Sentences with phrase «from oxygen isotope»

The continental glaciations of the Pleistocene left signatures on the landscape in the form of glacial deposits and landforms; however, the best knowledge of the magnitude and timing of the various glacial and interglacial periods comes from oxygen isotope records in ocean sediments.

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.

Calcareous nannofossils from approximately the past 7000 yr of the Holocene and from oxygen isotope stage 5 are present at 39 analyzed sites in the central Arctic Ocean.

Figure 1: Temperature anomaly calculated from oxygen isotope composition.

Here, we present a record of Holocene glacial ice discharge, derived from the oxygen isotope composition of marine diatoms from Palmer Deep along the west Antarctic Peninsula continental margin.

The record tells the story of the sudden release of an isotopically light source of carbon, triggering a fast warming in the deep sea of about 5 degrees C. Both the carbon isotope signal and the temperature (inferred from oxygen isotopes) then relaxed back toward their initial values in about 100,000 years.

These physical temperature measurements help calibrate the temperature record scientists obtain from oxygen isotopes.

Holocene hydrologic balance of tropical South America from oxygen isotopes of lake sediment opal, Venezuelan Andes.

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).

Not exact matches

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.

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.

Terada told Space.com that the evidence for where the ions came from was the isotope oxygen - 16.

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

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.

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.

The reason oxygen isotopes are present in a different pattern is because they are derived from sustained chemical reactions occurring on the surface of the outer solar nebula, rather than from a one - time event.

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.

To figure out those answers, Rybczynski turned to Ash Ballantyne, another grad student at Duke, who was using oxygen isotopes from tree cores to determine historical temperatures.

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.

Carbon and oxygen isotope analyses of teeth from the Ar.

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.

Warmer air temperatures cause more water containing the heavier isotopes oxygen - 18 or deuterium to evaporate from the surrounding ocean.

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.

«We identified the different isotopes of hydrogen and oxygen in the water, which allowed us to work out where the water came from.

From 1990 to 2010, the nitrogen isotope record indicates that oxygen content steadily decreased in the area, as expected.

What the team discovered was an odd oxygen isotope telling them that the sulfates came from gases that had undergone atmospheric reactions en route to the valley.

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

The ice shelf had been thinning slowly, however, which was evidenced by a change in the oxygen isotopes present in plankton preserved from the underlying water column.

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

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 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.

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

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.

The paleoclimate data, which included mainly changes in the oxygen isotopes of the calcium carbonate deposits, were then compared to similar records from other caves, ice cores, and sediment records as well as model predictions for water availability in the Middle East and west central Asia today and into the future.

Evidence for approximately contemporaneous global cooling in sediments that do contain YTT glass shards has been found in marine core oxygen isotope records from the South China Sea (3), as have terrestrial carbon isotope and pollen records from Northern India and Bengal (23).

This paper gives results from a stable oxygen isotope assessment of modern human and horse enamel δ18O values recovered from tooth enamel.

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).

Ancient sediments that once resided on a lake bed and the ocean floor show sulfur isotope ratios unlike those found in other samples from the same time, calling into question accepted ideas about when the Earth's atmosphere began to contain oxygen, according to researchers from the U.S., Canada and Japan.

u «The moon rocks, however, showed [oxygen isotope] ratios markedly similar to those of rocks from Earth.

Then the team restricted evidence to just three measurements that can be obtained from shell samples in sediment cores: cadmium concentration and carbon and oxygen isotope ratios in the calcium carbonate shells.

It's unknown where this space rock came from, but a Mars origin had been ruled out because of the rock's concentration of oxygen isotopes.

Sulfate sources and oxidation chemistry over the past 230 years from sulfur and oxygen isotopes of sulfate in a West Antarctic ice core.

The group of meteorites known as HED (howardite, eucrite, and diogenite) are thought to emanate from Vesta, as their oxygen isotope signatures are the same.

The oxygen isotopes of a meteorite can act as a fingerprint to identify the parent body it originated from.

Based on the temperature minimum recorded from the early Late Oxfordian of Kachchh, it was suggested that the widening of the Trans - Gondwanan Seaway may have led to increased upwelling in the Malagasy Gulf and to a cooling recorded in the oxygen isotopes of belemnites and other marine invertebrates from Kachchh [38].

In any event, pretty early on in the book (a bit after box 2.2, «The World According to Oxygen Isotopes») he says: that cores taken from «Intermediate depths in the ocean... show warming of perhaps 5C» and that this warming was caused by CO2 the source of which is still controversial.

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).