In situ EMPA and SIMS investigation of mineral geochemistry of mantle xenoliths from Cerro Nemby (25°24' S, 57°32' W), Paraguay
Cite as:
Bonazzi, Mattia; Zanetti, Alberto; Margutti, Roberto; Mazzucchelli, Maurizio; Vannucci, Riccardo (2023): In situ EMPA and SIMS investigation of mineral geochemistry of mantle xenoliths from Cerro Nemby (25°24' S, 57°32' W), Paraguay. GFZ Data Services. https://doi.org/10.5880/fidgeo.2022.038
Status
I N R E V I E W : Bonazzi, Mattia; Zanetti, Alberto; Margutti, Roberto; Mazzucchelli, Maurizio; Vannucci, Riccardo (2023): In situ EMPA and SIMS investigation of mineral geochemistry of mantle xenoliths from Cerro Nemby (25°24' S, 57°32' W), Paraguay. GFZ Data Services. https://doi.org/10.5880/fidgeo.2022.038
Abstract
Mantle xenoliths are hosted in lavas localized in the Nemby area (25°24' S, 57°32' W; Asunciòn-Sapucai-Villarrica graben, ASV, central Paraguay: Fig.1), where a small melanephelinitite plug (Cerro Nemby), with elliptical topography (800 x 500 m, about 100 m above the plain), contains very abundant mantle xenoliths (10-15% by volume of the plug) together with crustal xenoliths (Comin-Chiaramonti et al., 2001).
According to Le Bas (1987), lavas consist of nephelinite and subordinately of ankaratrite (CIPW Ab < 5 wt% e Ne > 20 wt%).
The average size of the mantle xenoliths (10-12 cm, max 45 cm, i.e. the largest observed in ASV) and the compositional range (lherzolite to dunite to pyroxenite) make these xenoliths particularly suitable for a study regarding metasomatic processe(s) affecting the Sub-Continental Lithospheric Mantle of central Paraguay.
The dunite results to be the most abundant xenolith type in such lavas. In-situ geochemical characterization was performed on silicates and glasses from very fresh xenoliths, which document a large variety of rock types. Five samples were investigated, namely: i) dunite 3209; ii) spinel harzburgite 3284; iii) spinel lherzolite 3293; iv) olivine websterite 3253 and v) olivine clinopyroxenite 3270. The analyses were directly carried out on thin petrographic sections (30 µm thick) of the selected samples.
Authors
Bonazzi, Mattia;Istituto di Geoscienze e Georisorse- C.N.R. U.O.S. of Pavia, Pavia, Italy
Zanetti, Alberto;Istituto di Geoscienze e Georisorse- C.N.R. U.O.S. of Pavia, Pavia, Italy
Margutti, Roberto;Dipartimento di Scienze della Terra e dell’Ambiente, Università di Pavia, Pavia, Italy
Mazzucchelli, Maurizio;Dipartimento di Scienze della Terra e dell’Ambiente, Università di Pavia, Pavia, Italy
Vannucci, Riccardo;Dipartimento di Scienze della Terra e dell’Ambiente, Università di Pavia, Pavia, Italy
Contact
Bonazzi, Mattia
(Postdoctoral fellowship); Istituto di Geoscienze e Georisorse- C.N.R. U.O.S. of Pavia, Italy;
Mass spectrometry la-icp laboratory (IGG-CNR, Italy); Laboratory of Geochronology and Radiogenic Isotope Geochemistry - Firenze (IGG-CNR, Italy)
Keywords
Mantle xenoliths, EPOS, multi-scale laboratories, compound material > igneous material > igneous rock > ultramafic igneous rock > peridotite, compound material > igneous material > igneous rock > ultramafic igneous rock > pyroxenite
CharacterString: Mantle xenoliths are hosted in lavas localized in the Nemby area (25°24' S, 57°32' W; Asunciòn-Sapucai-Villarrica graben, ASV, central Paraguay: Fig.1), where a small melanephelinitite plug (Cerro Nemby), with elliptical topography (800 x 500 m, about 100 m above the plain), contains very abundant mantle xenoliths (10-15% by volume of the plug) together with crustal xenoliths (Comin-Chiaramonti et al., 2001).
According to Le Bas (1987), lavas consist of nephelinite and subordinately of ankaratrite (CIPW Ab < 5 wt% e Ne > 20 wt%).
The average size of the mantle xenoliths (10-12 cm, max 45 cm, i.e. the largest observed in ASV) and the compositional range (lherzolite to dunite to pyroxenite) make these xenoliths particularly suitable for a study regarding metasomatic processe(s) affecting the Sub-Continental Lithospheric Mantle of central Paraguay.
The dunite results to be the most abundant xenolith type in such lavas. In-situ geochemical characterization was performed on silicates and glasses from very fresh xenoliths, which document a large variety of rock types. Five samples were investigated, namely: i) dunite 3209; ii) spinel harzburgite 3284; iii) spinel lherzolite 3293; iv) olivine websterite 3253 and v) olivine clinopyroxenite 3270. The analyses were directly carried out on thin petrographic sections (30 µm thick) of the selected samples.
pointOfContact
CI_ResponsibleParty
individualName
CharacterString: Bonazzi, Mattia
organisationName
CharacterString: Istituto di Geoscienze e Georisorse- C.N.R. U.O.S. of Pavia, Italy
CharacterString: Localization of the area of study, and position of Sierra Baguales, from which the mantle xenoliths were collected
geographicElement
EX_GeographicBoundingBox
westBoundLongitude
Decimal: -72.6518
eastBoundLongitude
Decimal: -72.3537
southBoundLatitude
Decimal: -50.5304
northBoundLatitude
Decimal: -50.7082
distributionInfo
MD_Distribution
transferOptions
MD_DigitalTransferOptions
onLine
CI_OnlineResource
linkage
URL: http://doi.org/10.5880/fidgeo.2022.038
protocol
CharacterString: WWW:LINK-1.0-http--link
name
CharacterString: Data Access - DOI
description
CharacterString: Data Access - DOI
function
CI_OnLineFunctionCode (codeList=http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode codeListValue=http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode_information): information
Released
Dataset
Abstract
;Istituto di Geoscienze e Georisorse- C.N.R. U.O.S. of Pavia, Pavia, Italy
Files
