COG3 Seminar - Margaret Hartley (University of Manchester)

Speaker: 
Margaret Hartley (University of Manchester)
Date: 
Friday, April 30, 2021 - 10:00am to 11:00am
Location: 
Virtual
 
The Fifth Element: Boron recycling in the Iceland mantle plume
 
Iceland’s 500 km of active neovolcanic zones provide a high-resolution and spatially continuous transect across a mantle plume. Basalts erupted near the plume centre carry geochemical signatures such as high 3He/4He that suggest melting of a primitive mantle component. Yet trace elements and lithophile isotope signatures also point to the presence of recycled oceanic lithosphere in the Icelandic mantle. Boron is an excellent geochemical tracer of recycled material, because it is re-introduced to the mantle through subduction of serpentinized oceanic lithosphere. In this talk I will present new boron isotope measurements from the Reykjanes Ridge and from a suite of crystal-hosted melt inclusions from North Iceland. Do Icelandic magmas carry distinctive boron isotopic signatures indicative of recycled crustal material? How are mantle-derived boron isotopic signatures modified by crustal assimilation? And to what extent can boron isotopic heterogeneity be resolved on the lengthscale of a mantle plume?

About this Series:

The Chemical Oceanography, Geology, Geochemistry, and Geobiology Seminar [COG3] is a student-run seminar series. Topics include chemical oceanography, geology, geochemistry, and geobiology. The seminars take place on Fridays from 10-11am, unless otherwise noted (term-time only). Contact: cog3_seminar_organizers@mit.edu