Araneiform and Lace Terrains
Araneiform and Lace Terrains
PSP_002651_0930  Science Theme: Seasonal Processes
The South Polar terrain on Mars contains landforms unlike any that we see on Earth, so much that a new vocabulary is required to describe them. The word “araneiform” means “spider-like.” There are radially organized channels on Mars that look spider-like, but we don’t want to confuse anyone by talking about “spiders” when we really mean “channels,” not “bugs.”

The shows an example of “connected araneiform topography,” terrain that is filled with spider-like channels whose arms branch and connect to each other. Gas flows through these channels until it encounters a vent, where it escapes out to the atmosphere, carrying dust along with it. The dark dust is blown around by the prevailing wind.

This second example shows a different region of the same image where the channels are not radially organized. In this region they form a dense tangled network of tortuous strands. We refer to this as “lace.”

Written by: Candy Hansen  (12 December 2007)

This is a stereo pair with PSP_002652_0930.
Acquisition date
18 February 2007

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
246.7 km (153.3 miles)

Original image scale range
53.8 cm/pixel (with 2 x 2 binning) so objects ~161 cm across are resolved

Map projected scale
50 cm/pixel

Map projection

Emission angle

Phase angle

Solar incidence angle
86°, with the Sun about 4° above the horizon

Solar longitude
186.4°, Northern Autumn

For non-map projected images
North azimuth:  107°
Sub-solar azimuth:  36.3°
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non-map           (333MB)

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RGB color
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EDR products

IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:

NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.