Naked Science Forum

Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: Streets on 19/06/2015 16:48:28

Title: What gives sandstone surfaces a melted appearance?
Post by: Streets on 19/06/2015 16:48:28

∴I found this 1"x 1" piece of sandstone in my yard in Euless Texas.  To my untrained eye, the surface appears to have been melted.  The layer of melting is a bit less than 1mm thick.  The circular features could be the result of bubbling but that is a guess.  It is not unusual to find this type of rock with indications of lava and fossilized wood and other vegetation in this area.  This example is the only one I have seen with the surface I described.  I would appreciate the opinion of an expert.

Title: Re: What gives sandstone surfaces a melted appearance?
Post by: Bass on 24/06/2015 04:39:31

I think you are just looking at varnish from weathering- common in desert environments.

Title: Re: What gives sandstone surfaces a melted appearance?
Post by: Streets on 25/06/2015 22:07:19

Well, if 16 miles west of Dallas is a desert, Why is the humidity a problem?  Thanks for the coulda, shouda, wouda, reply.  I'll wait for a second opinion.

Title: Re: What gives sandstone surfaces a melted appearance?
Post by: Bill S on 25/06/2015 23:10:19

I know very little about US geology, so I'm probably not a good one to comment.  One important thing to be sure of, though, is the real origin of the specimen.  Is it local, or could it have been imported; from a desert area, for example?

If you are sure it is local, then some local geological knowledge would help; for example, are there local examples of igneous intrusions?  could it be contact metamorphism?

http://geology.meetup.com/cities/us/tx/euless/

There seems to be geological interest in the area that might be worth tapping into.