Tracking (Tracing) Float (Conclusion)
Well it's time to get back to tracking float and to wrap things up for you. Remember, your key ability in this regard is to be able to recognize potential gold ores out in the field. Lacking that expertise, you may have a rough go of things.
7) The old timers sampled their way to the source. Just like most of us today, the old timers started sampling low-lying areas for traces of color. These included washes, streams, gullies, hillside saddles, or any other low-lying terrain that had the possibility of collecting placer gold or float as gravity moved it down and away from its source. When the gold ran out or disappeared from their pans, the old timers then began looking for float or traces of gold in elluvial trails leading away from those low-lying spots. This underlies the importance of understanding the significance of low-lying terrain in "picking up the trail" of a potential gold source. Again, in desert or dry gold areas this task was made much easier because of the lack of overgrowth or heavy vegetation that could mask the presence of float.
(The venerable gold pan is still your best sampling tool.)
8) Don't get too hung up on modern technology. Although gold metal detectors and pinpointers undoubtedly can help the modern-day float prospector, I'll pass on this admonition to you. Most of the rich, free-milling gold float and its parent lodes or veins has (have) been found and worked, especially if the ore bodies were economically feasible for development and mining when gold sold for $35.00 (USD) or less an ounce. So most ores left behind, missed, or bypassed were not of a high-grade nature. Sure, there's still some potential in various locations for the stereotypical, fantasy gold-in-quartz float and parent lodes, but that would be a strong exception rather than the rule in today's world unless you're really out in the deep boonies somewhere. So the point I'm attempting to make is this: those neat detectors and pinpointers will work just fine if the float you're tracking contains free-milling gold of a certain size or amount, but lesser ores will NOT register on your machines for the most part, if at all. So depend mostly on your knowledge of gold ores and a keen eye out in the field. When the day comes when metal detectors can detect the slightest traces of gold in float we'll all be very rich men and women (or, at the very least, the lode gold we recover will pay for our machines!).
(A definite asset as a prospecting tool but not the end all.)
9) Learn as much as you can about "contact zones." Many of the important gold strikes in the American West and Southwest (as well as in other countries) were centered along or near geological "contact zones." Simply put, contact zones are where two diverse types of country rock or bedrock come together. There are three main types of contact zones:
a) Depositional contact zones are those where a sedimentary rock was deposited over or adjacent to a geologically "older" rock.
b) Intrusive contact zones are those where one rock type has intruded into another rock type.
c) Fault contact zones are those where different rock types come into contact with each other due to geological faults or "slips."
By the way, there are numerous other geological sets and subsets to these three main contact zone types as you'll see if you delve into them further.
Now there's really no excuse for not knowing more about the importance of contact zones when it comes to gold genesis. The United States Geological Service (USGS) is a good starting point for maps, books, master's and doctoral theses, periodicals, and all sorts of information related to gold geology and, specifically, contact zones. If you're fundamentally opposed to dealing with a Federal bureaucracy, then hit the library or better yet, start using your home computer or smart phone to research what it is you need to learn. Better yet, get out there in the field and start using your eyes.
10) The old timers knew the importance of vegetation changes or variations in earth and rock strata...so should you. In truth, even though we can apply a generic "Hansel and Gretel" approach to tracking float, on the far end we aren't searching for a gingerbread house decorated with all sorts of candies and gum drops. The "float" that Hansel and Gretel followed was easy to spot and read. The float we want to track is not so easy to discern in many instances but there can be visual clues or "giveaways" that we can use as signposts in finding that bypassed outcrop or lode. Dramatic vegetation changes are one of those giveaways. Sudden or significant changes in the color or type of earth beneath our feet or in the rocks around us are another. If we come across float at a location where the vegetation suddenly changes dramatically either in size, type, or coverage we may be onto something (changes in altitude notwithstanding). Chemical solutions in certain gold ores can leach out over time due to environmental forces and can "pollute" the soil around them. These chemicals can stunt or even "poison" surrounding vegetation. Sudden changes in rock formations or types can signal the presence of a contact zone around you or even underneath your feet. If float is found in this sort of situation, a closer look at things is necessary on your part. The old timers were keyed into these sorts of things even if they didn't fully understand them from a geological perspective.
11) Metamorphics are your best bet. I'm sticking my neck out here, but I hope not too far. Areas where moderate or significant metamorphic change has occurred in the surrounding geology or country rock provide the best opportunities for the small-scale guy or gal to encounter float tracking opportunities and alluvial, elluvial, and lode gold deposits. It doesn't matter whether this metamorphosis has occurred in mountains, foothill regions, or deserts. Your chances of finding gold (and gold ores) are increased in these geologic regions, especially in the Western and Southwestern U.S. and/or Alaska (or certain "other" parts of the world). Understand, however, that metamorphic rock is also found in regions devoid of gold or significant amounts of the yellow metal. This is where you have to know your shit, brothers and sisters. There isn't one great catch-all when it comes to getting the gold in metamorphic regions. Or any region, for that matter. But if you're searching for float to track I do think metamorphic rock structures (or underlying geology) give you your best bet. But again, I'm no degreed geologist...just a small-time gold prospector and miner.
(There's gold in this metamorphic contact zone.)
(c) Jim Rocha 2019
Questions? E-mail me at email@example.com