More on Eolian and "Reverse Eolian" Dry Placers
("Toe-may-toes" or "toe-mah-toes?"
Jack, a Bedrock Dreams reader and supporter sent this comment in on my last post about eolian placers: "I read your posts with enthusiasm regularly. However, I don't agree with you on this. An eolian placer forms when the lighter material blows off of the gold, leaving the gold concentrated in place. Anyway, keep up the posts and the attitude. We need more of you in our world right now." I replied to Jack on this point agreeing to disagree, so let's pursue this topic on eolians a bit further.
First off, I want to thank Jack for expressing his opinion on this subject whether it coincides with mine or not. I also want to thank him for his kind words and ongoing support. Next, I urge all of you to follow Jack's lead here if you find I'm in direct error or have an alternate viewpoint on any aspect of gold prospecting or mining. I'm not here to try and lord it over anyone or imply I always know more than you do...I've learned a lot about small-scale gold mining and prospecting over the course of three and a half decades but I surely don't know it all (and you can take that last to the bank). OK, that out of the way, let's proceed.
"Goodies" Would Start Appearing
Years ago I spent my gold mining off time recovering "gold" (jewelry and coins) from the beaches of Southern California during the winter months when the big Pacific storms would roll in. There were many occasions during those events when I witnessed what Jack is talking about some distance up and away from the surf line where dry beach sands were being blown off by the high winds accompanying the storms. Note that I'm talking here about those instances where no accompanying rain was falling as well.
During these high wind events you could actually stand there and watch shallowly buried coins (and the occasional piece of jewelry) being uncovered by the force of those winds. As the winds lifted and blew the lighter materials and dross off to race away further inland, the "goodies" would start appearing and all I had to do was reach down with a sand scoop, pluck them up, and then deposit them into my recovery bag. For those of you who've never witnessed anything like this it's an amazing sight to behold and gratifying in more ways than one, to say the least. Now switch the concept of this event to shallow particles of gold or very thin flakes. Would those remain in place or would some be carried away?
When this concept is applied to what Jack's talking about you can easily see his point about eolian placers. Gold that's eroding out from a vein, outcrop, or ledge that's uncovered by strong winds or high-wind events is suddenly exposed to the naked eye. However, rightly or wrongly this is where I begin to diverge in terms of what I think a standard eolian is. Jack's view is that the concentrated gold remains in place but is uncovered and my view is that the lighter particles (fines, flat flakes, etc.) that are uncovered become wind borne and are carried away to form small deposits elsewhere. I even cooked up my own terminology to describe Jack's version of eolians, the "reverse eolian." Believe it or not (and I'm not trying to BS anyone here) "reverse eolians" was to be the very next topic in my series on dry washers, desert gold, and working dry ground.
(Is it reasonable to believe that very small and light "flour" gold like this could be carried away by strong winds and deposited elsewhere in a dry placer environment?)
I'll have to let the geologists and earth scientists out there answer that one (and feel free if you're one of those). In the mean time, there's always room for error on my part. If I am erroneous here then you can rest assured I'll come back to you all with hat in hand and apologize for getting things wrong and passing along bum info (something I wouldn't be very proud of).
Whatever the case, I want to thank Jack again for speaking up on this topic and providing an alternate viewpoint.
Best to all of you!
(c) Jim Rocha (J.R.) 2013
Questions? E-mail me at firstname.lastname@example.org
2009 Bedrock Dreams archives are now available: