wwp@yahoogroups.com:
Re: 11 hours until "History" starts ...
Bostjan Burger 2011-Sep-18 18:08:00
Yes it is only a thin coating. If you follow inside the cave, you can see the black manganese oxide on the roof of the cave and to the bottom variations of colors. Brown color is I suppose kind of ferrum oxide but also aluminium oxide can be found. White "sand" in a yellowish mud are small shells and brown spots are pieces of hematite. When the stones covered with manganese oxide are dry the color is dirty dark grey but when are wet the color is dark-violet or dark bluish almost "shiny" black. Here is a nice display of the contrast between manganese oxide and a "golden" color calcium carbonate with additives:?http://www.burger.si/Jame/NovaKriznaJama/03.html?. This is from some other cave which I documented in March 2009.
VR Panoramas are very good tool to analyse the subterranen and I ussually find morphology I didn't notice during the insitu work.
Bostjan
----- Original Message -----
From: Erik Krause <#removed#>
To: #removed#
Cc:
Sent: Sunday, September 18, 2011 6:20 PM
Subject: Re: 11 hours until "History" starts ...
Am 18.09.2011 02:19, schrieb Bostjan Burger:
> It is more metal-violet. Acctually variations (also bluish) - layers
> of a mananese oxide on a dolomite.
Interesting! So it isn't the stone itself but only a coating. I know
green and brown variants of mangan oxid. Have to ask my brother (a
geologist) how this forms...
best regards and congrats to this extraordinary pictures.
--
Erik Krause
http://www.erik-krause.d