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Deciphering Ontong Java Atoll, Nukumanu Atoll, and Kroenke Canyon, Western Equatorial Pacific final project report for RV Falkor FK141015 15 October 3 November 2014

Citation

Coffin, MF and Adams, N and Heckman, M and Ketter, T and Lucieer, VL and Neale, J and Reyes, AJ and Travers, AH and Whittaker, J, Deciphering Ontong Java Atoll, Nukumanu Atoll, and Kroenke Canyon, Western Equatorial Pacific final project report for RV Falkor FK141015 15 October - 3 November 2014, Institute for Marine and Antarctic Studies, University of Tasmania, FK141015 (2015) [Contract Report]


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Abstract

Kroenke Canyon on the Ontong Java Plateau (OJP) extends for approximately 500 km between its hypothesized origin at Ontong Java and Nukumanu atolls and its mouth at the transition between the Plateau and the Nauru Basin. For FK141015, RV Falkor departed Pohnpei, Federated States of Micronesia, on 15 October 2014, and arrived in Guam, USA, on 3 November 2014. During the voyage we acquired primarily EM302 multibeam data along 6,288 line-km over the 13 days in the survey area, augmented by EM710 multibeam data in shallower water. Overall, the EM302 ensonified 23,439 km2 of seafloor in the survey area, in water depths ranging from 87 m to 4,444 m (Figure ES1). XBT data (12 casts) were acquired routinely, and the CTD was tested, returning useful data from one cast.

Of similar scale and relief to the Grand Canyon (Arizona, USA), and with multiple tributaries, Kroenke Canyon incises pelagic sediment, sedimentary rock, and igneous rock of OJP. We mapped the thalweg of Kroenke Canyon from approximately 150 km northeast of the atolls to its mouth at the transition between the OJP and the Nauru Basin (Figure ES1). Due to the loss of HROV Nereus several months prior to FK141015, seafloor sampling that had been planned for the voyage was not possible, and the Knudsen CHIRP 3260 sub-bottom profiling system did not yield any sub-bottom data that had planned to be acquired. Due to shipyard delays, the number of ship-days available for FK141015 was reduced from the original 30 to 20, and correspondingly the number of ship-days available for science in the survey area was reduced from the original 23 to 13.

Ultimate project goals for FK141015 include: 1) understanding and modeling how submarine canyons and atolls form and evolve on oceanic plateaus, isolated from terrestrial influences and subject to sea level fluctuations; 2) testing potential genetic relationships between a) the atolls and Kroenke Canyon, and b) the atolls and OJP; and 3) contributing to assessing tsunami risk on low-lying atolls. Intended impacts are to advance knowledge of canyon and submarine landslide development globally, to better understand emplacement and post-emplacement volcanism of LIPs, and to improve tsunami risk assessment.

Item Details

Item Type:Contract Report
Keywords:canyons, deep sea
Research Division:Earth Sciences
Research Group:Geology
Research Field:Marine Geoscience
Objective Division:Environment
Objective Group:Ecosystem Assessment and Management
Objective Field:Ecosystem Assessment and Management of Marine Environments
Author:Coffin, MF (Professor Mike Coffin)
Author:Adams, N (Mr Nicholas Adams)
Author:Lucieer, VL (Dr Vanessa Lucieer)
Author:Travers, AH (Ms Amelia Travers)
Author:Whittaker, J (Dr Jo Whittaker)
ID Code:100997
Year Published:2015
Deposited By:IMAS Research and Education Centre
Deposited On:2015-06-05
Last Modified:2016-01-05
Downloads:0

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