How good is the fossil record?
The study, led by Dr Alex Dunhill, formerly at the Universities of Bristol and Bath and now at the University of Leeds, explored the rich and well-studied fossil record of Great Britain. Professional geological work has been done in the British Isles for over 200 years and the British Geological Survey (dating from the 1830s) has amassed enormous, detailed knowledge of every inch of the rocks and fossils of the islands.
Together with collaborators from the Universities of Bristol and Bergen, Dr Dunhill compared biodiversity through the last 550 million years of the British fossil record against a number of geological and environmental factors including the area of sedimentary rock, the number of recorded fossil collections and the number of named geological 'formations'. All of these measures have been used as yardsticks against which the quality of the fossil record can be assessed – but the new study casts doubt on their usefulness.
Dr Dunhill said: "We suspected that the similar patterns displayed by the rock and fossil records were due to external factors rather than the number of fossils being simply dictated by the amount of accessible rock. Our work shows this is true. Factors such as counts of geological formations and collections cannot be used to correct biodiversity in the fossil record."
The study benefits from the application of advanced mathematical techniques that not only identify whether two data sets correlate, but also whether one drives the other.
The results show that out of all the geological factors, only the area of preserved rock drives biodiversity. Therefore, the other geological factors – counts of fossil collections and geological formations – are not independent measures of bias in the fossil record.