On the origin of the Amerasia Basin and the High Arctic Large Igneous Province—Results of new aeromagnetic data

摘要: Abstract The history of the 2.5 million km2 Amerasia Basin (sensu lato) is in many ways least known global tectonic system. Radically different hypotheses proposed to explain its origin are supported only by inconclusive and/or indirect observations and several outstanding issues on remain unaddressed. difficulty lies geodynamic evolution signature being overprinted excess volcanism Alpha–Mendeleev Ridge complex, part High Arctic Large Igneous Province (HALIP) one largest ( > 1 km2) most intense magmatic magnetic complexes Earth. Here, we present results a 550,000 km2 aerogeophysical survey over poorly explored Lomonosov (near Greenland) adjoining Eurasia Basins that provides first direct evidence for consistent linear features between Alpha Ridges, enabling both HALIP be constrained. A landward Lower Cretaceous ∼ 138 – 125 120 ) Ma giant dyke swarm (minimum 350×800 km2) tentative oceanward Barremian (or alternatively lower Valanginian–Barremian) seafloor spreading anomalies revealed. Prior Cenozoic opening stretched from Franz Josef Land southern possibly further Queen Elisabeth Islands, Canada. points towards 250-km-wide donut-shaped anomaly Ridge, which propose was centre mantle plume, suggesting pronounced intrusive activity, associated with an took place well before Late Superchron caused continental breakup northern Basin. Our imply at as large parts area Ridges highly attenuated crust formed poly-phase LIP volcanic addition. Significantly, our early pre - overall scale rotational Eurasian margin rifted Canadian–southern about or more poles Mackenzie Delta (Alaska). findings provide key resolving plate reconstructions LIPs Mesozoic.