1/30/2013 - Aspects of Cenozoic Sedimentation and Tectonics on the Hikurangi


12:00 PM - 1:00 PM
Geology 1707

Presented By:
Kathleen M. Marsaglia - California State University-Northridge


The geology of North Island, New Zealand is largely a product of Paleozoic to Cenozoic plate-subduction processes with a Late Cretaceous to Oligocene pause associated with Gondwana rifting. The reinstatement of subduction in the Oligocene was accompanied by emplacement of an ophiolite-bearing allochthon. This subduction propagated eastward, evolving into the current Hikurangi convergent margin. There is evidence that since the Miocene, large-scale reentrants formed along the shelf edge in the forearc via submarine mass wasting. Some reentrants are associated with seamount subduction, a process also linked to modern slow-slip events (aseismic slip). This presentation focuses on the forearc sedimentary record of two of these re-entrants: the nuances of sediment supply from source-to-sink into the modern Poverty re-entrant and the recognition of a potential Miocene example in outcrop. The region is notable in that it was a Source-to-Sink focus site for the NSF MARGINS Program and is now an international primary site for the new NSF GeoPRISMS Subduction Cycles and Deformation Initiative. Furthermore, an Integrated Ocean Drilling Program Expedition is tentatively slated for 2015 that will drill the Poverty forearc to explore the origin of slow-slip events.

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