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Tertiary Rivers

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I have not done much book learning on this subject. In my travels I see things and wonder. In traveling down I-17 are places that look good for prospecting but the land is covered with lava, for lack of the proper word, and in some places it sure looks to me like theese later "lava" flows really changed the landscape like some of the places in CA. I think what I am wondering, has anyone found a place like this, in AZ, where they have found gold in a aceient stream that was covered with lava?

This is a yes or no question, I am not asking for anyones seceret spot. Thanks, Bunk

Bunk, I am still reading the USGS article on the Bradshaws. While it is not clear if this is Quatenary or Tertiary gravel, under PLACER DEPOSITS I found (P. 54):

Placer gravel has been worked in Minnehaha Flat and on Grove

Creek; on Chaparral Gulch and the adjoining ravines, near Mc-Cabe:

in Bigbug Creek as far down as Mayer; in Black Canyon from the

vicinity of Turkey Creek station to the junction of Turkey Creek with

Agua Fria River; in several gulches of the Humbug district, near the

south border of the quadrangle; and in Castle Creek, in ravines near

Copperopolis.

I hope you find that useful.

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Bunk-

"Placer gravel has been worked in Minnehaha Flat and on Grove

Creek; on Chaparral Gulch and the adjoining ravines, near Mc-Cabe:

in Bigbug Creek as far down as Mayer; in Black Canyon from the

vicinity of Turkey Creek station to the junction of Turkey Creek with

Agua Fria River; in several gulches of the Humbug district, near the

south border of the quadrangle; and in Castle Creek, in ravines near

Copperopolis"

I live there (black canyon city), this is my first post on these forums.

The bulk of the gold in the east side of the Bradshaw's IS from the Precambrian rock, spotable by the blue/green color (Yavapai schist formation) that says "I was formed with no oxygen". These are ancient "horizons" formed by black smokers when this was seabed. These horizons folded into the hills you see lining the east side of the Bradshaw's via the fault that runs approx N/S on the entire east side of the Bradshaw's.

That said, there are ancient riverbeds on the sides of those same hills from the south end of the Bradshaw's (minihaha flats through tip top) on north past Bumble Bee, Cleator, and in spots on all the hills surrounding the McCabe. There are signs of a single massive flood that deposited a red dirt filled with rounded yellow granite, complete with ancient charcoal indicating a massive fire that cooked the bedrock and released masses of flakes and dust when the rains came after the fire. These red, reduced beds of placer are found in thousands of places along the Bradshaw range. The best known examples come from big bug creek south of Mayer and the Minihaha.

An older river bed is found on the tops of most of the hills lining the east side of the Bradshaws, this ancient flow leaves MASSIVE hematite boulders smoothed like glass. In places there are thousands of chunks of hematite forming an obvious riverbed, complete with the heavier semi-precious stones like opalised agates mixed in with the massive, smooth hematite.

Wherever you find the massive hemitite, you should find good chunks of gold. I believe much of these deposits were mined, not just by whites in the last 500 years but the huge Anasazi ruins somewhat replicate the deposition of these massive hemitite riverbed deposits. The bulk of this mining was done by hand picking, so there are plenty of nuggets left for us.

Once a person has seen the products of Rich hill on the west side of the Bradshaws, the imagination gets carried away :)

As for your thoughts on the lave flows, I agree. I have seen the V of a stream bed full of lava in the road cuts along I17, thinking there must be remelted gold in the lowest part of the V. Just remember the lava's temperature was hot enough to vaporise the gold, unless it was rolled over & covered, it "steams" away from lava.

At least 5 one ounce+ nuggets have come from within a mile of my house in the last twenty years, all from the ancient Hematite deposits OR from the schist, almost all detected. some with REALLY cheap detectors (red baron anyone?).

Found a 4 grain nugget last Saturday, used my buddies 3500 minelab WHAT A MACHINE!

Found a handful of old bullets too, thought the one from between the huge boulders 24 inches down would turn out to be the big nugget of the year, 400 grain 45/70 bullet instead. Owell, the 4 grain nugget put extra shine on an already beautiful day.

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