GeologyRocksI don't suppose you guys can help me ID these?
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Inchmurrin Conglomerate?
Sat, 08/02/2008 - 18:25If it is any help Conic Hill is mapped as Early Devonian Inchmurrin Conglomerate. It is a conglomerate with clast sizes ~ 10 cm, mainly of quartzite in the lower part but also with igneous and volcanic clasts higher up.
Rock 1 could be upper, 2 lower
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The HBF is wellknown for
Fri, 09/05/2008 - 00:06The HBF is well known for making schists and metasediments, which is likely what you have here. I can't say I know a whole lot about Conic hill and it's local geology but I don't see anything particuarly conglomeritic about what you have there, so i'm tempted to rule that out.
Rock 1 appears to be your run of the mill mica schist, and I suspect the green mineral you see there may be chlorite, simply because I find it's the usual culpret for greeny colours in micaceous rocks and it's far more common than serpentine. I confess that i'm not really sure though. If you feel you have some hornblende in there as well it may very well even be epidote and cholrite both!
Rock 2 looks rather like quartz mangled with philosilicates, though given its location context it's gonna either be a quartzite or a metaquartzite (made from vein quartz or by silica sand fusing under high heat conditions). I suspect the latter, but you should be able to tell yourself from the texture of the quartz (metaquartzite is typically very grainy).
Hope that helps (a little).
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I don't suppose you guys can help me ID these?
Submitted by Rock Fly on Fri, 08/01/2008 - 17:49.Hiya,
I really enjoying going to various places and collecting the rocks, and then being able to identify them at home. I've managed to ID every rock I've found so far but I can't for the life of me figure these 2 out. I don't suppose you can help?
These were both found on Conic hill which is basically on the HBF.....this first one I think may be serpetinite but I'm not sure:
This second rock I really have no idea. It looks to have been pretty heavily metamorphosed by contact with heat?
In places it looks like hornblende...
And on one side there appear to be a change in composition, going from left to right the rock goes from near black, to mid grey, to a lighter grey.
Here's a bad attempt at a closeup:
It isn't a foliated metamorphic rock and it doesn't match anything else in my books, so I really am stumped and wondered if one of you lovely geologists may be able to help?
Thanks!