Using marine fossils, a large international collaboration decodes a fundamental process in Earth's history

Sedimentation is more important than other factors in the 'time averaging' of marine fossils

The investigators analysed more than 7,500 fossils, which were collected from a variety of oceanic environments around the world

The study decodes a fundamental process in Earth’s history and provides guidelines regarding the types of research questions that palaeontologists can investigate using marine fossils

ANSTO has contributed to a large international study which decodes a fundamental process in Earth’s history and provides guidelines regarding the types of research questions that palaeontologists can investigate using marine fossils.

Dr Quan Hua, an authority on radiocarbon dating, reconstructed regional marine post-bomb radiocarbon curves for age calibration of the fossil samples used in the research.

“The level of radiocarbon or 14C in the surface ocean is spatially different due to ocean circulation, such as currents and upwelling, and regional variations in air-sea CO2 gas exchange. Therefore, a marine post-bomb calibration curve connected to the current pre-bomb Marine20 data for each study region was constructed from published 14C data and the 14C data on known-age live-collected museum specimens produced by the study,” Dr Hua said.       

Scientists used a dataset of thousands of dated marine samples to determine which of several environmental factors contribute most to ‘time averaging’. This mixing phenomenon occurs when organisms that lived in different time periods are mixed and preserved together in the same fossil bed. 

The results, published in the prestigious journal PNAS, indicate that sedimentation is more important than other factors, such as the number of burrowing animals in a given area or the durability of fossils.