New paper: Glaciers on Mars could have been extensive, despite the lack of expected subsequent landforms
Click for full figure.
According to a new paper published this week, scientists now posit that glaciation could have been much more extensive in the geological history of Mars than presently believed, despite the lack of the expected subsequent landforms as seen on Earth.
From the abstract:
The lack of evidence for large-scale glacial landscapes on Mars has led to the belief that ancient glaciations had to be frozen to the ground. Here we propose that the fingerprints of Martian wet-based glaciation should be the remnants of the ice sheet drainage system instead of landforms generally associated with terrestrial ice sheets. We use the terrestrial glacial hydrology framework to interrogate how the Martian surface gravity affects glacial hydrology, ice sliding, and glacial erosion. …[W]e compare the theoretical behavior of identical ice sheets on Mars and Earth and show that, whereas on Earth glacial drainage is predominantly inefficient, enhancing ice sliding and erosion, on Mars the lower gravity favors the formation of efficient subglacial drainage. The apparent lack of large-scale glacial fingerprints on Mars, such as drumlins or lineations, is to be expected. [emphasis mine]
In other words, on Earth the higher gravity causes glaciers and ice sheets to slide, with the liquid water at the base acting as a lubricant. On Mars, the lower gravity slows that slide, so that the water at the glacier’s base drains away instead, causing erosion and the formation of a drainage pattern in the ground beneath the glacier or ice sheet.
The image above, from figure 1 of the paper, shows on the left a graphic of the two types of drainage patterns expected, and on the right two examples found on Earth (D1: Devon Island; D2: Northwest Territories). Orbiter images of Mars have found variations of these types of drainage patterns in numerous places in Mars’ mid-latitude glacial bands, as shown below.
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Click for full figure.
According to a new paper published this week, scientists now posit that glaciation could have been much more extensive in the geological history of Mars than presently believed, despite the lack of the expected subsequent landforms as seen on Earth.
From the abstract:
The lack of evidence for large-scale glacial landscapes on Mars has led to the belief that ancient glaciations had to be frozen to the ground. Here we propose that the fingerprints of Martian wet-based glaciation should be the remnants of the ice sheet drainage system instead of landforms generally associated with terrestrial ice sheets. We use the terrestrial glacial hydrology framework to interrogate how the Martian surface gravity affects glacial hydrology, ice sliding, and glacial erosion. …[W]e compare the theoretical behavior of identical ice sheets on Mars and Earth and show that, whereas on Earth glacial drainage is predominantly inefficient, enhancing ice sliding and erosion, on Mars the lower gravity favors the formation of efficient subglacial drainage. The apparent lack of large-scale glacial fingerprints on Mars, such as drumlins or lineations, is to be expected. [emphasis mine]
In other words, on Earth the higher gravity causes glaciers and ice sheets to slide, with the liquid water at the base acting as a lubricant. On Mars, the lower gravity slows that slide, so that the water at the glacier’s base drains away instead, causing erosion and the formation of a drainage pattern in the ground beneath the glacier or ice sheet.
The image above, from figure 1 of the paper, shows on the left a graphic of the two types of drainage patterns expected, and on the right two examples found on Earth (D1: Devon Island; D2: Northwest Territories). Orbiter images of Mars have found variations of these types of drainage patterns in numerous places in Mars’ mid-latitude glacial bands, as shown below.
» Read more
