Universität zu Köln

Gervasoni, Fernanda, Jalowitzki, Tiago ORCID: 0000-0001-9857-7876, Rocha, Marcelo Peres, Weska, Ricardo Kalikowski, Novais-Rodrigues, Eduardo, de Freitas Rodrigues, Rodrigo Antonio, Bussweiler, Yannick ORCID: 0000-0002-8107-7055, Rocha Barbosa, Elisa Soares, Berndt, Jasper, Dantas, Elton Luiz, Souza, Valmir da Silva and Klemme, Stephan (2022). Recycling process and proto-kimberlite melt metasomatism in the lithosphere-asthenosphere boundary beneath the Amazonian Craton recorded by garnet xenocrysts and mantle xenoliths from the Carolina kimberlite. Geosci. Front., 13 (5). HAIDIAN DISTRICT: CHINA UNIV GEOSCIENCES, BEIJING. ISSN 1674-9871

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Abstract

Here we present new data on the major and trace element compositions of silicate and oxide minerals from mantle xenoliths brought to the surface by the Carolina kimberlite, Pimenta Bueno Kimberlitic Field, which is located on the southwestern border of the Amazonian Craton. We also present Sr-Nd isotopic data of garnet xenocrysts and whole-rocks from the Carolina kimberlite. Mantle xenoliths are mainly clinopyroxenites and garnetites. Some of the clinopyroxenites were classified as GPP-PP-PKP (garnet-phlogopite peridotite, phlogopite-peridotite, phlogopite-K-richterite peridotite) suites, and two clinopyroxenites (eclogites) and two garnetites are relicts of an ancient subducted slab. Temperature and pressure estimates yield 855-1102 degrees C and 3.6-7.0 GPa, respectively. Clinopyroxenes are enriched in light rare earth elements (LREE) (La-N/Yb-N = 5-62; Ce-N/Sm-N = 1-3; where N = primitive mantle normalized values), they have high Ca/Al ratios (10-410), low to medium Ti/Eu ratios (742-2840), and low Zr/Hf ratios (13-26), which suggest they were formed by metasomatic reactions with CO2-rich silicate melts. Phlogopite with high TiO2 (>2.0 wt.%), Al2O3 (>12.0 wt.%), and FeOt (5.0-13.0 wt.%) resemble those found in the groundmass of kimberlites, lamproites and lamprophyres. Conversely, phlogopite with low TiO2 (<1.0 wt.%) and lower Al2O3 (<12.0 wt.%) are similar to those present in GPP-PP-PKP, and in MARID (mica-amphibole-rutile-ilmenite-diopside) and PIC (phlogopite-ilmenite-clinopyorxene) xenoliths. The GPP-PP-PKP suite of xenoliths, together with the clinopyroxene and phlogopite major and trace element signatures suggests that an intense proto-kimberlite melt metasomatism occurred in the deep cratonic lithosphere beneath the Amazonian Craton. The Sr-Nd isotopic ratios of pyrope xenocrysts (G3, G9 and G11) from the Carolina kimberlite are characterized by high Nd-143/Nd-144 (0.51287-0.51371) and epsilon Nd (+4.55 to +20.85) accompanied with enriched Sr-87/Sr-86 (0.70405-0.71098). These results suggest interaction with a proto-kimberlite melt compositionally similar with worldwide kimberlites. Based on Sr-Nd whole-rock compositions, the Carolina kimberlite has affinity with Group 1 kimberlites. The Sm-Nd isochron age calculated with selected eclogitic garnets yielded an age of 291.9 +/- 5.4 Ma (2 sigma), which represents the cooling age after the proto-kimberlite melt metasomatism. Therefore, we propose that the lithospheric mantle beneath the Amazonian Craton records the Paleozoic subduction with the attachment of an eclogitic slab into the cratonic mantle (garnetites and eclogites); with a later metasomatic event caused by proto-kimberlite melts shortly before the Carolina kimberlite erupted. (C) 2022 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Gervasoni, Fernanda UNSPECIFIED UNSPECIFIED UNSPECIFIED Jalowitzki, Tiago UNSPECIFIED orcid.org/0000-0001-9857-7876 UNSPECIFIED Rocha, Marcelo Peres UNSPECIFIED UNSPECIFIED UNSPECIFIED Weska, Ricardo Kalikowski UNSPECIFIED UNSPECIFIED UNSPECIFIED Novais-Rodrigues, Eduardo UNSPECIFIED UNSPECIFIED UNSPECIFIED de Freitas Rodrigues, Rodrigo Antonio UNSPECIFIED UNSPECIFIED UNSPECIFIED Bussweiler, Yannick UNSPECIFIED orcid.org/0000-0002-8107-7055 UNSPECIFIED Rocha Barbosa, Elisa Soares UNSPECIFIED UNSPECIFIED UNSPECIFIED Berndt, Jasper UNSPECIFIED UNSPECIFIED UNSPECIFIED Dantas, Elton Luiz UNSPECIFIED UNSPECIFIED UNSPECIFIED Souza, Valmir da Silva UNSPECIFIED UNSPECIFIED UNSPECIFIED Klemme, Stephan UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-686199
DOI:	10.1016/j.gsf.2022.101429
Journal or Publication Title:	Geosci. Front.
Volume:	13
Number:	5
Date:	2022
Publisher:	CHINA UNIV GEOSCIENCES, BEIJING
Place of Publication:	HAIDIAN DISTRICT
ISSN:	1674-9871
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CENTRAL SLAVE CRATON; U-PB; TRACE-ELEMENT; SM-ND; CARBONATITE METASOMATISM; ALTO-PARANAIBA; PETROLOGICAL CHARACTERIZATION; CLASSIFICATION SCHEME; PERIDOTITE XENOLITHS; CLOSURE TEMPERATURE Multiple languages Geosciences, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/68619