August 6, 2013
A Channel Within a Channel
image by Avani Soares, Brazil
Vallis Schröteri is considered the greatest of our satellite's channels, which actually consists of two channels. The biggest channel with a length of 155 km cuts through the Aristarchus Plateau, and the curved inner smaller channel (204 km long) runs through the interior of the larger channel; the #1 arrow shows where he keeps extending beyond the larger channel, and arrow 2 indicates a small piece of this same channel within the Cobra Head. This seems to be very similar to what occurs in Vallis Alpes! These two channels at Vallis Schröteri may have formed during two different volcanic events, or may represent a change in the volume of a single eruption with the passage of time. The channel is formed when lava flows were greater in volume. The internal channel subsequently passed through the interior of the bigger channel after a new eruption. Geologists have questions like, why did the internal channel flow farther than the larger channel? Was the flow of magma faster in the case of smaller channel? Scientists do not fully understand how the channels were formed on the surface of the Moon, but there are two main theories. Generally, channels formed when large volumes of very fluid lavas with low viscosity were expelled rapidly and began to flow. Molten lava can then have dug a channel on the surface of the moon through the erosive power of the flow of magma, which then drained, leaving behind only an empty riverbed. An alternative theory proposes that initially the lava channel overflows its edges, forming a confined flow channel instead of spreading over a large surface such as a mare. The Vallis Schröteri begins in a crater diameter of 6 km north of Herodotus. Some people call the beginning of the channel Cobra Head because remember a snake. The channel has a maximum width of 10 km. To have a comparison, the Grand Canyon on Earth, which was formed by the flow of water has a width ranging from 6.4 to 29 km.
See image; Capture with FireCapture. Stacking 90 frames using AS! 2 with post-processing in Photofiltre.
21st Century Atlas chart 28.
Yesterday's LPOD: Typical?
Tomorrow's LPOD: The Sparrow, the Moon And the Awning