Sentences with phrase «isotope ratios from»

Paleo temperatures from oxygen isotope ratios from the greenland ice cores show that a temperature increase of 0.7 °C will not bring the current temperature up to the level of the Medieval Warm Period let alone the Roman optimum and the MInoan Warm period which were both warmer than the medieval warm period.

A study by Thomas, Dennis et al 2009 [8] derived a high resolution temperature proxy record from oxygen isotope ratios from the ice core.

Stable carbon isotope ratios from tree rings record changes in the internal concentration of carbon dioxide and, in the northern Boreal zone, are regarded as a proxy for photosynthetic rate, and therefore summer sunshine.

Like the data used right through 0.02 to 66 My, the Freidrich et al collection comprises stable oxygen isotope ratios from the shells of tiny bottom - dwelling, deep - water marine organisms (benthic foraminifera).

That seems a way more satisfactory approach than the crude estimate in Hansen et al (2013) that I've been using, which relies on an interpretive leap from a deep water temperature proxy (oxygen isotope ratios from the microscopic shells of bottom - dwelling marine critters).

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.

No, some other animal probably converted the grass into meat on the hoof, and the hominids got the characteristic carbon stable isotope ratio from eating the grazing animal — they ate grass indirectly, at one remove.

Not exact matches

Waters produced from unconventional oil and gas wells typically have radium isotope ratios (radium - 228 to radium - 226) that are different than those from conventional oil and gas operations, he said.

Gas - source isotope ratio mass spectrometers are a special breed of a class of instruments — mass spectrometers — that are used in many different areas of science, from physics to biomedical science, for the separation of atoms and molecules of different charges and molecular weights.

Wang and Jacobsen examined seven lunar rock samples from different lunar missions and compared their potassium isotope ratios to those of eight terrestrial rocks representative of Earth's mantle.

Hallis previously used hydrogen isotope ratios in volcanic basalt rocks to conclude that Earth's water may in fact have been part of the very dust cloud from which the planet first condensed.

The team used records of oxygen isotope ratios (which provide a record of ancient water temperature) from microscopic plankton fossils recovered from the Mediterranean Sea, spanning the last 5.3 million years.

According to the model, the ratios of aluminum isotopes can be explained by the parent isotope having been injected in a one - time event into the planet - forming disk by a shock wave from an exploding star and then traveling both inward and outward in the disk.

The researchers determined from the isotope ratio that the Taylor Glacier samples were 120,000 years old, and validated the estimate by comparing the results to well - dated ice core measurements of atmospheric methane and oxygen from that same period.

Animals that live in the sea have ratios of carbon and nitrogen isotopes that differ from those found in terrestrial animals, and this isotopic signature is passed on to the people who eat them.

It is measurable in terms of oxygen and carbon isotope ratios and was compared to «environmental archive» data from other parts of the earth.

Barrick and Showers measured the relative ratios of the isotopes oxygen - 16 and oxygen - 18 in the phosphate from 54 samples of a near - complete T. rex skeleton.

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.

By testing many clay samples of known ages from both sides of the mountain range and comparing their ratios of heavy isotopes, Chamberlain and Poage found that the Southern Alps of New Zealand rose abruptly by 2 kilometers 5 million years ago.

The regular variation in isotope ratios suggests that rather than wandering at random from site to site, Diprotodon made the same round trip each year, following seasonal shifts in vegetation and rainfall.

David Hodell, Jason Curtis and Mark Brenner from the University of Florida obtained their evidence from the ratio of calcium carbonate to calcium sulphate in sediments from Lake Chichancanab, in Yucátan, Mexico, and from the proportion of heavy to light isotopes of oxygen in buried shells.

Although scientists know that the tools for reconstructing past climates at polar latitudes are far from perfect, he says, pinning down the relationship between isotope ratios and temperature is essential.

The scientists measured the isotope ratios in three ice cores from across East Antarctica, each of which dates back to at least 340,000 years ago.

To better understand the cycle of magma production, the researchers analyzed oxygen isotope ratios in quartz and zircon, water - and heat - resistant minerals, from volcanic rocks in the Yellowstone caldera.

The ratio of different strontium isotopes varies from place to place, providing clues to where an animal lived.

Knowing that strontium derived from land shows a slightly higher ratio of strontium 87 than strontium derived from hydrothermal circulation, the scientists compared isotopes in each type of barite.

We can separate these elements from the rock matrix and look at their exact chemical makeup, their isotope ratios.

Analysis of isotope ratios in hair samples showed how much of the bears» diets came from human food.

As photosynthesis favours the lighter isotope, carbon 12, over the heavier carbon 13, this «light» ratio finding suggests that organic material from biological sources may have been more abundant in diamond - forming zones early in the Earth's history than we find today,» explained Suzette Timmerman, lead author on the study.

Plants take up isotopes, or variants, of carbon and nitrogen in ratios that differ from one place to the next.

For this work, conducted at the University of Bristol including Morten Andersen (now Earth Science, ETH Zurich) along with researchers from the Durham (UK), Wyoming and Rhode Island (US), used the «fingerprint» carried in the ratio of the two uranium isotopes.

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

Eggshells contain carbon, which comes from the birds» diets, and because different plants have different ratios of carbon isotopes, the shells can be used as a rough record of what birds ate.

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.

By overlaying isotope ratios of these three elements, the South Africans were able to distinguish ivory not only from different regions and countries but also from parks as few as 150 miles apart.

To zero in on the possible cultural interaction, archaeologists Dušan Borić of Cardiff University in the United Kingdom and T. Douglas Price of the University of Wisconsin, Madison, analyzed ratios of isotopes of strontium in the teeth of 153 skeletons from nine sites at the Danube gorges.

The most convincing evidence for this, says Jouzel, comes from isotope ratios; ice that has frozen in site has a higher proportion of water molecules containing the heavy form of oxygen, oxygen - 18, than that of ice that has been transported over long distances by weather systems.

Yeakel and Dominy accessed these skulls and found that the Taita's ratio of nitrogen isotopes was distinct from the herbivores.

Extrapolating from their isotope ratios, the authors conclude that, over the 9 month period, the lions probably consumed around 10.5 and 24.2 humans, respectively, or around 35 humans total.

What's more, the ratio of ruthenium - 106 to the faster - decaying isotope ruthenium - 103, detected in smaller amounts last autumn, reveals that the fuel must have been removed from its reactor only a year or two earlier.

A mass spectrometer revealed the ratio of two forms, or isotopes, of strontium at the different stages, which can indicate where his drinking water came from when matched to an area's geology.

Dust from our own solar system has a characteristic ratio of heavy to light oxygen isotopes.

Because photosynthesis, but not respiration, prefers the lighter carbon isotope, the researchers could detect the separate carbon flows from each of the two processes by measuring the ratio of the two carbon isotopes.

«If a gust of air comes up from the forest with an isotope ratio that's off by one part in 30,000, we can tell,» Wehr says.

By measuring the ratio of carbon isotopes in the samples the team collected, they were able to tell how much carbon was from fossil fuel combustion.

The information about oxygen concentration comes from the isotopic composition of carbon or rather from the ratio between the stable carbon isotopes 12C and 13C.

To help track down where the cotton came from, the researchers are exploiting a principle that is already used by wine experts to verify where particular wines originate — the varying ratio of carbon - 13 to carbon - 12 isotopes found in crops from different areas.

Because the tiny creatures build their shells from materials in seawater, their calcium carbonate homes reflect the ratio of the two isotopes in the seas of that time.

The simple fact is that every scientist now involved in climate science, from the study of isotope ratios in deep ice cores to the emission of methane from tropical forests, is not only a scientist, but a political commentator and activist.

To date, we have a full complement of analyses for about three years of growth for one tusk from the Taimir Peninsula of Siberia (the Jarkov mammoth; ca. 20,300 rybp) and growth increment and tusk apatite carbon and oxygen isotope ratios for two to three years of growth from two tusks from Wrangel Island (4,400 and 4,120 year bp).