1. Gulf of California Synthesis / Discussion
Mike Oskin
Paul Umhoefer

2. Global Perspective on Gulf of CA
How does the Gulf of California compare to other rift settings?
Oblique rift in active margin setting
Rapid evolution from subduction to seafloor spreading
Dramatic variation in sediment input
What did we learn from understanding the Gulf of California?

3. Rapid rift localization compared to orthogonal rifts
Last Decade (+) of Research in Gulf of California – Salton trough focus site
Big Conclusions: Processes of continental rupture from the Gulf of California
Rapid rift localization compared to orthogonal rifts
• cessation of subduction 16 to 12 Ma
• focused oblique rifting in
Gulf for at least past 6 M.y.

4. Highly variable rupture style along strike
Last Decade (+) of Research in Gulf of California – Salton trough focus site
Big Conclusions: Processes of continental rupture from the Gulf of California
Highly variable rupture style along strike
• early transition to magmatic crust
at EPR, Guaymas basin
• protracted continental extension
& failed rift basins in southern Gulf
• detachment faulting in northern
Gulf beneath thick sediment

5. This is an active-margin rift
Last Decade (+) of Research in Gulf of California – Salton trough focus site
Boundary conditions vary significantly and exert first-order control on rift structure
• variations in rift obliquity
and sediment flux
• variably enriched mantle wedge
developed above subducting slab
• interaction with Basin & Range
and San Andreas fault system
• many conditions are aspects
of active margin setting
This is an active-margin rift

6. Sediment flux appears key to rupture process
Last Decade (+) of Research in Gulf of California – Salton trough focus site
Sediment flux appears key to rupture process
• Even moderate sedimentation leads
to production of hybrid magmatic-
sedimentary crust in the Guaymas basin;
thicker hybrid crust in northern Gulf.
• Extreme sedimentation in northern
Gulf may promote rift localization
but also vertical strain partitioning
(detachment faulting)
• Top-down control on continental
rupture style?