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Aeolian features on Venus: Preliminary Magellan results

Greeley, Ronald and Arvidson, Raymond E. and Elachi, Charles and Geringer, Maureen A. and Plaut, Jeffrey J. and Saunders, R. Stephen and Schubert, Gerald and Stofan, Ellen R. and Thouvenot, Eric J. P. and Wall, Stephen D. and Weitz, Catherine M. (1992) Aeolian features on Venus: Preliminary Magellan results. Journal of Geophysical Research E, 97 (E8). pp. 13319-13345. ISSN 0148-0227. doi:10.1029/92JE00980. https://resolver.caltech.edu/CaltechAUTHORS:20151104-151244915

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Abstract

Magellan synthetic aperture radar data reveal numerous surface features that are attributed to aeolian, or wind processes. Wind streaks are the most common aeolian feature. They consist of radar backscatter patterns that are high, low, or mixed in relation to the surface on which they occur. A data base of more than 3400 wind streaks shows that low backscatter linear forms (long, narrow streaks) are the most common and that most streaks occur between 17°S to 30°S and 5°N to 53°N on smooth plains. Moreover, most streaks are associated with deposits from certain impact craters and some tectonically deformed terrains. We infer that both of these geological settings provide fine particulate material that can be entrained by the low-velocity winds on Venus. Turbulence and wind patterns generated by the topographic features with which many streaks are associated can account for differences in particle distributions and in the patterns of the wind streaks. Thus, some high backscatter streaks are considered to be zones that are swept free of sedimentary particles to expose rough bedrock; other high backscatter streaks may be lag deposits of dense materials from which low-density grains have been removed (dense materials such as ilmenite or pyrite have dielectric properties that would produce high backscatter patterns). Wind streaks generally occur on slopes < 2° and tend to be oriented toward the equator, consistent with the Hadley model of atmospheric circulation. In addition to wind streaks, other aeolian features on Venus include yardangs(?) and dune fields. The Aglaonice dune field, centered at 25°S, 340°E, covers ∼1290 km^2 and is located in an ejecta flow channel from the Aglaonice impact crater. The Meshkenet dune field, located at 67°N, 90°E, covers ∼17,120 km^2 in a valley between Ishtar Terra and Meshkenet Tessera. Wind streaks associated with both dune fields suggest that the dunes are of transverse forms in which the dune crests are perpendicular to the prevailing winds. Dunes on Venus signal the presence of sand-size (∼60 to 2,000 μm) grains. The possible yardangs are found at 9°N, 60.5°E, about 300 km southeast of the crater Mead. Although most aeolian features are concentrated in smooth plains near the equator, the occurrence of wind streaks is widespread, and some have been found at all latitudes and elevations. They demonstrate that aeolian processes operate widely on Venus. The intensity of wind erosion and deposits, however, varies with locality and is dependent on the wind regime and supply of particles.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/92JE00980DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/92JE00980/abstractPublisherArticle
ORCID:
AuthorORCID
Arvidson, Raymond E.0000-0002-2854-0362
Weitz, Catherine M.0000-0002-4646-0825
Additional Information:© 1992 American Geophysical Union. Paper number 92JE00980. Received September 27, 1991; revised April 27, 1992; accepted April 28, 1992. We wish to thank the following for their contributions to this report: R. Blom and T. Farr for helpful discussions, D. Ball for photographic support, E. Lo for computational support, S. Selkirk for figure preparation, and S. Blixt for word processing. The Magellan Project and parts of the research described here are carried out by the Jet Propulsion Laboratory, California Institute of Technology, under contract from the National Aeronautics and Space Administration, and through contracts to individuals: JPL-958880 (Greeley) JPL-958496 and NAGW 1874 (Schubert), and JPL-957415 (Arvidson). Support for Plaut was provided by The National Research Council under the Research Associate Program.
Funders:
Funding AgencyGrant Number
NASA/JPL/CaltechUNSPECIFIED
JPLJPL-958880
JPLJPL-958496
NASANAGW 1874
JPLJPL-957415
National Research CouncilUNSPECIFIED
Issue or Number:E8
DOI:10.1029/92JE00980
Record Number:CaltechAUTHORS:20151104-151244915
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20151104-151244915
Official Citation:Greeley, R., et al. (1992), Aeolian features on Venus: Preliminary Magellan results, J. Geophys. Res., 97(E8), 13319–13345, doi:10.1029/92JE00980
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:61853
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:05 Nov 2015 02:48
Last Modified:10 Nov 2021 22:54

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