Martin Horejsi wrote:
Hi Matt,Conglomerates are different than breccias, meaning they form under different processes. Conglomerates by definition are coarse-grained, clastic (composed of rocks of different types) sedimentary rocks composed of fragments that are rounded, and greater than 1.5mm in diameter. These pieces are set in a fine-grained (<1mm) matrix.Earlier you mentioned about brecciation:
"composed of angular broken rock fragments held together by a mineral
cement or fine grained matrix. Basically it means a bunch of broken rocks
assembled together!:)"Matt, are conglomerates polymict breccias?
Also, what rock typesAll types can be breccais.
(metamorphic, sedimentary, etc.) can be breccias.
One last question, howThis is the tough question. On earth they are cemented by (usually) some mineralized fluid that passed through the cracks of the breccia. This can be calcium-carbonte or even gold! However meteorites may be a different story. The howardites are regolith breccias bound by the pulverized fragments of the asteroid surface, this is what makes them so friable. The impact melt breccias like Cat Mountain and Chico, look like they are held together by the actual melt from the impact, this gives them a swirling look. Finally the ordinary chondritic breccias such as L'Aigle and St. Michel look like they are cemented together similar to terrestrial rocks, however they are supposedly impact induced. I have seen breccia pipes related to porphyry copper systems here on earth that are remarkably similar. Hmmm.....
does the cementing process work in meteorites such as the brecciation
difference between Peekskill and Bison.
It was excellent!!!!Oh, Matt, last year on this List you asked me a question about
photographing meteorites. Well, I put together a response for you, but it
got out of hand and I decided to send it to Joel at Meteorite! instead of
posting it here (sorry about that Art). Anyway, if you have any other
questions about photographing meteorites, please ask.
I have gone completely digital with fairly good results (so I am told). I shopped around for the best camera I could afford that would allow me to take close-ups of meteorites. I chose the HP PhotoSmart digital camera. Granted it doesn't have all the bells and whistles of a $700-1500 camera does, but it can do the job and with ease! I have no problems keeping it in focus at a distance of 2 inches plus you can attach C-mounted lenses to it for even more detailed photos. For lighting I just use a couple of desk lamps. After the image is done I import it into Photoshop for processing, and that is it. I took a dozen images, completely processed and all, in 45 minutes.For the group: I have talked with several of you including master
photographers such as Michael Casper about using digital cameras to capture
images of meteorites . Since I get hit off-List with questions about
digital photography, it may be a point of interest for this List to share
equipment opinions and shooting techniques.Sincerely,
Martin
--
Matt Morgan
Mile High Meteorites
http://www.mhmeteorites.com
"If you dig it, do it once. If you dig it a lot, do it twice."
-Jim Croce