Andy Baker

Week 5 in the UNSW Earth and Environmental Science course is ‘The Sandstone City’.

One hundred students now have an understanding of  Sydney’s Hawkesbury Sandstone, a Triassic age rock deposited around 220 million years ago. The sedimentology of the sandstone suggests that it was originally formed by a very large river, probably slightly smaller than the modern day Bramaputra.

The students get to investigate this evidence first hand at the Argyle Cut, shown in the photo, the site of a former quarry where Sandstone was extracted for building stone.

The class also gets to inspect some of the oldest sandstone buildings in Sydney, understanding how the geological properties of the rock make it a good building stone.

Attractive iron bands form in some of the sandstone, often found as a decorative feature in buildings, facades and walls across Sydney. The class also investigate how this iron banding is formed.

And finally, with the help of planetary scientist Clare Fletcher, the students got to understand the how the skills they learnt in class could be applied to Mars and other planetary missions, where sedimentological observations are needed to infer if water or life has existed in the past.