The petrology and geochemistry of Vesteris Seamount, Greenland Basin: An intraplate alkaline volcano of non-plume origin.

Journal article


Publication Details

Author(s): Haase K, Devey C
Journal: Journal of Petrology
Publisher: Oxford University Press (OUP): Policy B - Oxford Open Option A
Publication year: 1994
Volume: 35
Pages range: 295-328
ISSN: 0022-3530
Language: English


Abstract


Vesteris Seamount is a solitary alkaline volcano in the Greenland Basin some 280 km NW of Jan Mayen. Topographic and geophysical studies have shown no sign of an associated plume trace. Evidence from ash layers in sediment cores around the volcano and dating of dredged samples show that it has been active in Quaternary times. The lavas from Vesteris studied here consist of basanites, tephrites, mugearite, and alkali basalts. Crystal fractionation models are consistent with the generation of the tephrites and mugearite from a basanitic parent. Extensive kaersutite fractionation is required late in the fractionation sequence to produce the extreme mugearite composition. Na-Al-Fe-rich green cores to many clinopyroxene phenocrysts at Vesteris suggest a fractionation history beginning at high pressure in the mantle. Differences between Vesteris and Jan Mayen in the ratios of highly incompatible trace elements such as Ce/Pb and Rb/Cs, which will not normally be fractionated from one another during mantle melting, suggest that the two are not derived from the same source. Relatively unradiogenic Sr isotope ratios (compared with Bulk Earth), and highly incompatible trace element patterns similar to those for St. Helena, suggest that Vesteris magmas are derived from a depleted, asthenospheric source. We propose that the Vesteris basanites are very low degree partial melts (̃1%) of this source, most probably those which give rise to the seismic low-velocity zone (LVZ). Such small-degree melts may preferentially tap small-scale heterogeneities in the asthenosphere. Vesteris lies at the intersection of two major structural trends in the Greenland Basin-(1) a zone of major reorientation of spreading direction on the Mohns Ridge north of Jan Mayen and (2) the extension of the Kolbeinsey Ridge axis. We propose that a combination of the extensional stress fields related to these two lineaments produces sufficient dilation of the lithosphere at Vesteris to allow magmas from the LVZ to reach the surface. © 1994 Oxford University Press.



FAU Authors / FAU Editors

Haase, Karsten Prof. Dr.
Lehrstuhl für Endogene Geodynamik


External institutions
GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel


How to cite

APA:
Haase, K., & Devey, C. (1994). The petrology and geochemistry of Vesteris Seamount, Greenland Basin: An intraplate alkaline volcano of non-plume origin. Journal of Petrology, 35, 295-328. https://dx.doi.org/10.1093/petrology/35.2.295

MLA:
Haase, Karsten, and Colin Devey. "The petrology and geochemistry of Vesteris Seamount, Greenland Basin: An intraplate alkaline volcano of non-plume origin." Journal of Petrology 35 (1994): 295-328.

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