I think you're right
Looks to me, color and all, like a huge accumulation of small "blueberries." The $64,000 question is what, if that's true, would get them all into one isolated place like this?
My guess is that prevailing winds and the shape of the hills next to this spot create a "lee" of some kind where these things tend to blow off the hills over thousands of years and then accumulate. Lighter particles keep going, and heavier ones stay where they were in the first place. Anybody know the prevailing wind direction here?