Ordovician paleontology in Australia and its global significance

Ordovician strata in the Cliefden Caves area, New South Wales: a case study in the preservation of a globally significant paleontological site

By I. G. Percival, B. D. Webby, and H. D. T. Burkitt

Summarized by Joseph Stump. Joseph Stump is an undergraduate geology major at the University of South Florida. After graduating high school in Sebring, Florida in 2004, Joseph was unsure about which career he wanted to pursue, making college difficult without an end goal to strive towards. In 2006 he enlisted in the United States Army as an airborne Satellite Communications Operator and Maintainer. Staff Sergeant Stump received an honorable discharge from the Army in 2016 and has been using the Post 9/11 GI Bill to earn his degree since then. Thus far, he has completed an Associates in Arts in Engineering from Hillsborough Community College and is currently in his final year of obtaining his B.S. in Geology, with a minor in Geographical Information System Technology. Joseph is set to graduate in Summer 2020. Upon graduation, he would like to pursue a career studying/monitoring/managing Florida’s water resources and coastal habitats.

Methods: The article utilized data gathered from at least 60 published scientific papers and nearly 300 species of fossils (including calcisponge stromatoporoids, sponges, corals, trilobites, nautiloids, conodonts, brachiopods, radiolarians, and cyanobacteria (‘algae’)) within the Cliefden Caves area of New South Wales, Australia, with several of these being endemic (localized) to this area, to support its significance for preservation of global significance. The main threat to this area, and the need for the preservation, is the proposed construction of a dam, which would result in the flooding and destruction of valuable scientific lands and the fossils within it. 

Results: The fossils contained within the rocks of this area include the world’s oldest known brachiopod shell beds. Brachiopod shells are excellent zone fossils, meaning they can help reconstruct the environment by the shape of their shells. Brachiopods are generally zoned by sediment grain size relationships of their shell shapes; meaning, certain species of brachiopods seem to correlate with different sizes of grains (i.e., different environments). Also present are the earliest indisputable rugose corals found anywhere on Earth, an extinct type of coral. If the proposed dam construction is approved in this area, one of the most diverse deep-water sponge faunas ever recorded is in jeopardy of being destroyed and lost from the fossil record forever. The authors of this article all agree that, despite the significant research already done on the area by scientists, there is more to be discovered in the area that holds truths to the history of life on Earth.

A Belubula shell bed from Cliefden Caves; this specific type only occurs in this locality, so far as scientists know. These brachiopods are preserved mostly articulated (both shells together) and in situ (in place where they originally lived on the sediment). Scale bar is a Australian 50 cent coin (32mm diameter)

Why is this study important? This area is important to study due to its ability to better understand the Earth’s geologic and paleontological history. During the Ordovician, the oldest complete vertebrate fossils can be found, and this is where plant life began to migrate onto land, with animals soon to follow. It is also important to understand the climate of Earth during this time frame, as it exploded with diversity (i.e., the Ordovician Radiation), but it ended with what some consider the second largest extinction in Earth’s biological record. Some argue that this extinction was not ecologically major; however, the best way to understand these events and uncover the facts is to study the geologic and paleontological evidence left behind (where available). The issue with studying the geology/paleontology of the Ordovician is the lack of availability of fossil evidence relative to other periods. The end of the Ordovician is marked by glaciation. When a glaciation occurs, oceanic water regresses (moves away from land) and when the glaciers melt, the ocean transgresses (moves towards land). The problem is that these dynamic ocean conditions causes major erosion of any sediments/fossils deposited and often deletes them from the geologic record as an unconformity (“missing time” in a sample of sediments). The flooding that will result from constructing a dam in the region will have the same history erasing effects on the paleo environment as the ancient sea-level changes.

The Big Picture: Human population growth requires a higher demand on water and electricity; however, the current plans of placing a dam in the Cliefden Caves area of New South Wales will have significant negative impacts on the availability of current geologic and paleontological important rocks. A universal fact of life is that if history is not learned from, it is doomed to be repeated. Current global conditions are trending towards a climate that is uninhabitable by the human species. The significance of understanding these events is that measures could possibly be put into effect to mitigate or prevent global cataclysm of anthropogenic causation. Although geological and paleontological research does not often go synonymous with saving lives, the discoveries from their research can potentially impact the longevity of our species and others’.

Citation: Percival, I.G., Webby, B.D., and Burkitt, H. D. T. “Ordovician strata in the Cliefden Caves area, New South Wales: a case study in the preservation of a globally significant paleontological site.” Australian Journal of Earth Sciences, 2019. https://doi.org/10.1080/08120099.2019.1574271


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