Did dry ice chunks on Mars gouge strange tracks into Red Planet?

By Amina Khan
June 12, 2013, 1:35 p.m.

... Scientists .. have finally determined that mysterious, long gouges down the Red Planet’s slopes were caused by large chunks of frozen carbon dioxide.

The findings, described in the journal Icarus, shed light on strange features -- so-called linear gullies -- that are unlike any observed on Earth.

Picked up by the Mars Global Surveyor, launched in 1996, the strange, long grooves puzzled planetary scientists for years. Unlike flows of water on Earth, which naturally create a sort of fan shape as debris travels down a hill, these grooves were deep and straight and were punctuated by a pit at the end ...

Mars gets far colder than Earth during its winter times, cold enough for carbon dioxide to form frost in its chillier regions. As spring warmed these icy regions, the researchers noticed that these strange gouges seemed to reappear ...

http://www.latimes.com/news/science/sciencenow/la-sci-sn-mars-dry-ice-sled-linear-gullies-20130612,0,3790213.story