Mineralisation genesis and targeting in Australia, North America and China Synopsis of talk for AusIMM at Bunbury, 3rd October 2019
Robert Watchorn
Mineralisation genesis and targeting in the Abitibi province Canada.
Australian geology and rings at 75 km depth. There is little correlation between the relatively undeformed Lithosphere below 60 km and the strongly deformed crust.
Mineralisation genesis and targeting (enlarge images to full screen).
Mineralisation genesis and targeting are described in the second half of the AusIMM talk I gave on 3rd October in Bunbury, Western Australia.
For details and registration to attend this talk see the following link —
The images detail my recent research In Australia, North America and North China on the mineralisation, exploration targeting and metallogeny related to the lithosphere and particular giant ring structures. The broad research findings are on each image.
Mineralisation in the Yilgarn craton on 75 km depth seismic tomography showing the association of mines with ring structures and linears and their intersections.Yilgarn 75 km depth plan and 30 S section tomography showing mines and correlating structures in plan and section. It is proposed that super-heated fluids, driven by mantle heat (>2000 C), ascend vertically, scavenging and concentrating minerals to form economic deposits on the way up. The continuation of the pathways seen in the lithosphere tomography can be seen as flower structure systems under the main mines on the Seismic traverse data. This is independent confirmatory evidence of the validity of the enhancement systems used. The plan correlates with the Seismic section and the seismic section correlates with the Seismic tomography section.Yilgarn 75 km depth plan and oblique section A (looking SE from north of Wiluna) tomography showing mines, rings and vertical mineralising pathways. All of the Yilgarn Uranium and Vanadium is located within the median ring of the Barrambie ring structure suggesting the original impact mineralogy introduced these metals to the system.Yilgarn 300 km depth plan tomography showing the association of mines with ring structures and linears and their intersections.Mineralisation genesis and targeting areas on Yilgarn 300km depth plan tomography showing mines. The source of the super-heated fluids is the brown grey boundary and the light coloured areas.Yilgarn structurally enhanced Landsat showing major mines and superimposed targets from 300 km depth tomography. It can be seen that the main mines are in these halos but there is a lot of area to explore that could be equally prospective but is covered.Pilbara 75 km depth plan and 20 S section tomography showing the association of mines with ring structures and linears and their intersections. Super-heated fluid pathways are seen on section 20 S. All BIF iron is inside the Coondewanna median ring.Mineralisation genesis and targeting areas on Pilbara 300 km depth plan tomography showing mines. The source of the super-heated fluids is the brown grey boundary and the light coloured areas. This is a much larger ring structure than Coondewanna. Mt Isa craton enhanced Landsat showing a giant ring structure enclosing the Mt Isa area mines. The main minerals inside this ring are copper, uranium, phosphate and silver led zinc.Mineralisation genesis and targeting areas on Mt Isa 300 depth plan tomography showing mines. The source of the super-heated fluids is the brown grey boundary and the light grey coloured areas.Gawler craton 75 km depth tomography showing the association of mines with ring structures and linears and their intersectionsMineralisation genesis and targeting areas on Gawler 300 km depth plan tomography showing mines. The source of the super-heated fluids is the brown grey boundary and the light grey coloured areas.Canada’s Abitibi sub-province 100 km depth tomography showing the association of mines with ring structures and linears and their intersections. Smaller rings are seen on the gravity image of the Abitibi west field lower left inset. The top right inset shows the extremely close agreement of the surface mines with the structures on the enhanced seismic tomography at 100 km depth. This close correlation exists in all fields studied so far and confirms the essentially vertical nature of the mineralising fluid pathways. It also gives great confidence that the enhancement method picks up real structures.North China 90 tomography with mines. The north China craton consists of one major impact. The mines, and the gold mines in particular lie in the annulus inside the median ring.Australian Canadian and North China 60 to 90 km depth seismic tomography showing the association of mines with ring structures and linears and their intersections. All of the Yilgarn craton Uranium and Vanadium is located within the rings of the Barrambie ring structure, Pilbara Iron is concentrated in the Coondewanna ring structure, Copper silver lead zinc is in the Isa ring structure suggesting the original impact mineralogy provided these metals to the system forming metallogenic provinces.The above images depict continent formation by Late Heavy Bombardment impacts and lava flooding forming the lithosphere before 3.8 Ga with the crust forming after the cessation of the LHB in about 3.8 Ga. Heavier mafic lavas were eroded off and the subsequently lighter cratons have survived by isostatic uplift. Mineralisation formed from 3.8 Ga onward by super-heated fluids scavenging minerals from the lithosphere and depositing them in the cooler crust.
This is a small selection of the images and explanation used in the talk. The full talk video will be available on the AusIMM website.
The most important finding to come from the research is the exploration targeting areas many of which are new to Australian geologists. The methodology in defining them is a new paradigm or a huge refinement of existing ones.
