Mars Reconnaissance Obiter – Behind The Black

On Mars you can find glaciers everywhere in the mid-latitudes

September 1, 2022 12:42 pm Robert Zimmerman

Click for full image.

Cool image time! If you ever decide to have some fun exploring the archive of images being sent back to Earth by the high resolution camera on Mars Reconnaissance Orbiter (MRO), always remember that the latitude of the image will almost immediately help to explain the strange features that you see in each picture.

The hi-res photo to the right, rotated, cropped, and reduced to post here, was taken on May 22, 2022 and provides us a great example. The jumbled features in the depression on the image’s right half surely look like the glacial features seen routinely in the 2,000-mile-long strip found in the 30 to 60 degree band in the chaos terrain of the northern lowland plains. In fact, it is likely that cycles of ebb and flow of those glaciers helped shape this chaos of buttes and mesas and cross-cutting canyons.

This picture however is nowhere near any chaos terrain, or that 2,000 long strip. In fact, it is instead in an area that appears mostly formed by tectonic and volcanic activity, as the overview map below shows.
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The epic lava flows of Olympus Mons

June 19, 2018 12:10 pm Robert Zimmerman

Lava flows off of Olympus Mons

The eruption of Kilauea volcano in Hawaii has garnered a lot of deserved press coverage, having added at least a 200 acres of new land and destroyed at least 700 homes. Similarly, the recent violent eruption of a volcano in Guatemala, killing 100 people in its wake, has also gotten much deserved news coverage.

The magnitude of both however would pale in comparison to the stupendous eruption that occurred several hundred million years ago at the solar system’s largest volcano, Olympus Mons on Mars. While Kilauea is about 100 miles across, Olympus Mons is about 370 miles wide, and is so large that because of the curvature of Mar’s surface it is literally impossible for a viewer on the ground to actually see the volcano, in its entirety.

Both volcanoes are shield volcanoes, however, which means the lava flows don’t necessarily come from the caldera, but often from vents on the volcano’s slopes. Eruptions might be violent, but they generally do not involve the powerful explosive force of the sudden eruption, as seen in Guatemala and at Mount St. Helens in 1980 in the U.S. Instead, the lava seeps out steadily and continuously, an unstoppable flow that steadily overwhelms the surrounding terrain.

Olympus Mons

The flows that created Olympus Mons however were an epic event probably lasting millions of years, which brings us to this post. In the June release of Mars Reconnaissance Orbiter high resolution images, I found the image above, cropped and reduced in resolution to post here. It shows lava flowing down off one of the many escarpments on the slopes of Olympus Mons. This is not at the edge of the volcano’s shield, but just inside it. The map at the right, created using the archive of MRO’s high resolution camera, indicates the location of this flow, shown by the left light blue rectangle on the southeast slope of the volcano’s shield. The red rectangles show all the other images MRO has taken of Olympus Mons.

The scale of the MRO image above gives an indication of how big that eruption at Olympus Mons was.
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