The laser ablation system is designed for microanalysis of d13C and d18O of small apatite and carbonate samples. The laser approach is less precise than the phosphoric acid method, but is the only option for very small samples such as rodent teeth, and precious samples such as hominid teeth where large sampling pits are unacceptable. The basic approach is outlined in Sharp and Cerling (1996) as modified by Passey and Cerling (2006).
The system pictured to the left uses a Photon-Machines Fusions 30 watt CO2 laser coupled to a custom-built extraction line. The extraction line is automated, freeing the user to focus on the laser-targeting aspect of the analysis. The system has been up and running since March 2011 and has been used to analyze early mammals from the Eocene of Wyoming, and fossil rodents from South African hominid-bearing cave deposits.
Dietary ecology of modern and fossil rodents in Africa (Passey, w/ Paul Sandberg, Matt Sponheimer, Peter Ungar, and others)
Eocene-Oligocene Paleoenvironments at Fayum, Egypt (Levin, Passey, w/ Erik Seiffert, Tom Bown, Elwyn Simons, and others)
Early Eocene paleoecology in the Bighorn Basin, Wyoming (Levin, Kraft, w/ Ken Rose)
Signals of hibernation in ground squirrels (Passey, w/ Tom Goodwin)