Crustal structure of the Lomonosov Ridge and the Fram and Makarov Basins near the North Pole

Forsyth, David; Mair, J. A.

doi:10.1029/jb089ib01p00473

Cited by 41 publications

(25 citation statements)

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“…They base their interpretation on seismic wide‐angle results (for location see Figure : LORITA profile). However, the crustal thickness of the LR plateau is 26–27 km [ Jackson et al ., 2010], which is roughly similar to the crustal thickness of the central LR near the North Pole (∼25 km) [ Forsyth and Mair , ]. Hence, differences in crustal thickness do not explain the elevated bathymetry of the LR plateau relative to the central LR, whereas differences in crustal thickness may explain the difference in bathymetry relative to the Klenova Valley (crustal thickness around 14 km) [ Jackson et al ., 2010].…”

Section: Discussionmentioning

confidence: 98%

New aero‐gravity results from the Arctic: Linking the latest Cretaceous‐early Cenozoic plate kinematics of the North Atlantic and Arctic Ocean

Døssing

Hopper

Olesen

et al. 2013

Geochem Geophys Geosyst

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[1] The tectonic history of the Arctic Ocean remains poorly resolved and highly controversial. Details regarding break up of the Lomonosov Ridge from the Barents-Kara shelf margins and the establishment of seafloor spreading in the Cenozoic Eurasia Basin are unresolved. Significantly, the plate tectonic evolution of the Mesozoic Amerasia Basin is essentially unknown. The Arctic Ocean north of Greenland is at a critical juncture that formed at the locus of a Mesozoic three-plate setting between the Lomonosov Ridge, Greenland, and North America. In addition, the area is close to the European plate, resulting in complicated interactions between all these areas that are difficult to resolve. In 2009, the 550,000 km 2 LOMGRAV aero-geophysical survey produced the first collocated gravity and magnetic measurements over the area, significantly increasing the data coverage. We present an interpretation of a new free-air gravity compilation, which reveals a regionally consistent structural grain across the Lomonosov Ridge, the Ellesmere and Lincoln Sea shelves, and the Alpha Ridge. We interpret the grain as evidence of latest Cretaceous ($80 Ma) regional extension in response to the northward propagation of Atlantic and Labrador Sea opening into the Arctic, west of Greenland. This interpretation is consistent with coincident alkaline volcanic activity evident in the borderlands of the Lincoln Sea. We further suggest that Eurekan crustal shortening contributed to the formation of the distinct Lomonosov Ridge plateau against an important fault zone north of Greenland. Our results provide new constraints for Cretaceous-Cenozoic plate reconstructions of the Arctic.

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Section: Discussionmentioning

confidence: 98%

New aero‐gravity results from the Arctic: Linking the latest Cretaceous‐early Cenozoic plate kinematics of the North Atlantic and Arctic Ocean

Døssing

Hopper

Olesen

et al. 2013

Geochem Geophys Geosyst

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“…Seismic surveys have also mapped the polar margin structure about 500 krn southwest of the study area and the Alpha and Lomonosov ridges near the North Pole (Forsyth and Mair 1984;Forsyth et al 1986, 19906;Jokat et al 1992). To the southeast, Niblett et al (1974) reported a conductivity anomaly coincident with the Lake Hazen Fold Belt and its projection offshore beneath the Lincoln Sea.…”

Section: Basic Magmatismmentioning

confidence: 95%

“…The Lincoln Sea plateau may have resulted from the breakup of a mafic complex related to the Kap Washington volcanics and a region of short-wavelength magnetic anomalies to the east of the study area near the Morris Jesup Rise (Kovacs 1982). The velocity structure beneath the Lomonosov Ridge near the North Pole includes a 3 -5 km thick upper crustal unit with a velocity of 4.0-5.2 kmls, a lower crust with a velocity of 6.2-6.7 kmls, and an upper mantle velocity of 8.3 kmls (Jokat et al 1992;Forsyth and Mair 1984).…”

Section: Geological and Tectonic Setting Oceanic Elementsmentioning

confidence: 99%

New seismic, magnetic, and gravity constraints on the crustal structure of the Lincoln Sea continent–ocean transition

Forsyth¹,

Argyle²,

Okulitch³

et al. 1994

Can. J. Earth Sci.

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A new seismic model of Canada's northeasternmost margin indicates a complex continent to ocean transition with similarities to both volcanic and nonvolcanic margins. The crustal structure beneath the Lincoln Sea includes: (i) a continental shelf with a uniform 3 km thick cover (velocity = 1.8-3.6 h i s ) overlying at least 6 km of synrift(?) basinal strata (velocity = 4.3-4.9 M s ) that terminate near the base of the slope; (ii) a thick unit of oceanic layer 2-type. velocity (5.4-5.8 h i s ) overlying a velocity structure resembling a volcanic margin; (iii) a high-velocity lower crust (> 7.4 kmls) resembling North Atlantic volcanic margins or the Alpha Ridge but different from the Lomonosov Ridge near the North Pole; (iv) a change in velocity structure 15-25 km seaward of the shelf-slope break that coincides with a distinct short-wavelength, highamplitude magnetic anomaly and the centre of a steep gravity gradient; and (v) a suggested Moho depth of 23 km beneath the Lincoln Sea margin along 63 O W .The velocity structure beneath the Lincoln Sea is transitional from thinned continental crust beneath the shelf to a structure with oceanic affinities to the north. Typical, 10 km thick oceanic crust is not apparent beneath the northern Lincoln Sea. The upper crustal structure resembles a rifted, nonvolcanic margin such as the Goban Spur, while the high lower crustal velocity resembles a volcanic margin like the Hatton Bank or an oceanic complex like the Alpha Ridge. North of the seismic survey, the enigmatic Lincoln Sea plateau may be an intruded Lomonosov Ridge segment or a volcanic complex similar to the Alpha Ridge or the Morris Jesup Plateau.Un modtle sismique nouvellement dabor6 pour la marge de 11extr6mit6 nord-est du Canada indique une transition continentale 21 ochnique complexe, prtsentant des traits cornrnuns aux marges volcaniques et non volcaniques. La structure crustale sous la mer de Lincoln inclut : (i) une plate-forme continentale avec une couverture uniforme d'une 6paisseur de 3 km (vitesse = 1,8-3,6 M s ) , qui recouvre au moins 6 km de strates d6pos6es dans un bassin en distension(?) (vitesse = 4,3 -4,9 h i s ) disparaissant p r b de la base du talus; (ii) une unit6 form6e d'une puissante couche oc6anique de vitesses de type-2 (5,4-5,8 h i s ) , sus-jacente B une structure de vitesses ressemblant B une marge volcanique; (iii) une crofite inf6-rieure de vitesses 6lev6es (>7,4 kmls) semblable aux marges volcaniques de 1'Atlantique Nord ou B la crgte d'Alpha, mais qui differe de la crgte de Lomonosov prts du p61e Nord; (iv) un changement dans la structure de vitesses B 15 -25 km vers le large de la discontinuit6 entre la plate-forme et le talus, coincidant avec une anomalie magnCtique de forte amplitude et de longueur d'onde courte distincte et avec le centre d'un gradient gravitaire abrupt; et (v) une profondeur sugg6r6e de 23 krn pour le Moho sous la marge de la mer de Lincoln, le long du 63" de longitude ouest.La structure de vitessses sous la mer de Lincoln indique le passage graduel d'une crofite ...

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“…Seismic refraction and gravity experiments show that the Lomonosov Ridge is the surface expression of a sliver of continental crust having a Moho at a depth of 25-28 km (Forsyth & Mair 1984;Weber & Sweeney 1985;Lebedeva-Ivanova et al 2006a). Although the Lomonosov Ridge is a prominent bathymetric feature adjacent to the Eurasia Basin, the continental crust on the Amerasia Basin side of the microcontinent extends beneath the lower-lying parts of the adjacent Podvodnikov Basin (Jokat 2005).…”

Section: Boundaries Of the Lomonosov Microcontinentmentioning

confidence: 98%

Chapter 49 A first look at the petroleum geology of the Lomonosov Ridge microcontinent, Arctic Ocean

Moore

Grantz²,

Pitman

et al. 2011

Memoirs

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The Lomonosov microcontinent is an elongated continental fragment that transects the Arctic Ocean between North America and Siberia via the North Pole. Although it lies beneath polar pack ice, the geological framework of the microcontinent is inferred from sparse seismic reflection data, a few cores, potential field data and the geology of its conjugate margin in the Barents–Kara Shelf. Petroleum systems inferred to be potentially active are comparable to those sourced by condensed Triassic and Jurassic marine shale of the Barents Platform and by condensed Jurassic and (or) Cretaceous shale probably present in the adjacent Amerasia Basin. Cenozoic deposits are known to contain rich petroleum source rocks but are too thermally immature to have generated petroleum. For the 2008 USGS Circum Arctic Resource Appraisal (CARA), the microcontinent was divided into shelf and slope assessment units (AUs) at the tectonic hinge line along the Amerasia Basin margin. A low to moderate probability of accumulation in the slope AU yielded fully risked mean estimates of 123 MMBO oil and 740 BCF gas. For the shelf AU, no quantitative assessment was made because the probability of petroleum accumulations of the 50 MMBOE minimum size was estimated to be less than 10% owing to rift-related uplift, erosion and faulting.

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Crustal structure of the Lomonosov Ridge and the Fram and Makarov Basins near the North Pole

Cited by 41 publications

References 10 publications

New aero‐gravity results from the Arctic: Linking the latest Cretaceous‐early Cenozoic plate kinematics of the North Atlantic and Arctic Ocean

New aero‐gravity results from the Arctic: Linking the latest Cretaceous‐early Cenozoic plate kinematics of the North Atlantic and Arctic Ocean

New seismic, magnetic, and gravity constraints on the crustal structure of the Lincoln Sea continent–ocean transition

Chapter 49 A first look at the petroleum geology of the Lomonosov Ridge microcontinent, Arctic Ocean

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