Assessing the role of clay and salts on the origin of MARSIS basal bright reflections

Journal
Date Issued
2022
Author(s)
•
•
Lauro, Sebastian Emanuel
•
Stillman, David E.
•
COSCIOTTI, BARBARA
•
•
Tangari, Anna Chiara
•
Soldovieri, Francesco
•
•
Caprarelli, Graziella
DOI
Abstract
Anomalously bright basal reflections detected by MARSIS at Ultimi Scopuli have been interpreted to indicate the presence of water-saturated materials or ponded liquid water at the base of the South Polar Layered Deposits (SPLD). Because conventional models assume basal temperatures (≤200 K) much lower than the melting point of water, this interpretation has been questioned and other explanations for the source of the bright basal reflections have been proposed, involving clay, hydrated salts, and saline ices. Combining previous published data, simulations, and new laboratory measurements, we demonstrate that the dielectric properties of these materials do not generate strong basal reflections at MARSIS frequencies and Martian temperatures. Plausible candidates remain perchlorates and chlorides brines that exhibit a strong dielectric response at much lower temperatures than other materials. This explanation might require that metastability could be maintained for a long period of time on a geological scale.
Volume
579
Start page
117370
Uri
Url
Issn Identifier
0012-821X
Ads BibCode
2022E&PSL.57917370M
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

EPSL-D-21-01124_Mattei et al revised.pdf

Description
preprint
Size

1.39 MB

Format

Adobe PDF

Checksum (MD5)

47d898b94cfbc24c842e03617a149c79

Loading...
Thumbnail Image
Name

1-s2.0-S0012821X22000061-main.pdf

Description
[Administrators only]
Size

2.53 MB

Format

Adobe PDF

Checksum (MD5)

074f41c5181ad772ea2112a6471d6522