Friday, September 12, 2008

More of the first day of field work

The loose blocks are part of the Chaos Jumbles with Dome C (straight back) and Dome D (peeking out over the trees). Hiking this area is difficult, as it is a bunch of loose blocks for miles and good balance is needed, because you will see why later.

In a previous post, I said the Chaos Jumbles were the result of Dome C collapsing around 300 years ago. When the dome collapsed it traveled down the north slope for several miles, ran up against Table Mountain on the other side of the valley, turned west and came to rest after several more miles. Manzanita Lake formed because the jumbles acted as a dam.

So back to the enclaves that are the key to my project. I really liked this enclave. It has both the medium and fine grained enclaves with host plagioclase. The size of enclaves for the Chaos Jumbles ranged from mm's to one I saw that was 2 ft, but it was the largest one I saw. Most where around a ft or smaller.


2 comments:

Karl Bischoff said...

I don't know whether you're made aware of comments on old posts, but I'll post this anyway. My name's Karl, I'm a 2nd year Geology student in Australia. We recently had a field excursion, and came across similiar 'enclaves' within a dacite, and I was wondering if you'd be able to tell me what the enclaves are composed of? My emails karl.bischoff@hotmail.com

In the off chance you get this and reply, thanks in advance! :)

Karl

Karl Bischoff said...

I don't know whether you're made aware of comments on old posts, but I'll post this anyway. My name's Karl, I'm a 2nd year Geology student in Australia. We recently had a field excursion, and came across similiar 'enclaves' within a dacite, and I was wondering if you'd be able to tell me what the enclaves are composed of? My emails karl.bischoff@hotmail.com

In the off chance you get this and reply, thanks in advance! :)

Karl