Isotope dating mount st helens
The Public Broadcasting Service (PBS) recently ran the story “1.8 million-year-old skull may revise understanding of human evolution.” Since the skull was unearthed in a medieval ninth century A. village in the former Soviet Republic of Georgia known as Dmanisi, the obvious question centers on the validity of the million year radiometric dating of the skull found within the same geological stratum as the medieval ninth century A. Without question, the theory of evolution from a single cell to a sophisticated carnivore demands millions and billions of years−not thousands of years. What’s driving the demand for millions of years dating; is it science or is it theory?
Sir John Herschel (1792-1871), a nineteenth century Victorian elitist, argued for “many thousand millions of years” for the age of the earth; an argument that paralleled the then popular uniformitarian theory advanced by the English geologist Charles Lyle.Radiometric dating is a process of measuring radioactive isotope decay rates of unstable atoms that loses energy by emitting radiation.The chemical element Argon (Ar) formed from the radioactive isotope Potassium-40 (U) are the most common types of elements studied in rocks for the radiometric dating of the rock.The use of Carbon dating is now recognized as too inaccurate and unreliable.Use of the radioactive decay of Uranium to Lead was first published in 1907 by radiochemist Bertram Boltwood (1879-1927) to measure the age of rocks.Boltwood’s first rock measurements estimated an age of the Earth at 400 to 2200 million years old.
Since then, other measurements have extended the age of the Earth.
Radiometric dating is not an absolute science since it must be based on assumptions; radiometric dating can only estimate an “apparent age.” As the executive director of the National Center for Science Education, Eugenie Scott, explains in : “If certain assumptions are made about it [radiometric dating], then, it can yield a date which could be called the apparent age.
Herschel’s “many thousand million years” and Lyle’s uniformitarianism shaped the cornerstone of Darwin’s theory.
In the first paragraph of the Introduction in The Origin of Species, Darwin highlighted the centrality of Lyle’s and Herschel’s influence of on his theory: “to throw some light on the origin of species — that mystery of mysteries, as it has been called by one of our greatest philosophers.” Herschel had used this signature phrase, “that mystery of mysteries,” in a letter to Lyle endorsing his Principles of Geology.
A long-age of the Earth is an absolute pre-requisite for the theory of biological evolution.
Based on evidence from radiometric dating, the age of the Earth has been estimated to be approximately 4.5 billion years.