Depends on the source, my understanding is there is 2 types...

Depends on the source, my understanding is there is 2 types Primary and Secondary. It's the secondary source that seems to be near surface and benefits from weathering (usually in Ionic Clay REE's) and it needs right conditions with rock underneath it I believe. MEK REE in bottom of WA is this type of REE. I suspect this applies to heavy REE.

Lynas rare earth are I think hard rock origin so im not sure if this also gives shallow higher grades from weathering.

If you look at drilling results in detail on the ann the grade is highest at (EOH), but obviously we are missing analysis from top 74M so interesting to see. The Niobium also seems to kick in at the same time the lead does in the drill hole, and wondering if this is related to it's formation.

The weathering effect is a bit like panning for gold, the lighter stuff gets eroded by wind etc, which means you get a high concentration the remaining clay.

Seems to be a lot of confusion about how REE even form.