A quick introduction to recognizing manganese oxide minerals in the field. The full Fieldcraft for Geologists series is here: geologyupskill.thinkific.com/
Iron and manganese oxides also "scavenge" other metals out of nearby soils and rocks, so when we take geochemical soil samples for Cu, Pb, Zn etc., we also analyse for Fe & Mn to see if they are present in sufficient quantity to be enhancing the other metal values and giving false indications of base metal mineralisation.
That's the most concentrated manganese samples I've seen since I was was a kid in the Mount Isa/ Cloncurry area. Then again. That's where this was filmed.
We saw manganese wad at the top of the Black Zone at the intermediate sulphidation Mt. Kare deposit in PNG, a smaller analogue to Porgera 15km away. It gave whopping big polymetallic anomalies. It'd sometimes have realgar and orpiment and was always with limonite so we used to code it HR in our mapping/logging for Halloween Rock ie. orange & black.........................
@@GeologyUpSkill Yes the Stage 1 B veins at Mt. Kare and Porgera are base metal carbonate. Sometimes rhodochrosite with Au bearing arsenical pyrite, galena, low Fe sphalerite and locally chalcopyrite.
All these years of rock hunting and geology I always thought it was MAGNESIUM dendritic pattern within the rock. Now I know that is wrong, its exactly MANGANESE oxide dendritic patterns within the rock. Thank you for the correction GeologyUpskill!
@@GeologyUpSkill Yes, retire from absolutely everything. One should be learning (or at least attempt to do so) right up until they're in the pine box after Florida.
True! New supplies of lithium and all the other metals required for the future energy transition will be a massive job for earth scientists of all disciplines.
I have a sample of manganese from Eagle Mountain, California, a major Kaiser mine that produced high quality iron for steel production during WW2. Do you have any information on what minor trace elements were presemt at Eagle Mountain? I also have some iron ore samples that are highly magnetic but have a fiborous green crystalene matrix around them. I also have some more solid matrix pieces of the green that have some sort of pyrite in them.
The fibrous green mineral is probably actinolite. I dont have any info on the Kaiser mine, but Manganese oxides are notorious for scavenging other metal cations from the surrounding environment so it will likely have a mixed bag. Pyrite would be unusual with manganese oxides because the pyrite would usually oxidise also.
Bingo! There seems to be a fluid event that extracts manganese from the carbonates in the Overhang Jaspilitie and dumps it in the Pilgrim Fault and related structures.
I just came back from a field work and we found tons on manganese concretions (plus Fe concretions and limonite after pyrite) but it still puzzles me what exactly was the source for that Mn. Oh well, at least I had tons of fun using my hydrogen peroxide on them hahaha
@@GeologyUpSkill I am not sure about the origin of the manganese, but in the area we mapped there were plenty of qz veins, we found limonite after py in metaquartzarenites and the area is studied exactly because it used to be (still is to some extent) a site for gold exploration. Still much to learn, though, since I'm still at the undergraduate level.
@@matheusviolante8364 dear matheus we have commercial interest in manganese mining , we are in the mining field since 35 years if have any potential reserves of manganese , if u can help in giving information we can exploration
usually not. There are lots of iron oxides that can develop a black surface crust that may include some manganese, but if the streak is brown or red, it's probably dominated by goethite and other iron oxides.
@@GeologyUpSkill Thanks! There was an old manganese mine on an island made up primarily of red chert. Many sources say the island (and therefore chert) is red from manganese oxides rather than iron oxides, but I was skeptical of whether this is possible. There are clearly contrasting black clusters of manganese throughout it.
