Direct dating fossils

01-Jul-2018 13:53

This video is part 4 of 13 in the Human Paleontology series.A trio of geologists has published what they called the first successful direct dating of dinosaur bone.SCU Postdoctoral Fellowship Renaud Joannes-Boyau To understand human evolution, archaeologists require precise chronologies so as to compare and contrast fossil collections.While indirect dating of the sedimentary matrices of human occupation sites are considered somehow more precise than direct dating techniques, their accuracy is frequently poor.Dating studies on paleoanthropological sites are usually carried out on material associated with the hominin remains, such as the sediment, charcoal or other fauna rather than the hominin specimen itself.This approach is, in many cases, not satisfactory because the relationship between the associated materials and the specimen is often uncertain.Some of the calculated "ages," though, lined up with the already assumed age of 64 million years, and these data were hand-picked to represent the "age" of the fossil.

It is no wonder that scientists were not interested in looking for collagen in these dinosaur bones, since no collagen could remain after a maximum of 30,000 years.

Additionally, the commonly used technique of radiocarbon dating reaches back only to about 50 to 60 ka and, as a consequence, many important questions in our understanding of human evolution cannot be addressed.

Recent advances in dating methods by Joannes-Boyau and Grun (2010; 2011) and Joannes-Boyau et al., (2009; 2010a,b and 2011) now allow for a more accurate non-destructive direct dating of human fossil remains, and have shown that most previous Electron Spin Resonance (ESR) age were underestimated by as much as 30% (Joannes-Boyau and Grun, 2011).

The scientists analyzed the abundance of radioactive isotopes of certain elements that had leeched into the edges of buried dinosaur bone from the San Juan Basin in northern New Mexico and southern Colorado.

Their new technique involved first polishing a slice of bone and then shooting a laser beam onto its surface.

It is no wonder that scientists were not interested in looking for collagen in these dinosaur bones, since no collagen could remain after a maximum of 30,000 years.Additionally, the commonly used technique of radiocarbon dating reaches back only to about 50 to 60 ka and, as a consequence, many important questions in our understanding of human evolution cannot be addressed.Recent advances in dating methods by Joannes-Boyau and Grun (2010; 2011) and Joannes-Boyau et al., (2009; 2010a,b and 2011) now allow for a more accurate non-destructive direct dating of human fossil remains, and have shown that most previous Electron Spin Resonance (ESR) age were underestimated by as much as 30% (Joannes-Boyau and Grun, 2011).The scientists analyzed the abundance of radioactive isotopes of certain elements that had leeched into the edges of buried dinosaur bone from the San Juan Basin in northern New Mexico and southern Colorado.Their new technique involved first polishing a slice of bone and then shooting a laser beam onto its surface.For example, an igneous rock from the Grand Canyon—which, unlike sedimentary rock, is a type of rock that has been considered "datable" because the relevant isotopes are locked up in its tiny crystals—was tested by standard means.