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SUMMARY:Ophiolite perspectives on oceanic mantle compositional heterogenei
 ty - Dr Brian O'Driscoll - University of Manchester
DTSTART:20190315T130000Z
DTEND:20190315T133000Z
UID:TALK121372@talks.cam.ac.uk
CONTACT:Ben Johnson
DESCRIPTION:This talk will consider the potential for ophiolite to inform 
 on questions of chemical and isotopic heterogeneity in the oceanic mantle.
  In simple terms\, such heterogeneities have been attributed to either ref
 ractory domains resulting from ancient melt extraction or ‘enriched’ p
 yroxenite. Ophiolites in particular allow for careful evaluation of these 
 issues\, as they facilitate easy access to mantle lithologies/structures a
 nd the opportunity for field-based observations to be paired with geochemi
 cal investigations. One potential caveat is that many ophiolites have unde
 rgone supra-subduction zone (SSZ) processing\, which has the potential to 
 obscure older geochemical and isotopic signatures. The highly siderophile 
 elements (Os\, Ir\, Ru\, Pt\, Pd\, Re) have proven especially useful ‘to
 ols’ in interrogating the nature and timing of primary mantle processes 
 that occurred in mantle peridotites\, before SSZ and other secondary effec
 ts that may have modified the rocks. The goal of this talk is to discuss t
 he length-scales\, timing and causes of refractory and enriched compositio
 nal domains in the oceanic mantle\, with specific reference to the HSE cha
 racteristics of two Iapetus Ocean (Lower Paleozoic) ophiolites on Shetland
  (Scotland) and Leka (Norway). The Shetland and Leka ophiolites formed dur
 ing SSZ processes\, so also offer the chance to constrain the effects of S
 SZ processes on the oceanic mantle.\n\n_Brian O’Driscoll is Senior Lectu
 rer in Petrology at the University of Manchester (UK). He received his BSc
  from University College Cork (Ireland) in 2003. His PhD was awarded by Tr
 inity College Dublin (Ireland) in 2007 for his work on various layered int
 rusions of the British and Irish Palaeogene Igneous Province. His research
  interests are mainly focused on elucidating the emplacement and solidific
 ation of magma bodies in the Earth’s crust\, as well as constraining mel
 t generation and migration in the upper mantle. He combines field observat
 ions with petrological\, geochemical\, and isotopic information from igneo
 us (and sometimes metamorphic) rocks to answer these sorts of questions._\
 n\n
LOCATION:Tilley Lecture Theater\, Department of Earth Sciences
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