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#1

bjarvie
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Joined: 09 September 2017
Posts: 52
Member
06 June 2018 05:10 pm

Can anyone shed some light on resources for mapping the strike zone on topo maps when out in the field?

Thanks in advance

#2

bbayjohn
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From: Batemans Bay, NSW
Joined: 05 February 2017
Posts: 28
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06 June 2018 05:26 pm

something like this mabe? You can download google earth to your phone or gps and run your selected map on it.
http://golddetecting.forumotion.net/t22 … ogle-earth

#3

bjarvie
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Joined: 09 September 2017
Posts: 52
Member
06 June 2018 06:44 pm

bbayjohn wrote:

something like this mabe? You can download google earth to your phone or gps and run your selected map on it.
http://golddetecting.forumotion.net/t22 … ogle-earth

Thanks mate but not quiet what i'm after but appreciate the share all the same.

I'm talking about mapping the length and direction of a vein or rock formation's on your own in a systematic way.

#4

Hunting the yellow
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From: down a hole
Joined: 20 December 2012
Posts: 1,795
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06 June 2018 10:24 pm

Google rock logger app for your phone its for the dip and strike and for long distances use a gps and plot the line of reef


A dream written down with a date becomes a goal a goal broken down into steps becomes a plan a plan backed by action becomes reality.

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#5

SWright
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From: Wodonga, VIC
Joined: 15 October 2013
Posts: 317
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07 June 2018 03:16 pm

G'Day Bjarvie

I was an exploration geologist so might be able to help. First of all you have to know exactly where you are on the map or aerial photo. Or if you are using an electronic device the same thing applies. Get hold of a geological compass or a prismatic compass will also do. Go to the vein and take a reading of the direction of the vein, rock, cleavage, bedding or whatever the feature is you want to measure. That is the strike of the unit. Correct the reading for magnetic drift and you will have a true strike at that point. I would take several readings all over a unit from one end to another.

If you cannot get hold of a compass and you have a large scale map simply plot the position of one end of the vein and then go and locate the other end of the vein and the line between them is the strike when you plot it on a map. Beware though that in rugged terrain there will be distortions to the true strike if the vein is dipping at a shallower angle than the vertical. Also not all strikes measured on individual veins by any means represents the true strike of the vein systems as a whole.

Araluen

5 users like this post: Dolphin, Dron, Chewy, bjarvie, Ilikecash

#6

bjarvie
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Joined: 09 September 2017
Posts: 52
Member
30 June 2018 08:56 pm

SWright wrote:

G'Day Bjarvie

I was an exploration geologist so might be able to help. First of all you have to know exactly where you are on the map or aerial photo. Or if you are using an electronic device the same thing applies. Get hold of a geological compass or a prismatic compass will also do. Go to the vein and take a reading of the direction of the vein, rock, cleavage, bedding or whatever the feature is you want to measure. That is the strike of the unit. Correct the reading for magnetic drift and you will have a true strike at that point. I would take several readings all over a unit from one end to another.

If you cannot get hold of a compass and you have a large scale map simply plot the position of one end of the vein and then go and locate the other end of the vein and the line between them is the strike when you plot it on a map. Beware though that in rugged terrain there will be distortions to the true strike if the vein is dipping at a shallower angle than the vertical. Also not all strikes measured on individual veins by any means represents the true strike of the vein systems as a whole.

Araluen

Thanks for taking the time to to but together your detailed response - much appreciated.

Can you please elaborate more on this " Also not all strikes measured on individual veins by any means represents the true strike of the vein systems as a whole" does this mean that general rule of thumb is that parallel veins within x proximity will almost always follow the same strike path angle overall putting aside distorted areas?

Over what distance does this generally hold true?

#7

SWright
Member
From: Wodonga, VIC
Joined: 15 October 2013
Posts: 317
Member
01 July 2018 12:35 pm

G'Day Bjarvie

The geometry of veins and who they form can be very complex and the formation of gold within each vein can also add directional complexities. Most veins within major faults or shear zones are not gold bearing as they are generally through flowing systems. That means the fluids carrying the gold do not have time enough to react with the rock its flowing through. This is critical because if the gold is already dissolved you must do something to the composition of the fluid to cause it to drop its load as it were. So veins associated with a larger system that for example splay off the through going system are your best bet. These will be at angles determined by the depth of formation of the fault system, how brittle the country rock system is and so on. These "splay" systems are what you want to look for and are not always that big. A good example are En Echelon veins. They form at angles up to 30 or 40 degrees off the main shear or fault going both directions from the main vein. They form like gashes or S shaped systems like this /////// or \\\\\\\ and sometimes cross over. The direction of each gash is as you see each dash. The direction of the vein system however is along the page from left to right or visa versa. Have a google of "quartz vein geometry". For a slightly more complex discussion try
https://www.researchgate.net/figure/Str … _258781935

Araluen

2 users like this post: Prospector B, jethro

#8

jethro
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From: North East , VIC
Joined: 06 September 2013
Posts: 612
Member
05 July 2018 12:08 am

bjarvie wrote:

Can anyone shed some light on resources for mapping the strike zone on topo maps when out in the field?

Thanks in advance

Ive done a bit of strike mapping using waypionts logged on a GPS then converting to a KMZ file and uploading to Google earth. then looking at theextension at either end for and indications of further mineralization or cross faulting that may have cut off the lode or reef. or shifted it off the line of strike.

Last edited by jethro (05 July 2018 12:09 am)


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