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fefe80
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Hi
I want ask how to know the age of Earth with superparamagnetism ( magnetic rock) ?
Thanks
I want ask how to know the age of Earth with superparamagnetism ( magnetic rock) ?
Thanks
fefe80 said:Hi
I want ask how to know the age of Earth with superparamagnetism ( magnetic rock) ?
Thanks
Yes and no. Magnetic studies certainly can yield a lower bound on the Earth's age.billiards said:The age of the Earth is known from radiometric dating. We cannot determine the age of the Earth from magnetic studies of rocks.
D H said:Yes and no. Magnetic studies certainly can yield a lower bound on the Earth's age.
http://www.sciencenews.org/view/generic/id/56925/title/Geophysicists_push_age_of_Earths_magnetic_field_back_250_million_years
billiards said:Well no, really. You cannot independently determine the age of a rock based on magnetic data. In the study you referred they measured the magnetic signature on a rock that they already knew was more than 3 billion years old -- which they then inferred the presence of a geomagnetic field at the time of the rock's formation.
D H said:Yes and no. Magnetic studies certainly can yield a lower bound on the Earth's age.
http://www.sciencenews.org/view/generic/id/56925/title/Geophysicists_push_age_of_Earths_magnetic_field_back_250_million_years
billiards said:Well no, really. You cannot independently determine the age of a rock based on magnetic data. In the study you referred they measured the magnetic signature on a rock that they already knew was more than 3 billion years old -- which they then inferred the presence of a geomagnetic field at the time of the rock's formation.
Bradenbraden said:As an aside, Earth's magnetic field is caused from the rotation of the hot metallic solid core; Earth has not always had this.
Superparamagnetism is a phenomenon where small particles of certain materials exhibit magnetic properties even though they are below their Curie temperature, which is the temperature at which a material loses its magnetization.
In the Earth's crust, there are small magnetic particles called magnetosomes that align with the Earth's magnetic field at the time of their formation. By studying the changes in the magnetization of these particles over time, scientists can determine the age of the Earth.
The most commonly used materials for superparamagnetism dating are magnetite and hematite, as they are abundant in the Earth's crust and have stable magnetic properties.
The accuracy of superparamagnetism dating depends on the quality of the samples and the reliability of the measurements. Generally, it is considered to have an accuracy of within 1% of the actual age of the Earth.
One limitation is that the method can only be used for relatively young samples, as the magnetic particles in older samples may have lost their magnetization due to geological processes. Additionally, the method is most accurate for samples between 10 million and 3.5 billion years old.