Planetary Science Research Discoveries. May 30, Titanium Isotopes Provide Clues to Lunar Origin The titanium isotopic mix is essentially identical in Earth and Moon, important new information with implications for the origin of the planets. Jeffrey Taylor Hawai’i Institute of Geophysics and Planetology The idea that the Moon formed as the result of the giant impact of a Mars-sized impactor with the still-growing Earth explains two central facts about the Earth-Moon system: This gives cosmochemists some confidence in the hypothesis, but they would greatly appreciate additional compositional tests. One undisputed point is the identical abundance of the three oxygen isotopes in Earth and Moon. Junjun Zhang and colleagues at the University of Chicago USA and the University of Bern Switzerland have added another isotopic system to the cosmochemical testing tool kit, titanium isotopes. They find that the ratio of titanium 50Ti to titanium 47Ti is identical in Earth and Moon to within four parts per million. In contrast, other solar system materials, such as carbonaceous chondrites , vary by considerably more than this—up to times as much.

Facts About Carbon

The letter m is sometimes appended after the mass number to indicate a nuclear isomer , a metastable or energetically-excited nuclear state as opposed to the lowest-energy ground state , for example m 73Ta The common pronunciation of the AZE notation is different from how it is written: For example, 14 C is a radioactive form of carbon, whereas 12 C and 13 C are stable isotopes. There are about naturally occurring nuclides on Earth, [7] of which are primordial nuclides , meaning that they have existed since the Solar System ‘s formation.

Primordial nuclides include 32 nuclides with very long half-lives over million years and that are formally considered as ” stable nuclides “, [7] because they have not been observed to decay. In most cases, for obvious reasons, if an element has stable isotopes, those isotopes predominate in the elemental abundance found on Earth and in the Solar System. However, in the cases of three elements tellurium, indium, and rhenium the most abundant isotope found in nature is actually one or two extremely long-lived radioisotope s of the element, despite these elements having one or more stable isotopes.

Absolute Dating • any method of measuring the age of an event or object in years • radiometric dating (which uses the concept of radioactive decay) is the most common method of absolute dating • used to determine the age of rocks and fossils.

Scientific American Editor Michael Moyer explains the process of radiocarbon dating. What is Carbon Dating? Carbon is one of the chemical elements. Along with hydrogen, nitrogen, oxygen, phosphorus, and sulfur, carbon is a building block of biochemical molecules ranging from fats, proteins, and carbohydrates to active substances such as hormones. All carbon atoms have a nucleus containing six protons. Ninety-nine percent of these also contain six neutrons. They have masses of 13 and 14 respectively and are referred to as “carbon ” and “carbon Carbon and carbon are thus isotopes of carbon Isotopes participate in the same chemical reactions but often at differing rates.

When isotopes are to be designated specifically, the chemical symbol is expanded to identify the mass for example, 13C. The abundance of 14C varies from 0. The highest abundances of 14C are found in atmospheric carbon dioxide and in products made from atmospheric carbon dioxide for example, plants. Unlike 12C and 13C, 14C is not stable. As a result it is always undergoing natural radioactive decay while the abundances of the other isotopes are unchanged.

How are past temperatures determined from an ice core?

The basis for palaeoclimatic interpretations of variations in the stable isotope content of water molecules is that the vapour pressure of H 2 16O is higher than that of H 2 18O. Evaporation from a water body thus results in a vapour which is poorer in 18O than the initial water; conversely, the remaining water is enriched in 18O. During condensation, the lower vapour pressure of the H 2 18O ensures that it passes more readily into the liquid state than water vapour made up of the lighter oxygen isotope Dansgaard, During the poleward transportation of water vapour, such isotope fractionation continues this preferential removal of the heavier isotope, leaving the water vapour increasingly depleted in H 2 18O.

Because condensation is the result of cooling, the greater the fall in temperature, the lower the heavy isotope concentration will be. Isotope concentration in the condensate can thus be considered as a function of the temperature at which condensation occurs.

People who ask about carbon (14 C) dating usually want to know about the radiometric[1] dating methods that are claimed to give millions and billions of years—carbon dating can only give thousands of years. People wonder how millions of years could be squeezed into the biblical account of.

Thus, in the standard notation, 11H refers to the simplest isotope of hydrogen and U to an isotope of uranium widely used for nuclear power generation and nuclear weapons fabrication. Authors who do not wish to use symbols sometimes write out the element name and mass number—hydrogen-1 and uranium in the examples above.

The term nuclide is used to describe particular isotopes, notably in cases where the nuclear rather than the chemical properties of an atom are to be emphasized. The lexicon of isotopes includes three other frequently used terms: The discovery of isotopes Evidence for the existence of isotopes emerged from two independent lines of research, the first being the study of radioactivity.

By it had become clear that certain processes associated with radioactivity, discovered some years before by French physicist Henri Becquerel , could transform one element into another. In particular, ores of the radioactive elements uranium and thorium had been found to contain small quantities of several radioactive substances never before observed. These substances were thought to be elements and accordingly received special names.

Uranium ores, for example, yielded ionium, and thorium ores gave mesothorium. Painstaking work completed soon afterward revealed, however, that ionium, once mixed with ordinary thorium, could no longer be retrieved by chemical means alone. Similarly, mesothorium was shown to be chemically indistinguishable from radium. As chemists used the criterion of chemical indistinguishability as part of the definition of an element, they were forced to conclude that ionium and mesothorium were not new elements after all, but rather new forms of old ones.

With considerable prescience , he extended the scope of his conclusion to include not only radioactive species but stable elements as well. A few years later, Soddy published a comparison of the atomic masses of the stable element lead as measured in ores rich in uranium and thorium, respectively.

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They form as water from the surface percolates into the ground and drips into the cave. Speleothems can be extremely sensitive to changes in climate and environmental conditions and they record these changes as variations in their chemistry. An excellent review of speleothem formation and their use for palaeoclimate reconstruction by Prof.

The Oxygen isotopes O, O, and O while the isotopes of H 2 iinclude H-1, H-2 and H-3 make the suitable combinations wherever necessary. These isotopes are considered as the ideal tracers of the sources of water mainly because they constutute the water molecules.

Arrange carbon atoms in one way, and they become soft, pliable graphite. Re-jigger the arrangement, and — presto! Carbon is also the key ingredient for most life on Earth; the pigment that made the first tattoos; and the basis for technological marvels such as graphene, which is a material stronger than steel and more flexible than rubber. Just the facts Atomic Number number of protons in the nucleus: C Atomic Weight average mass of the atom: From stars to life As the sixth-most abundant element in the universe, carbon forms in the belly of stars in a reaction called the triple-alpha process, according to the Swinburne Center for Astrophysics and Supercomputing.

In older stars that have burned most of their hydrogen , leftover helium accumulates. Each helium nucleus has two protons and two neutrons. Under very hot temperatures — greater than , , Kelvin , ,

GISP2 Oxygen Isotope Ratios

Used in fluorescent lights and in welding, this element gets its name from the Greek word for “lazy,” an homage to how little it reacts to form compounds. But in space, argon is made in stars, when a two hydrogen nuclei, or alpha-particles, fuse with silicon The result is the isotope argon Isotopes of an element have varying numbers of neutrons in the nucleus.

Direct dating of the oxygen-isotope record of the last deglaciation by 14C accelerator mass spectrometry. which have been reconstructed by oxygen-isotope .

Hide All Alley, R. Visual-stratigraphic dating of the GISP2 ice core: Basis, reproducibility, and application. Journal of Geophysical Research , 26, —26, Journal of Glaciology 40, — W, Balling, N, Past temperatures directly from the Greenland ice sheet. J, Stuiver, M, Waddington, E. New , year long Taylor Dome Antarctic 18O record indicates synchroneity of global glacial climatic fluctuations, submitted.

Facts About Carbon

The cornerstone of the success achieved by ice core scientists reconstructing climate change over many thousands of years is the ability to measure past changes in both atmospheric greenhouse gas concentrations and temperature. The measurement of the gas composition is direct: Temperature, in contrast, is not measured directly, but is instead inferred from the isotopic composition of the water molecules released by melting the ice cores.

Water is made up of molecules comprising two atoms of hydrogen and one atom of oxygen H2O.

A Cdating and oxygen-isotope diagram of a Holocene-reformed ice wedge on the Chara River (Transbaikal Region).

These two stable isotopes of carbon are found naturally on Earth. This matter is often isotopically selective, generally preferring to break the weaker, light-isotope bonds. Fractionation is constrained to definable ranges for relatively stable environmental conditions. See Evolution of carbon in groundwaters , in ch. Cosmogenically, 14C is created when cosmic rays in the Earth’s atmosphere cause some of the atoms in the upper atmosphere to fly apart into pieces.

Neutrons that come from these fragmented molecules run into other molecules, causing chemical reactions.

Isotopes of hydrogen

The most abundant is 16O, with a small percentage of 18O and an even smaller percentage of 17O. Oxygen isotope analysis considers only the ratio of 18O to 16O present in a sample. The calculated ratio of the masses of each present in the sample is then compared to a standard, which can yield information about the temperature at which the sample was formed – see Proxy climate for details. The addition of more energy is required to vaporize H O than H O, and H O liberates more energy when it condenses.

In addition, H O tends to diffuse more rapidly. Because H O requires less energy to vaporize, and is more likely to diffuse to the liquid surface, the first water vapor formed during evaporation of liquid water is enriched in H O, and the residual liquid is enriched in H O.

UNESCO – EOLSS SAMPLE CHAPTERS GROUNDWATER – Vol. II – Environmental Isotopes in Groundwater Studies – Pradeep K. Aggarwal, Klaus Froehlich, Kshitij M. Kulkarni ©Encyclopedia of Life Support Systems (EOLSS) examples of field studies. More specific advice on .

View images by clicking on link or reduced image: Each image opens into a new window. These primitive, medium sized apes lived in rain forests between 18 and 22 million years ago. This species and others such as Dryopithecus existed before the hominid line diverged on the path to humans. This lineage ancestral gibbons is believed to have diverged from the great ape and human lineages between 17 and 25 Mya Avers, Oreopithecus ‘s hand closely matches the pattern of early hominids, with a grasping capability including firm pad-to-pad precision gripping that apes are unable to perform presumably as a response to similar functional demands to hominids Moya-Sola et al, Bipedal activities made up a significant part of the positional behavior of this primate Kohler and Moya-Sola, Gorilla and human DNA only differs by 2.

Our DNA differs by only 1. The two species of Pan, the chimpanzee, P.

List of radioactive isotopes by half-life

HAVE you ever thought about how old your drinking water is or where it came from? How would you figure out the answers to those questions if you wanted to know? If you had access to Lawrence Livermore’s isotope tracing techniques, those questions might not be too difficult to answer. Since the inception of the Laboratory, Livermore scientists have been studying both radioactive and stable isotopes.

Support to the nuclear test program has given Livermore unparalleled nuclear chemistry expertise.

Australian Landscapes provides an up-to-date statement on the geomorphology of Australia. Karst, desert, bedrock rivers, coasts, submarine geomorphology, biogeomorphology and tectonics are all covered, aided by the latest geochronological techniques and remote sensing approaches.

See this page in: Hungarian , Russian , Spanish People who ask about carbon 14C dating usually want to know about the radiometric [1] dating methods that are claimed to give millions and billions of years—carbon dating can only give thousands of years. People wonder how millions of years could be squeezed into the biblical account of history. Clearly, such huge time periods cannot be fitted into the Bible without compromising what the Bible says about the goodness of God and the origin of sin, death and suffering —the reason Jesus came into the world See Six Days?

Christians , by definition, take the statements of Jesus Christ seriously. This only makes sense with a time-line beginning with the creation week thousands of years ago.

The Isotopes of Oxygen