• hydrogen
  • You know that water is made of hydrogen and oxygen atoms arranged in molecules of H 2 O, but you may not be aware that there are different types of oxygen atoms. (classzone.com)
  • The relative and absolute abundance of 16O is high because it is a principal product of stellar evolution and because it is a primary isotope, meaning it can be made by stars that were initially made exclusively of hydrogen. (wikipedia.org)
  • 17O is primarily made by the burning of hydrogen into helium during the CNO cycle, making it a common isotope in the hydrogen burning zones of stars. (wikipedia.org)
  • cores
  • In the 1990s, in addition to continued work on radiocarbon calibration and solar variability, he began work on oxygen isotopes from Greenland ice cores together with Pieter Grootes. (wikipedia.org)
  • behavior
  • Investigation of oxygen three-isotope behavior during thermal decomposition of naturally occurring carbonates of calcium and magnesium in vacuo has revealed that, surprisingly, anomalous isotopic compositions are also generated during this process. (open.ac.uk)
  • naturally
  • Since physicists referred to 16O only, while chemists meant the naturally-abundant mixture of isotopes, this led to slightly different mass scales between the two disciplines. (wikipedia.org)
  • glacial
  • In 1976 J. Van Donk obtained curves from a core in the equatorial Atlantic which yielded 42 isotope stages, representing 21 glacial and 21 interglacial stages. (encyclopedia.com)
  • trace
  • Combined with Sr isotope and trace element data, δ 18 Oplag values suggest a variable magma source characterized by differences in the mantle wedge or the subducted sediment component along the volcanic front. (geoscienceworld.org)
  • neutrons
  • Oxygen-15 and nitrogen-13 are produced in the atmosphere when gamma rays (for example from lightning) knock neutrons out of oxygen-16 and nitrogen-14: 16O + γ → 15O + n 14N + γ → 13N + n The oxygen-15 decays with a half-life of about two minutes to nitrogen-15, emitting a positron. (wikipedia.org)
  • evidence
  • The paper presents evidence that CAIs formed from several oxygen reservoirs, likely in distinct regions of the solar nebula. (nasa.gov)
  • variability
  • In the summer of 2006, researchers measured the oxygen isotope ratio of rainwater collected in the nation's capital, Niamey, to determine the connection between intraseasonal atmospheric variability and precipitation. (phys.org)
  • calcium
  • Using the NanoSIMS (nanometer-scale secondary-ion mass spectrometer) at Lawrence Livermore National Laboratory in Livermore, Calif., Simon and scientists from LLNL, University of California, Berkeley, and the University of Chicago measured the concentrations of oxygen isotopes found in a calcium-aluminum-rich inclusion (CAI) contained in a piece of the Allende meteorite. (nasa.gov)
  • temperature dependent
  • precision need to be as high as ~10−5, for that isotope signals of interest are often less than 10−3) The temperature dependent relationship is subtle (-0.0005% per oC) (Quade 2007). (wikipedia.org)
  • data
  • This data set contains complete low resolution (0.25 to 100 cm) oxygen isotope data from the WAIS Divide Ice Core WDC06A, 0 to 3404.7 m depth. (nsidc.org)
  • Processes
  • Nearly all chemical processes fractionate 17O and 18O in a mass-dependent way relative to 16O, a major exception being the formation of ozone from diatomic oxygen in the presence of UV radiation or electrical discharge. (open.ac.uk)
  • Different
  • For example, different sources and sinks of methane have different affinity for the 12C and 13C isotopes, which allows distinguishing between different sources by the 13C/12C ratio in methane in the air. (wikipedia.org)
  • useful
  • Zircon is also useful because its incorporation of other elements like uranium, lutetium, samarium, and oxygen can be analyzed to provide further insight into the age and conditions the crystal grew under. (wikipedia.org)
  • Zircons are known to be relatively retentive of their incorporated isotopes and thus very useful for microquantitative studies. (wikipedia.org)