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SUMMARY:Absolute Pacific Plate Motions and the Evolution of the Hawaii-Emp
 eror Seamount Chain - Paul Wessel - University of Hawai'i at Mānoa
DTSTART:20220504T150000Z
DTEND:20220504T160000Z
UID:TALK173150@talks.cam.ac.uk
CONTACT:Tom Winder
DESCRIPTION:The plate tectonics hypothesis remains a fundamental paradigm 
 in the Earth sciences. One avenue of research focuses on absolute plate mo
 tions (APM)\, seeking to determine models that may place lithospheric moti
 ons in a geodynamic framework. Traditionally\, APM models are inferred fro
 m seamount chain geometry and age progressions. A classic example is the a
 ssociation of the Hawaii-Emperor Bend with a prominent change in motion of
  the Pacific plate at 50 Ma. Yet\, the discovery of significant paleolatit
 ude anomalies along the Emperor Ridge has shifted modeling efforts from a 
 fixed hotspot reference frame to ones defined by moving hotspots. Incorpor
 ating plume drift has made modeling more challenging as direct observation
 s of plume drift are lacking. Predictions from mantle convection models th
 at broadly satisfy observed paleolatitudes have so far been the only appro
 ach to derive APM over moving hotspots. Nevertheless\, uncertainties in ma
 ntle rheology\, temperature\, and initial conditions make such models nonu
 nique and not precise. Furthermore\, the Pacific plate is particularly dif
 ficult to model due to a limited set of seamount ages and an absence of co
 ntinental crust from which reliable paleolatitude observations could be ma
 de\, necessitating oceanic drilling of seamounts. Unlike stable terrestria
 l locales\, volcanic seamounts undergo a rapid dynamic evolution over a ge
 ologically short period\, and it remains unclear if this evolution and sub
 sequent decay could induce tilting of the platform which might bias paleo-
 inclinations observed today.\n\nThis seminar will discuss recent developme
 nts in understanding the origin of the Hawaii-Emperor Bend and its signifi
 cance for APM studies. I will examine the evidence for plate and plume mot
 ions and review the paleomagnetic\, geometric\, and chronologic observatio
 ns from the Pacific basin. My ongoing Leverhulme Visiting Professorship at
  the University of Oxford involves modeling of the dynamic evolution of th
 e Hawaii-Emperor seamount chain and building a temporal model to mimic the
  construction and decay of the entire chain. The model will be used to loa
 d a suitable rheologic model for the lithosphere and allow us to examine p
 redictions of spatial and temporal variations of flexural deformation\, im
 plications for seamount tilt and the potential for bias in paleomagnetic i
 nclinations obtained from oceanic drill holes. In addition\, it will hopef
 ully provide new insight into the evolution of one of the most ubiquitous 
 landforms on Earth: seamounts
LOCATION:In person (Wolfson Lecture Theatre) and ONLINE - Details to be se
 nt by email
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