Lost Jim Lava Flow, Seward Peninsula, Alaska as an analog for lava–ice interactions on Mars

Abstract:

On Mars, volcanism within Elysium Planitia may have occurred as recently as ~10 million years ago, which associated lava flows being emplaced with ice-bearing permafrost. On Earth, there are few active volcanic regions that are cold enough to support permafrost, but the Seward Peninsula in Alaska is a prime location to study recent volcano–ice interactions. In the early 2000s, J.E. Beget and J.S. Kargel explored two areas in Alaska that exhibit features characteristic of explosive volcanism that may be the result of lava–ice interaction. These locations include the Lost Jim Lava Flow (65°29’N, 163°17’W) and several large maars (66°23’N, 164°29’W). The work presented here focuses on the Lost Jim Lava Flow, emanating from Lost Jim Cone and flowing West and North. The flow was erupted 1000-2000 years ago, covers ~225 km2, and ranges 3-30 m in thickness. Previous fieldwork identified pits along the margins of the flow that were interpreted to be collapse features (i.e., thermokarst) that formed as ground–ice beneath the lava melted due to heat transfer from the overlaying lava flow. This investigation utilizes stereo photogrammetry to generate high–resolution digital terrain models (DTMs) of these flow features to assess if these pits are indeed the products of thermokarstification, or if they are lava-rise pits formed by lava flow inflation. The DTMs were generated from ALOS PRISM data and DigitalGlobe Worldview 1 and 2 panchromatic satellite images taken as stereo–pairs or –triplets. With these new models the extent and morphology of the flow and pits will be categorized across the entire flow. These results are also compared to young lava flows on Mars, which may have experienced lava–ice interactions. Understanding the expression of such interactions on Earth may aid in the identification and interpretation of analogous eruptions on Mars.