Seismostratigraphy of the Siberian Sector of the Arctic Ocean and adjacent Laptev Sea Shelf

Abstract

A new seismostratigraphic model has been established within the Arctic Ocean adjacent to the East Siberian Shelf on the basis of multichannel seismic reflection data acquired along a transect at 81°N. Ages for the sedimentary units were estimated via links to seismic lines and drill site data of the US Chukchi Shelf, the Lomonosov Ridge, and the adjacent Laptev Shelf. Two distinct seismic units were mapped throughout the area and are the constraints for dating the remaining strata. The lower marker unit, a pronounced high-amplitude reflector sequence (HARS), is the most striking stratigraphic feature over large parts of the Arctic Ocean. It indicates a strong and widespread change in deposition conditions. Probably, it developed during Oligocene times when a reorientation of Arctic Plates took place, accompanied by the gradual opening of the Fram Strait, and a widespread regression of sea level. The top of the HARS likely marks the end of Oligocene/early Miocene (23 Ma). An age estimate for the base of the sequence is less clear but likely corresponds to base of Eocene (˜56 Ma). The second marked unit detected on the seismic lines parallels the seafloor with a thickness of about 200 ms two-way travel time (160 m). Its base is marked by a change from a partly transparent sequence with weak amplitude reflections below to a set of continuous high-amplitude reflectors above. This interface likely marks the transition to large-scale glaciation of the northern hemisphere and therefore is ascribed to the top Miocene (5.3 Ma).

Rift systems of the Russian Eastern Arctic shelf and Arctic deep water basins: link between geological history and geodynamics

“…Jokat's group Weigelt et al, 2014] studied the Podvonnikov Basin and, based on interpretation of a single regional seismic line, made conclusions that are generally similar to ours. They also identify a number of rifts at the base of the sedimentary cover section.…”

“…The breakuptype unconformity on the shelves with the age of about 56 Ma corresponds to the start of spreading [Drachev et al, 2010;Franke, 2013;Weigelt et al, 2014;. This boundary is traced on the slopes of the Lomonosov Ridge and can be tied up with boundaries of seismic sequences in the Arctic Ocean .…”

“…The structure of the Alpha-Mendeleev Rise is described in [Jokat, 2003;Bruvoll et al, 2010Bruvoll et al, , 2012Dove et al, 2010;Døssing et al, 2013;Hegewald, Jokat, 2013;Weigelt et al, 2014;Brumley, 2014;Nikishin et al, 2014]. In this paper, we will not discuss its structure as a separate topic.…”

“…1) [e.g., Laverov et al, 2013;Vernikovsky et al, 2013;Gaina et al, 2014;Pease et al, 2014;Nikishin et al, 2014;Petrov et al, 2016;Drachev, 2016]. Different versions of the stratigraphy of the ocean's sedimentary cover were presented in [Kim, Glezer, 2007;Backman et al, 2008;Bruvoll et al, 2010Bruvoll et al, , 2012Rekant, Gusev, 2012;Mosher et al, 2012;Døssing et al, 2013;Dobretsov et al, 2013;Weigelt et al, 2014;Jokat, Ickrath, 2015;Nikishin et al, 2014;Brumley, 2014;Rekant et al, 2015;Evangelatos, Mosher, 2016]. Large-scale seismic surveys were recently conducted on the shelves of the Laptev, East Siberian and Chukchi Seas, as well as in the deep-water part of the Arctic Ocean Rekant et al, 2015].…”

Ultraslow spreading, ridge relocation and compressional events in the East Arctic region: A link to the Eurekan orogeny?

“…The paleolatitude and longitude at the time of oceanic crust formation was approximated at 82 degrees north and 105 degrees east, respectively S1-4). A systematic pan-Arctic sedimentary package correlation following distinct seismic reflection character separated by sharp reflectors and linked to the ACEX borehole on the Lomonosov Ridge [4], has proposed ages of unconformities and sedimentary packages [31,44]. Magnetic anomalies identified in the central Eurasian Basin were also correlated with a series of seismic reflection profiles from the Amundsen Basin as additional constrain on the age model [31].…”