Stories about Norilsk.

One more story about Norilsk region.

Each time you hear one more company presents its Cu-Ni-PGE exploration project, and it is outside of Australia or Indonesia, I bet they would refer to all signs for a "second world class multibillion Norilsk-type deposit" (actually, there are seven of them in Norilsk-Talnakh ore field, but who counts?). The problem is that even among the whole Norilsk region (roughly 40,000 sq.km) that ore field (400 sq. km) is rather unique. There's only one more deposit in the region (Imangdinskoe) that is similar to Norilsk-Talnakh ore field. Therefore, in the real life you could expect anything from exploration, but everyone loves that story about "second Norilsk deposit". About one "outlier" object with native iron I wrote previously, now I want to tell about another one - we don't know what is that hahaha

Disclaimer: all the data is publicly available.

The link to google maps:

Kamenskyi Pluton was targeted about 300 km to the NE from Norilsk. First signs of it were found by geologists during regional stratigraphy mapping in 1930s and 1960s decades, as a findings of alkali gabbroid and ultramafic foid intrusive rocks among basalts. Also copper-zeolite mineralization, and Au-Pt grains in streams were found.

Later the airborne magnetic and gravity survey revealed smooth large anomalies in a Quaternary-Mesozoic sedimentary basin. The latter covers Triassic basalts, having thickness from tens to hundreds of meters.

In 1978 that area was covered by hydrogeochemical survey by open waters with a spectral emission of a dry residue. It also has found a complex hydrogeochemical anomaly spatially related to geophysical ones. The area of it is huge - about 200 sq. km. The absolute content is also extreme - Cu up to 0.9 mg/l, Ni - 2.6 mg/l, etc. Even gold was found there. Normally, that amount of metals could not stay long in a solution - it's the law of chemistry. But since that anomaly has not been neither confirmed, nor refuted. I could only say: samples were collected by multiple geologists, analysis from different batches, the whole survey was implemented by highly accredited specialized hydrogeochemical department, that worked since 1960s.

In 1998 the second regional geological map of that sheet (scale 200,000) has been published. I worked with both editors later. They told me, that there were two guys who visited basalts to the south of the anomaly. The first one brought samples and stored them in a warehouse, that burned down the next night. The second guy visited that place and went crazy - required immediate extraction and forgot about a career in geology. So there were actually no samples or thin sections on the hands at that moment.

In the recent past Norilsk Nickel also sent geologist there for a follow-up study, but no question was answered. Some samples were collected, but no theory or sign of a intrusion, and mineralization were excluded. It happens.

In the past century geologists tried to find the second Norilsk as well, so they applied the same model - worm-shaped high-density intrusion in a sedimentary Paleozoic sequences, what meant that it should be 1.5 km beneath the surface. Other signs were not considered. With my friend geophysist we tried to explain geophysical anomalies by large shallow low-density intrusion (gabbro vs ultramafic). Oasis modelling proved it as possible option. But the next question - where does the metal come from?

Although, there's a possible solution - Kola Peninsula Cu-Ni deposits (2000 km far from Kamensky pluton) could offer a model with late-stage sulphide veins in the upper-part of an intrusion. Or it could it be a result of low-density airborne geophysical survey - God knows how the picture will change with new detailed surveys?

Additionally, we were looking at a possible twin in Australia - Mordor complex:

but it's also just a concept yet. The lack of a neat model and standard deposits makes it really hard to propose that object for exploration. Two major Russian mining companies decided not to investigate that object, and to continue with greenfield exploration of IOCG deposits. We'll see.