WrightwoodCalif.com Forum

Public Forums => San Gabriel Mtns Flora - Fauna => Topic started by: storm on Sep 24, 06, 11:23:47 AM

Title: a few cross-section pics of local rocks
Post by: storm on Sep 24, 06, 11:23:47 AM
a friend let me use his rock saw so that i could slice open a few local rocks.  i hope that this can lead me to better understand the local geology...

meta-sediment (layers of limestone/calcite and quartzite--which can metamorphose into banded quartzite):
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectionmetasediment.jpg)

another meta-sediment, seemingly further along (metamorphically speaking) than the previous specimen.  i believe that the white layers are nearly marble (metamorphosed from limestone), while the brown layers are nearly quartzite (metamorphosed from sandstone):
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectionmetasediment2.jpg)

banded quartzite:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/crosssection--bandedquartzite.jpg)

three specimens of calcite:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/crosssection--calcite1.jpg)

(http://img.photobucket.com/albums/v190/stormbythesea/rocks/crosssection--calcite2.jpg)

(http://img.photobucket.com/albums/v190/stormbythesea/rocks/crosssection--calcite3.jpg)

talc-magnesite-calcite-nephrite jade:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/crosssection--talcactinolitemagnesi.jpg)

nephrite jade:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectionnephritejade.jpg)
Title: Re: a few cross-section pics of local rocks
Post by: Wrightwood on Sep 24, 06, 02:12:25 PM
Nice photos!

Thanks Storm for sharing your knowledge  :bow:
Title: Re: a few cross-section pics of local rocks
Post by: Naughty pines on Sep 24, 06, 03:43:58 PM
When I was in the lapidary club at work I was learning to identify various types of rocks.

The samples you photographed all look like Leaverite.





Leav er right there! :2thumbsup:
Title: Re: a few cross-section pics of local rocks
Post by: ezzpete on Sep 24, 06, 07:25:01 PM
that first image of the layerd rock is awesome. i've never seen anything like that around here.
Title: Re: a few cross-section pics of local rocks
Post by: storm on Sep 24, 06, 09:25:11 PM
all those rocks are scattered about in the levee that's below the Wright landslide.

here's one i found on saturday on the north side of Hwy. 2, down in one of the washes (sheep or heath?):
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/Rhodonite.jpg)

i and others think this is rhodonite, which metamorphoses from impure limestone.  if you know what the pink mineral/rock is, or if you've found some as well, i'd love to hear from you!

i've been told that a fellow had gone up Heath Canyon about 1000 feet and dug out about all the rhodonite he could find.  i think this was back in the 1960s...
Title: Re: a few cross-section pics of local rocks
Post by: Toolman on Sep 26, 06, 07:35:23 PM
Storm....nice photo's, and would like to cut some pieces myself.

 I've found several specimens of the meta-sediment which I've found in my yard whil eplanting and while hiking.

 One in particular that is indigenous to the W/W area and cool looking, is Actinolite, which I have collected several large and small. It would be interesting to see the interior structure.

 http://www.mindat.org/min-18.html

 A boy hood hobby was geology and I'm just starting to get back into it and can't find my hammer. ;D

 
Title: Re: a few cross-section pics of local rocks
Post by: storm on Sep 30, 06, 09:10:26 AM
Quote
One in particular that is indigenous to the W/W area and cool looking, is Actinolite, which I have collected several large and small. It would be interesting to see the interior structure.

actinolite:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectionactinolite.jpg)

actinolite schist:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectionactinoliteschist.jpg)

i think these might be albite crystals:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectionalbite.jpg)

i think this is diorite (form the Jensens area):
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectiondiorite.jpg)

here's a fine schist--notice the thin layers:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectionfineschist.jpg)

gneiss from the Post Office area:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectiongneiss.jpg)

black tourmaline in a schist:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectiontourmaline.jpg)

some meta-sediment from Onyx Peak near Big Bear Lake:
(http://img.photobucket.com/albums/v190/stormbythesea/rocks/cross-sectionOnyxPeakmetasediment.jpg)
Title: Re: a few cross-section pics of local rocks
Post by: storm on Sep 30, 06, 10:32:44 AM
on second thought, what i called albite crystals might be more diorite.  the white mineral in diorite is plagioclase feldspar, while the black material is amphibole (as far as i understand)...
Title: Re: a few cross-section pics of local rocks
Post by: ChrisLynnet on Nov 11, 06, 08:31:00 AM
These are great! My son and I are always picking up rocks and carting them home, but I don't know anything about them. Like Toolman, I used to love geology, including identifying rocks and minerals. I'd like to take up the hobby again, especially since it's something my 10-year-old and I would enjoy doing together.