lizzie wrote:
fanrgs, I am so sorry that I was never able to access your geology blog while we were on the road. I had looked forward to it so much. We found some beautiful rocks on the Taylor Highway between the Fairplay Mountain area and Chicken. There was a significant rock slide on the left and we had to park up the road and walk back. I know this information is useless because my notes are still in the TT and I can't even give you the mile marker number. The specimen we collected looked as it they had beautiful fern-like plant fossils imprinted on them but I understand this is really a mineral fossil? We would have liked to spend more time there but parking was precarious. Enjoy! lizzie
Lizzie, I'm glad you wanted to view the geology blog, but now you have me concerned! Did you try to access it on the road, but couldn't get it to boot? If so, I need to get into it and find out what is wrong with it. If not, did you try both
Milepost Alaska Highway Geology and
Milepost Alaska Highway Geology 2? I had to switch blog sites halfway through due to problems with Blogger/BlogSpot.
When we traveled the road today between Mt. Fairplay and Chicken, most of the rock we saw in the roadcuts was a light tan granite with darker brown staining on its slab-like surfaces. And Mt. Fairplay itself is a "stock", a much smaller igneous intrusive body than a "batholith" like the Coast Range Batholith between Stewart-Hyder and Skagway. This stock partly consists of granite and partly of dark gray syenite, a relatively rare igneous rock with big crystals of orthoclase feldspar, but almost no quartz. Because all of these rocks are igneous (with a few outcrops of metamorphic rock), there is little chance of finding a fossil, which are nearly always in sedimentary rock.
But I mentioned the dark reddish-brown staining I saw on some of the granite outcrops. What you may have found in the rockfall area (which must have been cleaned up by the time we got here) may have been a "pseudofossil." That is something that looks like a fossil, but has been formed chemically. In light-colored rocks containing iron and manganese, joints (fractures) in the rock may contain fern-like patterns of brown or purple that are deposited by tiny amounts of iron- or manganese-rich water. This type of pseudofossil is called a "dendrite." For more info on dendrites, see
"Dendrite".
I saw your earlier post about being home after your trip in a small travel trailer. We will have to compare notes on that sometime, as we are still in our 21' Mini Lite for another 3 weeks. We call it our "motel suite on wheels."
Glad you had a great trip!
