Impact of a Fixed Siberian Traps Mantle Plume on the Tectonics of the Arctic

Lawrence Lawver

Eruption of the Siberian Traps at the Permo-Triassic boundary [~250 Ma] produced more than 3 x 10⁶km³ of rapidly emplaced magma throughout a region almost 5 x 10⁶km² in extent (Reichow et al., 2009). Dates from the New Siberian Islands of 252 ± 2 Ma (Kuzmichev & Pease, 2007) indicate that Siberian Trap-related magmas are found ~500 km to the east of where they are generally shown to terminate to the west of the Lena River. Cenozoic opening of the Eurasian Basin would account for some of this discrepancy. A Siberian Trap mantle plume in an absolute reference frame fixed to the present day location of the Iceland hot spot, tracks through time across the Taimyr Peninsula region during the Late Triassic period and then across the north end of the Severnaya Zemlya archipelago by the end of the Triassic. With the exception of some Middle Triassic dates from Chelyabinsk (243 Ma; Reichow et al., 2009) and from the Taimyr Peninsula (~227 Ma; Walderhaug et al., 2005) there is no apparent expression of a hot spot track on Laurasia after the initial 250±1 Ma outpouring. Motion of Eurasia in a paleomagnetically controlled reference frame has the hotspot track from about 180 Ma to 140 Ma passing between Franz Josef Land and Svalbard. Histograms of conventional K-Ar age dates may imply initial ramping up from about 180 Ma until the time of crystallization ages for Svalbard (135 to 90 Ma; Maher, 2001). Hauterivian is taken as the time of the early phase of the High Arctic Large Igneous Province [HALIP]. By the end of the Valanginian, the hotspot track transfers from Eurasia to North America, near the tip of Ellesmere Island. Prior to the opening of the Amerasian Basin, the HALIP components (Bennett Island, Svalbard, Franz Josef Land, and Axel Heiberg Island) are all within a few hundred km of the fixed Iceland hotspot at 136 Ma. By middle Albian time, the Siberian Traps/Iceland hotspot is no longer impacting the Arctic Ocean region. The track moves down Baffin Bay before the major plate motions have the keel of Greenland passing over the hotspot at about 60 Ma, slightly after the age of the LIP found on Disko Island, West Greenland and about the time of the seaward dipping reflectors found off East Greenland, coincident with the opening of the North Atlantic.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013