Fragile Oasis

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Concentrated by Wind

Another proposed mechanism to concentrate meteorites is by wind. Blown about by wind, geologists have theorized that the wind can aide in their concentration. Before I saw the wind affects first hand, I discounted this theory as nonsense.

The Katabatic winds are second to none. We as humans living in our houses in cities have never seen the likes of wind like this. The wintertime katabatics have hurricane force winds that average 80 kilometers per hour with gusts up to 200 and last for weeks at a time. We occasionally see the effects of such winds when a hurricane blows through the Texas Gulf, turning everything upside down after only a few hours. It is beyond our normal human intuition to experience the effects these winds can have on the surroundings, especially when they persist for weeks to months without end. So when Antarctic explorers propose wind blown rocks as a major mechanism for sculpting the countryside, those who have never been here tend to scoff and discount such theories as nonsense.

I scoffed at such ideas of flying rocks but now I am true believer. On glacier ice, these winds move rocks, not just inches but kilometers. For multi-kilometers on the down wind side of a nanatak, there are rocks scattered all over the blue ice surface. Not just little tiny pebbles, but fist-sized to basket ball-sized parcels, and occasionally even larger, all neatly sorted by size as a function of distance from the source as if they were books on a shelf and a planetary librarian was in charge of putting them in order.

The larger rocks will have a sizable ablation pocket carved around the up-wind side, probably the result of both wind (the stagnation point) and solar heating. Like a mother rock tending to its brood, these pockets fill with a collection of neatly sorted baby rocks. Looking in these rock nests is a good place to find meteorites. One time we found six meteorites in such an ablation pocket. We first described this as an Easter egg basket;
however we made this discovery on Christmas day so we decided it was best to describe this as a cosmic cornucopia.

The wind is a major source of upheaval on the blue ice. The most complete theory for the concentration of meteorites in the blue ice regions of the Antarctic interior should contain elements of the "conveyor belt model," the "stranded ice model," and the "wind blown model." For the current state of knowledge, this seems to be the best we can do for arriving at a plausible explanation. We welcome any one to add to or subtract from these ideas in route to a better theory.

A field of rocks scattered from wind blown processes. Ablation pockets often form on the up wind side of large rocks (center rock is about 1.5 meters in diameter) that collect smaller wind blown rocks.

A series of wind deposited rock dunes on top of a thin layer of firm snow.