High resolution mapping of the Arctic Ocean deepest area: Molloy Hole

<p>New hydro-oceanographic data were collected in the Arctic Ocean during HIGN NORTH20 marine geophysical campaign performed in July 2020, in a COVID-19 pandemic period. HIGH NORTH20 was developed as part of the IT-Navy HIGH NORTH program, a Pluriannual Joint Research Program in the Arctic devoted to contribute to oceans knowledge in order to ensure ocean science improving conditions for sustainable development of the Ocean in the aim of United Nations Decade of Ocean Science for Sustainable development and the GEBCO - SEABED 2030 project. In order to contribute in exploration and high-resolution seabed mapping new data was collected using a multibeam echosounder (EM 302 - 30 kHz). The particular sea ice environmental condition with open-sea allowed to survey and mapping the Molloy Hole, the deepest sector of the Arctic Ocean, a key area in the global geodynamics and oceanographic context. A 3D model of the Molloy Hole (804 km<sup>2</sup>) and the detection of the deepest seafloor (5567m - 79° 08.9’ N 002° 47.0’ E) was obtained with a 10x10m grid in compliance to the IHO standards.</p>

Geohazard and Climate adaption: impacts and interconnectivity

<p>The forefront of science now is in bridging fields and making connections across different disciplines, challenging our current understanding of the Earth's changes and overall state. Some of the most challenging science questions now have to do with warnings for significant geohazards and Earth-Space systems' response to climate variability affecting adaptation processes, such as geosphere changes due to climate change and resultant strategies. In recent years, the study of pre-earthquake processes has led for example to developing the lithosphere-atmosphere-ionosphere-coupling concept. This in turn provides new information about the Earth's energy balance (Pulinets and Ouzounov, 2011). From space-born NASA and NOAA Earth observation of atmospheric conditions, we have shown the consistent occurrence of radiative emission anomalies in the atmosphere near or over regions of earthquakes, volcanoes, and geothermal fluxes. Our assessment shows that the latent heat released before major earthquakes is larger than the seismic energy released during the quake (Ouzounov et al., 2018). We find that the associated pre-earthquake phenomena for large events may create an additional thermodynamic contribution in the atmosphere and impact on climate, caused by sources of Earth de-gassing in the lithosphere and followed by ionization processes. Because of these findings, we start exploring major global geodynamics activities and their impact on atmospheric processes and climate through the geosphere coupling channels as a potential forward process of interaction between geohazards and climate adaptation. The reverse mechanism of climate adaptation's impact on geohazards is based on the initial idea that climate adaptation could force additional geohazards activities (McGuire, 2010). The removal of ice sheets may somehow or likely have permitted the release of stresses that had accumulated on previously confined faults, triggering earthquakes in the US, Canada, and Europe. How realistically is it to expect a change in the existing earthquake patterns in Europe, the USA, and Canada during climate change processes? It is plausible, but we do not yet know the answer. Our goal is to explore the coupling between geohazards processes and climate change processes through the lithosphere-atmosphere framework, focusing on dynamic environments, exhibiting a change in physical and thermodynamics processes over relatively small-time scales.</p>

Time Between 3 and 2 Ga: Transitional Events in the Earth’s History

—The time span between 3 and 2 Ga in the geologic history encompassed a number of key events on the cooling Earth. The cooling interrupted heat transfer within and across the mantle, which caused changes in Earth’s major spheres and in the mechanisms of their interaction. The great thermal divergence at 2.5 Ga and differentiation into the depleted upper asthenospheric and primitive lower mantle affected the compositions of oceanic basalts. The lower mantle cooling recorded by a systematic decrease in the temperature of komatiite magma generation at the respective depths began at 2.5 Ga and was accompanied by increasing abundance of arc basalts and by changes in the behavior of the Sr, Nd, and O isotope systems. It was the time when the continental lithosphere consisting of subcontinental lithospheric mantle and crust began its rapid growth, while the crust became enriched in felsic material with high contents of lithophile elements. Magmatism of the 3–2 Ga time span acquired more diverse major-element chemistry, with calc-alkaline and alkaline lithologies like carbonatite and kimberlite. The dramatic changes were driven by subduction processes, whereby the crust became recycled in the mantle and the double layer (D”) formed at the core–mantle boundary. The events of the 3–2 Ga interval created prerequisites for redox changes on the surface and release of free oxygen into the atmosphere. In terms of global geodynamics, it was transition from stagnantlid tectonics to plate tectonic regime, which approached the present-day style about 2.0–1.8 Ga.

Problems of global geodynamics

Global geodynamics is determined by thermal convection in the mantle which manifests itself on the surface by movements, relief, heat flow, and volcanism. Thermal convection in the Earth is complicated by the fact that the lithosphere is broken into rigid plates, the crust is broken into six separate floating continents and a number of islands, on the mantle bottom there are two giant piles of heavy material, at high convection intensity the ascending convective flows acquire a plume shape, and phase transformations take place in the mantle. The impacts of many factors on the mantle structure have been thoroughly studied and fairly well understood. It is pertinent to reconcile the new data on phase transformations at depths of 650 to 700 km with the seismic data on the positions of these boundaries. The ultimate problem of global geodynamics has not yet been solved; the three-dimensional structure of the whole-mantle flows, consistent with the observations in geophysics, geochemistry, geology, and numerical modeling, is not known even on a semischematic level.