HiRISE Updates Week of 2017 Dec 11

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HiRISE Updates Week of 2017 Dec 11

Post by bystander » Fri Dec 15, 2017 4:37 pm

Shane Byrne wrote:

Layered Ice Near the South Pole of Mars (ESP_023616_1005) (HiClip)

The two largest ice sheets in the inner solar system are here on Earth, Antarctica and Greenland. The third largest is at the South Pole of Mars and a small part of it is shown here.

Much like the terrestrial examples, this ice sheet is layered and scientists refer to it as the South Polar layered deposits. The ice layers contain information about past climates on Mars and deciphering this record has been a major goal of Mars science for decades. This slope, near the ice sheet’s edge, shows the internal layers that have this climate record.

With stereo images, we can tell the heights of these layers so we can measure their thickness and try to unravel the climatic information they contain. (Be sure to view the digital terrain model for this observation.)

This is a stereo pair with ESP_024025_1005.
HiRISE Science Team wrote:

A Valley Near the Northern Lowlands (ESP_050004_2170) (HiClip)

The goal of this observation is to determine the source of the ridge within a possible moraine that is also present in another HiRISE image. A moraine is a mass of rocks and sediment carried down and deposited by a glacier.

If the structure is a moraine, we should expect to find two sources of debris converging in the valley. If the sources are carrying lots of debris, there is a good chance of finding more moraine features further up the valley.
Natalie Glines and Ginny Gulick wrote:

Depressions and Channels on the Floor of Lyot Crater (ESP_052628_2310) (HiClip)

Lyot Crater (220-kilometers in diameter) is located in the Northern lowlands of Mars. The crater’s floor marks the lowest elevation in the Northern Hemisphere.

On the crater’s floor, we see a network of channels connecting a series of irregular shaped pits. These resemble terrestrial beaded streams, which are common in the Arctic regions of Earth and develop from uneven permafrost thawing.

If terrestrial beaded streams are a good analog, these landforms suggest liquid water flow in the past. If not then these pits may result from the process of sublimation and would indicate pockets of easily accessible near-surface ground ice, which might have potentially preserved evidence of past habitability.

This is a stereo pair with ESP_052694_2310.
Cathy Weitz wrote:

The Fault in Our Mars (ESP_052893_1835) (HiClip)

This image of northern Meridiani Planum shows faults that have disrupted layered deposits. Some of the faults produced a clean break along the layers, displacing and offsetting individual beds (yellow arrow).

Interestingly, the layers continue across the fault and appear stretched out (green arrow). These observations suggest that some of the faulting occurred while the layered deposits were still soft and could undergo deformation, whereas other faults formed later when the layers must have been solidified and produced a clean break.

This is a stereo pair with ESP_053038_1835.

Credit: NASA/JPL-Caltech/University of Arizona

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