. The Earth beneath the sea : History. Ocean bottom; Marine geophysics. SECT. 3] AGE DETERMINATION IN SEDIMENTS BY NATURAL RADIOACTIVITY 819. Fig. 3. Age determination using the ratio of two elements from radioactive series for the case when the decay constant of the parent element is much larger than the decay constant of the daughter element. The ordinate gives the ratio of the two radio- isotopes. The abscissa gives the time scale in non-dimensional imits as multiples of mean lifetime. same equation is applicable when the production of lead is used in age deter- mination by the use of the n
. The Earth beneath the sea : History. Ocean bottom; Marine geophysics. SECT. 3] AGE DETERMINATION IN SEDIMENTS BY NATURAL RADIOACTIVITY 819. Fig. 3. Age determination using the ratio of two elements from radioactive series for the case when the decay constant of the parent element is much larger than the decay constant of the daughter element. The ordinate gives the ratio of the two radio- isotopes. The abscissa gives the time scale in non-dimensional imits as multiples of mean lifetime. same equation is applicable when the production of lead is used in age deter- mination by the use of the natural radioactive series. B. Theoretical Method of Age Determination, Type 2 When two isotopes of the same element are radioactive and each forms a new radioactive element, the ratio of the radio-isotopes produced can be used for age determination. A condition is that the ratio of the two isotopes of the parent element is constant in nature. This is nearly always true of elements with a high atomic weight. The decay equation of each of the isotopes is iV«2 = :^iVi(l_e-M) A2 and iV<4 = ^iV3(l -A,( ). (8) By taking the ratio of these two, we obtain iV^ _ AiA4iVi (l-e-^2«) (9) When the ratio of the parent isotopes is constant, when concentrations are given in units of per cent-equivalent, and when the precipitation is faster than 1000 years, we obtain an equation for the age: t = X2 — A^ In A2 Nt^ (10). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hill, M. N. (Maurice Neville), 1919-. New York : Interscience Pub.
Size: 1645px × 1519px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectoceanbottom
