Volcanos and granite

[Cakewalk]

I noticed that the hills and mountians on the north side of town are clearly Volcanic in nature... They are littered with volcanic rock, The rest of the valley appears to be completly different in structure.



Discuss...

[BoyNhisDog]

I think a lot of Arizona is like that. A mix between volcanic activity and continental drift. Then there are the areas of laid down sediment that has eroded over the eons like the petrified sandunes around Page or the areas around the Petrified Forest.

Around Tucson we have both the volcanic ranges and the granite mountains pushed up by contenintal drift. Up along the rim there are some very high mountains formed by volcanic activity. This place was a real hot bed of geology for sure.

[montezumawell]

When it comes to learning geology, it's best to hark back to the KISS principla. 'Keep it simple, ...' There are dozens in decent introductory texts regarding the geology or Arizona and the SW. There are untold thousands of texts dealing with the subject on a professional level. So, where to turn? Our recommendation is 'Roadside Geology of Arizona' by Halka Chronic. It's simple, understandable and talks about geology where you can see it--right beside the roads you travel. Most of her excellent work is keyed to MP's (milepost markers) and she gently takes the reader from roadcuts into the deeper, more profund mysteries and majesties of our geologic legacies. The book is available in virtually every bookstore and you can often get it on Ebay for about half it's retail cost. Don't worry about buying the latest edition, these things haven't changed much since she did her first edition. Even though we have a fairly extensive geology library (at least for non-professional, totally amateur geologists), we always carry Halka with us so we can hark back to the KISS principal, too. She's darn good and a 'must have' for any curious traveler.

J&S in RR :P

[ck_1]

[quote='Cakewalk']I noticed that the hills and mountians on the north side of town are clearly Volcanic in nature... The rest of the valley appears to be completly different in structure....[/quote]


I eat breakfast each morning looking toward Pass Mountain (Usery) and the Sups with their ribbon of ash...I've wondered the same thing..

[Nighthiker]

I attended a presentation at REI in Paradise Valley tuesday night, the guest speaker was Ivo Lucchitta who is the author of Hiking Arizona's Geology. The presentation and the book are very good. Some other reference books include Roadside Geology of Arizona by Halka Chronic (already mentioned) Geology of Arizona by Dale Nations and Edmund Stump. The Arizona Geological Survey (web site http://www.azgs.az.gov) offers for sale many publications including roadside geology series. The salt river valley floor is mostly alluvium fill from erosion. The mtns are schists, granites and basalts. The sharp crunch you hear when walking the area NE of the valley is granite.