Mantle heterogeneity controls on small-volume basaltic volcanism

Journal article
(Original article)

Publication Details

Author(s): Mcgee LE, Millet MA, Beier C, Smith IEM, Lindsay JM
Journal: Geology
Publication year: 2015
Volume: 43
Journal issue: 6
Pages range: 551-554
ISSN: 0091-7613


Eruptions of basaltic material in small-scale volcanic fields located in intraplate settings display a very diverse range in physical and chemical characteristics. Despite its relevance to the understanding of volcanic hazards, the relationship between physical properties of eruptions (explosivity, volume, location) and chemical composition of erupted products has, to date, not been investigated. Here we present a relationship between mantle heterogeneity and extents of partial melting, and both erupted volumes and eruptive style from the Auckland Volcanic Field (New Zealand), and we suggest that this provides a general model for smallscale "monogenetic" magmatic systems globally. Small volcanic centers consistently take the form of nephelinitic tuff rings and scoria cones, whereas larger centers are produced from effusive eruptions of less alkalic magmas. Nephelinitic melts are generated by melting of a deep, carbonated source, whereas less alkalic melts are the products of melting of a shallower, noncarbonated source. U-Th-Ra isotope data from eruptions closely paired in space and time show that mixing between magmas is extremely limited as a consequence of different ascent mechanisms due to differential segregation of melts from varying sources (early, carbonated melts ascending by higher porosity channels, and later, uncarbonated melts by a more diffusive regime). This suggests that extraction of melt is nearly instantaneous in these environments. Our results stress the importance of melting and magma dynamics in determining the size and style of eruptions in small volcanic fields, and suggest that mantle controls should be an important consideration in volcanic hazard assessment.

FAU Authors / FAU Editors

Beier, Christoph PD Dr.
Lehrstuhl für Endogene Geodynamik

External institutions with authors

Durham University
Universidad de Santiago de Chile (USACH) / University of Santiago, Chile
University of Auckland

How to cite

Mcgee, L.E., Millet, M.-A., Beier, C., Smith, I.E.M., & Lindsay, J.M. (2015). Mantle heterogeneity controls on small-volume basaltic volcanism. Geology, 43(6), 551-554.

Mcgee, Lucy E., et al. "Mantle heterogeneity controls on small-volume basaltic volcanism." Geology 43.6 (2015): 551-554.


Last updated on 2019-06-04 at 14:50