New Zealand Gold Prospecting & Metal Detecting Forums Archive

Hi all.How far above the waterline would you consider too far for crevicing?
I'm talking good,well featured bedrock here and bearing in mind some of the rivers round here will go a good 10 or 15 feet above normal in a good flood.

Your question is interesting to say the least - I guess it depends on where you are , the river, the geology of the land. Many crevices might go well up the bank many yards and have very little in them after they leave the mean water level while others might have a great deal of gold well above the river. On my property there are crevices which were obviously found in the stream high on the mountain BUT due to the fact that they have been worked fifty yards inland from the stream and well above the water level it is apparent that the gold just kept on going.
My son and I were out not so long ago with him using my metal detector and the heaviest piece of gold at a quarter of a troy ounce was well up from the river in a series of crevices leading out of the river and up the bank.

It might be noted that as a river cuts down through the rock over the millennia it deposits gold as it goes so that the gold might be well above the river level, sometimes on terraces a 100 yards above where the river flows now and more.

Sometimes you might work a crevice above water level and get nothing in it while the next crevice down is loaded - the reason could well be that the unproductive crevice was found and worked in the early days while the productive one could have been well covered during the gold rush era and only uncovered during floods of the last few decades and therefore has gold in it.

It depends where you are but it never hurts to open a crevice at several spots along its length to see whats there rather than work it painstakingly from one end to the other for no return.

Not theories but fact - theres a difference between fact and theory and different areas have different characteristics - I learnt that to my cost many years ago. I do not believe that there are any hard and fast rules - for example I found a crevice once which went under a huge boulder - it was loaded with gold and of course the boulder had to be removed. Eventually I did remove it - absolutely no gold underneath...juyst one of those quirks. I had found around a troy pound of gold either on a ledge leading into a huge hole and immediately below the exit end of the huge hole so knew that we were going to get a fortune IN the hole - but there was only five or so ounces in it.
As for crevices - it depends on the river and geology of the land - and whose been there before you! Gold is where you find it - my son has found it more or less right on top of the mountain in clay and fine gravel well away from any crevice or creek!

Edited by user Saturday, 3 September 2011 8:06:54 PM(UTC)  | Reason: Not specified

from my limited experience of a few years looking for gold, its a numbers game. the deepest crevice usually wins hands down. the heavy heavy gold is always heading down until obstructed otherwise.
the usually has exceptions of course. you could find gold anywhere up the watercourse sides, at the present flood line or up where it flowed in ancient times.
i find it more productive myself to stick to cleaning out deep crevices/ cracks/channels etc in the water. the deeper the better. work it as far down as you can. that said i could head higher up in the hope of gold getting thrown up or stuck higher up from when the river was higher. personally i find the big gold at the bottom. its just so heavy.

Hi guys, Yes gold is where you find it. This statement may sound a bit frustrating to you newer fossickers for gold. There are the obvious places that you look for gold, or have been told to look for gold. Like the inside curve or bend in a river, the down stream side of rocks, boulders & obstuctions in the flow of the river. Where the river suddenly widens & the water pressure to push the gold on drops off quickly. Areas where gold drops out of the strong flow of the river during flood. Flood time is really the only time gold is going to get shifted about in a river so when a river is in flood that is the best time to check out its behavour. The river is a different kettle of fish in flood than in its normal flow. Look for the back eddies & areas of low pressure. These are the places the gold will drop out or be swept into.
Rivers are obvious transporters of gold but almost all the likely spots have been cleaned out years ago with the exception of flood gold. You could be lucky & strike an over looked crevice. If you do then Yehaa. Now this is all very well & good if you are dredging or sluice boxing. Crevices can be real gold mines & probably your best chance today to get a good haul.....if you are lucky & no one has been there before you. It does happen.
I take it that you all have an idea of how the gold got into the rivers in the first place, how it eroded away from its parent reef way up in the mountains & worked its way on down with the help of gravity & water etc.
Any way.....gold being where you find it....lets get away from the rivers....Ok.....you are up on a mountain side......how did the gold get there?? I am now talking DETECTING for gold. No river, not even a little dry gut or gully. No inside bends or boulders to look for. No sign of a river ever having been there. Gold is where you find it....how did it get there???
We need to look at geology, the art of land formation, its distruction & distribution. I am going to talk Central Otago here but the West coast is every bit the same. Otago has been through a torturous time geologicly with land upheaval, subsidence, faulting & folding, glaciation etc. The rivers that flow today are not how they have always been, nor is the land how it has always been. Glaciers are mountain demolishers & quartz reef destoyers (helping to free up the gold from the parent reefs) & valley creators. Huge powerful transporters of material. Ice, snow, wind & rain, freeze & thaw etc all have an influence on gold transportation & the land around it. Some rivers today are flowing in the opposite direction of what they once did. Some rivers now are high & dry on top of mountains, along with there gold. Gold is where you find it. No rhyme no reason as to how it got where it got today. Can do your head in trying to work it out. It will have you scratching your head. Observation & imagination are your key assets in this respect.
The interesting thing is that most gold I have detected high up in the mountains is usualy always in crevices. Here are some examples

Piece of gold between the coil & the crevice that it came out of



Close up



Most of this gold is quite rough & still has quartz attached. Not water worn gold.

















I got 5 pieces from these crevices. This was the start of the dig



Three pieces



Getting deeper & 2 more pieces



Close up of the crevices the gold was trapped in



This gold was water worn



There was no water worn rocks or signs of river stones any where. So how did the gold get transported & finaly trapped in these crevices?? I have found patchs of gold & tried all ways to try & trace it to a source. The gold being still pretty rough & with quartz still attached, I would have thought it hadnt traveled very far. I could find no source. No reef or stringer. The trail always lead to nothing. How did the gold get there? Tell me what you think.

Happy hunting

JW

Hi John.This is my theory for what its worth...
When the glaciers advanced,they picked up gold from the reefs and carried it downhill.When the ice melted and the glacier retreated the gold was deposited and lay on the surface for a while until rain and erosion did its thing and the gold did what it does best-finds the lowest point of any surface it moves over,ending up at the bottom of your crevice miles away from any obvious source.

The fact that the gold isnt really eroded to any great degree is kind of a hole in my theory I cant explain though so I may be talking rubbish!

Oh okay, that makes sense. They were pretty resourceful chaps those old miners......they did stuff that I wouldnt even dream of nowadays.

Hi there Overdog, I would say you are spot on the money. Your last comment about the gold not being very eroded isnt a hole in your theory but quite the opposite. It is what almost confirms the theory to a great extent. Once the glacier has gone through & smashed up the quartz reef containing the gold & the pieces have broken & shed from the reef with bits of quartz still attached get caught up in the ice flow. They are then just going along for the ride. Carried by the ice. No more real aggresive pounding & getting rolled bowled & arsehold, like it would be in the turbulance of a river enviroment & rocks & boulders pounding & flatening it & smoothening it to the water worn river gold that we know.
As Graeme has said the reef may have been totaly annihilated & nothing left of it. Like wise, there could have been a river system & the land since has been pushed up & the rivers water source gone & the gold trapped in the crevices was left behind when a glacier went through like a giant bulldozer wiping the surface clean of all the water worn boulders & other old water worn stream bed material. Pushing it god knows how many miles & leaving it as a pile of glacial moraine when the ice stopped & melted away. Or maybe at this stage the land rose up. Way up & above any river today. Like the bed rock in pic number 9 above. See how smooth that rock is. It has been ground smooth by the ice of a glacier I would say as ther is now no water worn maretial around or on it. This could account for the water worn gold I have found but no water worn rocks or other typical stream material. Different to detecting amongst the exposed bed rock that the old timers exposed with there gound sluicing & there tell tale rows & walls of the neatly stacked rounded river rock tailing piles.
Also, the rough gold I have found isnt distributed in any sort of patten or row. Like it would be in a stream enviroment. I have found a piece of gold & then stuck a stick in the ground, found another & placed another stick kept on doing this to see if there was a sort of straigh line patten. Maybe to a reef or stringer up hill shedding this gold. Thats if it was just eroding from the ground & not deposited by a glacier. There never was a patten to the golds distribution or a lead to a reef. It is big country out there & I havnt given up the search. I am liking to think it has come from a reef & not a glacier. Because if it was deposited by a glacier then it is just going to be a localised patch of gold that was randomly dumped when the ice melted away. If it is from a reef then I hope to be able to track it to the source, or what hopefuly is left of it. If not then my search will all be in vain. But while I am finding gold I will keep on looking.

So to get back to the first question asked on this thread about how far up could I expect to find gold in a crevice?
If the river or creek is draining country that has had a glacier go through, say like the Lake Wakaipu district, then the height you could expect to find gold in crevices above the river is to the highest hight that the glacier reached. Could be thousands of feet. Otherwise if it is just a creek or river that is carrying gold from much further afield & the only gold is in the actual stream itself then any crevices that are within reach of the highest floods of that water course. But then again you need to imagine if the river has been at a much higher elevation than it is today. Any old higher terraces etc. As I said earlier, rivers today & not how they have always been.
Very interesting topic though & I love this sort of stuff. I like the detective work in it & throwing around theories & fact & trying to work it out.

Happy hunting

JW :).

Edited by user Monday, 5 September 2011 8:05:08 PM(UTC)  | Reason: Not specified

Hi Karl, Thanks. Here are some pics of one of the West Coast Glaciers.

Note the material sitting on top of the ice. How far has that traveled? It will just get dropped when the ice finaly melts away.



This is a dying glacier (arent they all) so is retreating back up into the head waters from where it came. Dropping its load as it melts away. Exposing the rock walls that havnt seen the light of day for god knows how many thousands of years.



Note the pile of rocks in the forground. This is latteral moraine. All be it on a very small scale. Latteral moriane is rock that gets "bulldozed" to the side of the glacial ice tounge when it is advancing forward. If you have ever been to the Tasman Glacier it has massive latteral moraine.



JW :)

Awesome and interesting reading guys!! Did I read somewhere once that the alps had risen something 20km's in the last so many thousand years but it's rain, wind and earthquakes and general errosian that keeps em looking like they are? The 2 plates are constantly moving...especcially of late!!