| Summary: | Magnetic anomalies associated with new ocean crust formation in the Adare Basin off north-western Ross Sea (43–26 Ma) can be traced directly into the Northern Basin that underlies the adjacent morphological continental shelf, implying a continuity in the emplacement of oceanic crust. Steep gravity gradients along the margins of the Northern Basin, particularly in the east, suggest that little extension and thinning of continental crust occurred before it ruptured and the new oceanic crust formed, unlike most other continental rifts and the Victoria Land Basin further south. A preexisting weak crust and localization of strain by strike-slip faulting are proposed as the factors allowing the rapid rupture of continental crust. © 2016. American Geophysical Union. Received 11 APR 2016; Accepted 31 MAY 2016; Accepted article online 3 JUN 2016; Published online 21 JUN 2016. The aeromagnetic map in Figure 2 is available from F.F. and will be submitted to the NERC/BAS Polar Data Centre. Magnetic anomaly picks have been submitted to The Global Seafloor Fabric and Magnetic Lineation Data Base Project, link: http://www.soest.hawaii.edu/PT/GSFML/ML/index.html. The marine gravity data are available from GeoMap App, cruise NBP0701. The seismic data of Brancolini et al., 1995 are also available from the SCAR seismic Data Library System—http://sdls.ogs.trieste.it/. Sonobuoy data from NBP0701 are available from http://web.gps.caltech.edu/~clay/Adare_Sonobuoy/Adare_Sonobuoy.html). Adare Basin Sonobuoy data (2007), Sonobuoy Data from the Adare Basin, Antarctica. Caltech. Dataset. doi:10.7909/C37P8W9P. S.C. acknowledges funding from NSF grant OPP04-40959 and F.D. for funding from NZGSF. We acknowledge the critical reviews by John Behrendt and two anonymous reviewers that has greatly improved the paper. F.D. thanks Susan Ellis for advice. Published - Davey_et_al-2016-Geophysical_Research_Letters.pdf Supplemental Material - grl54560-sup-0001-SuppInfo.doc
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