Flow-Dynamic-Fan

Submarine sediment gravity flows (SGFs) are certainly the volumetrically most important flows for moving sediment across our planet. SGFs create a complex system of submarine canyons, channels and lobe also referred as submarine fans (SFs). SFs receive enormous amounts of organic matter and, therefore, are considered as one of the major sinks of atmospheric carbon dioxide. SGFs can transport microplastic fragments to the deep-sea with some of the highest concentrations of microplastics reported in submarine canyons. In view of oceanic health, predicting SF geometry and associated flow-processes has become a priority for Earth scientists. An exciting new approach to predict SF geometry is to evaluate the importance of flow parameters that have shaped the SF, such as flow criticality and especially supercritical flows because they represent the most powerful flows in deep-water environments. Research questions To this end, two challenges are identified: (1) How common are supercritical-flow deposits (SFDs) and what are the parameters controlling their distribution in SFs? (2) How can we reliably compare SFDs observed in visible rock exposure (also referred as outcrop) and SFDs observed in currently active SF in the deep ocean? Methods To respond to these questions, three approaches are targeted based on a multidisciplinary approach, involving rock (outcrop) observations, high-resolution images of the seafloor interpretation and laboratory-based analyses. (1) To address the first question, SFDs will be study in different geological context and in textbook outcrops in France (Annot Sandstones) and in Austria (Gosau Group); (2) To respond to challenge 2, laboratory experiments using micro X-ray CT technology will allow us to analyze the micro texture of the SFDs observed in the rock record to develop micro-scale criteria to identifying SFDs in the cores from the modern Kumano Basin (KB; offshore SW Japan); (3) On a larger scale, challenge 2 will be addressed by comparing seismic-scale outcrops (hundred meters to kilometers) with high-resolution seafloor images and seismic dataset acquired in the well-studied KB. What is innovatory about it? Although, over the last years, advances in digital modelling and artificial intelligence applied to geophysical dataset have helped considerably in the understanding of Earth Sciences, it is important to keep in mind that a solid background in traditional geology and basic concepts are fundamental to obtaining a reliable geological model. In this project, our innovative approach aims to establish models based on direct outcrop observations for future application to marine geophysical datasets and vice-versa. Another novel approach is to use micro CT scan technology which has a resolution two order of magnitude higher than medical-CT scan, to develop micro-fabric criteria towards inferring flow criticality from outcrop and core samples.