What is radiometric dating?
Paul Barrett: Elements go through radioactive decay by losing neutrons from their isotopes. This happens with a clocklike regularity and can be accurately measured. This is how we work out how long the work was deposited. Uranium into lead is an example [of a process] that takes millions of years. Its radioactivity depletion is well known, as its rate never changes, so it can be used as a sort of ‘natural clock’ for other elements.
Tell us about the discovery of soft tissue on bones. How important or even surprising was this?
Barrett: There’s actually very little soft tissue evidence found in T-rex in general. The only organic material that has been found is within the bones of one specific T-rex whose preservation is very different from the others. The interior of this animal’s bones haven’t been fully fossilised yet so there’s still some of the original protein content. This is really unusual; and the difference is still currently unknown.
There’s quite a lot of tissue evidence in the feathered dinosaurs that have been found. In exceptional circumstances, muscles and the original organic content of internal organs can be found.
Why had the soft tissue not decayed?
Barrett: It’s very rare [for this to happen] and in most cases it’s because the dinosaurs get buried so rapidly other animals cannot scavenge the material and bacteria cannot get in and rot it away. The fine grain sediment slows down the process and allows the matter to be preserved. In some other cases, bacteria are very helpful and form ‘mats’ that protect it from scavengers.
What is the most important fossil ever found in your opinion?
Barrett: If you asked a palaeoanthropologist, they would say the skeleton of ‘Lucy’ (3.2-million-year-old humanoid skeleton) or the first Neanderthal skeleton, which help establish the link between humans and more ancient humanoids. I would say one of the most important is archaeopteryx, as it showed a evolutionary link between reptiles and birds through descent.
Where is the best place to find fossils in the world?
Barrett: The best place is probably Alberta, Canada. You are literally guaranteed to find fossils minutes after you get out your car.
Dr. Paul Barrett is a Palaeontologist at the National History Museum