Giant Caldera in the Eurasian Basin of the Arctic Ocean: Evidence of Catastrophic Pleistocene Volcanic Event

Lead Author Alexey, Piskarev
Institution Contact 1. All-Russian Research Institute for Geology and Mineral Resources of the World Ocean "VNIIOKEANGEOLOGIA", 1, Angliysky Avenue, St Petersburg, 190121, Russia 2. St Petersburg State University, Universitetskaya Embankment, 7-9, St Petersburg, 199034, Russia
Co-Authors Daria Elkina 1. All-Russian Research Institute for Geology and Mineral Resources of the World Ocean "VNIIOKEANGEOLOGIA", 1, Angliysky Avenue, St Petersburg, 190121, Russia 2. St Petersburg State University, Universitetskaya Embankment, 7-9, St Petersburg, 199034, Russia
Theme Theme 1: Vulnerability of Arctic Environments
Session Name 1.1 Climate Change and Environmental Management in the Arctic
Presentation Type Poster
Abstract text The improved bathymetric map of the Arctic Ocean has clearly demonstrated contours of a giant volcanic caldera with the center at 81°31'N and 120°E. The caldera is about of 40x80 km stretching along the axis of the Gakkel Ridge rift valley. The size of caldera puts it on a par with the largest calderas of Toba and Yellowstone.
In 2014, data were first obtained on the caldera structure when the caldera was crossed by two seismic lines accompanied with multibeam echo sounding. It was established that the modern tectonic active rift valley i.e. divergent plate boundary dissects the caldera floor and has a width of ca. 10 km and a depth of ca. 500 m. Given that the average rate of spreading in the Eurasian Basin is 1 cm/yr, the rough estimate of the caldera age could be equal to 1 myr.
A huge amount of volcanic material erupted in the Arctic Ocean should be reflected in coevally formed sediments. Indeed, the sedimentary cores, which were sampled near the Mendeleev Rise at a significant distance from the caldera and from each other contain a few centimeter layers featuring with high values of magnetization. The youngest layer is of ca. 750 kyr determined by its proximity to the determined Brunhes/Matuyama boundary. Mineralogical analysis of the samples corresponding to this layer has shown a sharp increase of clinopyroxene and ore minerals simultaneously with a sharp depletion of "stable" minerals share i.e. garnet and others. These data confirm the volcanogenic nature of the sediment layer.
Thus, the Eurasian Basin of the Arctic Ocean is established as an area of a catastrophic volcanic eruption in the Pleistocene, which undoubtedly has had an impact on short-term climate change not only in the Arctic, but also globally.