Featured Research

from universities, journals, and other organizations

Debris flows on Arctic sand dunes are similar to dark dune spot-seepage flows on Mars

Date:
September 6, 2013
Source:
Southwest Research Institute
Summary:
Scientists have demonstrated that frozen water in the form of snow or frost can melt to form debris flows on sunward-facing slopes of sand dunes in the Alaskan arctic at air temperatures significantly below the melting point of water. The debris flows consist of sand mixed with liquid water that cascade down steep slopes.

A team of scientists from Southwest Research Institute (SwRI) has demonstrated that frozen water in the form of snow or frost can melt to form debris flows on sunward-facing slopes of sand dunes in the Alaskan arctic at air temperatures significantly below the melting point of water. The debris flows consist of sand mixed with liquid water that cascade down steep slopes.

SwRI scientists made their observations at the Great Kobuk Sand Dunes, in Kobuk Valley National Park, Alaska. This site serves as an Earth-based cold-climate "analog" to dunes on Mars. Debris flows formed on days when air temperatures measured continuously by the team remained below the melting point of water. Very few minutes of above-freezing ground surface temperatures are needed to locally melt frozen water and mobilize sand down steep slopes.

The scientists hypothesize that fresh patches of wind-deposited dark sand on bright white snow caused local hot spots to form where solar radiation was absorbed by the sand and conducted into the underlying snow. This enabled meltwater to briefly form and sand to be mobilized despite subfreezing local air temperatures. A similar mechanism may be responsible for triggering debris flows on frozen Martian sand dunes. The Alaskan debris flows formed at ground temperatures that may correspond to those occurring locally and seasonally on the surface of Mars, said hydrogeologist Dr. Cynthia Dinwiddie, a principal engineer in SwRI's Geosciences and Engineering Division.

The Alaskan debris flows are morphologically similar to small, defrosting-related "dark dune spot" seepage flows that seasonally form in late winter on frost-covered Martian sand dunes. Such features were described in detail by a number of other researchers, and in particular by a team from Collegium Budapest, Institute for Advanced Study in Hungary.

Dark dune spot seepage flow features gave rise to the popularly known "trees on Mars" optical illusion that was associated with Mars Reconnaissance Orbiter HiRISE images of the flows. Such imagery was published "upside-down" online in an inverted orientation relative to the downward direction of gravity flows on dune slip faces, thus creating the tree-like dendritic pattern.

Dark dune spots are non-uniformly distributed on all frost-covered dune surfaces on Mars, but only those occurring near dune crests or on steep slip faces result in downslope flows. A thin brine layer may form and flow downslope on Martian sand dunes after the seasonally deposited carbon dioxide frost layer has begun to locally sublimate. Because of preferential energy adsorption by these dark, ice-free surfaces, localized heating and thawing at scales too small for orbital sensors to identify may yield briny Martian debris flows under current climate conditions.


Story Source:

The above story is based on materials provided by Southwest Research Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. Donald M. Hooper, Cynthia L. Dinwiddie, Ronald N. McGinnis. Debris Flows on the Great Kobuk Sand Dunes, Alaska: Implications for Analogous Processes on Mars. Icarus, 2013; DOI: 10.1016/j.icarus.2013.07.006

Cite This Page:

Southwest Research Institute. "Debris flows on Arctic sand dunes are similar to dark dune spot-seepage flows on Mars." ScienceDaily. ScienceDaily, 6 September 2013. <www.sciencedaily.com/releases/2013/09/130906114258.htm>.
Southwest Research Institute. (2013, September 6). Debris flows on Arctic sand dunes are similar to dark dune spot-seepage flows on Mars. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2013/09/130906114258.htm
Southwest Research Institute. "Debris flows on Arctic sand dunes are similar to dark dune spot-seepage flows on Mars." ScienceDaily. www.sciencedaily.com/releases/2013/09/130906114258.htm (accessed July 30, 2014).

Share This




More Earth & Climate News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Big Waves In Arctic Ocean Threaten Polar Ice

Big Waves In Arctic Ocean Threaten Polar Ice

Newsy (July 30, 2014) Big waves in parts of the Arctic Ocean are unprecedented, mainly because they used to be covered in ice. Video provided by Newsy
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins