Yup, looks to me like there was a really hot 20 Km circle in the desert for a little while there almost 30 million years ago. And the silica sand melted down a

Yup, looks to me like there was a really hot 20 Km circle in the desert for a little while there almost 30 million years ago. And the silica sand melted down and resolidified as a glass which has inclusions that could be meteoric material.