New aero‐gravity results from the Arctic: Linking the latest Cretaceous‐early Cenozoic plate kinematics of the North Atlantic and Arctic Ocean

Abstract

[1] The tectonic history of the Arctic Ocean remains poorly resolved and highly controversial. Details regarding break up of the Lomonosov Ridge from the Barents-Kara shelf margins and the establishment of seafloor spreading in the Cenozoic Eurasia Basin are unresolved. Significantly, the plate tectonic evolution of the Mesozoic Amerasia Basin is essentially unknown. The Arctic Ocean north of Greenland is at a critical juncture that formed at the locus of a Mesozoic three-plate setting between the Lomonosov Ridge, Greenland, and North America. In addition, the area is close to the European plate, resulting in complicated interactions between all these areas that are difficult to resolve. In 2009, the 550,000 km 2 LOMGRAV aero-geophysical survey produced the first collocated gravity and magnetic measurements over the area, significantly increasing the data coverage. We present an interpretation of a new free-air gravity compilation, which reveals a regionally consistent structural grain across the Lomonosov Ridge, the Ellesmere and Lincoln Sea shelves, and the Alpha Ridge. We interpret the grain as evidence of latest Cretaceous ($80 Ma) regional extension in response to the northward propagation of Atlantic and Labrador Sea opening into the Arctic, west of Greenland. This interpretation is consistent with coincident alkaline volcanic activity evident in the borderlands of the Lincoln Sea. We further suggest that Eurekan crustal shortening contributed to the formation of the distinct Lomonosov Ridge plateau against an important fault zone north of Greenland. Our results provide new constraints for Cretaceous-Cenozoic plate reconstructions of the Arctic.

Plume origin of the Central Arctic uplifts evolution in the Amerasian Basin of the Arctic Ocean

“…Therefore, their common geological nature can be assumed. The magnetic field of the Lomonosov Ridge is not reflected as a cohesive structure of the interference type, which is almost indistinguishable from the magnetic anomalies of the Marvin Spur and Alpha Ridge [Døssing et al, 2013].…”

“…Magnetic anomalies of the Amerasian province abruptly cut off by a fault zone in the area of Greenland and Arctic Canadian Archipelago along the continental slope, but then, on the coast of the North American continent observed magnetic anomalies are similar to the anomalies of the Alpha and Lomonosov ridges [Døssing, 2013;Funck et al, 2011].…”

“…New substantive data on this subject were obtained during the interpretation of materials of high-precision aeromagnetic survey of LOMGRAV-2009[Døssing et al, 2013. The Southern Greenland part of the Lomonosov and Alpha ridges was allocated to local magnetic anomalies of the North-West strike.…”

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

“…Dossing et al [9] suggested that the Eurekan event may have affected the southern part of the Lomonosov Ridge and also could have triggered a certain amount of compression in the southern Eurasian Basin that resulted in volcanism and even subduction. The lack of fracture zones in the Eurasian Basin makes it difficult to track changes in spreading direction, but we would like to point out that a certain change in isochron orientation is visible in the magnetic anomaly data northwest of the Kara Sea (Fig.…”

“…In some areas, the faults were reactivated during SE-directed thrust tectonics in Mid-Eocene The idea of Eurekan deformation affecting areas beyond the Ellesmere Islands has been put forward in recent studies which combined knowledge of crustal structure from new geophysical data with results from modeling, and shows that the oceanic Amundsen Basin, the continental Lomonosov Ridge and the Morris Jessup Rise were all disturbed by significant Eurekan compression [10]. In particular, Dossing et al [9] suggested that Eurekan crustal shortening contributed to the formation of the distinct Lomonosov Ridge plateau against an important fault zone north of Greenland.…”