EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information
Phipps Morgan 1999
Phipps Morgan, J. (1999). Isotope topology of individual hotspot basalt arrays: Mixing curves or melt extraction trajectories?. Geochemistry Geophysics Geosystems 1: doi: 10.1029/1999GC000004. issn: 1525-2027.
Arrays of basalts from the same hotspot usually plot within an elongate tube-like field in 87Sr/86Sr-143Nd/144Nd-206Pb/204Pb space . Each hotspot array tube (HART) is commonly interpreted as the result of melting multiple basalt sources that are variably proportioned mixtures of the hotspot source components. I propose instead that a HART is the isotopic trace of the melt extraction trajectory produced by progressive melting of a heterogeneous source mixture characteristic to that hotspot. Melt extraction trajectories form when the sources of the individual hotspot basalts differ in the amount of previous melt extraction from the upwelling and melting plume mantle mixture. Sequential melts along a melt extraction trajectory trace a one-dimensional path through isotope space, independent of the number of distinct isotopic components in the initial source mixture. Subsequent partial mixing of the melts produced along a melt extraction trajectory would still tend to preserve this tube-like isotope topology. The melting physics that leads to a melt extraction trajectory also provides straightforward explanations for the 187Os/188Os contrasts between mid-ocean ridge basalts and their presumed abyssal peridotite source and for the enigmatic trace element and isotopic patterns of pyroxenite veins and peridotite exposed within orogenic lherzolites.
BACKGROUND DATA FILES

Abstract

Entire Document PDF

Keywords
Geochemistry, Chemical evolution, Geochemistry, Composition of the mantle, Geochemistry, Isotopic composition/chemistry, Oceanography, Biological and Chemical, Geochemistry
Journal
Geochemistry Geophysics Geosystems
Publisher
American Geophysical Union
2000 Florida Avenue N.W.
Washington, D.C. 20009-1277
USA
1-202-462-6900
1-202-328-0566
service@agu.org
Click to clear formClick to return to previous pageClick to submit