Mississippi Valley style deposits are interesting, these are...

Mississippi Valley style deposits are interesting, these are predominantly lead zinc deposits. They are usually hosted in limestones that is a breccia (fractured). These limestone bodies are usually old Reefs that are porous and return the best zinc grades. It is thought that these sulphides are from deep basin brines in this style of mineralisation.

I’m actually a bit surprised by this. Very curious style of mineralisation though it was partially interpreted in other areas in South Australia. The Stuart shelf is a basin in that sense as it has sediments, clearly there is more work here to look at. It looks to me like a hybrid model here. Another point is that these deposits normally aren’t big individually but are found in clusters much like oil fields in limestone reefs. In fact in the Mississippi Valley these deposits are linked to deeper oil limestone reefs as a theory is that the sulphides are forced up from deeper in the basin by natural aquifer pressure.