Jump to content

Glaciers & Gold

Recommended Posts

The earth has been warming and glaciers retreating for over 15,000 years. Almost everything in the part of Alaska I lived in was recently exposed by glaciers and been prospected the last couple hundred years. Glaciers are nature's bulldozers and they destroy and mix. The gold distribution in glacial material is generally random and sparse. Where water has had time to work glacial deposits new placers can form, but the short geologic time spans we are talking about usually mean small erratic deposits. The good news is that also means you can maybe find a gold nugget just about anywhere in glacial material.

If you watch the video a second time and pay attention to the area that becomes Alaska you will see that Anchorage, on the southern coast, was buried under 3000 feet of ice not too long ago. The interesting part is northern Alaska is largely ice free. This is extremely important. The placers are much older and more extensive in Interior Alaska than in the southern coastal areas.

The northern US was heavily glaciated and much of the material was pushed down from out of the north in Canada. I find glacial terrain interesting because glaciers have melt water running under them and along the edges, which form small oddball placers in the strangest places, and other placers are possible in the large outwash areas.

I am discovering there was a lot more glacial activity in the Sierras than I would have imagined and so this is still very relevant for me prospecting in California.

These links may not be for your exact area but all contain good information about glacial geology and prospecting.

Great freebie article Gold in Kansas

And a small related article at the ICMJ Undiscovered Placer Deposits in Alaska

Really good stuff starting page 117 on Gold Placers of Colorado

Placer Deposits of the Yukon

Geology of Tertiary and Quaternary Gold-Bearing Placers in the Cariboo Region, BC

Here is some really technical stuff for those so inclined Glacial Geology & Prospecting

Glaciers of California

A much more prospector friendly version can be had in an excellent but pricey book by Chuck Lassiter, Midwest Gold Prospecting at http://www.midwestprospector.com/book.html

I have a copy in my library of the best of the best. It is a high quality book with color maps and illustrations and a no-brainer at about half the cost. For $29.95 you have to just love books as much as me as that is as much as the Chris Ralph encyclopedia and this book would be a chapter in Chris book. That said, I have never seen the particular subject of glacial region prospecting covered better and more understandably anywhere else. It would be the go to primer for anyone interested in the subject.



  • Like 5
  • Thanks 1
Link to comment
Share on other sites

  Two very important geologic features to recognize while prospecting the Sierra Nevada are glacial activity and indications of ancient river channel. Time periods need to be more open to question/ debate as there are many non conforming discoveries that don't match assigned ages.

 In Plumas Co. there are Palm tree fossils and glacial scars almost within sight of each other. This ol' planet refuses to behave.

Link to comment
Share on other sites

I love observational geology. Most of the best stuff was people just like us looking at it all and applying common sense to what we see around us. It is still all a work in progress and some stuff changes as new information comes to light. Here is a newer report with lots of references that applies directly to my new backyard.

Late Pleistocene Glaciations in the Northwestern Sierra Nevada http://people.cas.sc.edu/ajames/Research/Pubs/03.INQUA.Log.pdf

I take a practical approach. Ages do not matter much, I just need practical information that I can use to find gold. Knowing an area was recently scoured by glaciers has a big impact on the likelihood of finding placers deposits of any sort there, even just residual placers. Those of us with detectors in particular prefer old land surfaces. But glacial deposits can hold small hidden placers, and those are very high on my interest list at the moment, which is what got me Googling away on this.


Link to comment
Share on other sites

I have to admit I have a heck of a time deciding what is old glacial material and what might be old stream material or even ancient beach deposits at times. They can grade imperceptibly from one into the other. Good news with a detector is, well, just detect the darn stuff and see what happens.

Lots of people have asked me about detecting around receding glaciers in Alaska. Given the number of people who have asked me about this over the years I think it must be the idea of never before seen ground that attracts people. Other than that there is nothing in particular to recommend glacial terrain. Gold placers relay on stream action sorting and concentrating material over millennia. Glaciers are more like bulldozers pushing and stirring everything up. Gold may be there but is more likely scattered. In the case where streams have been running under or next to a glacier and in streams issuing from glaciers there can be some shorter term concentration resulting in lean placers. Ultimately it depends on there being a gold source under or in the immediate vicinity of the glacier. Lacking these there will be no gold. Since glaciers have been receding for thousands of years they have of course been prospected already, and it is not likely that simply receding another mile will all of the sudden reveal gold that was not apparent before. The long story short is prospecting glacial material might produce some gold but due to the scattered poorly sorted material such gold tends to be sparse at best.

Link to comment
Share on other sites

Yeah, I like his stuff. Chris is more skeptical of portions of this one but still many good tips to be gleaned in the text and maps http://www.detectorprospector.com/forum/topic/227-free-book-the-upper-reaches-of-the-sierra-nevada-auriferous-gold-channels-california-and-nevada/

The thing is to not get bogged down the theory parts and just dig for the mentions of bits of geology here and there that might be worth prospecting.

  • Like 1
Link to comment
Share on other sites

  No one knows exactly what went on thousands or millions of years ago, its all theory based on what each person believes and see's in their findings. I love hearing about them all, and come to my own conclusions of what may have transpired years ago.

Its all very interesting to me.

Link to comment
Share on other sites

I have read a lot about the subject. It is very apparent as Steve said around the Anchorage area. I have claims on the Willow side of hatchers pass and you can see all kinds of glacial features. You can see where as the glaciers retreated they paused for some time to build up intermediate moraines. The earth does warm up and cool down but I am not getting into the debate. Back home in wyoming most of the lakes on the south side of the Wind River mountains are morainal lakes

Any way I read mid west prospecting and though it was a interesting and great book.

Link to comment
Share on other sites

Hey Steve, About 30 years ago I lived about 35 miles NW of Gerlach Nev.  and my Dad was raised in that country.  When I was a youngun  about 60 some years ago I was with my Dad traveling from Herlong Ca. to Gerlach and my  dad pointed out a dry lake between Nixon and Gerlach and said that when he was a kid he rode on a commercial fishing boat on that lake.  He told me what the lake was called but I can not recall.  So there have been some drastic changes within the last hundred years...

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Similar Content

    • By oldmancoyote1
      You have had a lot of success over the years.  I imagine you have found some wonderfully large masses of gold.  Think about each of those for a few moments, especially those in the lower 48.  Does anything appear as a common feature of their locations?  Surely not everything would fit the same mold, but was there anything present frequent enough to indicate one location might be a little bit more likely to yield big gold than another?
    • By afreakofnature
      The Mystery Formation of Extremely Rich Gold Veins Might Finally Be Solved
      MICHELLE STARR 24 MAY 2021 Gold, for all its wonderful uses, isn't hugely abundant in Earth's upper layers. For each ton of crust material, there's an estimated just 0.004 grams of the precious metal.
      Yet somehow, there are regions that contain "bonanza" abundances - hyper-enrichment, in the scientific parlance. How these gold veins form in time spans as short as days from hydrothermal systems that only contain trace amounts of the metal has been a geological mystery.
      It's one that now has an answer, from the most unlikely of clues: the separation and clumping of fat particles in soured milk.
      "Scientists have long known that gold deposits form when hot water flows through rocks, dissolving minute amounts of gold and concentrating it in cracks in the Earth's crust at levels invisible to the naked eye," geoscientists Anthony Williams-Jones and Duncan McLeish of McGill University in Canada stated in a Q&A.
      "In rare cases, the cracks are transformed into veins of solid gold centimetres thick. But how do fluids with such low concentrations of gold produce rare ultrahigh-grade gold deposits? Our findings solve the paradox of 'ultrahigh-grade' or 'bonanza' gold formation, which has frustrated scientists for over a century."
      Milk is an aqueous solution made up of several components, one of which is microscopic globules of fat. At the pH level of fresh milk - very close to neutral - these fat particles have a negative charge, which causes them to repel each other.
      The souring process involves bacteria in the milk converting lactose to lactic acid, lowering the pH level accordingly. This causes the surface charge on the fat particles to break down, and the fat particles separate from the milk serum and clump together with each other via coagulation, forming a sort-of gross decomposing milk fat jelly.
      Williams-Jones, McLeish and their colleagues found a similar process when using transmission electron microscopy to study gold deposits from the Brucejack Mine in British Columbia. This is one of the spots around the world where bonanza-grade mineralization can be found, up to 41,582 grams per ton.
      It's long been accepted that gold is transported by way of fluid through Earth's crust. However, in order to reach the abundances found in hyper-enrichment zones, previous studies suggested that the gold may have been dissolved in high concentrations in fluids containing chlorides or bisulfides, and transported and deposited that way.
      The other possibility is a colloidal solution, with solid nanoparticles of gold dispersed throughout hydrothermal and geothermal fluids. Since the gold nanoparticles hold a charge (like milk fat), they repel each other. When the charge breaks down, the gold particles clump together in a process similar to coagulation, known as flocculation.
      This has been indirectly demonstrated in the past; now, McLeish and colleagues have observed how it actually happens.
      "We produced the first evidence for gold colloid formation and flocculation in nature and the first images of small veins of gold colloid particles and their flocculated aggregates at the nano-scale," Williams-Jones and McLeish said.
      "These images document the process by which the cracks are filled with gold and, scaled up through the integration of millions of these small veins, reveal how bonanza veins are formed."
      For this process, the concentration of gold in the geothermal fluids only has to be a few parts per billion. It flocculates to form a jelly-like substance, which gets trapped in cracks in Earth's crust to form rich gold veins.
      This finding suggests that rich gold deposits may be more common than we thought, and may have occurred in several other contexts than previous estimates had allowed for. If other studies and further examination can back it up, the research could give us a new toolkit for understanding and locating gold deposits around the world.
      "We suspect that the colloidal processes that operated at Brucejack and other bonanza gold systems may also have operated to form more typical gold deposits. The challenge will be to find suitable material to test this hypothesis," Williams-Jones and McLeish said.
      "The next step will be to better understand the reasons why colloid formation and flocculation occurred on the scale observed and reconstruct the geological environment of these processes."
      The research has been published in PNAS.
    • By RiverRat
      I'm interested in any information on how gold veins/ lode deposits become offset and how to attempt to predict the amount of offset.
      Anyone have information on this?
    • By Libertas
      Interesting! Will be useful when we eventually have a colony there.
    • By Dances With Doves
      I only  went real nugget hunting one time in Stanton,Arizona in march 2002 because the late Charlie Wilson of Wilson metal   detectors took us as guests for a week.I was   using a Minelab gold machine he lent me that ran at 3  different freq.You had to choose one.I really envy you guys that get to do this in your area.I loved doing it even though I found no gold since i was  new at this type of hunting.The owner of the   Johnson mine even gave us permission to hunt his land which I thank him for.I  met Chris  Gholson and his  father and they were fantastic people.  
    • By mn90403
      So what caused it to break away?  Here is more on that theory.
  • Create New...