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SUMMARY:Tectonic pulsing\, climate cycles and contourites: drilling result
 s from IODP Expedition 339 - Dorrik Stow\, Heriot-Watt University 
DTSTART:20160308T160000Z
DTEND:20160308T170000Z
UID:TALK62475@talks.cam.ac.uk
CONTACT:John Maclennan
DESCRIPTION:The SW Iberian margin holds an unmistakable signal of Mediterr
 anean Outflow Water (MOW) following its exit through the Strait of Gibralt
 ar. It also represents a key area for understanding the effects of tectoni
 c activity both on evolution of the Gibraltar Gateway and on margin sedime
 ntation\, having major implications for global climate and oceanography. I
 t was therefore targeted for drilling by IODP Expedition 339 – some of t
 he principal results are presented here. \n\nFollowing opening of the Gibr
 altar Gateway (5.33 Ma)\, it was a further 1 My before a weak MOW started 
 to flow into the Atlantic (4.5- 4.2 Ma). It was not until the Late Pliocen
 e (3.2-3 Ma) and early Pleistocene (2.4-2.1 Ma) that a marked enhancement 
 of MOW circulation into the North Atlantic occurred\, evidenced by two wid
 espread depositional hiatuses\, which determined significant changes in se
 dimentary style and dominant process. Significantly\, MOW contributed to a
 n enhancement of the Atlantic Meridional Overturning Circulation and\, con
 sequently\, to global climate.\n \nTectonic controls on margin development
  are evidenced by the closure of the Atlantic-Mediterranean gateways in Sp
 ain and Morocco at just over 6 Ma\, the opening of the Gibraltar Gateway a
 t 5.3 Ma\, downslope sediment transport and contourite drift evolution. Ba
 sed on the timing of events recorded in the sedimentary record\, we propos
 e a tectonic pulsing in the region at a timescale of approximately 1 My\, 
 which we tentatively link with asthenosphere activity.\n\nThe Gulf of Cadi
 z is the world’s premier contourite laboratory and thus presents an idea
 l testing ground for the contourite paradigm. Following examination of ove
 r 4.5 km of contourite cores\, the existing models for contourite depositi
 on are found to be in good working order. Their further study has begun to
  allow us to resolve outstanding issues of depositional processes\, drift 
 budgets\, and recognition of fossil contourites in the ancient record onsh
 ore. The expedition also verified an enormous quantity and extensive distr
 ibution of contourite sands that are clean and well sorted. These represen
 t a completely new and important exploration target for potential oil and 
 gas reservoirs.\n
LOCATION:Harker 1 seminar room\, Department of Earth Sciences
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