Distribution of mid-latitude ground ice on Mars from new impact craters.
New impact craters at five sites in the martian mid-latitudes excavated material from depths of decimeters that has a brightness and color indicative of water ice. Near-infrared spectra of the largest example confirm this composition, and repeated imaging showed fading over several months, as expected for sublimating ice. Thermal models of one site show that millimeters of sublimation occurred during this fading period, indicating clean ice rather than ice in soil pores. Our derived ice-table depths are consistent with models using higher long-term average atmospheric water vapor content than present values. Craters at most of these sites may have excavated completely through this clean ice, probing the ice table to previously unsampled depths of meters and revealing substantial heterogeneity in the vertical distribution of the ice itself.
Byrne
Shane
S
Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. shane@lpl.arizona.edu
Dundas
Colin M
CM
Kennedy
Megan R
MR
Mellon
Michael T
MT
McEwen
Alfred S
AS
Cull
Selby C
SC
Daubar
Ingrid J
IJ
Shean
David E
DE
Seelos
Kimberly D
KD
Murchie
Scott L
SL
Cantor
Bruce A
BA
Arvidson
Raymond E
RE
Edgett
Kenneth S
KS
Reufer
Andreas
A
Thomas
Nicolas
N
Harrison
Tanya N
TN
Posiolova
Liliya V
LV
Seelos
Frank P
FP
D005118:Extraterrestrial Environment; D007053:Ice; D018535:Mars; D019110:Meteoroids; D013696:Temperature
D007053:Ice