Using light to describe the ancient world

NIR2011

I have just found out that I will be presenting a talk at NIR2011 in Cape Town (13-20 May). NIR2011 is an international conference that will showcase all of the latest research in the field of near infrared spectroscopy, including unusual applications like fossils.  I am going to be talking about Near infrared spectroscopy of fossil antelope bone from South Africa. Find out more from the conference website (www.nir2011.org), or you can email Professor Marena Manley (marena@nir2011.org) or Ms Deidre Cloete (deidre@nir2011.org) for more information, including registration details.

Near infrared spectroscopy of fossil antelope bone from South Africa

Daniel B. Thomas­, Cushla M. McGoverin and Anusuya Chinsamy­

Introduction: Raw materials for constructing bone are supplied by food, water and air, and are ultimately sourced from the external environment. Bone chemistry consequently records the living environment of an animal, and such information may persist after death and into the fossil record. Chemical alteration of bone during burial (diagenesis) may erase the life history signals from fossil bone, however, severely reducing the analytical utility of fossil material. We have used NIR spectroscopy to screen fossil bone for signs of diagenetic alteration.

Materials and methods: Fossil antelope bone from the Western Cape of South Africa was studied using two instruments: 1) large sample volume (bulk) measurements were collected using a Spectrum IdentiCheck FT-NIR, and 2) low sample volume (hyperspectral, chemical imaging) measurements were collected using a sisuChema short wave infrared imaging system.

Results and discussion: Bulk NIR spectroscopy indicated that secondary minerals had been deposited within the fossil bone. Fossils from different sites could be distinguished by secondary mineralogy, where bone from coastal Swartklip 1 featured calcium carbonate (calcite), and inland Elandsfontein Main exhibited clay mineral infill. Hyperspectral NIR spectroscopy allowed the distribution of secondary minerals to be mapped. Both clay and calcite were concentrated in cancellous spaces, as the residue of deeply infiltrating pore water. Water is the primary agent of diagenetic alteration, and NIR data indicated that the fossil antelope bones had been saturated.

Conclusions: NIR spectroscopy provided evidence for ancient pore water movement through fossil antelope bone. Different secondary minerals had accumulated inside bones from different sites, and informed of different palaeoenvironments. We found NIR spectroscopy to be a useful tool when screening fossil bone for evidence of diagenetic alteration.

Novelty statement: NIR data collected from fossil antelope bone provided evidence for ancient pore water suffusion. NIR represents a new, non-destructive tool for studying bone diagenesis.

Summary statement: Large and small sample volume near infrared spectroscopic data were collected from fossil antelope bone. Fossils from different sites were distinguished by secondary mineral deposits, which were found concentrated in cancellous spaces. Secondary minerals represent residues of ancient pore waters that would have suffused the fossil bones.

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Comments on: "NIR2011" (1)

  1. […] being held in Cape Town this week. Yesterday I presented work from a forthcoming publication, where we used NIR to study burial history. Two other talks describing NIR of minerals were also presented, demonstrating just how powerful […]

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