Last Wednesday Dr. Tollo was in Castleton with a

Last Wednesday Dr. Tollo was in Castleton with a group of geologists from all over the world to study several sites of outcroppings of rock on Big Battle Mountain and volcanic rocks on Route 615 in Castleton near Blackwater Creek. They hailed from China, Finland, Australia, New Zealand, France and other countries, and were attending the week long Hutton Symposium at the University of Maryland to study the origin of granite and related rocks.

Dr. Tollo brought them out to Castleton for the day. They all lunched at Mary Frances and Bill Fannon’s Laurel Hills Farm, cooled off in the pool, and then headed out in four vans to study several areas close by. The Fannon family owns the property which includes Big Battle Mountain.

The first stop was on the south side of Big Battle Mountain, approached from Route 640. After a short hike, the group found itself on a large outcropping of granite and felsite. Dr. Tollo said that the granite in the Robertson River Suite is very uniquf and allows geologists to learn about the geologic history of the area by studying the rocks. He said that by crushing and analyzing the granite, he has found that the granite is of an alkaline nature, with much potassium, sodium and calcium. “This alkaline nature of the Robertson River (Suite) is a common characteristic of granites occurring in rift zones around the world,” he said.

Fred Hutson, who did his master’s thesis here, was the student who discovered the volcanic rocks, along Route 615 near Blackwater Creek in Castleton. He said the rocks used to be mapped as sandstones, but through chemical analysis and microscopic study, he found that most of the rocks were volcanic. In an article by Dr. Tollo in the Virginia Explorer, he said that the rocks that Mr. Hutson found were identical compositionally to some of the granites on Battle Mountain. He said, “at least some Robertson River magmas did reach the surface and the rifting was accompanied by violent eruptions involving