This week we are sharing a bunch of interesting photos of places and samples from around Australia and the world. Enjoy.
Can You Do This? Mulga, Central Australia
– Associate Professor Hrvoje Tkalčić (Seismology and Mathematical Geophysics)
This camel photo was taken when Armando Arcidiaco (our technical officer) and myself were in the field to retrieve 6 ANU seismic instruments that we installed to monitor the aftershock activity from a large (magnitude 6.1) earthquake that shook central Australia on May 21, 2016. The shot was taken while Armando was driving and I was in a good position to observe the beautiful landscape and nature of Mulga National Park, about 100 km southwest of Uluru. There was a wild excitement in the animals due to an unusually large amount of water (a consequence of La Nina) and thriving vegetation in usually desolate areas.
Yellowstone National Park
Suzette Timmerman – PhD Student in Isotope Geochemistry
These photos were taken in Yellowstone National Park, United States. Melanie Sieber and I (Suzette Timmerman) were there as part of the Deep Carbon Observatory summer school 2016. At the summer school we were with +/- 35 researchers from various fields (microbiology, physics, seismology, geochemistry) to integrate our knowledge on the deep carbon cycle and applied it to Yellowstone. Underneath Yellowstone a large plume is supplying heat and brings up material from the lower mantle, which interacts with the upper mantle and crust. In the first photograph you can see deposits of various carbonates from a hot magmatic-hydrothermal fluid. The trees get white socks and die 10-100s of years before the hydrothermal activity is visible at the surface. In the second photograph you see various colours that are related to the type of microbes living there. In the middle of the spring the water is boiling and no microbes can exist, hence the blue colour. The temperature decreases outwards, resulting in different conditions and thus different microbes (yellow and orange colour).
– Michaela Flanigan (Master of Earth Sciences (Advanced) student)
This thin section is from one of the many basalts collected on Pacific islands by Prof. Ian McDougall in the 1970s. This specimen comes from Lord Howe Island NSW, which is the subject of my Master’s project. It is a cumulate, with large olivine crystals floating in a basaltic groundmass, with which they are probably not in equilibrium (confirmation forthcoming!). This means that this particular piece of magma was probably sitting happily near the bottom of a magma chamber when a new influx of magma swept it up to the surface and it was erupted. This photograph was taken on the Leica microscope in building J5, and photos like this are very useful reference material for using the microprobe and laser, so that you know what you’re looking at under the powerful microscopes!
Kelsie Long (PhD Student in Archaeogeochemistry)
This is a fish otolith. It is a calcium carbonate structure that grows in the inner ear of most animals, including humans. As the fish grows so does it’s otolith. It grows in layers like tree rings with each layer representing a year of the fish’s life. As each layer forms it takes up and preserves the chemical composition of the water the fish was living in (with some small deviations that I have to take into account). This composition can sometimes change with external conditions such as temperature, salinity and evaporation. I am studying the chemical composition of fish otoliths to learn more about past environments at the archaeological site of Lake Mungo in South Western NSW, where heaps of these otoliths and other fish remains are found in ancient fireplaces.
This particular image is of a modern golden perch (Macquaria ambigua) otolith that has been thin sectioned and viewed under a light microscope, so we can see the annual rings (you can tell how old the fish was by counting the white bands). If you look really closely you can make out the tiny spots where I’ve sampled the otolith’s chemical composition. The width of the otolith (from left to right in the image) is only around 1 cm, some of the annual layers are less than 1 mm thick!
This fish was originally from the Lachlan River but was kept in breeding tanks at the Narrandera Fisheries centre for the last 5 or so years of its life…before it and some of its fellows became an essential component of my PhD.