By Dominique Tanner

After spending two weeks finalizing drafts for a paper and negotiating logistics for the upcoming field-trip to Africa, I jumped at the opportunity to get out into the field. One of the benefits of dating another geologist is that you get to tag along on field-trips, or conversely, your breaks turn into rock-hunting holidays.

So Lloyd and I spent the Canberra Day long weekend sampling Mt. Dromedary (known as Gulaga to the local Yuin people), an 800m extinct volcano that dominates the landscape between Narooma and Bermagui. After negotiating permits, we were able to sample the syenite (a rare type of granite, rich in alkaline elements and poor in silica) which fills the core of the volcano.

The problem with sampling this particular volcano is that we had to walk up it with a sledgehammer, the track was almost ruined by the recent flooding – and in the long grass near the top of the mountain we encountered a snake. However, the views from the top of the mountain and the spectacular geology made the snake and the leeches worthwhile. I had really wanted to see the old gold mine at the top of the volcano, but unfortunately that track was completely washed away by the recent flooding.

We wanted to sample the syenite as a follow up to one of Lloyd’s PhD papers, to see if the intrusion of syenite into the core of the volcano reset the age of biotite in the surrounding granite. This is important as geochronologists at the ANU and other international universities use this biotite as a standard (or age reference) to date rocks with the K-Ar and Ar-Ar systems.

ANU Geology plaque at the summit of Mt. Dromedary

Lloyd recording xenoliths in the granites at the base of Mt. Dromedary

Mt Dromedary has a special connection with the RSES, as this is where the Geology Department used to run undergraduate field trips. Professor Tony Eggleton has even written a small book on the geology of the mountain, with reference to the ANU Geology plaques displayed all the way up the mountain.

So if you decide to walk up Mt Dromedary on your next holidays, make sure you keep an eye out for these plaques and look out for snakes!