How Come .......?

[Joe S (AK)]

So, why are there sometimes separate and distinct 'types' of Gold on a claim - at least where I work, and have worked, South of Denali Park? Sometimes the color is a bit different or sometimes sizes are distinct or sometimes the ground is just very different in color or texture or composition, corresponding to the differences in the found Gold.

Last winter I was trying to explain some of the reasons for that to mining friends in Australia and since it was a slow time of the winter I worked up something that was at the same time amusing, somewhat factual and easy to follow.

Whadda you think?

********

It's mid-winter in 2018 and I'm sitting in Northern Idaho waiting for Spring.

If I may, let me expand a bit on glaciers - and since I work 100% of the time in glaciated ground in Alaska, maybe I can let a bit of my hard fought (50+ hard years in the making) knucklehead knowledge rub off.

Also -----Lets make it fun, too!

Mentally, sit at a clean table with your elbows on the table. (It's OK, Mom said you could.) Put your arms straight out in front of you on the table, hands together. Starting under your chin and flowing straight away from you, and under your hands, is "Your Stream" on "Your Claim". Behind your back on each side are two mountain ranges. Behind your Left shoulder are 'The Left Mountains' and behind your right shoulder are 'The Right Mountains'.

To start off with let’s say that there is no Gold, at all, anywhere in front of you. None, Zip, Nada, Narry a bit! Let’s also say, for simplicity, that the "My Claim River" flows as it always has - straight from under your chin, under your hands and straight away to the edge of the table. A simple situation, right?

Now, from the Left Mountains a glacier develops. "The Left Glacier" builds in height and slowly starts to scour, cut, gouge and scrape off every hill and every bit of dirt from in front of its path. The extremely high ice wall pushes all this "stuff" in front of (or in top of) itself and it slowly flows around your left side to fill in the My Claim river valley in front of you with that loose rubble – all the way up to the top of the valley. The hills and small mountains that were sheared off and ground up by the Left Glacier had Gold buried in them, and so there is now "Red Gold" (some Copper in it as a natural alloy) left behind in the “Filled to the Rim” My Claim river valley.

Eventually things warm and the glacier melts in place. Thousands of years of rains and floods wash the lighter material downstream and off the edge of the table - leaving 'heavies' and Gold behind in the depressions in the bedrock under the "My Claim Stream". (Source and deposition of "Red Gold" in "My Claim River".)

'Things' calm down and weathered rock turns into soil, grasses, bushes and then trees return and grow and the streambed slowly returns to "normal".

Then the exact same thing happens when "The Right Glacier" develops and comes around from your right rear side. The Right Glacier again fills the river valley to the very top with it's shredded smaller mountains that the glacier has ground up. This time the Gold that was "acquired" by the glacier is "Light Gold" (some Silver content in the natural alloy) and it deposits over top of the remains of the Left Glacier, burying the old deposits of sand, gravel, clay, organic soils and Gold.

The wash-out and tree growing cycle occurs again. (Source and deposition of "Light Colored Gold" in "My Claim River".)

What is now left on My Claim and in the My Claim River are two separate "types" of Gold usually separate in their own layers but sometimes all jumbled together.

Kilometers high glaciers can carry rubble many Kilometers- or MANY, many Kilometers in front of themselves. When the climate changes and a glacier loses movement, beginning to 'stall', the Ice movement stops and it melts in place. As that happens,the wall of material being pushed drops in place - forming a "Terminal Moraine". Massive flooding results from the ice melting, creating Glacial Outwashes which can create massive clay, sand, gravel or boulder deposits over top of older deposits.

**************

Fun story - right? How accurate could it be, you ask?

**************
You, sitting at the table, are "Gopher Mountain" in the foothills on the South edge of Denali (Mt. McKinley) Park in Alaska. It is the site of a current, mine, belonging to a close friend of whom I have known for many years. I will have been mining there, off and on in the summers almost every year for 18 years this coming summer.

Both Right and Left Glaciations, coming from behind and on each side of Gopher Mountain occurred at least once. Those glaciations actually flowed around Gopher Mountain, leaving it's top as original with fill all around it.

"My Claim River" is on "Little Willow Creek" and the same claim is still there today. It still flows into Petersville Creek (just over the far edge of the table) near The Petersville State Recreational Mining Area.

The "Red and Light colored Gold" occurrences were borrowed from the Crow Creek area which is South of Anchorage and occurred at least 5 times. Some were small and some were large glaciations. Some glaciations carried more (and larger sized) Gold and some less while the colors of the Gold were different. The Glaciations came from not around a mountain at THAT location, but usually down the river valley. One glacier possibly traveled UP the valley (crazy, eh!)

In this large region of Alaska the Gold tends to be shallow, and due to that, when a glacier grinds the area down into bedrock there is no more Gold to be had from that singular source so it is (or can be) completely removed by the moving glacier. Since the natural alloy of Gold from one occurrence to another is often different, the placer deposits (from different events) can, at times, be quite different in appearance and travel with entirely different types of gravel and rock.

The claim that I own, on Gold Creek, is a high mountain claim and probably only had one or possibly two glaciations --- but --- the glaciers came from over the crest of the mountains and traveled sideways, **across** the small valley. My claim is located 2 streams to the West of my long time buddy's claim and is also on the South edge of Denali Park.

Joe

[Geowizard]

Imagine a Bulldozer;

Imagine a Bulldozer with a 10,400 foot wide blade...

Image, if you can at least 20 other bulldozers with blades a couple thousand feet wide pushing ground up mountain tops into the path of the dozer 3 miles above your mining claim...

Glacial Morain (gravel) 300 meters wide x 30,000 meters long x 300 meters deep = 900,000,000 cubic meters being pushed by another 900 million cubic meters of glaciers and till in the high country...

Scrambled Placer GOLD from hundreds of LODE deposits (maybe more) up in them-thar hills!

- Geowizard

[chickenminer]

Joe,
I'm glad class is in session .
Enjoyed your synopsis. Different gold coming off the same creek is always a
fascinating topic.
Must be a challenge figuring out those glaciated streams.

I've been amazed at the difference in gold I'm getting form the bench levels as
opposed to current creek level.
Every cleanup is like Christmas !

[Geowizard]

Putting on the x-ray glasses;




- Geowizrd

[Geowizard]

The purple regions;

This is a contour map of Resistivity in Joe's back yard...

North is up and Joe is kinda down on the lower right (South-East). You can see the township corner at the lower right of the image.

The purple regions are low Resistivity (conductors)... Glacial movement was from North-West to South-East.

(hint: Gold Nuggets are conductors)...

- Geowizard

[Geowizard]

The (yellow) bulls eyes;

Quartz intrusives are circular or nearly circular... yellow or green. Green is better...

- Geowizard

[Geowizard]

Quartz intrusives;

Quartz is made of silica...

Silica is the same as glass and is non-conductive... It is the common source of GOLD.

The GOLD in nugget form is not connected and does not give a geophysical response like a massive sulfide or other major conductor.

There's more....

- Geowizard

[Lanny]

So, why are there sometimes separate and distinct 'types' of Gold on a claim - at least where I work, and have worked, South of Denali Park? Sometimes the color is a bit different or sometimes sizes are distinct or sometimes the ground is just very different in color or texture or composition, corresponding to the differences in the found Gold.

Last winter I was trying to explain some of the reasons for that to mining friends in Australia and since it was a slow time of the winter I worked up something that was at the same time amusing, somewhat factual and easy to follow.

Whadda you think?

********

It's mid-winter in 2018 and I'm sitting in Northern Idaho waiting for Spring.

If I may, let me expand a bit on glaciers - and since I work 100% of the time in glaciated ground in Alaska, maybe I can let a bit of my hard fought (50+ hard years in the making) knucklehead knowledge rub off.

Also -----Lets make it fun, too!

Mentally, sit at a clean table with your elbows on the table. (It's OK, Mom said you could.) Put your arms straight out in front of you on the table, hands together. Starting under your chin and flowing straight away from you, and under your hands, is "Your Stream" on "Your Claim". Behind your back on each side are two mountain ranges. Behind your Left shoulder are 'The Left Mountains' and behind your right shoulder are 'The Right Mountains'.

To start off with let’s say that there is no Gold, at all, anywhere in front of you. None, Zip, Nada, Narry a bit! Let’s also say, for simplicity, that the "My Claim River" flows as it always has - straight from under your chin, under your hands and straight away to the edge of the table. A simple situation, right?

Now, from the Left Mountains a glacier develops. "The Left Glacier" builds in height and slowly starts to scour, cut, gouge and scrape off every hill and every bit of dirt from in front of its path. The extremely high ice wall pushes all this "stuff" in front of (or in top of) itself and it slowly flows around your left side to fill in the My Claim river valley in front of you with that loose rubble – all the way up to the top of the valley. The hills and small mountains that were sheared off and ground up by the Left Glacier had Gold buried in them, and so there is now "Red Gold" (some Copper in it as a natural alloy) left behind in the “Filled to the Rim” My Claim river valley.

Eventually things warm and the glacier melts in place. Thousands of years of rains and floods wash the lighter material downstream and off the edge of the table - leaving 'heavies' and Gold behind in the depressions in the bedrock under the "My Claim Stream". (Source and deposition of "Red Gold" in "My Claim River".)

'Things' calm down and weathered rock turns into soil, grasses, bushes and then trees return and grow and the streambed slowly returns to "normal".

Then the exact same thing happens when "The Right Glacier" develops and comes around from your right rear side. The Right Glacier again fills the river valley to the very top with it's shredded smaller mountains that the glacier has ground up. This time the Gold that was "acquired" by the glacier is "Light Gold" (some Silver content in the natural alloy) and it deposits over top of the remains of the Left Glacier, burying the old deposits of sand, gravel, clay, organic soils and Gold.

The wash-out and tree growing cycle occurs again. (Source and deposition of "Light Colored Gold" in "My Claim River".)

What is now left on My Claim and in the My Claim River are two separate "types" of Gold usually separate in their own layers but sometimes all jumbled together.

Kilometers high glaciers can carry rubble many Kilometers- or MANY, many Kilometers in front of themselves. When the climate changes and a glacier loses movement, beginning to 'stall', the Ice movement stops and it melts in place. As that happens,the wall of material being pushed drops in place - forming a "Terminal Moraine". Massive flooding results from the ice melting, creating Glacial Outwashes which can create massive clay, sand, gravel or boulder deposits over top of older deposits.

**************

Fun story - right? How accurate could it be, you ask?

**************
You, sitting at the table, are "Gopher Mountain" in the foothills on the South edge of Denali (Mt. McKinley) Park in Alaska. It is the site of a current, mine, belonging to a close friend of whom I have known for many years. I will have been mining there, off and on in the summers almost every year for 18 years this coming summer.

Both Right and Left Glaciations, coming from behind and on each side of Gopher Mountain occurred at least once. Those glaciations actually flowed around Gopher Mountain, leaving it's top as original with fill all around it.

"My Claim River" is on "Little Willow Creek" and the same claim is still there today. It still flows into Petersville Creek (just over the far edge of the table) near The Petersville State Recreational Mining Area.

The "Red and Light colored Gold" occurrences were borrowed from the Crow Creek area which is South of Anchorage and occurred at least 5 times. Some were small and some were large glaciations. Some glaciations carried more (and larger sized) Gold and some less while the colors of the Gold were different. The Glaciations came from not around a mountain at THAT location, but usually down the river valley. One glacier possibly traveled UP the valley (crazy, eh!)

In this large region of Alaska the Gold tends to be shallow, and due to that, when a glacier grinds the area down into bedrock there is no more Gold to be had from that singular source so it is (or can be) completely removed by the moving glacier. Since the natural alloy of Gold from one occurrence to another is often different, the placer deposits (from different events) can, at times, be quite different in appearance and travel with entirely different types of gravel and rock.

The claim that I own, on Gold Creek, is a high mountain claim and probably only had one or possibly two glaciations --- but --- the glaciers came from over the crest of the mountains and traveled sideways, **across** the small valley. My claim is located 2 streams to the West of my long time buddy's claim and is also on the South edge of Denali Park.

Joe

Loved this explanation, and that's why the most recent places I've worked had three distinct types of gold in the same ancient channel. I loved how you provided a great visualization for the process.

All the best,

Lanny