South Africa boasts some of the most effective fossil information on Earth. Fossils are present in strata and rocks in lots of components of the nation. Some are billions of years previous.
There are microfossils courting again to the Archaean epoch, between 3.5 billion and three.3 billion years in the past, within the Barberton Greenstone Belt within the Mpumalanga province. The fossils of now extinct invertebrates that lived round 444 million years in the past have been discovered within the Western Cape province. So, too, have fossils of giant animals like sivatheres (giraffids) and sabretooth cats, 5 million years previous. The nation’s fossils additionally include an exceptional file of human ancestry, mapping our evolutionary historical past by means of time.
But fossils aren’t simply items of the previous that enable scientists to look backwards. They additionally present geologists with vital details about what future environments could appear to be, play a job in coverage decision-making and have turn out to be a part of our every day lives – typically with out us realising it.
Fossils in man-made constructions
Fossils have offered people with constructing blocks in architectural constructions for hundreds of years. The pyramids of Giza in Egypt are round 4,500 years previous; the stones they are constructed from are hundreds of thousands of years previous – 56 million to 34 million years, to be extra exact. The constructing blocks of the pyramids include trillions of fossilised stays of an ocean-dwelling organism known as foraminifera.
These organisms are nonetheless discovered within the oceans immediately. When they die, their shells turn out to be preserved and fossilise in sediment; this hardens into rock over a really lengthy interval of time. The stone from which the pyramids are constructed known as nummulitic limestone – a reputation derived from the foraminifera species it is made of, Nummulites gizehensis.
And it is not simply historical civilisations that used fossils for constructing. Many trendy buildings and constructions in North America and Europe are created from constructing or paving stones containing fossils. These constructing stones have been quarried from fossiliferous rock layers dated to the Jurassic or Cretaceous intervals when dinosaurs nonetheless roamed the Earth.
Even in South Africa, some imported constructing stones include fossils. The Bishop Gray Monument on St George’s Square in Cape Town, as an example, accommodates marble with Mesozoic-aged cephalopod fossils that date again greater than 65 million years.
Fossils as indicators of financial sources
We use minerals, petroleum, oil and pure fuel every day. These geologic sources must be found and evaluated earlier than extraction. In areas the place fossils happen, geologists use them to this point rocks and sediments to seek out and consider these sources.
Certain fossils are helpful in that they supply an age to sediments or rocks; the organisms or animals that fashioned the fossils lived solely throughout a slim time interval in Earth’s historical past. Some rock strata home fossils that lived throughout an age and in an atmosphere that might be linked to trendy financial sources.
This is vital to find the place sure rock models are that can level to financial reserves. Fossils, significantly microfossils – the stays of very small to microscopic-sized animals or organisms – have been utilized in mineral, petroleum and oil exploration globally. In South Africa, microfossils discovered within the Karoo Basin within the centre of the nation, the south coast and offshore of the west coast have all been utilized in oil, mineral and petroleum exploration.
Fossil fuels
When animals, organisms and crops die in sure environments and turn out to be buried below thick layers of sediment, warmth and strain remodel their stays in such a approach that they turn out to be part of petroleum, pure fuel or coal.
For the previous 150 years huge quantities of these reserves have been extracted to supply a serious supply of the world’s vitality wants. Fossil fuels have performed an immeasurable position in powering the worldwide financial system. They generate electrical energy, hold autos transferring and hold trade operating. Today it’s estimated that practically 80% of South Africa’s vitality wants are met by fossil fuels, significantly coal.
However, fossil fuels are a non-renewable vitality supply. Burning them contributes to each local weather change and well being points. There is an ongoing debate in South Africa, as in most different components of the world, about methods to use extra renewable vitality relatively than relying so closely on fossil fuels.
Estimating future environmental modifications
Burning fossil fuels causes environmental hurt – however learning fossils helps geologists to reconstruct previous environments, providing insights into possible future environmental change.
Geologists or palaeontologists research rocks that include fossils to know the environments they as soon as inhabited. They then use this data to estimate how environments, sea ranges or the oceans will change with time. An instance of that is the Pliocene interval (5.3 million to 2.6 million years in the past). It is commonly described as similar to trendy local weather change: throughout the Pliocene, a number of world geologic occasions occurred which led to immediately’s oceanic configurations.
But one thing was lacking throughout the Pliocene – people. Nonetheless, scientists try and mannequin what Earth’s pure responses are to rising carbon dioxide within the environment, along with the results of people, by learning the Pliocene when carbon dioxide ranges have been at related ranges to immediately.
Eugene Bergh, Senior lecturer, North-West University
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