The Naracoorte Caves in South Australia is considered one of the best fossil sites in the world, with a record of over half a million years.

As specified in a ScienceAlert report, among the remains preserved in layers of sand are the bones of many "iconic Australian megafauna species" that turned extinct between 48,000 and 37.000 years back.

 

The reasons for the extinction of these said species are strongly debated. However, the older the fossils that can be found, the better those in the field can understand the species' evolution and extinction.

To date, identifying the exact age of the caves has been quite challenging. Nevertheless, the study demonstrates, for the first time, how the old caves of Naracoorte are, and the answer is up to 500,000 years older than most people previously thought.

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Naracoorte Caves
(Photo: Wikimedia Commons/Alpha from Melbourne, Australia)
The Naracoorte Caves in South Australia is considered one of the best fossil sites in the world, with a record of over half a million years.

Understanding How Biodiversity Responds to Climate Change Over Time

The study's findings published in the Communications Earth & Environment journal shed new light on this important site's antiquity. The study authors hope this will help understand how biodiversity responds to climate change over time.

Essentially, caves can be unusual time capsules, frequently preserving the remnants of long-extinct plants and animals in exquisite detail. South Australia's Naracoorte Caves is one example.

The cave complex is the only World Heritage site in South Australia. Among the significantly diverse and complete fossil records are the remnants of iconic megafauna such as the marsupial predator known as Thylacoleo Carnifex, huge herbivore also called Zygomaturs Tribulus, and browning sthenurine kangaroo, also known as Protodon goliath among others.

Paleontologists have dug and dated many of these fossil deposits and reconstructed the skeletons of several megafauna species.

According to The Conversation, when this report first came out, the caves formed when groundwater seeped through cracks in limestone cracks, as they dissolved and formed cavities.

'Speleothems'

The dating approach used involved analyzing the attractive calcite formations inside the caves. These collectively are called "speleothems," including stalagmites, flowstones, and stalactites.

Small amounts of uranium, a radioactive element, are looked inside when speleothems are forming. Over time, such an element slowly decays into the "element lead," as the study specified. 

This takes place at a known, constant rate. Meanings, uranium can be used in speleothems as a natural rock to date them.

Doing so involved extraction of uranium and lead from a speleothem in a lab. Then, the researchers measured each element and computed the age of the sample very accurately.

Since speleothems only begin growing once a subterranean activity is formed and over the groundwater table, the oldest speleothem age shows the cave's minimum age itself.

For this, the team discovered the cave started forming at least 1.34 million years back, making them about 250,000 up to 500,000 years older than the past computations.

Climate Change and Human Impacts

The study findings will help paleontologists target new excavation sites to search for older fossils, hoping to find valuable additional evidence of how the unique biodiversity of the continent has changed.

The researchers said their new approach could help solve how old fossil deposits at other cave complexes are, in Australia and all over the world, where speleothems are vertebrate fossils are discovered.

Essentially, the richness of plant and animal species in Australia is facing an uncertain future because of climate change and other human impacts.

Lastly, investigating sites like Naracoorte Caves helps paleontologists and archeologists understand how climate change has influenced biodiversity before and what might also happen in the future.

Related information about archeological finds that are older than commonly thought is shown on Global News's YouTube video below:

 

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