Types of uranium dating
Types of uranium dating
Perhaps another reason for the interest in time is that humans are bound by time and can’t move around in it as they can in space.The best they have is consciousness with a limited ability for such movement providing memories of past times and hopeful pictures of future times.
– (a) Radiometric ages for some minerals may not give the time of emplacement of the volcanic or granitic rock because the minerals were formed earlier and the emplaced magma was not hot enough to melt them.With a half-life of about 5000 years, it is mainly useful for archaeology and not expected to give reliable ages beyond about ten half-lives or about 50,000 years.(b) Rubidium decaying to strontium, potassium decaying to argon, uranium and thorium decaying to lead, and [sometimes] samarium decaying to neodymium are used to date inorganic minerals and rocks.For example in a 1969 article, volcanic rock from Mt.Rangitoto in New Zealand gave potassium-argon ages of hundreds of thousands of years, but trees destroyed by the lava gave carbon-14 ages of hundreds of years.Seventh-day Adventists show their great interest in time by having it as part of their name, referring to a recent seven-day creation in the past and a soon-coming advent of Christ in the future.
Within this philosophical and theological context of time, the next sections discuss geological time as determined by radiometric dating: (1) how the technique works well and (2) some young-earth creationist responses.
The exact age is easily determined with a simple equation.
Of the many radioactive parent-daughter pairs of atoms, about half a dozen are used for age dating. (a) Carbon-14 methods can date organic material such as bones, wood, and shells directly.
For example, loss or gain of parent or daughter atoms might be expected if the sample shows signs of mechanical breakdown, chemical weathering, or metamorphic high pressures and temperatures.
Following are three of the many reasons that scientists put confidence in radiometric dates: (1) Decay rates appear to be constant.
Tolkien’s, The Hobbit, Gollum gives a riddle to Bilbo: This thing all things devours: Birds, beasts, trees, flowers; Gnaws iron, bites steel; Grinds hard stones to meal; Slays kings, ruins town, And beats high mountain down. This riddle exemplifies how time normally results in decay and destruction.