Karst Pinnacles in Australia as a Geological Clock

A team of researchers, including Dr Matej Lipar and Dr Mateja Ferk from the Anton Melik Geographical Institute at ZRC SAZU, has published a scientific paper in the prestigious journal Science Advances. The paper, titled Ironing out complexities in karst chronology: (U-Th)/He ferricrete ages reveal wet MIS 5c, explores the timing of formation of karst pinnacles in Australia, where the authors have been conducting research for some time. These formations hold vital clues about past climatic conditions in the region, stretching far back into Earth's geological history.

The researchers describe their findings in detail:

"We investigated iron-rich rock nodules, ranging in size from peas to golf balls, found cemented on the pinnacles in the world-renowned Nambung National Park in Western Australia. By precisely measuring the amount of helium trapped in the iron—produced by the radioactive decay of uranium and thorium—we discovered that these nodules act as a kind of geological clock, recording when they were formed. The ages of the nodules closely align with the formation of the large limestone pinnacles, pointing to an exceptionally wet climatic period around 100,000 years ago. During this time, heavy rainfall dissolved the limestone, sculpting the pinnacles, while a surface soil layer developed, allowing the iron nodules to form. This reconstructed climate phase appears to have been the wettest in the last 500,000 years—markedly different from other parts of Australia at the time and a stark contrast to the modern Mediterranean climate of Western Australia."

The full article is available at this link.