Alpha-Mendeleev Rise, Arctic Ocean: A double volcanic passive margin

Seismic data and ancient zircons discovered on the Mendeleev Rise, Arctic Ocean, indicate continental crust

“…There is now strong evidence that the Amerasia Basin is largely floored by continental crust and to be of Early Cretaceous age [2][3][4][5][6]11,12 . The Alpha-Mendeleev Rise is thought to have formed from continental crust that underwent significant stretching and was heavily magmatized by large amounts of basaltic material 1,2,6,10,[12][13][14] . As a result, the crust of the Rise is considered to comprise a mixture of continental and basaltic material 15 .…”

“…The two possible explanations for this are that either there was a younger phase of magmatism or, as suggested by Skolotnev et al 14 zircons that formed contemporaneously with volcanism experienced recrystallisation in the Late Cretaceous. Detrital zircons with ages of about 120 Ma have been identified in sandstones with Barremian to Aptian microfossils on the Mendeleev Rise, indicating that sedimentation took place synchronously with the volcanism 6,21 4B) has one coherent group of 22 grains with a mean age of 2675. 1 ± 11.6 Ma.…”

“…It includes flood basalt (trap) areas in Franz Josef Land, Svalbard, the northern part of the Canadian Archipelago, and the De Long Island region. Geophysical data from the Arctic Mega-Project identified volcanic plateaus on the Lomonosov Ridge, north of Wrangel Island and elsewhere 6 . The entire area of the Alpha-Mendeleev Rise and most of the associated, flanking, deep-water basins are covered by, and likely intruded with, HALIP magmas, some of them comprising seaward-dipping reflectors (SDRs).…”

“…The entire area of the Alpha-Mendeleev Rise and most of the associated, flanking, deep-water basins are covered by, and likely intruded with, HALIP magmas, some of them comprising seaward-dipping reflectors (SDRs). The age of HALIP magmatism is ~130-80 Ma with a peak in magmatic activity between 125 and 100 Ma 4,6,12,18 .…”

“…As a result, research in the Arctic Ocean greatly expanded. In Russia, this was implemented as the Arctic Mega-Project which started in 2005 [1][2][3][4][5][6] Under this project, a vast amount of seismic, gravity and magnetic data were obtained which revealed a detailed picture of the structure of entire crust in many regions. They were supplemented by rock samples dredged from the ocean floor 2,7 .…”