• Harvey Thorleifson, Chair
    Minnesota Geological Survey
  • Carrie Jennings, Vice Chair
    Minnesota Geological Survey
  • David Bush, Technical Program Chair
    University of West Georgia
  • Jim Miller, Field Trip Chair
    University of Minnesota Duluth
  • Curtis M. Hudak, Sponsorship Chair
    Foth Infrastructure & Environment, LLC


Paper No. 9
Presentation Time: 3:45 PM


PENDLETON, Matthew W.1, BLEACHER, Jacob E.2, HAMILTON, Christopher W.2 and GLAZE, Lori S.2, (1)Department of Geological Sciences, University of Idaho, 825 West 7th Street, 322 Mines Bldg, Moscow, ID 83844, (2)Planetary Geodynamics Laboratory, NASA Goddard Space Flight Center, Code 698, Greenbelt, MD 20771,

The Tharsis region on Mars includes Pavonis, Ascraeus, and Arsia Montes. At least five major mantle-sourced magmatic-tectonic episodes are suggested to have produced radiating and circumferential structural features in and around Tharsis, but the region also includes numerous small volcanic vents. The genetic relationships between the Tharsis Montes and neighboring vent fields are poorly constrained. The goal of this project is to characterize the location of small vents east of Pavonis Mons and constrain the number of discrete vent fields in this region in order to postulate how related magma production events contributed to the development of the Tharsis. Mapping of volcanic vents east of Pavonis Mons reveals a variety of small-vents (tens of km in diameter). This study uses data from the Thermal Emission Imaging System, Context Camera, and Mars Orbiter Laser Altimeter. Small vents were primarily identified based on the presence of radiating lava flows from a common topographic high point, or linear fissure. Each vent was assigned a coordinate at the center of the inferred eruptive activity to represent the pathway through which magma reached the surface. We identified 126 vents and analyzed their locations using sample-size-dependent nearest neighbor statistics to test for significant departures from randomness. Relative to a homogeneous Poisson model, the volcanic vents exhibit a significant tendency toward clustering. This suggests that volcanic vents formed closer together than a random model predicts. However, mapping does not lead us to believe that multiple, temporally and spatially distinct magma generation events are responsible for the development of this field because we do not see consistent embayment of one group by another. Clustering is therefore inferred to result from closely-spaced vents occurring within the same volcanic edifice or fissure. However, structural controls might have also concentrated volcanism within several broader regions.
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