Jump to content

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.

 

post-1-0-17935800-1423067310_thumb.jpg

  • Like 4
  • Thanks 1
Link to post
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 post
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.

post-1-0-16612600-1423079496_thumb.jpg

Link to post
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 post
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 post
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 post
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 post
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 post
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 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.
       
      https://www.sciencemag.org/news/2021/03/remains-impact-created-moon-may-lie-deep-within-earth 
    • By Allen M
      Hello, 
       
      I was out this past weekend with my Gold Monster 1000. Here is a picture of a rock that I came across that had crystals and what I believe is black sand. I have come across black sand by it self and has done the same issue with my machine. Reading and sounding hot and then a blank sound as well. 
      1) I assume that you can find black sand like this still in a rock with Quartz.
      2) Is is not true that usally when you find black sand you may end off finding gold as well because black sand and gold go together. 
       
      here are four pictures of the rock.
       
      Allen
       




    • By oneguy
      Stumbled onto this interesting article form another site......  Not sure where to post this but Steve can relocate it where he see's fit?
      https://www.westcoastplacer.com/paleochannel-hunting-guide/
       
    • By nebulanoodle
      I nabbed a pretty neat find the other day and I think it was sunbaker...
      Is it only a sunbaker if you saw it before you disturbed it or is it still a sunbaker if the rock that it's lodged in tells a sunbaker tale? Every dirt dog can tell what half of a float rock was in the ground and what half was face up. 
      This is a rock with a nugget lodged in it that tells one of those sunbaker tales. 
      Is it a sunbaker?
      -OR-
      Was it a sunbaker?
      -...OR-
      Is it not a sunbaker?

      It's wedged in there really good! I haven't tried to yank it out because it's so unique as a sort of specimen of a bedrock nugget trap. I've picked at it and got no movement, plus it survived getting tossed around in my pack on my hike.
      An interesting find too! One of those days, patch hunting a new area (this new area hasn't met the three nugget threshold). All I had in my pocket was trash and my nug jug only held my test nugget. But lo, another signal! Few and far between, they are out here. Giving the spot a boot scrape moves my target. Probably surface trash, a bullet. Gotta know. These 4 rocks. These 3. These 2. That one... it's not a hot rock? Turned in hand to reveal a little smooshie stuck in a crack! WHOA!!!
      My strongest theory is that this "specimen" is a remnant of the bedrock that trapped some gold, all the bedrock having been eroded away. The gold since washed down the hillside and into the main drainage, perhaps all the way into the basin... But hopefully it has only travelled just past where I stopped detecting for the day and I get a whopper bonanza another day! 😂 Yeah right.
×
×
  • Create New...