HiRISE Updates Week of 2017 May 08

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HiRISE Updates Week of 2017 May 08

Post by bystander » Fri May 12, 2017 7:33 pm

Alfred McEwen wrote:

Colorful Impact Ejecta from Hargraves Crater (ESP_049818_2005)

The collision that created Hargraves Crater impacted into diverse bedrock lithologies of ancient Mars. As a result, the impact ejecta is a rich mix of rock types with different colors and textures.

The crater is named after Robert Hargraves who discovered and studied meteorite impacts on the Earth.

This is a stereo pair with ESP_049963_2005.
Alfred McEwen wrote:

An Ancient Valley Network (ESP_049977_1610) (HiClip)

Most of the oldest terrains on Mars have eroded into branching valleys, much like many land regions of Earth are eroded by rain and snowmelt runoff. This is the primary evidence for major climate change on Mars billions of years ago.

How the climate of Mars could have supported a warmer and wetter environment has been the subject of scientific debates for 40 years. A full-resolution enhanced color closeup reveals details in the bedrock and dunes on the valley floor (upper left). The bedrock of ancient Mars has been hardened and cemented by groundwater.
Alfred McEwen wrote:

Stratigraphy Exposed by an Impact Crater (ESP_049990_1635) (HiClip)

Geologists love roadcuts because they reveal the bedrock stratigraphy (layering). Until we have highways on Mars, we can get the same information from fresh impact craters.

An enhanced color closeup reveals these layers filling a larger crater, perhaps a combination of lava, impact ejecta, and sediments.
Alfred McEwen wrote:

Landslide! (ESP_050033_1920) (HiClip)

This image finally completes a stereo pair with another observation acquired in 2007. It shows a fresh (well-preserved) landslide scarp and rocky deposit off the edge of a streamlined mesa in Simud Valles, a giant outflow channel carved by ancient floods.

The stereo images can be used to measure the topography, which in turn constrains models for the strength of the mesa’s bedrock. Do look at the stereo anaglyph.

This is a stereo pair with PSP_005701_1920.

Credit: NASA/JPL-Caltech/University of Arizona

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