I think I can explain the arc shape.
Lets use some imagination here. Lets take a conical shaped drinking cup, turn it upside down, and put it on a flat surface.
Take a handful of sand, and pour it directly over the top of the cone.
The sand will disperse down the cone and out in an arc like pattern around the cone.
In a larger scale, take a mountain peak, and introduce a million years of precipitation pouring down upon it. The run off will take a least course of
resistance, which will spread around the peak outward, again, in an arc like pattern extending out from the peak.
Its nothing more than gravity and the flow of silt and other materials from the peak.
Nothing magical here, folks.
As to the center of the continents, well, one could easily just cherry pick all of the peaks in a continent and display only those that are close to
the center, whereas, there are peaks like this in any continent where you have higher ground and then lower ground, relatively speaking. So unless
the OP is going to post the actual coordinates of his find for me to examine, I could easily pick the highest ground on ANY continent for purposes of
his illustration to make the "data fit" the equation.
Blondes. Well, this could be nothing more than a phenomenon where you have migration of people over the course of history with light skin to a
particular region, i.e. higher elevations/lower elevations, where a particular area was more akin to accommodating fair skinned people versus dark
skinned people. For example, look at the population of the middle east/africa where dark skin is the norm. Look at Finland or Sweden where light
skinned blondes are prevalent. Its all about geography.
Of course, this is only a theory.
Since these arcs would have had to been a development over millions of years of nature at work, and once all of the continents were closer together
and combined into one grand land mass, there really isn't a reason why these arcs could have been manufactured by intelligence, since at the time of
there was only ONE continent. So this dissolves the OP's theory that these arcs were
placed at the center of continents for some "reason"
4 Arcs on 4 continents? No. Just 4 arcs chosen at random for purposes of the OP's illustration.
Of course, to understand this explanation, one needs to disregard what the Bible has to say about the earth being only 6000 years old.