Sentences with phrase «lighter isotopic composition»
And Hallis suspects that the deepest, most primitive material in the mantle should have an even lighter isotopic composition than the inclusions her team measured.
http://www.sciencemag.org/ Not exact matches
The results, published online today in Science, reveal that the inclusions have a much lighter isotopic signature than does the ocean, suggesting that the composition of seawater has indeed evolved over time.
point out that isotopic composition of airborne methane has become lighter since 2008, indicating greater wetland / ruminant emission.
[Response: My recollection is that Zachos had the same observation from ODP cores, that surface - dwelling forams were either isotopically heavy or light, never transitional, but bottom - dwellers could be found with transitional isotopic composition.
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 methane produced by the burning of biomass, like wood, contains more of the heavier isotope (carbon - 13) relative to the lighter isotope (carbon - 12), than methane which is produced in wetlands,» explains Professor Thomas Blunier, Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.The researchers have measured the isotopic composition of the methane in ice cores that are drilled up from the Greenland ice cap at the NEEM project in northwestern Greenland.