{ "title": "In the Transition Zone", "authors": "HiRISE", "metadata": { "thumbnailURL": "https://static.uahirise.org/anews/2020-09-11/ESP_025675_2255.jpg", "excerpt": "Nestled between mesas, this image shows the valley floor where eroded rocky and/or soil debris appears to have flowed viscously from the msea walls across the valley to merge." }, "version": "1.5", "identifier": "ESP_025675_2255", "language": "en", "layout": { "columns": 10, "width": 1024, "margin": 85, "gutter": 20 }, "documentStyle": { "backgroundColor": "#faf7f2" }, "components": [ { "role": "heading1", "layout": "heading1Layout", "text": "HiPOD: 11 September 2020" }, { "role": "divider", "layout": "bigDividerLayout", "stroke": { "width": 3, "color": "#8c2028" } }, { "role": "title", "layout": "halfMarginBelowLayout", "text": "In the Transition Zone" }, { "role": "photo", "layout": "fullBleedLayout", "caption": "You can see polygonal patterns in one part of the terrain in this cutout. Less than 5 km across. (NASA/JPL/UArizona)", "URL": "https://static.uahirise.org/anews/2020-09-11/ESP_025675_2255.jpg" }, { "role": "body", "format": "html", "layout": "hipodMarginLayout", "text": "
Nestled between mesas, this image shows the valley floor where eroded rocky and/or soil debris appears to have flowed viscously from the msea walls across the valley to merge. A leading theory is that ice and snow became entrained with the soil debris as it shed from the mesa. This combined ice-rich debris then flowed slowly downhill. “Rock glaciers” on Earth are an analogous landform that flow viscously like a glacier, lubricated by ice trapped in the pore spaces.
In our observation, there are light toned viscous debris that overlays a darker toned surface. Both surfaces sport irregular fracture patterns and evidence that substantial erosion has since taken place. The upper viscous-flow surface also contains abundance small, regular polygonal patterns. Such patterns are commonplace in permafrost on Earth, and are typically considered strong evidence for shallow subsurface ice.
ID: ESP_025675_2255
date: 18 January 2012
altitude: 301 km
NASA/JPL/UArizona