PIA04845: Gullies in Nirgal


Gullies in Nirgal

Caption:

MGS MOC Release No. MOC2-535, 5 November 2003

This is a Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) narrow angle image of gullies carved into debris on the south-facing wall of Nirgal Vallis, an ancient martian valley. The gullies were conduits for sediment that has accumulated at a point where each channel met the valley floor. The aprons of debris are superposed upon the large ripple-like dunes, suggesting that the gullies are younger than these bedforms. Gullies such as these might have been formed by a liquid, such as water, seeping from the layered bedrock exposed in the valley wall, or perhaps by mass movement of the smooth-surfaced debris that covers much of the lower two-thirds of the valley wall. This picture is located near 28.6°S, 41.5°W. The image covers an area 3 km (1.9 mi) across and is illuminated by sunlight from the upper left.

Cataloging Keywords:

Name Value Additional Values
Target Mars
System
Target Type Planet
Mission Mars Global Surveyor (MGS)
Instrument Host Mars Global Surveyor
Host Type Orbiter
Instrument Mars Orbiter Camera (MOC)
Detector
Extra Keywords Dune, Grayscale, Water
Acquisition Date
Release Date 2003-11-05
Date in Caption 2003-11-05
Image Credit NASA/JPL/Malin Space Science Systems
Source photojournal.jpl.nasa.gov/catalog/PIA04845
Identifier PIA04845