SURVEY AND FIELD ANALYSIS OF FAN-SHAPED FEATURES IN NORTHERN NORWAY: ARCTIC ANALOGS FOR EXPLORATION ON MARS

Fan-shaped features are ubiquitous on Earth and Mars and record the change from confined to unconfined flow in a fluid-rich system. On Earth, fan-shaped features in the Arctic can be used as modern analogs for fans that may have formed under a warm and wet Martian climate scenario during the Noachian and Early Hesperian time periods (4.7-3.2 Ga). Fans on Mars exhibit many of the same geomorphic characteristics as fans on Earth, including a wide variety of sizes and slopes indicative of fluid-rich (e.g. delta) to fluid-poor (e.g. alluvial fan) depositional environments.

Here, we present results from two studies of fan-shaped features in the Arctic: (1) a survey of >300 fan-shaped features mapped using orbital data on the Norwegian Svalbard Archipelago; and (2) field observations from 12 fan-shaped features in the Finnmark county of northernmost Norway. In both locations, fan-shaped features include alluvial fans (sheetflood and debris flow-type), fjord-head deltas (a subset of fan-deltas), and deltas with broad distributary networks. In the latter two cases, winter sea ice acts to stabilize the delta plain, and hypopycnal flow results where freshwater flows into more saline waters of fjords and the Arctic Ocean. With respect to astrobiological investigations, preserved organic material is most likely to occur in the submarine portions of fan-deltas or deltas, making such features on Mars ideal targets for crewed or robotic missions in the future.