What rocks are used for radiometric dating
Also, by extrapolating backward in time to a situation when there was no lead that had been produced by radiogenic processes, a figure of about 4.6 billion years is obtained for the minimum age of the Earth.
This figure is of the same order as ages obtained for certain meteorites and lunar rocks.
Down to depths of a few kilometres the strength of rocks would be expected to increase.
At greater depths the temperature effect should become dominant, and response to stress should result in flow rather than fracture of rocks. Rubey, demonstrated that fluids in the pores of rock may reduce internal friction and permit gliding over nearly horizontal planes of the large overthrust blocks associated with folded mountains.
Van ’t Hoff’s aim was to explain the succession of mineral salts present in Permian rocks of Germany.
His success at producing from aqueous solutions artificial minerals and rocks like those found in natural salt deposits stimulated studies of minerals crystallizing from silicate melts simulating the magmas from which igneous rocks have formed.
In 1912 another German physicist, Max von Laue, realized that X-rays were scattered and deflected at regular angles when they passed through a copper sulfate crystal, and so he produced the first X-ray diffraction pattern on a photographic film.
Jacobus Henricus van ’t Hoff, one of the founders of physical chemistry.
Between 18 he elucidated the complex sequence of chemical reactions attending the precipitation of salts (evaporites) from the evaporation of seawater.
The SHRIMP (Sensitive High Resolution Ion Microprobe) enables the accurate determination of the uranium-lead age of the mineral zircon, and this has revolutionized the understanding of the isotopic age of formation of zircon-bearing igneous granitic rocks.
Another technological development is the ICP-MS (Inductively Coupled Plasma Mass Spectrometer), which is able to provide the isotopic age of the minerals zircon, titanite, rutile, and monazite.