Sentences with phrase «at oxygen isotope ratios»
When the jet stream got loopy In order to track the jet stream's behavior thousands of years ago, Bowen and his fellow researchers looked at oxygen isotope ratios from lake cores and cave formations in the eastern and western United States.
https://www.scientificamerican.com/ Not exact matches
The ratio of oxygen isotopes in seawater depends on the water temperature; the value of this ratio at any point in evolutionary time is «frozen» into the chemical composition of certain marine fossils.
They then compared the oxygen isotope ratio in Yonderup dripwater with that predicted by a model (which simulated the dripwater δ18O based on measurements of rainwater δ18O), as well as that measured at a different cave in the region.
Nevertheless, some scientists claim that ratios of oxygen isotopes in marine fossils from the east coast of the US indicate that the Antarctic ice sheet melted at least partially during the Pliocene.
Environmental scientist Suzanna Richter and plant physiological ecologist Brent Helliker, both at the University of Pennsylvania, measured the ratio of two isotopes of oxygen — rarer oxygen - 18 and more common oxygen - 16 — in samples of wood.
Back at their Georgia Tech lab, they analyzed the stalagmites for the ratio of oxygen isotopes contained in samples of calcium carbonate, the material from which the stalagmites were formed.
The analysis below used the ratio of oxygen isotopes in the stalagmites to estimate the water temperature at the time they were formed.
Carbon and oxygen isotope ratios both shift at the same boundary; the former shows disruption of the carbon cycle, while the latter shows an abrupt warming of about 6 degrees.
Looking at the isotopic record from the PETM, scientists see both carbon and oxygen isotope ratios spiking in exactly the way we expect to see in the Anthropocene record.