Ann: Follow-up on High Grade Copper Hits at Forrest and Wodger, page-30

Yep. Syngenetic and epigenetic are descriptions we geologists give to our interpretations of ore deposit formation.

In the case of volcanogenic massive sulphides, they are considered syndenetic because of (viz. the second para) their confinement within coherent volcanic stratigraphy, timing that is broadly contemporaneous with the host sequences, etc. However, it's not as strict as "bound by the rocks they lie within" - for instance, the feeder zone or pipes below VMS's (using the typical model of them) occur transgressively throughout the footwall units. ie; there's stratabound and stratiform (morphological descriptions) syngenetic, and theres podiform, vein, shear, pipe, breccia, diatreme and other types of transgressive syngenetic mineralisation, and also epigenetic mineralisation of the same forms.

Indeed, you can have stratabound epigenetic mineralisation, where fluids preferentially replace a key unit within a sequence, but it wouldn't be described as stratiform.

So, the interpretation of mineralisation genesis often follows on from a study of the form and morphology of the mineralisation, how it sits within or transgresses the host stratigraphy, and draws on inferences about its timing made from studying textures, structures and paragenetic indicators (eg, timing of sulphides etc).

It is best to leave commentary on this to the company geologists who have made the observations in detail, although sometimes it's obvious enough from the photos that it is possible to put the boot in, so to speak. For example, Ventnor's images from Thaduna were obviously a breccia style but they referred to it as a black shale host, so it was obvious (to me, anyway) they didn't fully understand it at the time or if they did weren't willing to let it on. Now itt's SFR's "graphite alteration" which is LOLworthy because it's actually bitumen. And so it's often hard to believe the presso explanation if they put out photos that are at odds with observations.

Anyway. The question still stands. If you hire an apple farmer to farm apples, and put them in an orange orchard, should you expect miraculous improvements in your apple cider?