Which type of geological deposit is most closely associated with rare earths?

The type of geological deposit most closely associated with rare earth elements is the titaniferous magnetite deposit. These deposits primarily contain iron and titanium, and they are often enriched in rare earth elements due to the geochemical processes that occur during the formation of these minerals.

Rare earth elements are typically found in minerals associated with igneous processes, especially in types of rocks such as carbonatites and alkaline igneous rocks. Titaniferous magnetite deposits are significant sources of titanium and can also host rare earth elements as byproducts due to their unique geological formations and mineral content.

In contrast, the other types of deposits mentioned do not have the same strong association with rare earth elements. For example, gold-quartz veins primarily focus on gold deposits, strata-bound uranium deposits are significant for uranium resources, and shallow hydrothermal deposits generally do not produce rare earth elements in notable quantities. This is why titaniferous magnetite deposits are considered the most relevant for rare earth elements.