georefid:2012-066970SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1017/S09541020100009692011-01-01publicationgeorefid:2012-066970doi:10.1017/S0954102010000969Mortimer, N.GNS Science, Dunedin, New ZealandauthorPalin, J. M.University of Otago, New ZealandauthorDunlap, W. J.University of Minnesota, United StatesauthorHauff, F.IFM-GEOMAR Leibniz Institute for Marine Sciences, GermanyauthorCambridge University Press, Cambridge, United KingdompublisherdocumentHardcopyAntarctic Science23 (3)297-306The Ross Sea is bordered by the Late Precambrian-Cambrian Ross-Delamerian Orogen of East Antarctica and the more Pacific-ward Ordovician-Silurian Lachlan-Tuhua-Robertson Bay-Swanson Orogen. A calcsilicate gneiss from Deep Sea Drilling Project 270 drill hole in the central Ross Sea, Antarctica, gives a U-Pb titanite age of 437 + or - 6 Ma (2sigma ). This age of high-grade metamorphism is too young for typical Ross Orogen. Based on this age, and on lithology, we propose a provisional correlation with the Early Palaeozoic Lachlan-Tuhua-Robertson Bay-Swanson Orogen, and possibly the Bowers Terrane of northern Victoria Land. A metamorphosed porphyritic rhyolite dredged from the Iselin Bank, northern Ross Sea, gives a U-Pb zircon age of 545 + or - 32 Ma (2sigma ). The U-Pb age, petrochemistry, Ar-Ar K-feldspar dating, and Sr and Nd isotopic ratios indicate a correlation with Late Proterozoic-Cambrian igneous protoliths of the Ross Orogen. If the Iselin Bank rhyolite is not ice-rafted debris, then it represents a further intriguing occurrence of Ross basement found outside the main Ross-Delamerian Orogen.completedAreal geologyabsolute ageAntarcticaAr/ArdatesDeep Sea Drilling ProjectDSDP Site 270geochemistrygeochronologyigneous rocksIselin BankLeg 28lower Paleozoicmetamorphic rocksNeoproterozoicPaleozoicPrecambrianProterozoicRoss OrogenyRoss SeaSouthern OceantectonicsU/Pbupper Precambrianurn:org.iodp:exp:28urnlargerWorkCitationcampaignurn:org.iodp:exp:28:site:270urnlargerWorkCitationstudyurn:org.iodp:exp:28urnlargerWorkCitationcampaignEnglishgeoscientificInformation-178.3011-178.3011-77.2629-77.2629