The crustal structure of the eastern Chatham Rise region - Results of the 2016 geophysical survey SO246 by the R/V Sonne


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Karsten.Gohl [ at ] awi.de

Abstract

The easternmost Chatham Rise is a key focus area for understanding the Cretaceous tectonics of the New Zealand region. It is the region where seafloor spreading between New Zealand and Antarctica first initiated. The West Wishbone Ridge, a major 1200 km long, northeast trending, gravity and bathymetry lineament intersects the Chatham Rise immediately east of where the Hikurangi Plateau LIP abuts the northern Chatham Rise, and 150 km east of the Chatham islands. The southeast Chatham Rise was once adjacent to Marie Byrd land in Antarctica, a key research focus area for the Alfred Wegener Helmholtz Institute (AWI), Germany. A seven-week seismic reflection/refraction and volcanic rock-dredging survey was conducted across the eastern Chatham Rise by the Alfred Wegener Helmholtz Institute in early 2016 using the new R/V Sonne research vessel. The survey collected four crustal scale seismic reflection and refraction lines across the eastern Chatham Rise, two seismic reflection lines across the Wishbone Ridge complex, and numerous dredges of seafloor volcano structures on the southeast Chatham Terrace, guided by multibeam swath data. GNS Science operated their gravity meter and magnetometer throughout most of the survey. The initial results from the survey will be presented and linked with existing data and concepts on the structure of the Chatham Rise accretionary prism structure (Rakaia versus Pahau) and its onshore South Island prolongation. The nature of the West Wishbone Ridge and similar Cretaceous fault structures and their role in Gondwana breakup will also be discussed.



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Conference (Talk)
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Primary Division
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Not peer-reviewed
Publication Status
Published
Event Details
Annual Conference Geoscience Society of New Zealand, 28 Nov 2017 - 01 Dec 2017, Auckland.
Eprint ID
45569
Cite as
Davy, B. , Gohl, K. , Werner, R. , Barrett, R. S. and Riefstahl, F. (2017): The crustal structure of the eastern Chatham Rise region - Results of the 2016 geophysical survey SO246 by the R/V Sonne , Annual Conference Geoscience Society of New Zealand, Auckland, 28 November 2017 - 1 December 2017 .


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