Younging is a way up indicator, so you know if your fold is a syncline or anticline. It is important for knowing the stratigraphic way up if you want to target a footwall position.
Talc schist can be one of two things in a VMS camp. Talc (the mineral) is a magnesium silicate, and you form it from metamorphism of Mg enriched rocks. There's a few ways to do this;
1) Skarns, where you have dolomite (Ca-Mg carbonate) in a marl (dirty limestone) = Mg + Si = Talc
2) Ultramafic rocks with olivine (MgSiO4) or pyroxene + metamorphism = Talc
3) Mafic rocks where you alter them, and remove enough Fe, Al, Na, Ca to drive the composition into being Mg enriched = talc
So, since there's no clear evidence of dolomite, and the Narracoota Volcanics have ultramafic and mafic rocks, the talc schist is either #2 or #3. The chromium and nickel values of the narrcoota will tell you if you have a talc-altered basalt, or a talc metamorphosed ultramafic rock, and AUR will have this from the pXRF analysis it has done.
So, the talc schist could be evidence of VHMS alteration. But I have seen a lot of talc altered basalt which is just low-grade carbonate alteration....and was probably formed in sub-seafloor VHMS zones that just didn't have the legs to make it to an ore deposit.
These things can put you at sea in terms of knowing where to go in exploration. You have the alteration, the geochemical trace elements, etc, but without the DHEM you are borked. So I would say AUR is getting it all sorted out here. But, like I said, sometimes these alteration systems just don't make it to ore deposit size, so....GLTAH.
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