PLANETARY VOLCANIC ANALOGS AND LAVA FLOW RESEARCH IN NEW MEXICO (Invited Presentation)

There are over 1,000 geologically young volcanoes with associated ash and lava flows distributed across New Mexico, a significant resource for planetary volcanological analog research. A few examples include one of the largest young super eruption calderas, the Valles Caldera, similar in morphology and eruption style, if not likely composition, to many highland paterae; youthful lava flows and associated volcanoes; young small shield volcanoes comparable to those in the plains surrounding the Tharsis region and the surface of Venus; hydromagmatic eruption centers (maars) and their eruption products; young structurally exposed and sectioned volcanic vents (volcanic necks); a large radial dike swarm, analogous to the radial pattern of fractures centered on the Tharsis region; spring deposits and cratered spring cone structures; and two of the largest volume young lava flows on the continent.

The large volume lava flows are a natural laboratory for investigating the emplacement process of large volume lava flow fields occurring on Mars and other planets. Recent research on these in collaboration with Jim Zimbelman, Jake Bleacher, Brent Garry, Chris Hamilton, and Steve Self is the subject of this presentation. The research has centered on the McCartys lava flow field, a young, large volume basaltic lava flow covering approximately 220 km² and extending 52 km from south to north on pre-existing valley floors sloping < 1 degree. Estimates of the flow-field volume are between 3 and 7 km³. Because of the large volume and because evidence for inflation of the surface is prevalent, the McCartys lava flow permits examination of many of the hypotheses about the physical emplacement process of large volume lava flows, the role of lava inflation in that process, and the application of the results to understanding the architecture of flows and time scale of flow field emplacement. Part of these efforts has been the identification of surface textures inconsistent with initial formation as thick flows, or more consistent with formerly thin (1 to 2 m thick) lavas. Mapping of the overlapping relationships between individual inflated sheet flows has enabled the first estimates of emplacement time for the field as a whole. This in turn has resulted initial estimates of the environmental consequences of aerosols released at the time of eruption.