Radar investigations of Apollinaris Mons on Mars: Exploring the origin of the fan deposits

Elmaarry, Mohamed Ramy; Heggy, E.; Dohm, J.M. (2014). Radar investigations of Apollinaris Mons on Mars: Exploring the origin of the fan deposits. Planetary and space science, 103, pp. 262-272. Elsevier 10.1016/j.pss.2014.09.007

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Apollinaris Mons is an isolated volcano on Mars straddling the boundary between the southern highlands and the northern plains. One of its most distinctive features is its massive fan-shaped deposit that extends from a breach on its summit to distances of more than 150 km and drapes its entire southern flank. The composition and formation mechanism of these deposits remains controversial. We investigate the radar properties of the fan deposits (FD) of Apollinaris Mons using low-frequency sounding radar data in combination with high-resolution images and crater-size frequency analysis to constrain their inner shape and bulk composition. Our analysis indicates that the FD attains an irregular thickness and is gradually thinner towards their lateral margins. The crater-size frequency analysis shows that they may have undergone repeated resurfacing, which is suggestive of long-term evolution. Our analysis of Shallow Radar (SHARAD) radargrams traversing different sections of the FD reveals multiple and different subsurface interfaces among the radargrams crossing the thinnest part, which suggests a layered and complex inner shape. Our estimates for the bulk real part of the dielectric constant of the FD ranges from 3 to 5, which is consistent with an icy-silicate mixture or pyroclastic composition. Therefore, we conclude that lahars or pyroclastic flows are the most likely mechanism that created the FD, yet we cannot rule out additional contributions from lava flows. A combination of multiple processes is also possible since the deposits appear to have been modified by fluvial processes at a later stage of their formation.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute

UniBE Contributor:

Elmaarry, Mohamed Ramy

Subjects:

500 Science > 520 Astronomy
600 Technology > 620 Engineering
500 Science > 530 Physics

ISSN:

0032-0633

Publisher:

Elsevier

Language:

English

Submitter:

Cléa Serpollier

Date Deposited:

14 Apr 2015 11:45

Last Modified:

08 Oct 2015 09:28

Publisher DOI:

10.1016/j.pss.2014.09.007

BORIS DOI:

10.7892/boris.66573

URI:

https://boris.unibe.ch/id/eprint/66573

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