dose large gold grow ?? here's a book on the exact theory quite interesting talks about Australian gold fields download to view better. this has been scanned by me from an 1897 book
This map shows what I mean (Ballarat goldfield). The black squares are mine shafts on quartz reefs (not alluvial shafts). Circles with a dot in them are gold nuggets larger than 15 kg. Alluvial gold leads are also shown as streams. You can see that the nuggets are all on top of or only slightly downhill of the quartz reefs (which are denoted by shafts), even when they occur in streams (in fact a number were above stream level).goldierocks said:Interesting historically, but 121 years out of date. The person who wrote it did not have a good knowledge of nuggets - he says that they don't occur in quartz in Victoria and NSW (try Holtermanns at Hill End) and that streams could not have moved nuggets like the Welcome Stranger so it must have grown in situ in a stream. However the Welcome Stranger did not come out of a stream, nor did most nuggets over 15 kg found on the Ballarat goldfield (for example). They were found on hillsides in soil usually a few tens of metres at most downhill of the quartz veins that they had weathered out of (the Welcome Stranger still had more than 20 kg of quartz attached to it. So a bit of an armchair theorist.
Just like it takes a grain of dust to grow a rain drop :Y: LPSWright said:G'Day Mungoman
I am afraid not. The true concretionary gold nuggets like those in WA or parts of the GT were you can show that the gold is not a giant specimen that has weathered out of a long gone reef, occurs in soils with a large concentration of gold it is true, but the gold is in parts per billion or parts per trillion. It would take at the minimum tens of thousand of years to concentrate the gold onto a potential nugget. In WA we studied this extensively and found that it is humic acids in slightly saline soils that disolves the gold, transport it to near surface where it deposits on clays. how a nugget is actually triggered we cannot determine or even why it continues to grow after seeding. Extremely saline ground water disolves gold and when it gets hypersaline will deposit again. Can't think of anything that would not end up destroying the delicate balance of the formation of nuggets that could speed up the process.
Araluen
And SWright and I are talking about different environments - in WA nuggets can enclose iron pisolites formed in the weathering zone. But not in streams.....20xwater said:And like a snow flake no 2 nuggets are alike because the environment it was created in is allways different from another, the formula of life...Brian Cox is a legend!
And yet a sulphide is categorised as aninimate, I disagree..
The shafts on the map show you that there are three parallel reef systems that strike north-south for 16 km (smaller nuggets all the way, you know, pissy little things of a kg or ten), and the 15 kg nuggets occur on all three - Ballarat West, Ballarat East and Little Bendigo (also called Nerrina).goldierocks said:This map shows what I mean (Ballarat goldfield). The black squares are mine shafts on quartz reefs (not alluvial shafts). Circles with a dot in them are gold nuggets larger than 15 kg. Alluvial gold leads are also shown as streams. You can see that the nuggets are all on top of or only slightly downhill of the quartz reefs (which are denoted by shafts), even when they occur in streams (in fact a number were above stream level).goldierocks said:Interesting historically, but 121 years out of date. The person who wrote it did not have a good knowledge of nuggets - he says that they don't occur in quartz in Victoria and NSW (try Holtermanns at Hill End) and that streams could not have moved nuggets like the Welcome Stranger so it must have grown in situ in a stream. However the Welcome Stranger did not come out of a stream, nor did most nuggets over 15 kg found on the Ballarat goldfield (for example). They were found on hillsides in soil usually a few tens of metres at most downhill of the quartz veins that they had weathered out of (the Welcome Stranger still had more than 20 kg of quartz attached to it. So a bit of an armchair theorist.
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