Dating fossils accurate
National Institute of Standards and Technology (NIST)."Radiometric dating still reliable (again), research shows." Science Daily. After two years of searching for a special radioactive decay that would provide an indication of new physics beyond the standard model, an experiment deep under ground near Carlsbad has so far found ...The introduction of "old" or "artificial" carbon into the atmosphere (i.e., the "Suess Effect" and "Atom Bomb Effect", respectively) can influence the ages of dates making them appear older or younger than they actually are.This is a major concern for bone dates where pretreatment procedures must be employed to isolate protein or a specific amino acid such as hydroxyproline (known to occur almost exclusively in bone collagen) to ensure accurate age assessments of bone specimens.Recent puzzling observations of tiny variations in nuclear decay rates have led some to question the science behind carbon-14 dating and similar techniques.However scientists tested the hypothesis that solar radiation might affect the rate at which radioactive elements decay and found no detectable effect.Desmond Clark (1979:7) observed that without radiocarbon dating "we would still be foundering in a sea of imprecisions sometime bred of inspired guesswork but more often of imaginative speculation." And as Colin Renfrew (1973) aptly noted over 30 years ago, the "Radiocarbon Revolution" transformed how archaeologists could interpret the past and track cultural changes through a period in human history where we see among other things the massive migration of peoples settling virtually every major region of the world, the transition from hunting and gathering to more intensive forms of food production, and the rise of city-states.However, as with any dating technique there are limits to the kinds of things that can be satisfactorily dated, levels of precision and accuracy, age range constraints, and different levels of susceptibility to contamination.
Regardless of the particular 14C technique used, the value of this tool for archaeology has clearly been appreciated.
In contrast to relative dating techniques whereby artifacts were simply designated as "older" or "younger" than other cultural remains based on the presence of fossils or stratigraphic position, 14C dating provided an easy and increasingly accessible way for archaeologists to construct chronologies of human behavior and examine temporal changes through time at a finer scale than what had previously been possible.
The application of Accelerator Mass Spectrometry (AMS) for radiocarbon dating in the late 1970s was also a major achievement.
The unswerving regularity of this decay allows scientists to determine the age of extremely old organic materials -- such as remains of Paleolithic campfires -- with a fair degree of precision.
The decay of uranium-238, which has a half-life of nearly 4.5 billion years, enabled geologists to determine the age of the Earth.
For example, rootlet intrusion, soil type (e.g., limestone carbonates), and handling of the specimens in the field or lab (e.g., accidental introduction of tobacco ash, hair, or fibers) can all potentially affect the age of a sample.