Characterization of the sub-continental lithospheric mantle beneath the Cameroon volcanic line inferred from alkaline basalt hosted peridotite xenoliths from Barombi Mbo and Nyos Lakes
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Tartalom: http://www.elsevier.com/locate/jafrearsci
Archívum: REAL
Gyűjtemény: Status = Published
Subject = Q Science / természettudomány: QE Geology / földtudományok: QE07 Economic geology / gazdasági földtan
Subject = Q Science / természettudomány: QE Geology / földtudományok: QE03 Geodynamics / geodinamika
Subject = Q Science / természettudomány: QE Geology / földtudományok: QE02 Geochemistry / geokémia
Type = Article
Cím:
Characterization of the sub-continental lithospheric mantle beneath the Cameroon volcanic line inferred from alkaline basalt hosted peridotite xenoliths from Barombi Mbo and Nyos Lakes
Létrehozó:
Pintér, Zsanett
Patkó, Levente
Tene, Flore
Kovács, István János
Tchouankoue, Pierre
Falus, György
Konc, Zoltán
Tommasi, Andrea
Barou, Fabrice
Mihály, Judith
Németh, Csaba
Jeffries, Teresa
Dátum:
2015
Téma:
QE02 Geochemistry / geokémia
QE03 Geodynamics / geodinamika
QE07 Economic geology / gazdasági földtan
Tartalmi leírás:
We carried out detailed petrographic, major and trace element geochemical, microstructural and FTIR analyses on eight characteristic ultramafic xenoliths from Nyos and Barombi Mbo Lakes in the continental sector of the Cameroon Volcanic Line (CVL). The studied xenoliths are spinel lherzolites showing lithologies similar to the other xenoliths reported previously along the CVL. They have protogranular and porphyroclastic textures. One of the Barombi xenolith contains amphibole, which had not been previously reported in this locality. Amphibole is common in the Nyos xenoliths suite. Peridotite xenoliths from both localities show some chemical heterogeneity, but Barombi xenoliths generally are less depleted in basaltic elements with respect to Nyos xenoliths. Trace element compositions of Nyos spinel lherzolites show a moderately depleted initial (premetasomatic) composition and variable enrichment in REE. Evidence for both modal and cryptic metasomatism is present in Nyos xenoliths. Rare earth element patterns of clinopyroxene suggest that interaction between mafic melts and the upper mantle occurred beneath the Nyos locality. Barombi Mbo xenoliths, on the other hand, record a small degree of partial melting. The Barombi Mbo xenoliths have weak, dominantly orthorhombic olivine crystal preferred orientations, whereas Nyos ones have strong axial-[010] patterns, which may have formed in response to transpression. Nominally anhydrous mantle minerals (NAMs) of the Barombi Mbo xenoliths show generally higher bulk concentrations of ‘water’ (70e127 ppm) than Nyos xenoliths (32e81 ppm). The Barombi Mbo xenoliths could originate from a juvenile segment of the lithospheric mantle, which had been originally part of the asthenosphere. It became a part of the lithosphere in response to thermal relaxation following the extension, forming a weakly deformed lower lithospheric mantle region along the CVL. The Nyos xenoliths, however, represent a shallow lithospheric mantle bearing imprints of several depletion and enrichment events probably prior or following the extension (at ~30 Ma).
Típus:
Article
PeerReviewed
Formátum:
text
Azonosító:
Pintér, Zsanett and Patkó, Levente and Tene, Flore and Kovács, István János and Tchouankoue, Pierre and Falus, György and Konc, Zoltán and Tommasi, Andrea and Barou, Fabrice and Mihály, Judith and Németh, Csaba and Jeffries, Teresa (2015) Characterization of the sub-continental lithospheric mantle beneath the Cameroon volcanic line inferred from alkaline basalt hosted peridotite xenoliths from Barombi Mbo and Nyos Lakes. Journal of African Earth Sciences, 111. pp. 170-193. ISSN 1464-343X
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