As I understand it, practically speaking the discovery of such mineral deposits involves the identification of the relevant rock associated with the relevant time period, which is more about physical identification than time and doesn't really require dating beyond that identification. If it occurs in, say, a rock identified as Triassic, all that's necessary is recognizing the rock called Triassic. I could probably do this myself without having a clue about its age.
So using your super sleuthing geology skills how do you identify which granite intrusions are Mesoproterozoic and which are not?
In parts of southern Australia almost all the large copper deposits are hosted in igneous rocks aged around 1590 Million Years old. Yet there are younger granites and volcanics which are mineralogically, and texturally very similar. These are barren. Which is why major multinational mining companies spend money on radiometric dating, and indeed often keep the results confidential to give themselves a competitive advantage.
So please withdraw your comment about 'true science'.