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Crustal structure of the East Siberian Continental Margin, Podvodnikov and Makarov basins based on refraction seismic data (TransArctic 1989–1991)
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
Polar Marine Geological Research Expedition (PMGRE).
2011 (English)In: Arctic Petroleum Geology / [ed] Anthony M. Spencer, Don Gautier, Antonina Stoupakova, Ashton Embry, Kai Sørensen, London: Geological Society of London, 2011, 395-411 p.Chapter in book (Other academic)
Abstract [en]

The c. 1500 km long refraction and shallow reflection seismic profile, TransArctic 1989–1991 from the East Siberian shelf northwards across the Podvodnikov and Makarov basins, provide a four layer model of the crust: Layer I (Vp=1.7–3.8 km/s) of sedimentary formations of late Mesozoic and Cenozoic age; Layer II (Vp=5.0–5.4 km/s) of older sedimentary rocks on the shelf and possibly also mafic volcanics in the basins; Layer III (Vp=5.9–6.5 km/s) and Layer IV (Vp=6.7–7.3 km/s) of crystalline crust. The East Siberian margin has c. 40 km thick continental crust, mainly composed of layers III and IV, both c.15 km thick. Beneath the Podvodnikov Basin, the Moho depth varies from c. 20 km bsl at southern and northern ends to c. 30 km bsl at the centre beneath the Arlis Gap; it probably was formed by longitudinal extension of continental crust during the late Mesozoic. The edge of the Alpha-Mendeleev Ridge, separating the Podvodnikov and Makarov basins, has a crustal thickness of c. 25 km, mainly composed of layers III and IV. The deep Makarov Basin is probably composed of oceanic crust, 8–12 km thick, but includes spurs of continental crust, rifted off the Lomonosov Ridge.

Place, publisher, year, edition, pages
London: Geological Society of London, 2011. 395-411 p.
Series
Memoir series of the Geological Society of London, ISSN 0435-4052 ; 35
Keyword [en]
refraction seismic, reflection seismic, crustal structure, Arctic Ocean, Amerasia Basin, East Siberian Margin, Podvodnikov Basin, Makarov Basin
National Category
Geophysics
Research subject
Geophysics with specialization in Seismology
Identifiers
URN: urn:nbn:se:uu:diva-121762DOI: 10.1144/M35.26ISBN: 978-1-86239-328-8 (print)OAI: oai:DiVA.org:uu-121762DiVA: diva2:306497
Note
Based on a paper presented at the 33rd International Geological Congress (33IGC), Oslo, Norway, 6-14 August, 2008Available from: 2010-03-31 Created: 2010-03-30 Last updated: 2012-04-16Bibliographically approved
In thesis
1. Geophysical Studies Bearing on the Origin of the Arctic Basin
Open this publication in new window or tab >>Geophysical Studies Bearing on the Origin of the Arctic Basin
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Deep troughs and ridges of the Arctic Basin are some of the least known features of the Earth's crust. Some of the ridges, eg. Chukchi and Nordwind, are connected directly to the continental shelves and are certainly submarine promontories of the latter. The character of the Lomonosov Ridge as a narrow slice of continental crust that separated from the Eurasian margin in the early Cenozoic (by opening of the Eurasian Basin), is not in doubt. Recent drilling (ACEX) and piston coring have confirmed this interpretation. However there are many other ridges and some of the troughs that are of uncertain origin.

Seismic research in combination with potential field data over the East-Siberian margin, Podvodnikov and Makarov basins and the Mendeleev Ridge, presented here, provides a framework for understanding this enigmatic part of the Earth. The constrained models of the crust illustrate their structure. The crust beneath the East Siberian margin is up to 40 km thick; it thins to about 20 km towards to the Podvodnikov Basin. The models over the Arlis Gap, in the middle of the Podvodnikov Basin, and the Mendeleev Ridge have shown that the crust beneath both these features is anomalously thick (up to 28–32 km) and has a velocity structure that suggests the presence of highly attenuated continental crust. The crustal thickness over the Makarov Basin varies from 8 km to 15 km.

Reflection profiles provide evidence of the character and thickness of the sedimentary cover (mostly Cenozoic and late Mesozoic), both on the ridges and beneath the troughs. Presented here is evidence that some of the ridges (eg. Marvin Spur) appear to be fragments of continental crust rifted off the Lomonosov Ridge (with a similar, unconformable Cenozoic cover); however, they gently plunge into and beneath troughs (eg. Makarov Basin).

Reflection seismic data collected by the HOTRAX expedition in 2005 over the central part of the Lomonosov Ridge illustrate the sedimentary structure on the top of the Ridge and in an internal basin. The main sedimentary units can be interpreted by correlation with the ACEX results. The major fault separating the surrounding ridges from the internal basin appears to have a roll over anticline in the hanging wall, suggesting that the basin was created by a growth fault. The seismic lines provide evidence of gently folded basement beneath the Lomonosov Ridge with intra basement reflections are usually parallel to the upper surfaces; in combination with velocities (c. 4–5 km/s), these suggest the presence of old well-consolidated sediments.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2010. 79 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 729
Keyword
refraction seismic, reflection seismic, crustal structure, Arctic Ocean, Amerasia Basin.
Research subject
Geophysics with specialization in Seismology
Identifiers
urn:nbn:se:uu:diva-121757 (URN)978-91-554-7771-4 (ISBN)
Public defence
2010-05-07, Axel Hambergsalen, Geocentrum, Villavagen 16, Uppsala, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2010-04-07 Created: 2010-03-29 Last updated: 2010-04-07

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