What happens at a dig – Part 2

Glimpsing their haul from the previous day, I saw that all the significant finds were neatly marked for sorting and transportation. There were piles and piles of rock, exposing jaws, teeth, and vertebrae.

A jaw bone.

South GAG site

Cross-section of bone (from a giant leg?).

South GAG site

A vertabra.

South GAG site

As the morning drew on, the pile of ‘potential’ rocks grew, but as a novice, I couldn’t identify anything without professional help. Later, I found out that the team had found the jaw of a nimbadon (a sheep-sized diprotodon), but unfortunately for me it had already been bagged-up, ready for transportation.

What were inside those rocks? It was frustrating that unlike at Wellington Caves, where the fossils were preserved in loose sediment that could easily be washed away, extracting fossils from limestone required time and effort. I guess it’s like the difference between digital and film photography. Wellington was like digital photography, where you could almost instantaneously view your finds. However the fossils in Riversleigh limestone, like developing film, required the rocks to be transported back to the labs at UNSW, where they would be submerged numerous times in a weak acid solution. Eventually the limestone would dissolve to reveal the bones inside it. Like an expectant photographer developing film, hopefully I can one day visit UNSW to get a glimpse of this year’s finds. It would really round-off my Riversleigh experience.

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