Most often, this is a rock body, or unit, which has formed from the cooling of molten rock material (called magma).
Examples are granites (formed by cooling under the ground) and basalts (formed by cooling of lava flows at the earth’s surface).
Thus, geologists refer to uranium-lead (two versions), potassium-argon, rubidium-strontium, or samarium-neodymium dates for rocks.
Note that the carbon-14 (or radiocarbon) method is not used to date rocks, because most rocks do not contain carbon.
Both are complete atoms in every sense of the word.
However, while the number of neutrons varies, every atom of any chemical element always has the same number of protons and electrons.
Ages of many millions of years for rocks and fossils are glibly presented as fact in many textbooks, the popular media, and museums. One has only to wait: time itself performs the miracles.”1 Yet few people seem to know how these radiometric dating methods work.
For decades, the biologists have boldly proclaimed that, whereas we cannot observe today one type of creature evolving into a totally different type of creature, “Time is the hero of the plot. No one even bothers to ask what assumptions drive the conclusions.
Read more'Well organized, beginning with the basic physics (nuclear structure, radioactivity, nucleosynthesis) then proceeding to how geochronometry actually works, including technical details of mass spectrometry and error analysis, then tackling the ways in which various isotope systems have been used to help understand the history of the earth and the solar system.' Doug Macdougall, Emeritus Professor of Earth Science, Scripps Institution of Oceanography, University of California, San Diego'The book is, in my opinion, well organized. I like the way in which the author has presented the physical fundamentals in the early chapters, then the applications to the evolution of the earth and other parts of the solar system later.' Marion E.
Bickford, Professor Emeritus, Syracuse University, New York'From what I have seen in the chapters, the book is well presented and I personally and many others in the field would welcome it.' Sir Robert Keith O'Nions, Former President and Rector of Imperial College London'Gopalan wanted to produce a concise book for nonspecialist students and researchers.