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The geochemical peculiarity of "Plio-Quaternary" volcanic rocks of Sardinia in the circum-Mediterranean area

Michele Lustrino, Leone Melluso and Vincenzo Morra
The geochemical peculiarity of "Plio-Quaternary" volcanic rocks of Sardinia in the circum-Mediterranean area (in Cenozoic volcanism in the Mediterranean area, Luigi Beccaluva (editor), Gianluca Bianchini (editor) and Marjorie Wilson (editor))
Special Paper - Geological Society of America (2007) 418: 277-301

Abstract

Late Cenozoic volcanic rocks on the island of Sardinia are mildly alkaline-transitional lavas, dominantly hawaiites, mugearites, and transitional basalts with minor phonolites and trachytes, which from approximately 80% of the entire sample population. Tholeiitic basaltic andesites form the remaining 20% of the analyzed rocks. The oldest lavas, the ca. 6.6-4.4 Ma radiogenic Pb volcanic group, are in southern Sardinia; they have geochemical characteristics very similar to most Circum-Mediterranean Anorogenic Cenozoic Igneous Province rocks. After a gap of approximately 0.5 m.y., volcanism occurred in central and northern Sardinia, from ca. 3.9 to ca. 0.1 Ma. These products, the unradiogenic Pb volcanic group, are geochemically very different. Their geochemical characteristics (relatively high SiO (sub 2) , low CaO, and CaO/Al (sub 2) O (sub 3) , relatively high Ni, relatively low high field strength elements, low heavy rare earth elements, high Ba/Nb and La/Nb, slightly high (super 87) Sr/ (super 86) Sr, and unradiogenic (super 143) Nd/ (super 144) Nd and (super 206) Pb/ (super 204) Pb ratios) are considered to be derived from an orthopyroxene-rich lithospheric mantle source. The origin of this enrichment in orthopyroxene is a consequence of SiO (sub 2) -rich melt derived from delaminated and detached ancient lower continental crust reacting with mantle peridotite. The presence of two distinct groups of rocks (unradiogenic Pb volcanics and radiogenic Pb volcanics) in a very close geographic position is related to the existence of a lithospheric discontinuity running roughly E-W in southern Sardinia.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 418
Title: The geochemical peculiarity of "Plio-Quaternary" volcanic rocks of Sardinia in the circum-Mediterranean area
Title: Cenozoic volcanism in the Mediterranean area
Author(s): Lustrino, MicheleMelluso, LeoneMorra, Vincenzo
Author(s): Beccaluva, Luigieditor
Author(s): Bianchini, Gianlucaeditor
Author(s): Wilson, Marjorieeditor
Affiliation: Universita di Roma La Sapienza, Dipartimento di Scienze della Terra, Rome, Italy
Affiliation: Universita di Ferrara, Dipartimento di Scienze della Terra, Ferrara, Italy
Pages: 277-301
Published: 2007
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 978-0-8137-2418-8
References: 119
Accession Number: 2007-084315
Categories: Isotope geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Includes appendix
Illustration Description: illus. incl. 3 tables, sketch maps
N38°49'60" - N41°30'00", E08°15'00" - E09°45'00"
Secondary Affiliation: University of Leeds, GBR, United KingdomUniversita di Napoli Federico II, ITA, Italy
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 200739
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