous Province and can be related to the remnants of the Archean lithospheric mantle of the São Francisco Craton beneath the area. The garnets from Rondônia are mostly G5 (pyroxenitic) and G9 (lherzolitic) with a higher abundance of G3 (eclogitic) and G4 (pyroxenitic/eclogitic) relative to the Alto Paranaíba Igneous Province. Higher pressures and temperatures were calculated for the samples from Rondônia (40-60 kbar and 1030-1380 ºC) compared to samples from Minas Gerais (25-40 kbar and 730-1000 ºC). The peridotite xenoliths from Rondônia show P-T equilibrium conditions in the diamond stability field and can be the source of at least part of the diamond from the area. The P-T stability fields of the xenoliths from both locations are aligned close to the 40 mW/m2 geotherm. The data indicate that the cratonic 40 mW/m2 geothermal gradient in Rondônia may be related to a process of thermal relaxation of the lithospheric mantle after the Paleoproterozoic to Mesoproterozoic tectonothermal events of the southwestern Amazonian Craton until the sampling of the xenoliths by the magma in the Permian-Triassic.Composition and P-T conditions of the lithospheric mantle beneath the Azimuth 125º Lineament, Northern and Southern Brazil: constraints from peridotite xenoliths enclosed in diamond-bearing kimberlites Accepted manuscript -Uncorrected pre-proof This is a PDF file containing an unedited and non-definitive version of a manuscript that has been accepted for publication by the Journal of the Geological Survey of Brazil -JGSB, which serves to provide early visibility of the article. Being an uncorrected preproof version, errors may appear during the production process (language review, formatting and proof review), and these can affect the final content of the article and all legal disclaimers (https://jgsb.cprm.gov.br/index.php/journal/6).

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A intrusão diamantífera Abel Régis (Carmo do Paranaíba, MG): kimberlito ou lamproíto?

Cited by 5 publications

References 9 publications

Mineral chemistry from the Alfeu-I lamproite (Southern Brazil) and its contribution to understand the mantle heterogeneity under South American Plate during the Gondwana breakup

Mineral chemistry from the Alfeu-I lamproite (Southern Brazil) and its contribution to understand the mantle heterogeneity under South American Plate during the Gondwana breakup

Occurrence of dravitic tourmaline in a diamond-bearing breccia: a possible lamproite deposit in the Alto Paranaíba Igneous Province

Composition and P-T conditions of the lithospheric mantle beneath the Azimuth 125º Lineament, Northern and Southeastern Brazil: constraints from peridotite xenoliths enclosed in diamond-bearing kimberlites

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