Cavedale Lava Samples

[Cantclimbtom]

Thank you

 

[Brains]

Basaltic volcanics have a significant iron content and include a variety of iron based minerals. Some of these are sulphide rich. Oxidation of the material and alterations by the mineralising fluids may lead to both sulphur containing deposits and limonitic iron deposits. It would appear that the Sulphur has been leached away leaving the limonite and other oxides ( rust!). Minerals within the material can alter to clay. In some fresh deposits the clay can be very soft, and when opened up small grains of pyrite are visible, showing alteration without oxidation.

 

[nobrotson]

Really interesting stuff Phil thanks for sharing