Infrared Light and the Quality of Fossil Preservation – #365papers – 2018 – 62

Beasley, Bartelink, Taylor, and Miller, 2014, Comparison of transmission FTIR, ATR, and DRIFT spectra: implications for assessment of bone bioapatite diagenesis: Journal of ARchaeological Science, v. 46, p. 16-22.

What’s it about?

One of the challenges of studying the chemistry of fossil bones and teeth is being confident that the chemistry of the fossils is unaltered from its original state (that is, the bones and teeth still faithfully record the chemistry of the living animal they came from). During the process of fossilization, the mineral and chemical structure of bones and teeth are altered from what they were in life, a process called diagenesis. Continue reading

Methods for Extracting Proteins from Fossils: Paleoproteomics – #365papers – 2018 – 38

Cleland and Schroeter, 2018, A comparison of common mass spectrometry approaches for paleoproteomics: Journal of Proteome Research, DOI: 10.1021/acs.jproteome.7b00703

What’s it about?

Recently, there has been great discussion about the extraction of proteins from fossils. This paper outlines various methods, and their strengths and weaknesses, for extracting proteins from ancient bones. Continue reading

What X-Rays and Absorptions Really Tell Us About Fossilization – #365papers – 2018 – 24

Stathopoulou, Psycharis, Chryssikos, Gionis, and Theodorou, 2008, Bone diagnesis: New data from infrared spectroscopy and X-ray diffraction: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 266, p. 168-174.

What’s it about?

The authors here use two different methods to gain a sense of the changes in the shapes and sizes of crystals of the bone mineral bioapatite due to the process of fossilization. They also consider the various differences in composition (i.e. how much fluorine, hydroxyl, or carbonate) is present in the bioapatite. While this is done nominally to look at the effects of fossilization, it appears to be better at fingerprinting different localities. Continue reading

Why Can’t We Just Measure Alteration of Bone Due To Fossilization? – #365papers – 2018 – 23

Trueman, Privat, and Field, 2008, Why do crystallinity values fail to predict the extent of diagenetic alteration of bone mineral? Palaeogeography, Palaeoclimatology, Palaeoecology, v. 266, p. 160-167.

What’s it about?

Bones are composed of little crystals of the mineral referred to as bioapatite with organic materials (collagen, blood vessels, and cells that regulate the growth of bioapatite, etc) spread throughout. When an animal dies, the organic materials decay and the bioapatite crystals change their shape and size. There are methods by which we can readily measure the shape and size of the crystals, which, presumably, would tell us just how altered the bones are due to the fossilization process. This would then let us know how accurate any geochemical analyses we do with the bone are.

Only that the shape and size of bone crystals doesn’t actually work as a good measure of the alteration due to fossilization. Continue reading

How Do the Early Processes of Fossilization Affect the Chemistry of Bones and Teeth? – #365papers – 2017 – 41

#365papers for February 10, 2017

Tutken, Vennemann, and Pfretzschner, 2008, Early diagenesis of bone and tooth apatite in fluvial and marine settings: Constraints from combined oxygen isotope, nitrogen and REE analysis: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 266, p. 254-268.

What’s it about?

This paper discusses how we can determine how altered a geochemical signal in a fossil bone or tooth might be, comparing bones and teeth that fossilized in both freshwater (river) and marine (ocean) environments. The authors used collagen content, nitrogen content, and the abundance of Rare Earth Elements (REEs) to attempt to estimate alteration. Continue reading

The Effects of Fossilization on Bones – #365papers – 2017 – 37

#365papers for February 6, 2017

Keenan, Engel, Roy, and Bovenkamp-Langlois, 2015, Evaluating the consequences of diagenesis and fossilization on bioapatite lattice structure and composition: Chemical Geology, v. 413, p. 18-27.

What’s it about?

Translating the title into English explains what the paper is about:

When bones and teeth fossilize, their mineral component (bioapatite) changes its crystal shape and size as well as undergoes some chemical changes. How big of a problem is that if you are trying to use the chemistry of the fossil to understand the life and environment of the animal? Continue reading

Rare Earth Elements in Conodont Apatite – #365papers – 2017 – 30

#365papers for January 30, 2017

Zhang, Algeo, Cao, Zhao, Chen, and Li, 2016, Diagenetic uptake of rare earth elements by conodont apatite: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 458, p. 176-197.

What’s it about?

Rare earth elements (REEs) are heavy elements that are uncommon in bones and teeth (composed of bioapatite mineral) in the living animal, but that are often concentrated in the mineral matrix during fossilization. In the past, REEs in conodont bioapatite were thought to be a good record of the REE content of the ocean waters in which they swam. Continue reading