Hi George:My daughter...

Question
Hi George:

My daughter is doing a report for school, and she needs to know
how different rock types affect climbing rules.  

Thank you for any information you can give us.

Sincerely,
Gloria

Answer
Dear Gloria---I assume that you are asking how different rock types effect the climbing--if not--mail me back.

As a geologist who has looked at this issue--and written a paper on it for a Tucson Rock Guide--I am prepared.

Here is a quick overview:

1. Limestone is the most common rock for sport climbs. Limestones are massive, and when fractured, the cracks tend to fill-in with calcite. So, most limestone involves climbing pockets and edges--Lime stone with more silica tends to have more edges--wout--more pockets.

2. Alpine climbing often involves "chrystalline" rocks like granite and gneiss. Traditionally these routes follow fracture systems and often involve crack-climbing.

3. Sandstone can be edge-dominated climbing, as at the titled beds of the Garden of the Gods or Patashtin Pinnacles in WA, or crack-dominated, as at Canyonlands.

4. Volcanic rocks often entail climbing cooling fissures, as seen in basaltic columns.

For more, just ask specifics.

Good Luck--George