domingo, 27 de abril de 2014

Liquid Water Flowing on Mars as Recently as 200,000 Years Ago Say Researchers

Researchers from the University of Gothenburg say water was flowing on Mars as recently as 200,000 years ago. The scientists say the southern hemisphere of Mars is home to a crater that contains very well-preserved gullies and debris flow deposits. The scientists say the geomorphological attributes of these landforms provide evidence that they were formed by liquid water in geologically recent time. Their research was published here in the scientific journal ICARUS (International Journal for Solar System Studies).

Andreas Johnsson at the University of Gothenburg, says in a statement, "We have discovered a very young crater in the southern mid-latitudes of Mars that shows evidence of liquid water in Mars' recent past."

The type of liquid water the researchers are talking about is known as a debris flow. This occurs when a sediment on a slope becomes too saturated with water and a flow of debris (such as dirt, stones, clay) and water is released from the sediment. The debris flow leaves behind evidence in the form of surface features like lobate deposits and paired levees along flow channels.

Johnsson identified these features on Mars in the crater and compared them to known debris flows on Svalbard, a Norwegian archipelago in the Arctic Ocean. Crater statistics allowed Andreas Johnsson and his co-authors to determine that the age of the crater to be approximately 200,000 years. This means the crater was formed long after the most recent proposed ice age on Mars, which ended around 400,000 years ago.

Johnsson says, "Our fieldwork on Svalbard confirmed our interpretation of the Martian deposits. What surprised us was that the crater in which these debris flows have formed is so young."

Photo: NASA/JPL/UofA for HiRISE
Posted on April 27, 2014 here

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