The World’s Largest Submarine Canyon—Kroenke Canyon in the Western Equatorial Pacific

Tuesday, 15 December 2015
Poster Hall (Moscone South)
Millard F Coffin1, Nicholas Adams1, Joanne M Whittaker1, Vanessa Lucieer2, Mark Heckman3, Tomer Ketter4, Jennifer F Neale5, Andres Reyes6 and Amelia Travers1, (1)University of Tasmania, Hobart, Australia, (2)University of Tasmania, Institute for Marine and Antarctic Studies, Hobart, Australia, (3)University of Hawaii at Manoa, Honolulu, HI, United States, (4)Israel Oceanographic and Limnological Research, Haifa, Israel, (5)University of Southampton, Southampton, United Kingdom, (6)University of Guam, Mangilao, Guam, United States
Kroenke Canyon lies on the Ontong Java Plateau (OJP) in the western Equatorial Pacific, between the Solomon Islands and the Federated States of Micronesia. In late 2014 aboard the Schmidt Ocean Institute’s RV Falkor, we mapped, albeit incompletely, the Canyon for the first time, revealing that it is both the longest (>700 km) and the most voluminous (>6800 km3) submarine canyon yet discovered on Earth. Kroenke Canyon appears to originate in the vicinity of Ontong Java (Solomon Islands) and Nukumanu (Papua New Guinea) atolls, and presumably began to develop when the atolls were high-standing volcanic islands surmounting the ~120 Ma igneous basement of the OJP. The Canyon is characterised by numerous tributaries and significant mass wasting. Kroenke Canyon incises the layer-cake stratigraphy of OJP sediment and sedimentary rock, mostly carbonate with some interbedded chert, which has provided numerous slip surfaces for submarine landslides. The carbonate compensation depth (CCD) roughly coincides with the depth of the transition between the OJP and the neighbouring Nauru Basin. As a result, despite the large volume of sediment eroded and transported by canyon-forming processes, only a minor fan is evident in the Nauru Basin because most of the carbonate has dissolved.