Sea floor dating
The obtained ages range 4 to 16000 years, showing that the ESR method has a wide application age range. The barite crystals occur in sulfide chimneys and in deposits, incorporating radium ions that are in the hydrothermal fluid.
As a radium ion has an ionic radius similar with barium, radium ions easily replace barium in barite to have high concentration up to several tens Bq/g of .
Although the age range of several hundred years is essential to estimate the life time of hydrothermal activities, dating methods for this age range were lacking. (2013) examined sulfide deposits in the South Mariana Trough sea-floor hydrothermal field to compare the ESR ages obtained for barite and the U-Th ages for sulfide minerals extracted from the same portions.
They showed that the ESR ages are roughly consistent with the U-Th ages. (2015) made the first practical systematic dating work with ESR on barite of sea-floor hydrothermal sulfide deposits taken at Okinawa Trough on total of 18 samples (60 subsamples) with new formulas which take the radioactive disequilibrium of Ra daughter nuclei into account.
Prices in € represent the retail prices valid in Germany (unless otherwise indicated). Prices do not include postage and handling if applicable. Electron spin resonance (ESR) dating of barite has been recently developed and is now practically applied to barite extracted from sea-floor hydrothermal deposits.
The reader will find it useful to be familiar with the article on geomagnetic reversals and the article on marine sediments before reading further.
5, in which the sum of the accumulated doses from all , the age would not correctly be estimated for those more than 5000 or 6000 years old.
High precision methods may become available in the future.
After drying in an oven at 60°C for several days until the weight did not change, the water mass was estimated from the difference in the masses as the ratio of the mass of water to the dry mass to be 30.3%.
The sample was then crushed and the bulk concentrations of and HF.