Ben Tobin has questions about the Grand Canyon’s caves. The University of Kentucky geologist started learning about caves as a young man, in part because his mother was a geologist, and a childhood fascination grew over time. … When he was in college, an internship in Arkansas doing cave tours got him hooked, and eventually his work brought him out West, to Grand Canyon National Park. Tobin specializes in what’s known as karst hydrology. These are underground systems made up of soluble rock such as limestone. To Tobin, caves are like another world, with blind animals, fossils and archeological finds.