Identifying ultramafics in wa

View previous topic View next topic Go down

Identifying ultramafics in wa

Post  goldchaser on Fri Jan 20, 2017 8:51 pm

Ok gurus school me please,i get confused amongst the low silica rocks over here,the ultramafics are as far as i know are igneous but ironstone is sendimentry,id like to be able to tell the difference on the ground,ironstone quartz,greenstone laterites etc im fine with but sometimes im sure some of the ironstone we find gold near maybe is not ironstone but ultramafic material im not sure,magnetite type material?
 I think its an interesting subject cause walking the hills we see all different types of ironstone,some shiny(not laterite pebbles) brown threw to near near polished black outcrops,will expand some more tomorrow etc,just informed where late for a bbq......


Last edited by goldchaser on Fri Jan 20, 2017 8:53 pm; edited 1 time in total (Reason for editing : spell check)
avatar
goldchaser
Contributor Plus
Contributor Plus

Number of posts : 1219
Age : 50
Registration date : 2009-03-20

Back to top Go down

Re: Identifying ultramafics in wa

Post  goldtalkleonora on Fri Jan 20, 2017 10:30 pm

Hi Goldchaser....mate...I'm just a busted A*s* prospector and definately no rocklicker (geo) so take anything i have to say with caution.
It's a bit hard to work out what it is your actually asking?? My opinion for what it's worth is don't worry about Ultramafics other than....if you see green (olivine) then look REAL hard as it's a great indictaor. Your ironstone is a far better indicator for gold than QTZ...and the small shiny round balls you mention are also a VERY good sign. Pisolites refer to the formation of the little ironstone balls (you can get pisolitic limestone for example) and as luck would have it gold nuggets can be formed in a silmilar fashion......point is....ANYWHERE near old or new mining activity and you see massive Fe pisolites...detect it. QTZ has little to do with it....Fe is the key. Don't know if that's what your after????
avatar
goldtalkleonora
Good Contributor
Good Contributor

Number of posts : 121
Registration date : 2015-06-01

http://www.goldtalkleonora.com.au

Back to top Go down

Re: Identifying ultramafics in wa

Post  goldchaser on Sat Jan 21, 2017 11:17 am

goldtalkleonora wrote:Hi Goldchaser....mate...I'm just a busted A*s* prospector and definately no rocklicker (geo) so take anything i have to say with caution.
It's a bit hard to work out what it is your actually asking?? My opinion for what it's worth is don't worry about Ultramafics other than....if you see green (olivine) then look REAL hard as it's a great indictaor. Your ironstone is a far better indicator for gold than QTZ...and the small shiny round balls you mention are also a VERY good sign. Pisolites refer to the formation of the little ironstone balls (you can get pisolitic limestone for example) and as luck would have it gold nuggets can be formed in a silmilar fashion......point is....ANYWHERE near old or new mining activity and you see massive Fe pisolites...detect it. QTZ has little to do with it....Fe is the key.  Don't know if that's what your after????

Thanks Tony yep thats how we roll most the time and have had some success,not much lately though i can tell ya that,spend alot of time on the laterites but rarely get anything unless theres ironstone reefs coming up threw it,and yep we dont worry about the quartz but it usually wont be to far away and especially greenstone if theres gold around
 Sometimes out there amongst areas mainly heavy with laterites-ironstone reefs etc i wonder if the odd outcrop is actually ironstone or am i seeing ultramafics on the odd occassion,on the ground after 4+ yrs in wa im starting to get there,took a couple of years and finding bits and runs in virgin ground helps,not really a question thats easily answered unless ya have a geo out there with you i supposse.
Heres another question,have you found patches on the lower laterites (the heavily weathered hills with small pissolite gravels) with no other outcrops around,to me they seem barren of gold if nothing elses has come up through them. I call them the lower laterites as opposed to the hills with the caps slowly breaking down and they are usually the more coffee rock colour.
Anyway where off on a faultline today looking about,might take cuppla pics as its the type of country as above.......
avatar
goldchaser
Contributor Plus
Contributor Plus

Number of posts : 1219
Age : 50
Registration date : 2009-03-20

Back to top Go down

Re: Identifying ultramafics in wa

Post  goldtalkleonora on Sat Jan 21, 2017 2:41 pm

g'day Goldchaser.....yes...laterites are our speciality. It's tricky when you see geology outcropping...like you said about the ironstone. It could be an in situ structure or it could easily be 'float' ie transported material. Don't forget that pieces float around that could have started off bigger than a house...100 million years later you see the bits about the size of a car and smaller. If your working laterites then you need to understand supergene (secondary) enrichments...come and do a course and I'll tell you all about them !! Laterites are where the big patches still are today...and very few people work them. You also have to bring significant errosion into the equation....which means the gold could be anywhere!! and movement within the near surface weathering environment....around Leo/Lav that's 0m up to 100m deep.
avatar
goldtalkleonora
Good Contributor
Good Contributor

Number of posts : 121
Registration date : 2015-06-01

http://www.goldtalkleonora.com.au

Back to top Go down

Re: Identifying ultramafics in wa

Post  adrian ss on Sat Jan 21, 2017 7:17 pm

goldchaser wrote:Ok gurus school me please,i get confused amongst the low silica rocks over here,the ultramafics are as far as i know are igneous but ironstone is sendimentry,id like to be able to tell the difference on the ground,ironstone quartz,greenstone laterites etc im fine with but sometimes im sure some of the ironstone we find gold near maybe is not ironstone but ultramafic material im not sure,magnetite type material?
 I think its an interesting subject cause walking the hills we see all different types of ironstone,some shiny(not laterite pebbles) brown threw to near near polished black outcrops,will expand some more tomorrow etc,just informed where late for a bbq......

Ultramafic Rocks:
Are realy realy good diamonds wot av been smuggled out of Africa by tha Mafica.....To easy aye!!?  T29

Yeah well it was too much temptation. DOH!


Last edited by adrian ss on Sun Jan 22, 2017 7:11 am; edited 1 time in total
avatar
adrian ss
Contributor Plus
Contributor Plus

Number of posts : 1077
Age : 70
Registration date : 2015-07-03

Back to top Go down

Re: Identifying ultramafics in wa

Post  goldchaser on Sat Jan 21, 2017 9:05 pm

Not big on courses tony im a bit old school (learn on the ground)but i might be tempted if your courses are more geology related that sounds interesting,i dont want to spend half a day listening about different detector settings mate,you know where im coming from,so if its mainly geology yeah might be in for sure,things went better today,found gold on this faultline,so have a start on some ground that i dont think has seen much attention yet if any,had to chip a 12gr bit out of cap rock and of course hammer and chisel were at home in the quad,so 2  1/2 hr round trip,didnt have time to take any pics of the ground today sorry
avatar
goldchaser
Contributor Plus
Contributor Plus

Number of posts : 1219
Age : 50
Registration date : 2009-03-20

Back to top Go down

Re: Identifying ultramafics in wa

Post  flyspecks on Sat Jan 21, 2017 9:48 pm

Well done on the 12grammer dave, looks like your just about to hit the mother load. Smile
avatar
flyspecks
Contributor Plus
Contributor Plus

Number of posts : 932
Registration date : 2011-05-17

Back to top Go down

Re: Identifying ultramafics in wa

Post  goldtalkleonora on Sat Jan 21, 2017 9:53 pm

if you dig some more out of the cap..let me know...you could be onto a good dab.
avatar
goldtalkleonora
Good Contributor
Good Contributor

Number of posts : 121
Registration date : 2015-06-01

http://www.goldtalkleonora.com.au

Back to top Go down

Re: Identifying ultramafics in wa

Post  goldchaser on Sat Jan 21, 2017 10:19 pm

goldtalkleonora wrote:if you dig some more out of the cap..let me know...you could be onto a good dab.

will do tony,i'll check ya courses out but wont be up through leo until may id say,working some back country south until it cools but might slip up and learn some more on laterites earlier depending on your dates,we havent done anything on our block we spoke about also,if ya coming to kal give us a buzz
hope so flyspecks,overdue for a decent run thats for sure Very Happy
avatar
goldchaser
Contributor Plus
Contributor Plus

Number of posts : 1219
Age : 50
Registration date : 2009-03-20

Back to top Go down

Re: Identifying ultramafics in wa

Post  goldtalkleonora on Sun Jan 22, 2017 10:57 am

Hi Goldchaser,
Probably your time on the ground will teach you what you need to know. As long as your aware of it...then you'll look for it and the rest is just hard work!!
Best of luck.

Tony Pilkington
avatar
goldtalkleonora
Good Contributor
Good Contributor

Number of posts : 121
Registration date : 2015-06-01

http://www.goldtalkleonora.com.au

Back to top Go down

Re: Identifying ultramafics in wa

Post  goldchaser on Tue Jan 24, 2017 11:42 am

goldtalkleonora wrote:if you dig some more out of the cap..let me know...you could be onto a good dab.

nothing zero zilch tony,combination of around 12hrs in the area not one other signal,no rubbish about either,the bit was in a fair size washout in a gully so the slopes we hit and i spent a fair amount of time looking for ironstone outcrops upstream on the ridges to no avail,then 250 mtrs due south i found a broken down ironstone reef,i thought here we go but not a target there either and it did skirt the edges of where the laterites  are laying also,steeper hills ridges etc are mainly greenstone,these spots do my head in sometimes,klm's sqr of ground and ya walk straight onto something decent then put the time in for no results,we'll move along a bit and float back here on the odd occasion
avatar
goldchaser
Contributor Plus
Contributor Plus

Number of posts : 1219
Age : 50
Registration date : 2009-03-20

Back to top Go down

Re: Identifying ultramafics in wa

Post  Reno Chris on Wed Jan 25, 2017 4:39 pm

Ultra-mafic rocks include things like Dunite and Peridotite, and rocks formed by their alteration like serpentine. They are rocks with lots of iron and magnesium, and only a little silica. They are often found in and around greenstone belts. The problem in WA is that everything is so strongly weathered on the surface, its all just red clay and laterite. I was in WA and finding gold for a week before I saw an outcrop of unweathered rock that looked like the greenstone I am familiar with. When you walk over red clay and laterite in WA, it might well be greenstone or ultramafics underfoot, but you'd never know it unless you dig a hole down 20 meters to get through the weathered zone.
avatar
Reno Chris
Good Contributor
Good Contributor

Number of posts : 106
Registration date : 2010-04-07

Back to top Go down

Re: Identifying ultramafics in wa

Post  Guest on Wed Jan 25, 2017 4:54 pm

Reno Chris wrote:Ultra-mafic rocks include things like Dunite and Peridotite, and rocks formed by their alteration like serpentine. They are rocks with lots of iron and magnesium, and only a little silica. They are often found in and around greenstone belts. The problem in WA is that everything is so strongly weathered on the surface, its all just red clay and laterite. I was in WA and finding gold for a week before I saw an outcrop of unweathered rock that looked like the greenstone I am familiar with. When you walk over red clay and laterite in WA, it might well be greenstone or ultramafics underfoot, but you'd never know it unless you dig a hole down 20 meters to get through the weathered zone.

Totally agree mate, I have spent many years in WA prospecting and very rarely see unweathered rock.
Better of studying up on supergene enrichment, and learning the associated minerals.

( clarification for those confused by the terminology, mafic means dark, so ultramafic just means very dark rocks )

Guest
Guest


Back to top Go down

Re: Identifying ultramafics in wa

Post  goldtalkleonora on Wed Jan 25, 2017 5:50 pm

Hi Renochris....it's all "mud" over here mate.

Goldchaser...I have sent you a pm mate.....
avatar
goldtalkleonora
Good Contributor
Good Contributor

Number of posts : 121
Registration date : 2015-06-01

http://www.goldtalkleonora.com.au

Back to top Go down

Re: Identifying ultramafics in wa

Post  goldchaser on Thu Jan 26, 2017 5:19 pm

thanks fellas,reno cris where i work (superpit),wish i could get a good pic,on our western wall you can see large dips in the geology between the greenstone base up to about 100mtrs odd and heavily weathred down to roughly 150mtrs in some spots,its an eye opener but good to see as its just a huge cross cut of the ground,laterites-oxides and the orange stuff(saprolite?) down fairly deep,as tony said laterite up to 100mtrs deep in areas,you'd get a kick out of it,its a good sight.....
geez id love to be let lose with an excavator and detector on a few of these dips,could be a whole lot of fun im thinking.....
avatar
goldchaser
Contributor Plus
Contributor Plus

Number of posts : 1219
Age : 50
Registration date : 2009-03-20

Back to top Go down

Re: Identifying ultramafics in wa

Post  Sponsored content


Sponsored content


Back to top Go down

View previous topic View next topic Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum