Sentences with phrase «carbon stable isotope ratio»
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.
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«We took a sample every 10 metres,» says Louis Honegger, a researcher at UNIGE, «measuring the ratio between 13C (heavy carbon stable isotope) and 12C (light carbon stable isotope).
Using spectroscopy, stable isotope ratios (carbon, nitrogen and sulphur) were investigated in the collagen of the bones, along with the ratio of strontium to calcium in the bone mineral.
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.
For instance, radiocarbon dating determines the age of biological remains based on the ratio between the carbon isotopes (atoms of the same element with different numbers of neutrons) carbon - 12 and carbon - 14 it holds - this proportion changes as radioactive carbon - 14 breaks down while stable carbon - 12 does not.
Qualitatively, the slow ventilation is consistent with very saline and very cold deep waters reconstructed for the last glacial maximum (Adkins et al., 2002), as well as low glacial stable carbon isotope ratios (13C / 12C) in the deep South Atlantic.
Another option is to test fossil teeth for the ratio of stable isotopes present for a given element, such as the ratio of carbon C12 to C13.
Stable carbon isotope ratio analyses on trace methane from ice samples.
One group of students has been drilling modern and fossil teeth to obtain samples that will be analyzed to examine stable carbon and oxygen isotope ratios.
Comparison of stable carbon isotope ratios in the whole wood, cellulose and lignin of oak tree - rings Dr. Ron Towner from the Laboratory of Tree - Ring Research at the University of Arizona explains the principles behind dendrochronology and why this dating
Stable isotope ratios in atmospheric methane and carbon dioxide provide a window on the sources as well.
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.
The size of the carbon injection is estimated from changes in the stable carbon isotope ratio 13C / 12C in sediments and from ocean acidification implied by changes in the ocean depth below which carbonate dissolution occurred.