Sinkholes can form anywhere that water can erode the bedrock, such as limestone. Add it erodes, a cavity is created, which eventually collapses and
creates the sinkhole. They're actually pretty common in the desert.
Oddly enough I watched a show on tv last night about sink holes and they showed us 3 huge ones thousands of years old. I would have thought they were
meter hits, but apparently no, they were sink holes. From that information clearly sink holes are not a new phenomenon - just a dangerous and
unwanted one.