BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Magma cracking through the lithosphere - Adina Pusok\, University 
 of Oxford
DTSTART:20241106T140000Z
DTEND:20241106T150000Z
UID:TALK220483@talks.cam.ac.uk
CONTACT:Tom Merry
DESCRIPTION:Magmatism plays a key role in the operation of plate tectonics
 \, yet the details of magma generation in the mantle and transport to the 
 surface remain unclear. In this talk\, I will focus on the problem of magm
 a transport across the ductile–brittle lithosphere with an application t
 o the Turkana Depression\, East African Rift. Magma transport changes from
  porous flow in the hot\, ductile mantle to fluid-filled fractures\, known
  as dikes and sills\, in the cold\, brittle crust. Accurate representation
  of these processes in geodynamics models is crucial for understanding lit
 hospheric deformation\, as magma transports heat and impacts lithospheric 
 stresses. \n\nThe Turkana Depression\, located between the Ethiopian and E
 ast African plateaus\, represents a curious case of the interaction betwee
 n magmatism and tectonics. It is missing the narrow\, magma-rich morpholog
 y observed in the Main Ethiopian Rift that cuts through the Ethiopian Plat
 eau\; instead\, diffuse faulting and isolated volcanic centres are widespr
 ead over several hundred kilometers. Even more enigmatic\, Turkana has exp
 erienced less magmatism than adjacent plateaus\, despite having the thinne
 st crust along the East African Rift south of Afar and overlying a mantle 
 inferred to be hot and partially molten. Here\, I hypothesise that lithosp
 heric weakening relative to the Ethiopian Plateau has been the key control
  on magma transport across the lithosphere in the Turkana Depression and s
 ubsequent rift development. Using newly-developed models that incorporate 
 the two-phase flow theory with a brittle–ductile (viscoelastic–viscopl
 astic) rheology of rocks\, I show that magma extraction across a thin\, we
 akened lithosphere is slower than across a thick\, elastic lithosphere. Th
 e results suggest that the pre-rift thermal and/or mechanical weakening of
  the lithosphere can explain the magma-poor character of the Turkana regio
 n for most of its tectonic history.
LOCATION:Wolfson Lecture Theatre
END:VEVENT
END:VCALENDAR