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A Global Catalog, Spatial Analysis, and Morphometry of Venusian Channelized Lava Flows

Session: Petrology, Volcanology, and Mantle Plumes across the Solar System, Part I

Presenting Author:

Mr. Ian T.W. Flynn, Ph.D.

Authors:

Flynn, Ian T.W.¹, Crown, David A.², Smrekar, Suzanne E. ³, Ramsey, Michael⁴

(1) University of Pittsburgh, Pittsburgh, PA, USA, (2) Planetary Science Institute, Tucson, AZ, USA, (3) Jet Propulsion Laboratory, Pasadena, Californa, USA, (4) University of Pittsburgh, Pittsburgh, PA, USA,

Abstract:

Lava flows are a commonly observed volcanic feature on the surface of Venus. Here we focus on characterizing the distribution, morphology/morphometry, and geologic associations of a specific flow morphology – channelized flows with adjacent constructed levees. Channelized flows are identified by the brightness contrast in Magellan SAR data between the darker central channel and the adjacent brighter lateral levees. Terrestrial channelized lava flows commonly form during periods of high effusion rates early in an eruption and/or over moderate to steep pre-flow topographic slopes. Identification and description of this flow morphology on Venus can be used for comparative planetology, to determine emplacement conditions occurring early in an eruption, and to provide locations for targeted observations in future missions (i.e., VERITAS and EnVision). We constructed a global Venus Channelized Flow Catalog (VCFC) using Magellan left-look FMAP data. It contains 515 candidate flows that are primarily associated with coronae and volcanoes, with a small subset associated with volcanic paterae. We performed detailed morphologic measurements on a subset of 28 flows that are proximal to high emissivity surface anomalies at Abeona, Chloris, Hathor, Idunn, Mertseger, and Mielikki Montes, detected in Venus Express Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) data. These regions potentially contain the most recent volcanic activity on Venus. Many of the flows have morphological features similar to channelized flows observed on Earth and Mars, such as branching, pirating of older central channels, and variations in sinuosity; however small scale (<75 m/pixel) morphologic details are not revealed at the spatial scale of the Magellan data. These flows have an average observable flow length, channel length, and area of 54.6 km, 33.2 km and 411.9 km², respectively. Many of these flows are emplaced on the flanks of volcanoes and are not visibly associated with a source vent; therefore, results are treated as minimum estimates. The average area of the Venusian flows is ~12x larger than for all the lava flows emplaced during the 2022 Mauna Loa (35.7 km²) eruption and ~100x times larger than the 2021 Fagradalsfjall, Iceland (4.8 km²) eruption.