Desert spirals in The Verneukpan, South Africa
May 12, 2016 5:01:17 GMT
Admin and diane9247 like this
Post by Hill on May 12, 2016 5:01:17 GMT
A few years ago GEC member lifeiznuts found a location with hundreds of spirals neatly arranged on the desert surface. A discussion took place over time hypothesizing everything from recently exposed signs of ancient civilizations to gold mining. The original thread is archived HERE. (Note: Google has removed the archives they promised to keep and the link now take you to a "May we help you" link.)
I finally came up with what I think is a good explanation:
"Everything now seems to me to point to claiming the land for farming or at least habitat change. This area does have a short rainy season and the pan does contain water at least in some years. The straight lines and later the loose curves and finally the spirals were probably cut into the pan by something like a contour trencher during a dry time of year. The tractor treads would not have left much of an impression themselves. If work were attempted during the wet season any tractor might have bogged down. This is also why you see discrete spirals rather than all of them connected together as they would be if created by vehicle tracks alone."
"The oldest trenches, based upon the number of plants growing along them, are probably the straight rows bordering a large number of spirals. The loose curves seem to have been created next based on the plant growth along them. The tight spirals are likely the last to be created because they show relatively little growth."
Recently I saw the same explanation on a TV show called What On Earth? HERE'S WHAT OUR EYES IN THE SKY SEE!. In general the show often causes me to yell at the screen because there's dramatic music, deep-voiced end-of-world sounding narration and lame conclusions. If they do reach a reasonable conclusion it is often after first positing Bermuda Triangle, aliens, secret base type conspiracy hokum. But this time, after all of the wildly speculative stuff, they actually interviewed the one of the farmers responsible for the spirals. He explained that when they had extra time they used a tractor to cut the spirals in the hope of retaining a bit more water in the soil from rain which falls in their rainy season.
I finally came up with what I think is a good explanation:
"Everything now seems to me to point to claiming the land for farming or at least habitat change. This area does have a short rainy season and the pan does contain water at least in some years. The straight lines and later the loose curves and finally the spirals were probably cut into the pan by something like a contour trencher during a dry time of year. The tractor treads would not have left much of an impression themselves. If work were attempted during the wet season any tractor might have bogged down. This is also why you see discrete spirals rather than all of them connected together as they would be if created by vehicle tracks alone."
Contour trenchers break-up hard pans, trap rainfall, improve infiltration, and promote the rejuvenation
of resident grasses and the germination, emergence, and establishment of seeded grasses.
"The oldest trenches, based upon the number of plants growing along them, are probably the straight rows bordering a large number of spirals. The loose curves seem to have been created next based on the plant growth along them. The tight spirals are likely the last to be created because they show relatively little growth."
Recently I saw the same explanation on a TV show called What On Earth? HERE'S WHAT OUR EYES IN THE SKY SEE!. In general the show often causes me to yell at the screen because there's dramatic music, deep-voiced end-of-world sounding narration and lame conclusions. If they do reach a reasonable conclusion it is often after first positing Bermuda Triangle, aliens, secret base type conspiracy hokum. But this time, after all of the wildly speculative stuff, they actually interviewed the one of the farmers responsible for the spirals. He explained that when they had extra time they used a tractor to cut the spirals in the hope of retaining a bit more water in the soil from rain which falls in their rainy season.
Nice updates, Hill.