Jump to content
Sign in to follow this  

Why So Many Big Nuggets In Oz

Recommended Posts

As I read the amazing "Reg Wilson" threads about the numerous large nuggets found in Australia I began thinking about the amazing depositional situation that created them.  I have "Googled" a bit to try and find any literature on the subject, but have not found anything to satisfy my curiosity.

 .  Can anyone recommend any papers or books that describes the creation of the Australian deposits.  I understand how gold is deposited, but what is unique about the Australian situation that resulted in so much large gold?




Share this post

Link to post
Share on other sites

Unlike most U.S. geologic information Australia reports and publications are largely private fee access type reports. Pub,ic reports are rare. Here is a start.

Victorian Gold Deposits 1998

“The Palaeozoic succession of Victoria represents a major world gold province with a total production of 2500 t of gold (i.e. 78 million oz). On a global scale, central Victoria represents one of the most gold mineralized areas outside the Witwatersrand of South Africa, and remains the prime example of a ‘slate belt’ gold province (also known as ‘turbidite-hosted’, or ‘shale-greywacke’ gold province).”

Victorian Geology

Geology of Victorian Gold Occurances 1908

  • Like 1
  • Thanks 1

Share this post

Link to post
Share on other sites

Thank you Steve.  I will certainly check these out.  

Geology is very interesting to me.  I graduated from Montana School of Mines (so named in 1963), but with a degree in Petroleum Engineering.  Nevertheless I did take courses in geology, petrology and mineralogy.  I forgot most it of over the years as I was more involved with the drilling and production of oil and wells.  I have renewed my interest in geology since taking up the hobby  of detecting for gold.  I missed out on the "golden age" of detecting while pursuing my career in Petroleum and raising a family in areas not even close to gold.  So be it.


Share this post

Link to post
Share on other sites

I always liked geology from a young age, and once thought I might go to college for it, but instead just learned from reading it for decades. Fascinating stuff. Here is a presentation that has some good maps, etc....

https://www.smedg.org.au/Bendigo Ionex Aug07.pdf

As far as "why" questions go it is always good to remember that even now most of what is presented are just theories. These guys for instance have a completely new theory as to the ultimate gold source for some Australian gold.

My old geology teacher put it thus when asked a "why" question - "the conditions were favorable". Prospectors simplify even that into "gold is where you find it"!

This one is not Australia but is one of my favorite recent summaries of gold deposit models:

Models and Exploration Methods for Major Gold Deposit Types." Ore Deposits and Exploration Technology, Paper 48. By Robert, F., Brommecker, R., Bourne, B. T., Dobak, P. J., McEwan, C. .J., Rowe and R. R., Zhou, X.

From the conclusion:

"There has been significant progress in the last decade in the understanding of the geology, settings and controls of the diverse types of gold deposits, including the recognition of new deposit types in new environments. Such progress has been paralleled with the development of data integration, processing and visualization techniques, and of advances in geophysical, geochemical and spectral detection techniques. Geologists are now better equipped than ever to face the increasingly difficult challenge of finding gold. However, one of the key lessons of the last decade, as reminded by Sillitoe and Thompson (2006), is that the exploration work needs to remain grounded in geology, especially in the field, and the elaborate detection techniques and tools available will only find their full power when closely integrated with a good geological framework."

Sounds like a prescription for successful nugget detecting to me!

  • Like 2

Share this post

Link to post
Share on other sites

I struck it rich! With this site that has a huge number of free downloads



Lots more there to explore.

  • Like 2

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Similar Content

    • By mn90403
      “Australia’s all-time record annual gold production (314 tonnes) … might well be exceeded*,” said Dr Sandra Close, from mining consultancy* Surbiton.
    • By phoenix
      The five cent piece is the smallest coin in circulation in Australia now and most of my photos where I have used a coin for scale I have used a 5 cent and the creature on the coin is the echidna.  In the 7 years I have lived in Victoria I have only ever seen maybe a dozen echidnas, but what makes this guy so special is this morning he was in my back yard.😯😯😯         The half grammer came from Cockatoo Bush a couple of years ago, but I have seen way more half grammers than echidnas. 🙂 Dave

    • By PG-Prospecting
      Ive attached a lidar map of the main area i prospect.  Id like to get peoples knee-jerk reactions on where they would swing a detector knowing large nuggets (they have generally been very crystalline with a few specimens found) have been found in the creek.  So what would be your number 1, 2, and 3 spots to focus on.  Ive detected around a good bit and have yet find anything outside of the creek, but i want to see if im missing something obvious. lol  
      Search Area 1.pdf
    • By DDancer
      This year, 2018, I'm working thru the year to pay up on last years not so great stab at a golden prospects in Australia last year, 2017.  It was a great trip, always is, but a lot of little factors kept me gold poor *which I use to pay for food, fuel and amenities* so I leaned on the credit card a little to hard.  Hahh!  No one ever said I'd get rich but ehh~ One can dream by the camp fire.~~  Another driving factor for this post is that my email does not like to send pictures so this is for you all who have asked "Where are the pictures?" when I tried to send them.
      Well that aside Its Always A Good Go down under.  I stayed mostly in the region of Kalgoorie last year, hard hunted land that, so I could be of help and hang around with my mates in Coolgardie while they fixed up a new caravan and ute.  The gold was small and hard to come by but I still got a few ounces in littles from the EL's I applied for, and yes sent the reports in for, but in all here are a few good days on the scales :

      And here are what most days went like.  I only had a few days streaches during the weeks out bush where I caught the skunk... but I entertained myself otherwise 😉

      I did find one small meteorite but it chose to find the hole in my pocket instead of coming home with me.  Bugger.  But while I was out and about I decided to look for another mineral I knew occured in the region were I was and took a few days driving the fence lines to find it.  Chrysoprase.  Never did find the mine that my mate pointed me towards but I did find an area that had the right indicators, what is called white and blue chrysoprase and chalcedony, and on stopping there I took a couple of days to speck around.

      I was finding mostly low grade stuff, the above picture, but found one good bit with just the tip sticking out like an iceberg:

      Among other interesting rocks like this one, semi-crystalline quartz with some nice shiny bubbly limonite and from another area of flats a fulgerite, solidified lightning strike:

      So my rock hounding itch was scratched 🙂
      Now camp is always a treat in the mornings and evenings but I also mentioned I kept myself entertained on days when I was not finding much.  Aside from just enjoying nature and walking Kays getting no where on the gold a few days of yabbie fishing made for a great reliefe after catching the skunk.  I visited various dams nearby and treated myself to a Yabbie feast on many evenings.

      So all in all a great time, good eats and nice finds.  If you want to go my suggestion is : Make a Plan and stick to it.   You wont be dissapointed.  There were a great many other things that occured but like I said, a short story.
      Regards and go live the dream.  Next year who knows..... I'm thinking opal or sapphires myself with a little gold and yabbie.

      Thanks for reading,

    • By Edsped
      I’ve taken the equinox underwater with the Hungarian headphones twice now and I think I’ve experienced the best and worst scenario for the equinox.
      Firstly I went into a popular rock pool which I’ve detected successfully with one of my Pulse Induction machines (ATX) with decent success although I did ok, I had to greatly reduce sensitivity and increase pulse delay for it to be stable but still it was enough to find about 60 coins and a few rings in this small pool HOWEVER, the equinox was very very unhappy in these conditions and struggled to signal when the coin was placed on the rocks which was 2- 3 inches on our 10c coins (which is very similar in size and conductive to a nickel and therefore general gold ring territory) but when detecting purely through salt water it was capable of 7-8” on the same coin (just estimating but it was MUCH more than over the rocks)
      I messed around with sensitivity, discrimination, different modes (was using beach 2), sweep speed, swing height, ground balancing with tracking on and off, recovery speed as well as testing to see if the test items would register in all metal (if they came up as iron) to no avail, I don’t know what kind of rock it is but detectors clearly don’t like it.
      Next outing was a sandy beach with sandstone rocks and clay base which the detector functioned adequately over.  I only used beach 2 and found recovery speed 4 is good because swing speed is slower under water so theoretically gives more depth, the sensitivity couldn’t really be run over 14 (I was 2m deep in salt water) at this location apparently but 10c targets were recoverable from 8” 
      The Hungarian headphones aren’t very loud underwater (even to my 24 year old ears) which seems to be a theme with the equinox so I believe it COULD be that the 3.7V lithium battery is insufficient to run these kind of Piezo’s but I’m far from an expert.
      Anyway, the nox went well and found some smaller than usual gold pieces 👍
      Today’s treasure:

    • By Steve Herschbach
      I like some of the creative photography experiments here with gold nuggets and more....