geology instructor (
last edited: 6/5/15
types of features in this study
Surface features with erosional aprons are usually isolated blocks or hills surrounded
by a raised ring of debris at the base of the hill-like structures. The term sedimentary
apron was chosen to identify these structures without naming the cause of process
that deposited these rings of debris. The debris could be carried down slope by either
debris flows, creep, glacial action, or a combination of these processes.
The actual number of features with erosional aprons is much greater than the data
presented in the following views. Features with erosional aprons were identified in the
areas of highest resolution using GoogleEarth-Mars. Only about 40% of latitudes 45
degrees North and 45 degrees South had the necessary high resolution coverage.
for a larger collection of erosional aprons go
planetary distribution of erosional aprons
view of features with sedimentary aprons-North Pole
The largest concentration is a belt around latitude 45 degrees North.
view of features with sedimentary aprons- South Pole
A much smaller number of features are found in the 45 degrees South latitude.
comparison between distributions of erosional apron features and
craters with patterned floors
view of North pole- erosional aprons ( purple) vs. craters with patterned floors (white)
Both features are found in the same region around 45 North latitude.
another view of the North pole tipped towards the observer
There is a strong correlation between the distribution patterns of erosional apron
features and craters with patterned floors.
view of South pole- erosional aprons ( purple) vs. craters with patterned floors (white)
The small number of features with erosional aprons found in the southern hemisphere
of Mars also fall within the belt of craters with patterned floors.
Because of the concentration of both
sedimentary aprons and craters with
patterned floors along the 45 degree latitudes, temperature must be considered
in any discussion about the formation of these landforms.
The lack of features with sedimentary aprons in
the Martian southern hemisphere may have
several causes. First, these is a lack of small hill structures in the southern 45 degree latitude belt.
Second, there are probably age and lithologic differences between the northern and southern
hemisphere tied into the dichotomy between these two hemispheres.