The transition of lava flows from smooth pahoehoe to rough `a`a is commonly documented for Hawaiian lavas, and is governed by the rheological conditions of the lava. The rheology of the lava itself depends on the physical properties, such as temperature, density, and crystallinity, and therefore should also apply to any other type of lava.  As part of NASA’s FINESSE project (P.I. Jennifer Heldmann), this study explores the relationship between rheology, physical properties, and lava flow morphology for a channelized lava flow at the Craters of the Moon National Monument and Preserve, Idaho. Field and laboratory techniques, namely mapping of lava flow morphology, UAV imagery for digital topography models at cm-scale resolution, sample collection and their petrographic descriptions, as well as viscosity measurements, are being used to evaluate the relation between lava flow morphology and physical properties of the lava. Results demonstrate that the hypothesis is true, and that morphology corresponds to specific values in physical properties. Therefore, tying lava flow morphology (expressed as surface roughness) to physical properties can be used to infer these for lava flows on Earth and other planetary bodies, such as the Moon, Mars, Mercury, and Venus.

Speakers:

Dr. Alex Sehlke - 

NASA Ames Research Center
Postdoctoral Research Fellow

Volcanoes have fascinated Alexander Sehlke since his childhood. He started studying Geosciences at the Leibniz University of Hannover, Germany in 2005. In 2011, Alexander began his doctoral studies at the Department of Geological Sciences at the University of Missouri – Columbia, and received his PhD in 2015. He studied the rheological evolution of terrestrial and planetary basalts during cooling and crystallization, experimentally. His studies on lava flow emplacement and the mechanism of the development of diverse lava surface morphologies were complemented by field investigations on both active and inactive lava flows erupted on the Big Island of Hawaii, Guatemala and Costa Rica. Field work included sample collection and measurements of the geometry of channelized sections within lava flows and different type of surface morphologies (e.g., pahoehoe, transitional, `a`a). Alexander is currently a NASA post-doctoral fellow at NASA Ames Research Center, located in the heart of Silicon Valley. He continues to study volcanic landforms, focusing on the Moon, Near Earth Asteroids (NEA’s) and the surface of Mars and its moons, as part of NASA’s FINESSE (Field INvestigation to Enable Solar System Sciences). He is also working with NASA’s BASALT (Biologic Analog Science Associated with Lava Terrains) project to evaluate handheld science instruments and how they can be incorporated into future human exploration missions of our solar system.

Questions and Answers after the telecon:

• What are the differences in frames on Slide 30 and 31?

  • The split images are actually both in Idaho at the Blue Dragon Flow. Slide #30, the right frame is about 100 meter further down flow compared to the image on the left.  For slide #31, the locations are quite far apart, about 300 meters between each frame. 

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