I think you are maybe pushing the Noonyereena bucket a bit uphill. As I've said before, Franco can draw a mud map on a 1:250K map outlining where he thinks it sits, but there's a difference between that and knowing that it occupies the immediate vicinity of Orient.
The Naracoota has 3 lithogeochemical affinities; arc, back-arc and continental. As I said before, you can be on the arc, in the continental back arc, or even on the continent. The arc is Fortnum (andesites, agglomerates, etc), and certainly up at DeGrussa you have a sequence with some back-arc affinities and some continental margin affinities (turbidites), the definite back-arc is the thicker dolerite and **bro dominated parts at Orient / T10, and the continental affinities sit in the contemporaneous volcanics in the Yerrida Basin (which are probably unprospective).
The more **bro and dolerite you have, the less sediment there is to drive circulation and metal scavenging in Besshi's. This is why DeGrussa, Monty, Horseshoe and indeed Forrest-Wodger sit on that transition between sedimentation and mafics, and are all interleaved.
So I've always considered the huge gravity anomalies underlying the centre and south of the Bryah to represent that overdose of mafics. The process might be at work, but without the sediments to cook up, you find it harder to brew up a decent VHMS.
I could of course be wrong. Just my opinion, but you look at the sections from orient and it's 80-90% mafics and 10-20% sediments.
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