could very well be......i would almost bet that the red clays are higher in iron.....most of the clay around here are from very fine high mineral silt deposits from the bottom of a huge inland see 60 plus million years ago from some of the first erosion of the then new Rocky Mountains....it has nearly no organic matter and alot of the stuff in it is more alkaline.....when the exposed clay gets wet with the snow melt at the end of winter it cracks quite a bit as it drys and unless organic matter such as dead grass and such blows into these cracks and starts to decompose not much of anything can grow in it....even most of the cacti wont grow in it, and the ones that do look pretty rough.....
we have one form of clay around here call bentonite...when it gets wet it swells up and actually forms a seal aslong as its wet and water will not move through it.....they use it alot in the lining of ponds, dump grounds, oil drilling pads and such cause what ever liquid that gets on it WILL NOT move through it if the layer is thick enough....
im not familiar with the exact geology of your area but i would guess that the red clay you guys have is alot older than the stuff we have here and its had many more million years to collect stuff via ground water and run off moving through it....the Appalachian Mountains started forming 480 million years ago....the Rockies are less than 1/4 that old......im sure in another few hundred million years the clay here will change forms more than a bit....
we have one form of clay around here call bentonite...when it gets wet it swells up and actually forms a seal aslong as its wet and water will not move through it.....they use it alot in the lining of ponds, dump grounds, oil drilling pads and such cause what ever liquid that gets on it WILL NOT move through it if the layer is thick enough....
im not familiar with the exact geology of your area but i would guess that the red clay you guys have is alot older than the stuff we have here and its had many more million years to collect stuff via ground water and run off moving through it....the Appalachian Mountains started forming 480 million years ago....the Rockies are less than 1/4 that old......im sure in another few hundred million years the clay here will change forms more than a bit....