PIA03836: Tantalus Fossae
 Target Name:  Mars
 Is a satellite of:  Sol (our sun)
 Mission:  2001 Mars Odyssey
 Spacecraft:  2001 Mars Odyssey
 Instrument:  THEMIS
 Product Size:  1189 x 3007 pixels (w x h)
 Produced By:  Arizona State University
 Producer ID:  20020625A
 Full-Res TIFF:  PIA03836.tif (1.705 MB)
 Full-Res JPEG:  PIA03836.jpg (442.6 kB)


Original Caption Released with Image:

(Released 25 June 2002)

The Science

The Story
The first thing that catches your eye in the image above is a string of round pits that are strewn dramatically on the surface. Although they may look like craters, nothing came hurtling in from the sky to make them. Instead, collapses along a lava tube have created this long dotted line on the Martian surface. The lava tube, a hollow feature beneath the surface, can't always withstand the weight from above, and so collapses in places, forming pits like the ones seen here.

Throughout the rest of the image are a series of depressed valleys known as grabens that run roughly from the northeast to the southwest. They formed when the crust of the Martian surface was stretched so fast that it broke along faults. When that happened, the rock in between fell downward into the space created by the extension, creating the long subtle streaks of lowered terrain. They were probably created when Alba Patera, the shield volcano of this area, was elevated or "uplifted" through tectonic forces.

This area of long valleys is named after Tantalus, a king of ancient Lydia who, according to legend, betrayed the gods and was sent to Hades. In this subterranean place, he was forced to stand in water up to his chin underneath the branches of fruit trees. Every time he tried to drink, the water would recede, and every time he tried to eat, the boughs would move the fruit just out of reach. You can easily see where the word "tantalize" comes from.

Scientists are intrigued so much by the history of this area that they seek to understand its elusive past. Luckily, their interests are much more in reach than those of poor Tantalus. A number of channels in this image (running downhill from the west-northwest to the east-southeast) help them understand the chain of events that worked to create the compelling features in this region.

Take a look at the channels close-up and see if you can tell whether the channels or the grabens happened first. A rule of thumb is that if one feature is on top of another or cuts across it, it is younger than the feature it covers or cuts. One of the channels in the center of the image is great to study. Toward the right side of the image, the channel cuts across a fault, indicating it formed before the graben. Follow the channel westward, however, and you'll see that a large fault cuts the channel, indicating that this graben formed after the channel. That probably means this criss-crossed region went through a seeming eternity of torture itself, as the land kept tearing and stretching, as channels were carved and recarved, as lava tubes formed and then finally collapsed, only to have their walls erode in further streaks as well.
Image Credit:
NASA/JPL/Arizona State University

Image Addition Date: