In addition to its paved runways, Edwards AFB in California has several runways on the bed of Rogers Dry Lake, famously used in the past for (among other things) Space Shuttle landings. Satellite imagery shows these runways marked with a very high-contrast black-looking material. One can also spot vehicle tracks around the markings. There are also other interesting markings on the dry lake bed using what looks like the same material, such as a distance scale and a compass rose.
What material or method is used to make these markings? How are the markings maintained, as I imagine natural weathering would quickly cover up such markings?