Thanks for the offer, Nick, a link to your presentation would be fun, I find these things interesting because they do remind me of proximal VMS deposits. Is Erebus the only place these are found?
Some results from late night googling:
http://www.exo.net/~pauld/antarctica/erebus.html
According the the text, the cave in the second picture leads to a lava tube. Now that's cool.
Here's some interesting shots from the air: http://www.ig.utexas.edu/research/projects/agasea/field/updates/agasea_field_012105.htm
Some good shots here:
http://tea.armadaproject.org/pennycook/12.9.1999.html
Space/Science » in reply to re: Good point.
A couple of google finds: