That is the geochemical question.
I've collected concretionary rock samples from the fossil locality in central-western Queensland I'm studying, and am now in the process of (partially) destroying them. Why/how/WHAT?
Well, I want to examine the types of minerals in the rocks, including their structure and chemical composition, because we don't know much about the depositional environment under which dinosaur, fish, and crocodile remains were fossilised. Due mainly to the fact that no-one has investigated it yet, but also because there is very little outcrop at the site. Which means I won't be constructing a nice long stratigraphic section, which is normally used to conduct facies analysis, which in turn indicates the likely depositional environment (i.e. deep sea, or river channels, or floodplains and so on). Instead, I'm relying on geochemical indicators of environment.
The analyses I'm undertaking are destructive or partially destructive. Polarised light microscopy, scanning electron microscopy (SEM), and electron microprobe analyses, although non-destructive, require thin sections or small stub samples from sliced-up rock. X-ray diffraction (XRD) requires samples that are crushed into a fine powder. Inductively coupled plasma atomic emission spectrometry (ICP-AES) and stable isotope analysis require dissolving the rock in acid which becomes, in the case of ICP-AES, atomized into a mist-like cloud.
These rocks, having survived 101 million years of erosion and a ~1000km car ride back to Brisbane, are now literally dust.
For Science!
But seriously, this is work that absolutely has to be undertaken, to understand how and under what conditions these dinosaur, crocodile, and fish remains became fossilised.
I've collected concretionary rock samples from the fossil locality in central-western Queensland I'm studying, and am now in the process of (partially) destroying them. Why/how/WHAT?
Well, I want to examine the types of minerals in the rocks, including their structure and chemical composition, because we don't know much about the depositional environment under which dinosaur, fish, and crocodile remains were fossilised. Due mainly to the fact that no-one has investigated it yet, but also because there is very little outcrop at the site. Which means I won't be constructing a nice long stratigraphic section, which is normally used to conduct facies analysis, which in turn indicates the likely depositional environment (i.e. deep sea, or river channels, or floodplains and so on). Instead, I'm relying on geochemical indicators of environment.
The analyses I'm undertaking are destructive or partially destructive. Polarised light microscopy, scanning electron microscopy (SEM), and electron microprobe analyses, although non-destructive, require thin sections or small stub samples from sliced-up rock. X-ray diffraction (XRD) requires samples that are crushed into a fine powder. Inductively coupled plasma atomic emission spectrometry (ICP-AES) and stable isotope analysis require dissolving the rock in acid which becomes, in the case of ICP-AES, atomized into a mist-like cloud.
These rocks, having survived 101 million years of erosion and a ~1000km car ride back to Brisbane, are now literally dust.
For Science!
But seriously, this is work that absolutely has to be undertaken, to understand how and under what conditions these dinosaur, crocodile, and fish remains became fossilised.
Above photograph: Crushed/powdered rock samples in vials, ready for geochemical testing.
Taken by C. Syme.
Taken by C. Syme.
