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Alluvial fans are found across a range of climates and are built from a combination of fluvial and debris flow processes. Correct identification of process is critical to reconstructing the climate and water histories of alluvial fans on Earth and Mars. Theory and data from subaerial Earth fans are often used to estimate paleoflow discharges and sediment fluxes for martian fans; however, most terrestrial work has been conducted on fans that are in hot, dry climates with runoff sourced from rainfall. This differs from the prevailing interpretation that martian fans were sourced from snowmelt under warming periglacial conditions. To characterize processes and rates of periglacial fan formation, we conducted a field-based study of the Black Mountain alluvial fan in the Aklavik Range, Canada. We observed active fluvial bedload transport as well as several small debris flows that had initiated from ice-filled gullies. Following a runoff event of ~0.005 mm/hr to ~0.2 mm/hr across the fan, we estimated sediment fluxes of ~0.04 m3/hr. Under bankfull conditions, we estimated runoff rates between ~0.01 mm/hr to ~14 mm/hr and corresponding sediment fluxes of ~0.3 m3/hr to ~550 m3/hr. This suggests that moderate flow events, well below the maximum runoff production rates suggested for Mars, are capable of entraining and transporting appreciable amounts of sediment by fluvial processes. However, sedimentological and geomorphological observations suggest that ~67% of the fan was deposited fluvially; the remainder was deposited by mass flows. Our results emphasize the need to take care in interpreting martian sedimentary processes and climate from fan surface morphology alone. [ABSTRACT FROM AUTHOR]

Canada ratified the United Nations Convention on the Law of the Sea (UNCLOS) in 2003. With that ratification is an obligation to submit data and information to the U.N. pertaining to the limits of the country's extended continental shelf (ECS); the portion of the juridical continental shelf that extends beyond 200 nautical miles. A team of Canadian scientists, managers, and legal experts that included representation from three Federal Departments (Natural Resources Canada, Fisheries and Oceans Canada, and Global Affairs Canada) with additional support from other departments, spent 13 years compiling and acquiring data to provide the scientific evidence to support delineation of Canada's seaward most maritime limit. The submission has the potential to provide Canada with 2.4 million km2 of additional submarine landmass in the Atlantic and the Arctic oceans over which Canada exercises sovereign rights for the purpose of exploring and exploiting its natural resources. Specific information such as the tectonic framework of the continental margin, the geomorphology of the margin and in particular the continental slope, the geologic nature of adjoined ridges, rises, and plateaux, and sediment thickness within adjacent basins are examples of fundamental pieces of geoscientific information needed to substantiate Canada's outermost maritime limits. This paper highlights a number of segments of Canada's continental margins to showcase this scientific evidence and how it is applied in the UNCLOS context. In doing so, the paper demonstrates the geologic complexity of Canada's margins as illustrated in scientific publications that have resulted from these new data collections, while at the same time presenting new scientific evidence and interpretations. This collection of data and information provides a wealth of new knowledge in Canada's offshore regions. The massive data compilation in the Atlantic led to conception of continental margins, in a source-to-sink scenario, as having an equilibrium base level or graded form, comparable to river systems. Departures from this shape relate to the interplay of sedimentary processes and in particular to those processes that do not fit the source-to-sink paradigm. For example, a significant part of the Atlantic margin is shown to be heavily influenced by along-slope geostrophic currents that generated massive contourite drift deposits. These deposits reflect lateral transport of sediment that had a significant impact on the morphology of the margin. The role of mass transport processes in shaping continental margins is also highlighted, and in particular the collapses of entire segments of the margin were observed. The prominent role mass failure processes play in delivering sediment to the adjacent abyssal plain is also critical in the ECS context. These observations challenge the entrenched notion of a continental margin comprising a shelf, slope, and rise and in particular the concept of the "continental rise". Prior to 2006, regions of the Arctic Ocean seaward of the Canadian landmass had fewer than 5000 km of seismic reflection data. The massive efforts of Arctic coastal States to map their margins for ECS purposes have led to a leap in technological advances to acquire data in ice-covered seas and have led to a wealth of new geoscientific knowledge. Perhaps foremost amongst this knowledge is demonstration that Canada Basin is indeed a fully developed ocean basin, albeit significantly infilled with sediment. Based on this knowledge and identification of related structures, new realistic tectonic scenarios for opening of the Amerasia Basin are proposed that include a significant component of transform or strike-slip motions. With seismic velocity and rock sample information, the continental nature of Alpha and Mendeleev ridges has been substantiated. Even bathymetric data were lacking in the Arctic and new editions of seafloor maps now support grids of 500 m spacing; although some regions remain sparse. Once thought to be relatively stagnant, sedimentary processes such as found in many ocean basins were discovered in the Arctic Ocean. Evidence of geostrophic currents, sediment mass failures, and deep-sea turbidity current channels were found to be ubiquitous, even in the deepest parts of the Arctic's basins. [ABSTRACT FROM AUTHOR]