Deep Leads - New Brunswick's Potential for Buried Placer Gold Deposits
Deep leads or Buried placer gold deposits are challenging targets for prospectors to locate given the obvious, they are buried. These alluvial gold deposits though are different than your conventional high bench deposits or ancient channel deposits as they are much deeper, older and form as a result of different processes.
Buried gold placer deposits form in deep valleys which in ancient times would have had gold bearing streams or rivers occupying them. Over times these valleys have become filled by layers of clay, gravel and sand which can be hundreds of feet in depth. The other way that these deposits form is through volcanic activity. The old streambeds over time carve gutters into the valley floor which hold the gold in situ. From there volcanic activity can completely fill the valley in with volcanic rocks such as basalt creating a completely new landscape which gives no indication of the riches beneath. These deposits were extensively worked in Australia in the Victoria gold district. Although these deposits can prove to be very profitable they are seldom worked as they require extensive equipment and are exceedingly difficult to locate. I have provided the best example I could find of a deep lead.
You can see in the photo below the gold deposits are confined beneath a basalt flow which makes it nearly impossible to reach without first tunneling through the rock.
Is there potential for these deposits in New Brunswick? Well I think the closest thing we have to deep leads could be buried in the moncton area. Sedimentary rocks covered by peat bogs have shown good gold grades and given the geology of these areas old rivers could have formed deposits deep beneath these. Really the only way to find out is to drill target areas and send the drill cores away for analysis, hoping that you don't go broke before you find one.
One theory that I have regarding gold in these deep lead deposits is areas which glacial deposits have completely filled previously gold bearing areas. While looking at surfical maps of the province we do find that there are some regions where glacial till is meters upon meters deep. Look at that data now we have to wonder if in earlier times the bedrock at the base of these depressions would have hosted gold bearing streams. One example of this I can provide is in the 21/h05 NTS block of our province. At the base of a mountain I stumbled across and area which appeared to have an underground stream flowing through it. It looked like a sinkhole in the valley and was several hundred yards from any body of water. The washout was about 8ft deep and I could see bands of sand and gravel sorted through the strata. Against my better judgement I dug down in the washout and panned samples from each zone. I didn't find gold but there was lots of black sands. As I progressively got deeper I was getting into a dangerous situation, sand/gravel are unstable so digging to any depth isn't safe without proper equipment. Just before I called it quits I hit something in the bottom of the hole. A large boulder with waterworn features on it. At this point to get a sample I had to have my prospecting partner hold me by my legs while I reached in to grab a sample. I panned it and found even more black sand than the higher levels. Had I found an old riverbed? Where the water still flows undergound and is only now showing due to increased precipitation? Who knows. it's too dangerous to find out and honestly I would love to go back there to see if I can find some gold but I just don't have the resources. For now I will keep this place a secret. Maybe in the future I will find out. I think the biggest thing I'm indicating here is keep an open mind when you are looking for gold. Mother nature has done some incredible things over the years and there are alot of processes that took place in our province that we are still not aware of today.
Hope you all enjoyed. - Until next time.
JMR
