Wednesday, January 9, 2019

January 5th Field Trip Report

Water the Transformer of Our Country Side 
Ann McMahon, Text and Photography

Stoners were treated to another superb geological trip Saturday with Mary Dowse, PhD as tour guide.  Mary thoughtfully planned a trip for anyone of any capability and then supplied narratives explaining the world around us in simple lay terms.

This time we traveled from Silver City north on highway 180 to the Catwalk north of Glenwood, stopping at selected places to understand how the countryside transformed over the last million years.  Water, acting with other geological affects, was the main long-term sculptor accompanied by volcanic activity and tectonic shifts.

Sediments Near Continental Divide
Thirty to thirty five million years there was a series of calderas and volcanic activity in the Mogollon area forming the volcanic rocks found at the Catwalk. Starting 15 million years ago faulting formed the Mangas Valley which was slowly filled by sediment from the mountains.

Prior to a million years ago, water from the Gila River, and rivers and streams to the north flowing from the Mogollon Mountains, formed valley in the area of Buckhorn. Eventually the Gila River cut through the Middle Box to Redrock, drained the lake and allowed the erosion of some of the gravels in the valley.
Agate Found in Sediment North of Buckhorn
Example of Volcanic Gas Holes and Small Fault Lines
Mary Explains How Water Changes Landscapes

At our final stop on the Cat Walk in Whitewater Creek canyon, Mary discussed how powerful the flow of water can be in changing the shape of the landscape no matter how hard or dense the rock.  We also discussed how fires in the mountains above and changes just in the last 100 to 20 years, have had a major impact on the shape and landscape of the Canyon.

Thursday, January 3, 2019

January 2019 Newsletter

The new Beacon is now available!  

Please click here for a PDF version of the newsletter than you can view and print.