Vegetative mapping for alluvial Gold in Ordovician soils

Environment and sustainability in Tasmania

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Vegetative mapping for alluvial Gold in Ordovician soils

Post by Philski » Tue Sep 16, 2014 11:50 am

One of the most remarkable events in modern prospecting methods is the advent of the internet and the easy access to remote area sensing data and satellite imaging. From hundreds of reliable sources.

The Historical use of Vegetative mapping to define areas containing gold bearing deposits is steeped in tradition, folklore and quite some mystique. The early Victorian Gold miners in the 1850s used the exact same method to help find and sink on the shallow Gold leads
Image source: Google Maps. Web:

The Victorian example was originally looking at because in Tasmania. we get the exact same association. With the same species of tree! I then noticed the vegetation in the Central Victorian Gold Fields (Golden Triangle) is a different colour to the rest of the vegetation in the state. And knew it was related to soil condition. And, It is. its because of the Ordovician sediments laid down 490 million years - 430 million years ago. And, neatly Dividing the Cambrian and later Silurian systems. The area above in Victoria produced the most big gold on the planet.

Ever want to know why? well so did i.

i used the same imaging to find all major Australian Ordovician sedimentary gold deposits in a few minutes. fragments of 490 million year old Ordovician occur in Tasmania. Moina, Back Creek, Lisle, Mathinna, Beaconsfield, Calder/ Wynyard, bald hill, Gladstone and upper Scamander, etc. And, as far away, as the Northern Territory. The vegetation changes are being mapped in each.

The Cratons in WA and SA are much older than the east coast. so ive not worried about it till this one is done. Its more than enough country for one person to do.

This is not an exhaustive explanation to why gold occurs in some places and not others. And i'm not going to go into how to use it to pinpoint areas. But, by using the vegetation you can predict the soil below, without even being there. And, the likelihood of gold being found. Its as passive as i can get.

All Ordovician areas in Australia are well known gold fields, Hill end, in NSW etc and it correlates perfectly to what we have in Tasmania. The vegetation helps delineate the area on the ground.

Gold occurs in many other areas, but non so rich in the East as the Ordovician.
Image source: Geoscience Australia. Web:
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Re: Vegetative mapping for alluvial Gold in Ordovician soils

Post by Fox » Wed Sep 17, 2014 9:50 pm

An observation I have made while travelling through the Victorian goldfields is the similarity of the geology to that in NE Tasmania. In road cuttings I am seeing near vertical bedded rocks virtually identical to our Mathinna beds - same colours, textures, strike direction and association with other rock types, granite intrusives and basalt flows filling ancient valleys and burying old river beds ( deep leads ).
Some people may be wondering what the Fox is finding with his metal detector. The answer is ABSOLUTELY HEAPS!!
But I won't be putting up any photos of my finds, not because I don't want to share. It's just that I'm sure everyone's seen bullets, buttons and nails before - I've got a bag full of 'em. Certainly doing my bit for the environment by removing toxic lead and hazardous sharps and other rubbish.

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