Sentences with phrase «isotopic ratios»

Atmospheric scientists call this shift the Suess effect, and the change in isotopic ratios of carbon due to fossil - fuel use is easy to see over the last century.

The study of the rubidium / strontium isotopic ratios in a set of meteorite samples shows the general approach to

In collaboration with the Institute for Arctic and Alpine Research (INSTAAR) of the University of Colorado, ESRL / GMD now routinely monitors carbon isotopic ratios of CO2 and CH4.

«This suggests that measuring isotopic ratios of downwind gases might potentially tell us something about the nuclear yield or size of an underground nuclear explosion,» Carrigan says.

A group of scientists believe that a previously unexplained isotopic ratio from deep within Earth may be a signal from material from the time before Earth collided with another planet - sized body, leading to the creation of the Moon.

Rainfall oxygen isotopic ratios are good indicators of the amount of rainfall occurring throughout the region, as determined by a modern - day calibration study recently published by another graduate student in Cobb's lab.

When they redid the dating calculation using published isotopic ratios and their more precise elemental ratio, they found that it took just 2 million to 4 million years to form Mars, not the tens of millions of years Earth must have taken to agglomerate.

Based on measurements of Jupiter and the solar wind, which are thought to preserve the hydrogen isotopic ratio of the protosolar nebula, scientists think nebular water had an extremely light hydrogen isotopic signature — much closer to what the Baffin Island lavas suggest about the deep mantle's water.

A team led by Charles R. Carrigan at Lawrence Livermore National Laboratory (LLNL) used field experiments to build a new, complex model that predicts isotopic ratios of noble gases that would be released from such explosions (Sci.

Putting a probe into the atmosphere to measure noble gases and key isotopic ratios is an example, another being measurements of magnetic fields, charged particles, and plasmas to understand ice giant magnetospheres.

By measuring the abundance of noble gases and certain isotopic ratios in the planets today, we think we can learn more about the temperature at which the planets formed, and hence, their distance from the Sun at that time.

Reference Lind K., Melendez J., Asplund M., Collet R. & Magic Z., The lithium isotopic ratio in very metal - poor stars, Astronomy & Astrophysics.

This enabled a direct measurement of the 12C / 13C isotopic ratio for the Orion hot core of 14 + / - 1 and an estimated maximum value of 21.

Also, the rocks astronauts brought back from the Moon have identical oxygen and titanium isotopic ratios as those on Earth.78 If large impactors came from Earth, most moonquakes should be on the near side.

Problems remain in the interpretation of the measured Pb isotopic ratios to transform them into ages.

he cites Semiletov / Shakhova but does not as these authors do not, tell you what the Ch4 isotopic ratio is.There is observation of aerobic methane production in the pacific region of the arctic waters.

Lourantou, A., Chappellaz, J., Barnola, J. M., Masson - Delmotte, V. & Raynaud, D. Changes in atmospheric CO2 and its carbon isotopic ratio during the penultimate deglaciation.

Their simulations also show that isotopic ratios of radioactive xenon gas are dependent on the magnitude of the explosion.

In other words, if all of the terrestrial carbon today (in forests, animals, soils, etc.) were converted to carbon dioxide and returned to the global inorganic carbon pool, the change in the global carbon isotopic ratio would only be a third as big as that observed during the PETM!

Like a chemical fingerprint, the isotopic ratio between Earth's samples and the carbonaceous chondrites» samples matched.

By comparing the isotopic ratios of nitrogen and carbon in the lions» remains with that of contemporary lions, humans and herbivore prey, Justin Yeakel of the University of California, Santa Cruz, estimates the lions ate around 35 people.

By comparing the isotopic ratios of nitrogen and carbon in the lions» remains with that of contemporary lions, humans and herbivore...

Researchers at the University of Geneva (UNIGE), Switzerland, — together with colleagues at the University of Lausanne (UNIL) and American and Spanish scientists — have been working on an analytical method that combines observing deep - water sedimentary strata and measuring in them the isotopic ratio between heavy and light carbon.

Because the isotopic ratios of carbon and hydrogen display geographic variation, the composition of a feather can reveal where the bird was when the feather grew.

But roughly 2.45 billion years ago, the isotopic ratio of sulfur transformed, indicating that for the first time oxygen was becoming a significant component of Earth's atmosphere, according to a 2000 paper in Science.

Using core samples of the seabed in three locations, the scientists measured the isotopic ratio of nitrogen - 15 to nitrogen - 14 in the organic matter therein; the ratio can be used to estimate the extent of anoxia in these OMZs.

The isotopic ratios from the calves» early years of life consistently displayed a trend toward lower nitrogen - 15 values, reflecting the decreased contribution of milk to the overall diet, Cherney said.

The scientists analyzed the samples» isotopic ratios — a telltale chemical signature of what the animals ate during their lifetimes.

One of Mojzsis's former coauthors, geochemist Gustaf Arrhenius of the Scripps Institution of Oceanography, showed how the Isua carbon - isotopic ratio could arise by geologic activity alone, if certain iron minerals in the rock were melted and pressed together over time.

But she had to improve the sensitivity of the technique so that it could detect the isotopic ratio in DNA from the roughly 6 - gram sliver of neural tissue in the hippocampus thought to produce new neurons, the dentate gyrus.

Initial SAM results show an increase of 5 percent in heavier isotopes of carbon in the atmospheric carbon dioxide compared to estimates of the isotopic ratios present when Mars formed.

Isotopic Ratio of 13 - C: 12 - C in carbonate minerals.

Potassium - Argon Dating I Limitations of the If you read further in my second potassium - argon dating page: K - Ar - dating page 2 You will see that Ar dating method can overcome these limitations of conventional k - ar dating, and has the added advantage that potassium and argon are determined on the same sample and that only measurements of the isotopic ratios of argon are required.

Ar dating method can overcome these limitations of conventional k - ar dating, and has the added advantage that potassium and argon are determined on the same sample and that only measurements of the isotopic ratios of argon are required.

Larger planets will probably have more energy from these sources, but the radiogeneic inventory of the planet is a wild card (it's hard to know the isotopic ratios of exoplanets).

The task is complicated, however, because nitrogen, when cycling through the atmosphere or deposited on land or in water, is subject to influences that can alter the isotopic ratios, thus masking the source.

The chemical and physical characteristics of the fossils — including the species as well as their chemical composition and isotopic ratios — provide reliable proxy records for past temperatures by calibrating them to modern temperature records.

Curiously, the PETM was accompanied by an exceptionally large change to the global carbon cycle as indicated by a large drop in the isotopic ratio of 13C to 12C in the ocean and on land.

Conversely, a decrease of biological uptake, leads to a decrease of the isotopic ratio (i.e., it gets «lighter»).

Isotopic ratios?

If he wanted to apply his scientific credentials to a scientific matter in climate, he might turn to what the isotopic ratio of carbon (13C / 12C) needs to be in atmospheric CO2 concentration to constitute a fingerprint of human origin.

His dissertation was on the geological origin of carbonatites based on his analysis of the isotopic ratio of strontium (87Sr / 86Sr).