Sentences with phrase «oxygen isotopes in»

In the 1970s, the first comprehensive analysis of oxygen isotopes in sediments from cores taken from the sea floor established for the first time that the timing of the Ice Ages was linked to subtle changes in the Earth's orbit around the Sun as suggested long ago by Serbian mathematician Milutin Milankovitch.

Shemesh, A., and D. Peteet, 1998: Oxygen isotopes in fresh water biogenic opal — Northeastern US Alleröd - Younger Dryas temperature shift.

Although a previous estimate based on this approach yielded a MAT of approximately — 5 °C, additional information from oxygen isotopes in mosses at the site allowed us to calculate isotopic enrichment in the cellulose of fossil trees, thereby reducing assumptions and increasing the precision of our MAT estimates (see the Data Repository).

Although it is unclear how much of the water pool available for photosynthesis is derived from winter versus summer precipitation, research on oxygen isotopes in modern larch suggests that larch rely on spring snow melt and thus integrate the isotopic signal of annual precipitation (Sugimoto et al., 2002).

By examining time lags between observed changes in oxygen isotopes in a section of sediment from near Millville, New Jersey, the authors estimate that:

The ratios of oxygen isotopes in their shells are entirely controlled by temperature.»

Broecker later remarked that the relatively smooth temperature record of oxygen isotopes in deep - sea sediments «tended to lull scientists into concluding that the Earth's climate responds gradually when pushed.»

An ice drilling pioneer, Oeschger was now measuring oxygen isotopes in glacial - era lake deposits near his home in Bern, Switzerland.

The analysis below used the ratio of oxygen isotopes in the stalagmites to estimate the water temperature at the time they were formed.

Broecker used changes in oxygen isotopes in deep - sea cores, analyzed by Emliani during 1955 - 1966, to point out the sawtooth nature of glacial cycles — a slow cooling followed by rapid warming.

Using modern spatiotemporal records of oxygen production and oxygen isotopes in terrestrial precipitation, the authors demonstrate that their proposed relationship is robust over the modern seasonal cycle.

Now in a Climate of the Past paper, Seltzer et al. present a new record of oxygen isotopes in atmospheric O2 derived from two Antarctic ice cores.

The scientists analyzed the ratio of the oxygen isotopes in the hydration water and in the calcium carbonate.

Lower amounts of stable hydrogen and oxygen isotopes in the ice indicate colder weather, Persoiu said.

In order to measure the proportions of the oxygen isotopes in the zircons, the team, led by scientist Alexander Nemchin, used a device called an ion microprobe.

«Oxygen isotopes in ancient bones and teeth reflect the water animals are living in or drinking,» said Kim, a former postdoctoral researcher at the University of Wyoming.

By measuring the oxygen isotopes in the sea ice, the scientists were able to deduce where and when the ice was formed.

In the study, the researchers examined nitrogen and oxygen isotopes in N2O samples collected from permafrost peatland sites in northwestern Russia.

Age is critical because it takes about 200 million years for oxygen isotopes in the seas and crustal rocks to be homogenised by cycling through thermal vents in the ocean floor.

Karlos Muehlenbachs of the University of Alberta measured the ratio of oxygen isotopes in the oldest rocks known on Earth, which formed 3.96 billion years ago.

The Earth's water must have come from its interior, according to a scientist who has studied the ratios of oxygen isotopes in rocks.

As part of that effort, a team including UChicago cosmochemist Nicolas Dauphas performed the largest study to date of oxygen isotopes in lunar rocks, and found a small but measurable difference in the makeup of the moon and Earth.

One way you can tell is by looking at different oxygen isotopes in the fossilized skeletons of ocean microorganisms.

In the past decade, paleoclimatologists have reconstructed a record of climate change over the last millennium by consulting historical documents and examining indicators of temperature change like tree rings, as well as oxygen isotopes in ice cores and coral skeletons.

By applying uranium - thorium dating to the corals and measuring ratios of oxygen isotopes in their skeletons, her lab reconstructed ocean temperatures for much of the last 7000 years.

Knudson and Ravelo based their findings on an analysis of carbon and oxygen isotopes in the calcium carbonate shells of tiny marine organisms called foraminifera, which are preserved in seafloor sediments.

These spectra also indicated the ratio of oxygen isotopes in Vesta's rocks.

Mark, who focuses on the Andes region, developed a method of determining how much of a community's water supply is glacier - fed by analyzing the hydrogen and oxygen isotopes in water samples.

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.

The ratio of two oxygen isotopes in the larch's cellulose would give Ballantyne a temperature range.

For the new study, the researchers used an extremely precise laser - based method to measure oxygen isotopes in a range of Earth rocks, meteorites and three lunar samples gathered by the Apollo astronauts.

To find out, he looked at the oxygen isotopes in 32 fossil teeth.

According to Robert Clayton, a professor emeritus at the University of Chicago in Illinois who pioneered the use of oxygen isotopes in cosmochemistry, the authors may have done little more than find a more precise method of measurement.

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.

Notably, Terada and his colleagues say, previous studies have shown that the overall proportions of oxygen isotopes in the ozone layer also are skewed toward above - average concentrations of oxygen - 17 and oxygen - 18.

Not exact matches

The rover's Sample Analysis at Mars (SAM) instrument that analyzes the soil and atmosphere around the rover using a mass spectrometer, a gas chromatograph and a tunable laser spectrometer to detect oxygen and carbon isotopes in carbon dioxide and methane samples to see if they are biochemical in origin.

Both the eggshells and the embryo bones were analyzed in order to determine their oxygen isotope composition.

The ratio of strontium to calcium in a given layer of coral reef — as well as the amount of a heavier isotope of oxygen in the carbonate itself — reflect the temperature in this historical record, but the isotopic information also reveals rainfall.

«Oxygen in the water that mammals drink is preserved in the phosphate in their teeth, so these can be used to calculate 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 StateIn 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 Statein the eastern and western United States.

By analyzing isotopes of oxygen preserved in herbivore teeth and tusks, they can quantify the aridity of the region and compare it to indicators of plant type and herbivore diet.

Analyses of samples brought back from the Apollo missions in the 1970s showed that the Moon has the same abundances of the three stable isotopes of oxygen as Earth.

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.

But the team's measurements of the oxygen isotope ratios in the creatures» teeth, a sensitive paleo - thermometer, suggest that the climate where these dinosaurs lived probably averaged about 10 ° Celsius over the course of a year — substantially colder than most of the dinosaur era, and in fact close to that seen in northeastern China today, Xu notes.

But more accurate measurements of oxygen isotopes published in 2016 only confirmed that the isotopic compositions are not distinguishable.

They found that the oxygen isotope ratio in Yonderup dripwater was 2 ‰ (2 parts per thousand) higher than expected.

In his talk, Agee presented the results of the isotope analysis for oxygen as well as hydrogen.

Retired University of Wisconsin, Madison, archaeologist Doug Price analyzed strontium, oxygen, and carbon isotopes in 20 teeth from Tollense.

The researchers found that a certain kind of oxygen isotope was present in the lunar soil, an isotope that occurs on Earth.

The new sea - level record was then used in combination with existing deep - sea oxygen isotope records from the open ocean, to work out deep - sea temperature changes.