Jump to content
SteveE

Polishing cross section of a stromatoporoid

Recommended Posts

SteveE

Greetings from Central PA.  I'm  a total noob when it comes to fossil prep.   Today I have a flattish piece, about 10" across and 1" thick.  It from a large outcrop of wavy laminations that I believe are from a Keyser Formation stromatoporoid.   It's pretty weathered and too hard to tell if pillars are present.   So I'd like to try to grind/polish one edge.   I have a good collection of metal and woodworking sanders and grinders available but nothing specifically designed for rocks.

 

So my QUESTION IS.... is there a reasonable way to grind/polish the edge of this sample to look for stromatoporoid pillars?   I'm just guessing that false negatives are common doing this sort of thing. so I thought I'd seek expert advice before I just make up some hatchet job only to get iffy results.

 

Thanks

Share this post


Link to post
Share on other sites
TqB

At 1" thick, a circular tile saw should work OK, and you can then grind and polish with a few grades of wet and dry paper (used wet). Otherwise, I guess an angle grinder suitable for masonry should produce a flat enough surface to wet and dry.

Share this post


Link to post
Share on other sites
Shamalama
12 hours ago, SteveE said:

Greetings from Central PA.  I'm  a total noob when it comes to fossil prep.   Today I have a flattish piece, about 10" across and 1" thick.  It from a large outcrop of wavy laminations that I believe are from a Keyser Formation stromatoporoid.   It's pretty weathered and too hard to tell if pillars are present.   So I'd like to try to grind/polish one edge.   I have a good collection of metal and woodworking sanders and grinders available but nothing specifically designed for rocks.

 

So my QUESTION IS.... is there a reasonable way to grind/polish the edge of this sample to look for stromatoporoid pillars?   I'm just guessing that false negatives are common doing this sort of thing. so I thought I'd seek expert advice before I just make up some hatchet job only to get iffy results.

 

Thanks

Any chance you can post a picture of your find before you grind it down?  The Keyser does have some stromatoporoids but the specimens I have collected are mound shaped and pretty clear as to their origin.   Here is a blag post I did years ago on some Stromatoporoids that I found in the Keyser and other formations.  http://viewsofthemahantango.blogspot.com/2010/06/stromatoporids.html

Share this post


Link to post
Share on other sites
SteveE

Thanks Tarquin,  I guess the angle grinder is first up.  It will be interesting to find out if the sample chips away faster than it cleans up

 

And greetings Shamalama!  I have been regularly reading your blog for awhile now, thanks for all the great info.  I'm also pretty noobish at ID.  Maybe its the sheet-ish stromatolites I've read about too.  Looking for pillars is really an effort at ID, and I collected the piece to dive into the polishing learning curve.  The outcrop is large (10ft?), very curvy, and as it weathers its delaminating.   I didn't take photos of the outcrop but will try to get back before it really snows.  There are many veins of a soft mineral (calcite I assume).   In the last photo, I only dampened part.  The green is from the algae.    I'll post follow up pics after I've done some hatchet work on it

 

   crIMG_3192.thumb.jpg.0b3f17a5a290c2e03538b250ab70a4c3.jpg

 

crIMG_3193.jpg.a0f55e50df3286cc47146b60e6255b7b.jpgIMG_3195.thumb.JPG.a21922fec201199ce8b282ad4264276d.JPG

 

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Recently Browsing   0 members

    No registered users viewing this page.

×