TY - JOUR

T1 - Bathymetry, controlled source seismic and gravity observations of the Mendeleev ridge; implications for ridge structure, origin, and regional tectonics

AU - Dove, Dayton

AU - Coakley, Bernard

AU - Hopper, John

AU - Kristoffersen, Yngve

PY - 2010/11

Y1 - 2010/11

N2 - Multichannel seismic (MCS), seismic refraction, and gravity data collected down the flank of the Chukchi Plateau, but predominantly over the Mendeleev Ridge have been processed and interpreted to describe the crustal style of the ridge, as well as the structural history. These results provide constraints on the origin of the ridge, and the tectonic evolution of the Amerasian Basin. MCS images reveal two primary sediment sequences separated by an unconformity that persists across the entire Mendeleev Ridge. The basement and lower sediment sequence exhibit pervasive normal faulting. The upper sequence is laterally conformable and not effected by faulting, thus the regional unconformity dividing the two sequences is interpreted to mark the end of extensional deformation. Modeling of sonobuoy seismic refraction data reveals upper crustal P-wave velocities ranging from 3.5 to 6.4 km s-1 approximately 5 km into the basement. The velocity structure of the Mendeleev Ridge is consistent with either a volcanic rifted continental margin, or an oceanic plateau origin. Observed gravity anomalies over the ridge are reproduced by a model consisting of bathymetry, sediment and basement horizons from the MCS data and a single crustal layer of 2.86 g cm-3. This result is consistent with homogeneous, mafic crust. The similar velocity and density structures of the Mendeleev and Alpha ridges is consistent with a model where the two ridges are contiguous and share a common geological origin. Gravity modelling over the transition between the Chukchi Plateau and the Mendeleev Ridge suggests the two features have differing compositions and distinct emplacement histories. Three tectonic models are presented for the origin of the Alpha Mendeleev Ridge (AMR) that satisfy constraints set by this and previous studies: (1) a rifted volcanic continental margin, (2) an oceanic plateau formed at a spreading centre-perpendicular to the AMR and (3) an oceanic plateau formed at a spreading centre-parallel to the AMR.

AB - Multichannel seismic (MCS), seismic refraction, and gravity data collected down the flank of the Chukchi Plateau, but predominantly over the Mendeleev Ridge have been processed and interpreted to describe the crustal style of the ridge, as well as the structural history. These results provide constraints on the origin of the ridge, and the tectonic evolution of the Amerasian Basin. MCS images reveal two primary sediment sequences separated by an unconformity that persists across the entire Mendeleev Ridge. The basement and lower sediment sequence exhibit pervasive normal faulting. The upper sequence is laterally conformable and not effected by faulting, thus the regional unconformity dividing the two sequences is interpreted to mark the end of extensional deformation. Modeling of sonobuoy seismic refraction data reveals upper crustal P-wave velocities ranging from 3.5 to 6.4 km s-1 approximately 5 km into the basement. The velocity structure of the Mendeleev Ridge is consistent with either a volcanic rifted continental margin, or an oceanic plateau origin. Observed gravity anomalies over the ridge are reproduced by a model consisting of bathymetry, sediment and basement horizons from the MCS data and a single crustal layer of 2.86 g cm-3. This result is consistent with homogeneous, mafic crust. The similar velocity and density structures of the Mendeleev and Alpha ridges is consistent with a model where the two ridges are contiguous and share a common geological origin. Gravity modelling over the transition between the Chukchi Plateau and the Mendeleev Ridge suggests the two features have differing compositions and distinct emplacement histories. Three tectonic models are presented for the origin of the Alpha Mendeleev Ridge (AMR) that satisfy constraints set by this and previous studies: (1) a rifted volcanic continental margin, (2) an oceanic plateau formed at a spreading centre-perpendicular to the AMR and (3) an oceanic plateau formed at a spreading centre-parallel to the AMR.

KW - Arctic region

KW - Controlled source seismology

KW - Gravity anomalies and Earth structure

KW - Large igneous provinces

KW - Oceanic plateaus and microcontinents

KW - Submarine tectonics and volcanism

UR - http://www.scopus.com/inward/record.url?scp=77958559058&partnerID=8YFLogxK

U2 - 10.1111/j.1365-246X.2010.04746.x

DO - 10.1111/j.1365-246X.2010.04746.x

M3 - Journal article

AN - SCOPUS:77958559058

VL - 183

SP - 481

EP - 502

JO - Geophysical Journal International

JF - Geophysical Journal International

SN - 0956-540X

IS - 2

ER -