The gravity is telling you that there's something dense down...

The gravity is telling you that there's something dense down there as compared to the usual density assumed for the crust. The gravity meter measures minute differences in the earth's gravity field between the instrument and the centre of the earth. Given the lower crust is pretty homogeneous, and the mantle is assumed to be homogeneous.

The gravity meter measures differences in the upper crust - and the greatest density contrast is often between dense mafic rocks (basalts, dolerites, etc) and less dense sediments, within the veneer of sediments, here represented by the Yerrida basin.

That area of the Yerrida is composed of, basically, 4 units of rock. The Windplain Group sediments, the Mooloogool Group sediments (mostly shale), the Killara Volcanics (basalts and dolerites) and the Eararheedy Basin (sediments).

So, it's not really much of a stretch to say that the most likely thing detected is going to be the only mafic units within cooee.

The supposed Perseverance Fault is a good candidate for mineralisation. It is also a good place to erupt mafic volcanics. Volcanics fault = a chance of VHMS. However, the Yerrida Basin in this area, at the time the Killara was erupted up the faults, is not what I personally would call a fantastic setting to develop the ore deposit type.

So, ultimately, no this is not a direct method of detecting the bucks. It gets you in to an area with a possibility of a VHMS. But it's more likely to be just an accumulation of mafic rocks along a structure. It's up to GTE to drill a hole and see.