Taxonomy term

isotope

Beryllium: the rain bringeth and the rain taketh away

High in Earth’s atmosphere, cosmic rays collide with oxygen atoms, shattering the oxygen into smaller atoms, including radioactive beryllium-10. Atmospheric beryllium-10 that falls to Earth’s surface — in precipitation or aboard dust particles — is known as meteoric beryllium-10. Researchers often use the ratio of meteoric beryllium-10 to nonradioactive beryllium-9 in soil as a tracer of soil age and processes. As beryllium-10 has a long half-life — about 1.4 million years — scientists have used it for studies of both short- or long-term soil dynamics.

25 Feb 2019

"Cradle of Humankind" fossils can now be dated

Robyn Pickering was taught as an undergraduate about a collection of limestone caves in northern South Africa known collectively as the Cradle of Humankind for the trove of early hominin fossils discovered there. She learned that, unlike hominin fossils unearthed in East Africa, whose ages have been constrained by dating the surrounding layers of volcanic ash, the fossils in the Cradle — including well-preserved specimens of Australopithecus africanus and the recently discovered Homo naledi, among others — were impossible to date independently. Now, Pickering, an isotope geochemist at the University of Cape Town, and her colleagues have figured out a way to date the South African fossils after all. In a recent study published in Nature, the researchers report ages for flowstones — horizontal deposits of calcium carbonate that form natural cements on cave floors — across eight caves in the Cradle of Humankind. The flowstones sandwich fossil-bearing sediment layers, allowing age ranges for the fossils to be determined.

05 Feb 2019

Climate cooling a driver of Neanderthals' extinction

Neanderthals disappeared from Europe roughly 40,000 years ago, and scientists are still trying to figure out why. Did disease, climate change or competition with modern humans — or maybe a combination of all three — do them in? In a recent study, researchers offer new evidence from Eastern Europe that climate change was a major player in the Neanderthals’ disappearance.

30 Nov 2018

Lunar isotopes suggest early water on Earth

The moon is a child of catastrophe, born from a massive collision between the young proto-Earth and a Mars-sized object during the formation of the solar system. 

30 Jul 2018

LIP split by South Atlantic breakup was sourced from deep

Massive volumes of rock called large igneous provinces (LIPs) have formed many times throughout Earth’s history, fed by some of the planet’s mightiest volcanic events. The volcanic eruptions, sometimes lasting millions of years and pouring hundreds of thousands of cubic kilometers of lava onto the surface, have influenced continental breakups, past climate change and mass extinction events. For everything that’s known about LIPs, however, many questions about them remain, including how far below the surface the erupted magma originate. In a recent study, researchers report that the origins of the Paraná-Etendeka LIP likely lay deep in Earth’s interior.

16 Mar 2018

Isotopes reveal sources of centuries-old alabaster artifacts

When geologists think of alabaster, they likely envision blocks of gypsum, its main mineral constituent; when art historians hear the word, statues crafted from the soft rock may come to mind. A new study focused on the sources of centuries-old alabaster artworks has geologists thinking about art history, and art historians pondering geochemistry. In the study, published in Proceedings of the National Academy of Sciences, researchers used isotope fingerprinting along with historical records to tie medieval and Renaissance alabaster sculptures to the quarries from which their materials were excavated.

26 Feb 2018

Isotopes suggest ancient turquoise mine was prolific

Few minerals are more iconic in the Desert Southwest than turquoise. The blue-green gemstone, which offers a stark contrast to the dusty red southwestern deserts, has been coveted for thousands of years by indigenous peoples, conquering Spaniards and now by a growing market around the world. Despite its past and present cultural significance, especially among indigenous populations, little is known about the early history of turquoise mining. Researchers have now uncovered previously unknown details about a historic turquoise mining site in Arizona that suggest it was more prolific than once thought.

05 Feb 2018

Stable isotopes offer novel methods of disease detection

Stable isotope techniques developed by geoscientists are being applied to studies of human health, and one in particular has shown promise as an improved way to determine bone loss, a problem for astronauts, as well as those on bed rest and aging populations here on Earth. 
08 Jan 2018

Nutrient deficiency delayed life after mass extinction

After Earth’s most severe mass extinction, life took up to 9 million years to recover — millions of years longer than after other extinction events. New research published in Geology suggests that a collapse in the ocean’s productivity might have been the cause.

25 Nov 2016

Helium escape may help predict volcanic activity

Europe’s tallest active volcano, Mount Etna, rises 3,300 meters above the island of Sicily, which lies just off the coast of Italy’s “toe.” Within 100 kilometers of more than 3 million people, Etna frequently rumbles and occasionally belches. As recently as last May, explosions accompanied lava fountains and ash erupted from one of the volcano’s craters over several days. This was just one of many eruptions in a long line of events, with historical documents dating similar outbursts back to 1500 B.C. Scientists cannot pinpoint when Etna will next erupt, but in a new study in Geology, researchers have identified a clue that may help them better understand how the volcano’s inner plumbing system changes just prior to an eruption.

17 Aug 2016

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