Andy Armstrong

An ultrahigh-latitude submarine channel: Northern Chukchi Rise

Eight dedicated mapping cruises have taken place since 2003 in the mostly ice-covered waters north of Alaska to 83.5° N (Mayer et al. 2010), using the USCG Icebreaker Healy . Due to the generally heavy sea-ice conditions (the sea-ice edge was typically encountered at about 75° N), most surveys involved single multibeam swaths that covered specific targets. During the 2012 record sea-ice minimum, however, the ice margin was at about 80° N which allowed mapping using overlapping multibeam surveys (Mayer & Armstrong 2012). The complete-coverage surveys of 2012 revealed a previously unknown submarine channel (informally named ‘Weather Channel’) that is one of the most northerly submarine channels mapped to date and is probably related to glacial processes. ‘Weather Channel’ is about 160 km long, first appearing at a depth of about 3300 m on a relatively flat basin floor in what is probably a pull-apart basin separating the northern extension of Chukchi Rise from Chukchi Cap (Brumley et al. 2009). It lies in the middle of the basin, approximately 13 km north of the base of Chukchi Cap and 9 km south of the topographic highs of the …