So what's up folks? What do you see in this Rorschach Ink Blot of an outcrop? I want to recognise Elisabeth for authorising the use of this photo for you to analyse. See what I did there? Just finished this book, which I enjoyed very much. So much that I have been making a bunch of word nerd puns since I read it.
I would like Elisabeth to recognise that her institution stole the world's greatest university president from my institution. No hard feelings though.
8 comments:
I see a fault with a narrow dike on it running right-left through the hammer, offsetting a dark dike that has at least two types of inclusions, one of which may be the lighter granitic rock to the right.
Looks to me like a plag phyric zenolith rich dike with orientated zenoliths, some of them the host granite. The dike is offset by a fault that is occupied by another dike, a fine grained, glassy looking one, possibly psuedotachyllite. At the top of the photo is a granite clast that right up against the side, looking like an undisplaced part of the granite. The thin chill margin on the larger dike is most visible on the right above the hammer.
I see the fault, but I also note that the dark part which SilverFox sees as offset is a noticeably different width above and below the fault, making me want to walk along it to see if, perchance, the offset is even greater and, in fact, these are two different dark units that were brought together by movement along the fault.
heck if those aren't all great comments! now i have to see them side by side with the photo....
and I will acknowledge what my institution has done. but I have such a hard time calling a place "mine" -- I clearly would not make a good university president!
oh, one other thing -- I think the thing you are calling glassy and possibly pseudotachylite (running right to left and under hammer) is a quartz vein/dike.
Structure comment - no reason the offset on that little fault has to be parallel to the plane of the photograph. In fact I would guess it is not.
Oops. quartz veins aren't always white. I guess I was too eager for the exotic
Ah, a quartz vein!
Also, because the offset units are intrusive, there's no way to really say that the offset on both units isn't somewhat similar, because we don't know the original shape of the dark-light contact on the right side of the photo - at least that was my original thinking.
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