An international research team from the Hebrew University of Jerusalem has gained fascinating insights into Earth's history by studying unfinished diamonds. These special stones, often rejected by the trade as unsightly, contain valuable information about their origins dating back 2.6 billion years.
The scientists analyzed dull, yellowish diamonds from South Africa that still contain liquid inclusions. These substances provide information about the conditions deep inside the Earth when the diamonds were formed. In the enclosed liquids, they found uranium and thorium, which decay into the helium-4 isotope.
By calculating the decay rate of helium, the researchers were able to determine the age of the diamonds they examined and date them to several geological periods. In principle, the research basis is the same as that used in archaeology, where, for example, the decay of carbon is used to determine age.
The following results emerged from the research:
- The oldest specimens formed between 750 million and 2.6 billion years ago, during significant tectonic activity in South Africa (formation of the first multicellular organisms and the breakup of supercontinents such as Rodinia).
- The middle diamonds date from a period 300 to 540 million years ago, contemporaneous with the growth of the Naukluft Mountains in Namibia (the origin of the first plants and forests on land, as well as arthropods and mammals).
- The youngest diamonds formed 85 to 118 million years ago, shortly before they reached the surface through subterranean eruptions. (Habitat of dinosaurs and pterosaurs - in the Jurassic and Cretaceous periods)
Analysis of the fluids revealed different chemical compositions depending on the time of formation, indicating specific geological events. These findings make diamonds unique "time capsules" that provide valuable insights into Earth's geological evolution.
