Sentences with phrase «isotopic compositions of»
We determined the chemical and isotopic compositions of the liquid CO2 found on Yonaguni IV knoll hydrothermal site, as well as those in hydrothermal fluid venting from the surrounding chimneys.
https://wattsupwiththat.com/
«They tell us the story of the chemical and isotopic compositions of the atmospheric carbon dioxide.»
On the basis of anomalous isotopic compositions of oxygen and magnesium, 14 oxide grains from two primitive meteorites (Bishunpur and Semarkona) have been identified as circumstellar condensates.
The combination of geological and taphonomic evidence, the assemblage of small - mammal and avian fossils, and the taxonomic and isotopic compositions of remains from larger mammals indicate that Aramis was predominantly a woodland habitat during Ar.
To better understand the likelihood of such a scenario in the Earth - Moon system's origin, Richard C. Greenwood and colleagues analyzed the oxygen isotopic compositions of a large set of lunar and terrestrial samples.
In 2001, however, a team of scientists reported that the isotopic compositions of a variety of elements in terrestrial and lunar rocks are nearly identical.
Dust found in the ice gives a record of what was in the air thousands of years ago, whether from volcanic eruptions or human activity, and the isotopic composition of the hydrogen and oxygen molecules in the snow give a record of the temperature of the earth at the time.
Paleontologists will focus especially on the chemical and isotopic composition of Lyuba's baby tusks.
They plan to explore what other traces of elements are present in the inclusions, as well as make measurements of the isotopic composition of some elements, which could reveal exactly how the metal forms and how it interacts with rocks in the mantle.
This is a particularly useful region because the oxygen isotopic composition of the seawater is largely determined by the flow of water through the Strait of Gibraltar, which in turn is sensitive to changes in global sea level — in a way like the pinching of a hosepipe.
Unlike previous methods, the clumped isotope paleothermometer technique does not rely on assumptions about the isotopic composition of seawater.
Finally, the carbon isotopic composition of Ar.
To create their new temperature record, which spans 3.5 million years at the end of the Cretaceous and the start of the Paleogene Period, the researchers analyzed the isotopic composition of 29 remarkably well - preserved shells of clam - like bivalves collected on Antarctica's Seymour Island.
The dental morphology, wear, and enamel isotopic composition of the Aramis kudu species are all consistent with such placement.
They also used satellite precipitation data to «backsolve» the brine's origins using sodium concentrations, oxygen and hydrogen isotopes, as the isotopic composition of water reflects the condensation temperature and precipitation rate over time.
However, researchers don't really know the true hydrogen isotopic composition of Earth's water, says Lydia Hallis, a planetary scientist at the University of Glasgow in the United Kingdom and lead author of the new study.
The team believes that the relationship between temperature and the isotopic composition of water vapour changes as climate warms.
The Temagami Banded Iron Formation, which was formed 2.7 billion years ago during the Neoarchean period, can be used as an archive because the isotopic composition of many chemical elements such as Hafnium and Neodymium directly mirrors the composition of Neoarchean seawater.
By comparing the results to the isotopic composition of the trapped gas, the researchers revealed how dense the Martian atmosphere was at the time when the gas became trapped in the meteorite.
But we found the isotopic composition of the deep water was similar to that of modern rainfall, which means the system in the Sydney Basin has been relatively stable for thousands of years.
Co-author, Christophe Lécuyer explained: «According to this method, it is possible to calculate the temperature of the water in which these fish lived by applying an equation linking the isotopic composition of the fossilised remains to the temperature of mineralisation of their skeleton.
This temperature curve, established using an isotopic thermometer, is widely applied for reconstruction of past environmental conditions and in this case, is based on the isotopic composition of the oxygen contained in the fossilised remains of fossil marine fish (bone, teeth, scales).
The hydrogen isotopic composition of lunar water also varies from region to region, much more dramatically than in Earth.
As part of the study, Cherney measured the isotopic composition of tail hairs from a mother - calf pair of African elephants at the Toledo Zoo.
One of the key new capabilities of the Goddard Astrobiology Analytical Laboratory was instrumentation with high enough sensitivity to determine the isotopic composition of an amino acid molecule, according to Elsila.
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.
So planetary scientists must investigate thoroughly the sources, sinks and isotopic composition of this gas, along with other organic molecules and trace constituents in both gaseous and solid samples.
http://adsabs.harvard.edu/abs/1999GBioC..13..445Q «The isotopic composition of atmospheric methane» Quay et al 1999 (This study suggests that ~ 18 % of atmospheric methane in 1999 is from fossil fuel sources)
They collect corals of sediments, they take samples of the various calcareous organisms in them and do measurements for instance of the isotopic composition of the shells.
Ice core measurements of the isotopic composition of nitrate: new results and interpretation.
Assessing the anthropogenic influence on atmospheric oxidants using the oxygen isotopic composition of sulfate and nitrate from the WAIS - Divide ice core.
One of these differences is in the isotopic composition of the plant materials.
[Response: Your question was not at all vague, I just don't remember hearing much about the isotopic composition of methane in the atmosphere.
Keep in mind that the classic paper by Hayes et al (1976) showed that isotopic composition of forams in marine cores fluctuated on orbital time - scales in accordance with Milankovitch.
point out that isotopic composition of airborne methane has become lighter since 2008, indicating greater wetland / ruminant emission.
To carry out the study, the researchers developed a new sample extraction and mass spectrometry method that allowed them to precisely measure the carbon isotopic composition of methane in very small ice core samples.
«Pore Fluid Constraints on the Temperature and Oxygen Isotopic Composition of the Glacial Ocean.»
«Sediment cores in Arctic lakes show that there have been significant 20th - century declines in the nitrogen isotopic composition of organic nitrogen,» Steig said.
[5] Linsley et al. (2006) reconstructed sea - surface temperature and sea surface salinity in the southwest Pacific starting circa 1600CE by measuring the oxygen isotopic composition of four Porites coral records from Rarotonga and two from Fiji.
Next paper: Bemis, B. E., H. J. Spero, J. Bijma, and D. W. Lea (1998), Reevaluation of the oxygen isotopic composition of planktonic foraminifera: Experimental results and revised paleotemperature equations, Paleoceanography, 13 (2), 150 — 160.
This is temperature dependent, is independent of the isotopic composition of the precipitating water (seawater, freshwater etc.) and thus independent of storm tracks, the position of the ITCZ, monsoon strength etc..
Changes in proxy records, either physical (such as the isotopic composition of various elements in ice) or biological (such as the width of a tree ring or the chemical composition of a growth band in coral), do not respond precisely or solely to changes in any specific climate parameter (such as mean temperature or total rainfall), or to the changes in that parameter as measured over a specific «season» (such as June - August or January - December).
Empirically and theoretically, isotopic composition of precipitation and site temperature are strongly correlated in time and space (10, 11); colder places and colder times have isotopically lighter precipitation.»
The classic paleothermometer is the stable - isotopic composition of water in the ice core (10).
Within these archives, scientists can measure the isotopic ratios of oxygen and hydrogen to deduce changes over time in the isotopic composition of environmental waters, such as precipitation, seawater, and groundwater.
Charles, C.D., D. Rind, R. Healy, and R. Webb, 2001: Tropical cooling and the isotopic composition of precipitation in general circulation model simulations of the ice age climate.
Because of these confounding factors, palaeoreconstructions based on the isotopic composition of organic carbon (δ13C) will almost certainly have to be based on the isotopic signatures of organic compounds that can be associated with a single species, or group of physiologically similar species
The Medieval Warm Period in AD 980-1250 is the most distinctive climate period in the whole sediment sequence identified by changes in sediment colour, X-ray density, varve thickness, LOI, as well as the isotopic composition of hydrogen in kerogen.
(Partisan) description: The authors studied the isotopic composition of carbon (δ13C) and hydrogen (δD) in organic matter found in two sediment cores retrieved from Lake Korttajarvi.
Until now, this view was based mainly on reanalysis of ca estimates from the isotopic composition of carbonates in paleosols, the only extensive proxy record to span most of the Phanerozoic.