Are you sure you want to report this post?
You may optionally give an explanation for why this post was reported, which will be sent to the moderators along with the report. This can help the moderator to understand why you reported the post.
Posted by: Donald Kasper
Very good. The southern Brazil/Paraguay region is full of big amygdules, I must be wrong and you proved it. How old are these lavas? Cretacecous. Okay, where was South America in Cretaceceous? Farther south in a desert belt. Okay, what is the brown staining? Humic acid leaching from being moved up to the equator where plant matter in groundwater stained them. Now you know.
Would you like for me to tell you where Germany was in Permian? Okay, if the shells of geodes are kaolinized and the agates are full of kaolinite, those are 300-400 million year old agates and that was weathering.