TY - JOUR
T1 - The nature of the acoustic basement on Mendeleev and northwestern Alpha ridges, Arctic Ocean
AU - Bruvoll, Vibeke
AU - Kristoffersen, Yngve
AU - Coakley, Bernard J.
AU - Hopper, John R.
AU - Planke, Sverre
AU - Kandilarov, Aleksandre
N1 - Funding Information:
We thank captain D. Oliver and the crew of the USCG icebreaker Healy. Healy cruise 0503 was supported by NSF award # 0449898 to Geophysical Institute, University of Alaska, Fairbanks, and # 0447440 to Texas A&M University, College Station, Texas. MCS acquisition and Norwegian participation was funded by the Norwegian Petroleum Directorate. We are grateful to the Healy 2005 Seismic Team* for their effort and companionship during the cruise.
PY - 2012/1/5
Y1 - 2012/1/5
N2 - The Alpha-Mendeleev ridge complex, over 1500. km long and 250-400. km wide, is the largest submarine structure in the Arctic Ocean basin. Its origin is unknown, but often inferred to represent a large igneous province where domains of continental crust may also be a possibility. We investigate the basement geology of part of this large scale feature using 1100. km of multichannel seismic reflection data, sonobuoy recordings and marine gravity data acquired in 2005 from USCG icebreaker Healy. The sonobuoy results show top and intra-acoustic basement velocities in the range of 2.3-4.0. km/s and the seismic reflection attributes define three main acoustic facies: 1) continuous high amplitude reflections often with abrupt breaks, 3) weak wedge geometry and 3) segmented, disrupted to chaotic reflections. The acoustic characteristics and seismic velocities compare more closely with basement on Ontong Java Plateau than normal ocean crust or wedges of seaward dipping reflections at volcanic margins. The acoustic facies are interpreted to represent basalt flows and sills capping voluminous tuff deposits and possible sediments. At least two volcanic centres are identified. The upper volcanic carapace on the surveyed part of Mendeleev and northwestern Alpha ridges was emplaced during a brief igneous episode no later than Campanian (80. Ma) and most likely part of wider Late Cretaceous circum Arctic volcanism. The horst and graben morphology on Mendeleev Ridge is largely a result of post-emplacement faulting where a number of the major extensional faults remained active until a late Miocene intrusive event.
AB - The Alpha-Mendeleev ridge complex, over 1500. km long and 250-400. km wide, is the largest submarine structure in the Arctic Ocean basin. Its origin is unknown, but often inferred to represent a large igneous province where domains of continental crust may also be a possibility. We investigate the basement geology of part of this large scale feature using 1100. km of multichannel seismic reflection data, sonobuoy recordings and marine gravity data acquired in 2005 from USCG icebreaker Healy. The sonobuoy results show top and intra-acoustic basement velocities in the range of 2.3-4.0. km/s and the seismic reflection attributes define three main acoustic facies: 1) continuous high amplitude reflections often with abrupt breaks, 3) weak wedge geometry and 3) segmented, disrupted to chaotic reflections. The acoustic characteristics and seismic velocities compare more closely with basement on Ontong Java Plateau than normal ocean crust or wedges of seaward dipping reflections at volcanic margins. The acoustic facies are interpreted to represent basalt flows and sills capping voluminous tuff deposits and possible sediments. At least two volcanic centres are identified. The upper volcanic carapace on the surveyed part of Mendeleev and northwestern Alpha ridges was emplaced during a brief igneous episode no later than Campanian (80. Ma) and most likely part of wider Late Cretaceous circum Arctic volcanism. The horst and graben morphology on Mendeleev Ridge is largely a result of post-emplacement faulting where a number of the major extensional faults remained active until a late Miocene intrusive event.
KW - Arctic Ocean
KW - Basement structures
KW - Circum arctic volcanism
KW - Mendeleev and Alpha ridges
KW - Oceanic plateau
KW - Reflection/refraction seismic
UR - http://www.scopus.com/inward/record.url?scp=84855318364&partnerID=8YFLogxK
U2 - 10.1016/j.tecto.2011.10.015
DO - 10.1016/j.tecto.2011.10.015
M3 - Article
SN - 0040-1951
VL - 514-517
SP - 123
EP - 145
JO - Tectonophysics
JF - Tectonophysics
ER -