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SUMMARY:A dynamic lithosphere-asthenosphere boundary: the PI-LAB experimen
 t at the Mid-Atlantic Ridge and a global perspective - Catherine Rychert -
 - Woods Hole Oceanographic Institution
DTSTART:20231025T150000Z
DTEND:20231025T160000Z
UID:TALK205369@talks.cam.ac.uk
CONTACT:Lisanne Jagt
DESCRIPTION:Plate tectonics revolutionized our understanding of how the Ea
 rth works\, providing a framework for volcanism\, earthquakes\, continenta
 l formation and breakup and the geologic record of climate change. Yet\, w
 hat makes a plate “plate-like” and where and how the rigid lithospheri
 c plate transitions to the underlying weaker asthenosphere are widely deba
 ted. Ocean lithosphere is an ideal location to study the lithosphere-asthe
 nosphere boundary (LAB)\, given that it is young and tectonically simple i
 n comparison to continents. However\, even beneath the oceans reports of t
 he depth and the factors controlling the LAB are variable\, perhaps becaus
 e they come from different methods with different resolutions and in diffe
 rent locations. I present new geophysical constraints on the LAB from the 
 PI-LAB (Passive Imaging of the LAB) experiment using a range of methodolog
 ies\, techniques\, and resolutions in one location near the equatorial Mid
 -Atlantic Ridge. We find that the LAB has a variable character depending o
 n location: simple\, with monotonic age progression\, undulating\, and und
 erlain by a thin melt channel. The result reconciles seemingly discrepant 
 and variable reports of the LAB and partial melt from previous studies. Pu
 tting the result in the context globally and considering continental setti
 ngs\, temperature determines the thickness of the plate to first order. Ho
 wever\, the LAB is dynamic. Melt generation and migration also affect the 
 depth and definition of the LAB and play a role in driving plate tectonics
 . 
LOCATION:Wolfson Lecture Theatre (virtual)
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