Helium isotopes in early tertiary basalts, northeast Greenland: evidence for 58 Ma plume activity in the north Atlantic-Iceland volcanic province

Marty, B., Upton, B.G.J. and Ellam, R.M. (1998) Helium isotopes in early tertiary basalts, northeast Greenland: evidence for 58 Ma plume activity in the north Atlantic-Iceland volcanic province. Geology, 26(5), pp. 407-410. (doi: 10.1130/0091-7613(1998)026<0407:HIIETB>2.3.CO;2)

Abstract

³He/⁴He ratios in olivine phenocrysts have been measured in 58 Ma basaltic lavas from the Hold with Hope region of northeast Greenland. These lavas constitute a part of the North Atlantic volcanic province. The samples exhibit a wide range of ³He/⁴He ratios between 1.7R_a and 21R_a (R_a =the atmospheric ³He/⁴He ratio =1.386 x 10^-6), which is comparable to the previously recorded range for Quaternary Icelandic basalts. These He isotope variations may partly result from crustal assimilation, but ³He/⁴He ratios higher than those of mid-ocean-ridge basalts support early participation of plume-head material at the onset of volcanic activity in the North Atlantic volcanic province. As with the Deccan-Reunion plume and the Ethiopia-Afar plume, this long-term contribution of ³He-rich material is fully consistent with models that ascribe a deep (i.e., deeper than the convective mantle that drives plate tectonics) origin for plume-source material, but contradicts those that postulate a shallow-mantle origin for continental flood basalts and large igneous provinces.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Ellam, Professor Rob
• Authors: Marty, B., Upton, B.G.J., and Ellam, R.M.
• Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Geology
• ISSN: 0091-7613
• ISSN (Online): 1943-2682