the age of granite can be determind using radiometric dating, explain the basis for the determination of a 238 U- Pb radiometric date of 1120 Ma for a granite.
I have as the answer
238 U decays to Pb with an experimental law, that is the amount of U and Pb in granite are functions of the time. The inverse function allows granite lifetime from its composition considering that radioactive parent elements, the mathamtical expression that relates to radioactive decay to geological time called age equation
Does this answer the question as it is worth 10 marks (which i cant afford to drop)
please help
It is right, however, the wording on the first sentence is cumbersome. Why don't you just write something like U238 decays to Pb in a known rate, so that that knowing the ratio of Pb to U, one can determine time elapsed since the U was placed in the sample of granite.
The function is not an inverse, it is an expontential decay.
You might want to talk about the technique in more detail, for example the use of the key mineral zircon. You could also include a little on the decay equation.
A useful rule of thumb when answering questions is that if 10 marks are available then the marker may expecting up to 10 points to be made.
is this the right equation
t = 1/constant 1n (1 + d/p)
thanks for all your help
thanks for that but i thought it would need to be more as 10 marks are up for grabs, and i didn't think what i wrote would be enough
The equation you provided, t = 1/constant ln(1 + d/p), is not the correct equation for calculating the age using the U-Pb radiometric dating method. The correct equation for determining the age of a geological sample using U-Pb dating is as follows:
t = (1/λ) * ln[(λ * d) + 1]
Where:
t = age of the sample
λ = decay constant for uranium
d = ratio of radiogenic lead (Pb) to parent uranium (U) in the sample
To calculate the age using this equation, you would need the value of the decay constant (λ), which represents the rate at which the parent uranium decays to radiogenic lead. This value can be determined through experimental measurements or obtained from reliable sources.
Please note that this equation is a simplified version and does not account for potential complexities or variables that may be present in specific cases. In practice, the dating process involves more detailed calculations and considerations for various factors to obtain accurate ages.
While providing a correct equation is important, it is also essential to explain the underlying principles and assumptions of the U-Pb radiometric dating method and discuss the significance of the age determination in the context of granite formation. Adding additional information, such as the use of zircon minerals and how the decay equation relates to geological time, can potentially enhance the quality of your answer and help you gain more marks.