Cenozoic geodynamics of the Ross Sea region, Antarctica: Crustal extension, intraplate strike-slip faulting, and tectonic inheritance

An integrateds tudyo f onshorea ndo ffshoreg eologyo f the RossS ear egion (namely, Victoria Land, north of Ross Island, and the Ross Sea, Antarctica) has revealed a complexp, ost-Eocenete ctonicf ramework.R egionalN W-SE right-laterals, trike-slipf aults are the outstandingfe atureo f this frameworka nd overprinta n older Mesozoice xtensional event,r esponsiblefo r formationo f N-S basinsi n the RossS ea. The Cenozoicf ramework includesk inematicd eformationa ndr eactivationa longt he NW-SE faults,i ncluding formationo f pull-apartb asinsb, othp ositivea ndn egativef lower structuresa,n dp ush-up ridges.N -S extensionafla ultsa re well developedb etweenN W-SE faultsa nd indicateE -W extensiond uringt he Cenozoicp, roducedb y the NW-SE right-laterasl trike-slipm otion togethewr ith regionalc rustale xtensionN. NW-SSE compressionin, ducedb y the rightlateral, s trike-slipk inematics,i s indicatedb y locally invertedN E-SW faultsa ndb asins.T he evolutiong, eometrya, ndl ocationo f the RennickG rabena ndt he LantermanR angef it well into thism odel.V ariationsi n the deformationaslt ylea crossth e regionc anb e linkedt o correspondinvga riationsin the bulk crustalr heology,f rom brittleb ehaviori n the west,t o ductile deformation( at subseismic-scalree solution)n ear the EasternB asin. A semibrittle regiont hatf avorsN -S clusteringo f Cenozoicm agmatica ctivity lies in between.I n this region,C enozoicv olcanoesd evelopa t the intersectionosf the NW-SE andt he majorN -S faults.T he NW-SE faultsc ut almostc ontinuallyf rom the RossS eat o EastA ntarctica throughl ithospherics ectorsw ith differentr heologya nd thicknessA. t leastt wo of the NWSE faultsc orrespondto older Paleozoict erraneb oundariesin northernV ictoria Land. The NW-SE faultsl ink in the SouthernO ceanw ith majort ransformfa ultsr elatedt o the plate motions of Australia, New Zealand, and Antarctica.