Hi deputy,

Not sure who posted this originally, but here is a write up on the geology of McFaulds Lake: 

Geological Theory/Facts of Genesis of McFaulds Lake:


I seldom say this, In my view this post, with the up to date Geological information contained herein , is a must “keeper” to cut and paste, for future reference, to those interested/invested in the McFaulds Area….this post has taken weeks to research and put together….
Information credit will be given to their Sources, accordingly, and in all cases referred to herein, these are their professional opinions, based on their interpretations of fact findings studies , to which , I have then added/applied my kowledge/information/opinions of the McFaulds Area…I have decided to post this information, knowing that I have met their requirements, which are proper “credit” and non commercial use…proper credits are listed below, and as you all know/may know, I have not /and am not being paid by anyone to post on these forums.. .I do so simply to provide information and my considered opinions…..just your usual cautionary statements…
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I will begin with Prof. A.J. Naldrett, world renowned Geology professor and probably “THE” or one of , the world experts on MMS , Ni Cu PGEs …
I met Prof. Naldrett of a few occasions and attended a good number of his lectures on MMS Ni Cu PGEs, in Toronto, and have read much of his written papers on said subject, long before McFaulds came along….I will not go into very complex and extremely difficult geological terms and theories..I will try to describe some theories here, as simple as possible, under the circumstances of the very complex subject of geology in general and super complex McFaulds geology in particular….
Below are 3 general “findings” by Prof. Naldrett of his studies of worldwide MMS Ni Cu PGEs deposits :
"Magmatic Ni-Cu sulfide deposits form as the result of the segregation and concentration of droplets of liquid sulfide from mafic or ultramafic magma.When most major Ni-Cu sulfide deposits, including those at Kambalda, Western Australia, are viewed in the light of studies at Noril'sk, Sudbury, Jinchuan and Voice’s Bay, three factors become apparent:
(i) the concentration of sulfides in channels or conduits through which much magma has flowed (feeder conduits for intrusions are much more prospective targets for exploration than the base of the intrusions themselves);
(ii) (ii) the interaction of the source magma with country rocks, either leading to the incorporation of sulfur, or the felsification of the magma in question;
(iii) (iii) fractional crystallisation of sulfide liquid giving rise to Cu-rich ores which may be far removed from the 'source' ore.
Anthony J. Naldrett Key factors in Genesis of MMS Ni Cu PGE implications for exploration."
The first point is relatively simple , and as I have posted previously, that these NI Cu PGEs sulfides are accumulated and deposited in magma conduits or “feeders” conduits for much larger intrusions, wherein successive introductions of Magmas have occurred…BUT once you have ‘prospected “ and found these magma conduits mineralized with Ni Cu PGEs , then many Geologists recommend drilling much deeper for the “source” (parent) magma responsible for these deposits as these deeper bases of the Magma are usually also “mineralized”…especially in the case of McFaulds, wherein good evidence exists of the regional.presence of Chromite layers , and enxtensive titomagnetite layers, that are good evidence for the proposition that very HOT, Dynamic Magmas , existed at McFaulds, and were responsible for the mineralized “feeder conduits” the type of Dynamic Magmas that could host Massive Nickel Sulfides, near or at their base….more on dynamic magmas and their “plumes” in another post some time…
from BMK news and my discussions :
That these thick madfic gabbro-ultramafic sills have high nickel and possible Platinum Group Element (PGE) potential has now been proved by the presence of nickel sulphide in more than one place, as well as the regional presence of chromitites and laterally extensive titanomagnetite layers evidence for hot magmas of the type that may host large massive nickel sulphide deposits near their base.
The second point is extremely important and very relevant to the formation of McFaulds area deposits, which would include the Speatacular NOT discovery, and the BMK Ni discovery, and of course hopefully many more as yet hopefully undiscovered discoveries…
"(ii) the interaction of the source magma with country rocks, either leading to the incorporation of sulfur, or the felsification of the magma in question;"

So then from this statement we conclude that in order for magmatic sulfides to concentrate in one area and remain in situ, either Sulfur from the surrounding country rock, or more importantly as in McFaulds case, “Felsification” with the contact magmas…
We have all heard and read many/most of the uninformed and geologically ignorant posters/doubters refer to the “granodiorite, which they describe as having limited NOT’s ore bodies. …..Nothing could be further from the “truth/facts”…
You will recall that in most all NOT drill holes to date, the mineralization ended in “ granodiorite”…It is my opinion, that , what existed prior to the NOT mineralization event, was Large “granite” bodies as the country rock…these “granites” are/were in fact all felsic, containing up to 65%to 90% of quartz and alkai felspars, therefore they are felsic. The “feslsificatiion” referred to above, potentially occurred when the “mafic” parent magma, probably a gabbro, came into contact withand mixed with the “granites” country rocks and assimilated and transformed it into “grano-diorite”, thereby felsification of the Parent Magma in question..so that diorite part, is the “mafic” component parts of the parent gabbro? magma, which assimilated with the “granites” felsic country rock , then transformed them into “granodiorites”. This felsification,into the Granodiorite, in my opinion in this case is what created the “trap” for the Ni Cu PGEs sulfides, in situ, which accumulated near the edges of this process….
So the “granodiorite” is GOOD news, since that was part of the Parent magma, and the “trap” for the Ni Cu PGEs mineralization in NOT’s Area discovery…Thus the granodiorite does not limit NOT’s Spectacular discovery, or many likely future such discoveries in the McFaulds area…….
The third point is:
"(iii) fractional crystallisation of sulfide liquid giving rise to Cu-rich ores which may be far removed from the 'source' ore. "
As most of you know, SPQ has discovered many, more than 10 so called VMS deposits containing Cu and Zn…However some of their discoveries were only Cu with no Zinc…some were as much as 8% Cu…..this leads me to believe That those Cu only discoveries , were as the result of “fractional crystallisation” of the parent magma/s that gave rise to Ni ores, which may be far removed from the source(parent) ore…
Implications of this“fractional crystallization” for McFaulds may be;
1. These rich Cu only discoveries made by SPQ are part of the magmatic processes which gave rise to the Ni Cu PGEs of NOT and likely many other such deposits along the belt at McFaulds..
Alternatively, these SPQ Cu only discoveries give potentially, some evidence that such Ni Cu PGEs deposits also exist in SPQ claims, both east and west, since these Cu discoveries were made some 25 Kms east, and 25 Kms west ,and away from NOT’s Ni Cu PGEs deposit.
Further confirmation of these Ni deposits, spread out throughout McFaulds belt, comes from BMK who discovered a 93 Ft. section of drill core assaying about .40% Ni., in their MacNNUGET claims some 25 Kms west and away from NOT, which BMK is drilling now…
2. Thus there is both evidence for a GIANT parent magma, for the entire McFaulds area, or more likely,a series of Large mafic magma intrusions which potentially gave rise to a series of Ni Cu PGEs deposits, and farther away potentially the Cu only deposits and potentially, Massive Sulfides Ni deposits at their base, as above noted….
Here are some other very important and NEW findings/interpretations about the Geology/Geological setting for McFaulds…this information is borrowed from MNMD, Ont Gov. Open File Report-OFR 6192, Scott and Rainsford, 2006, from Aeromagnetic data , and revised terrain maps….this report is their interpretation of the data collected…
I would advise anyone who is serious about learning more on McFaulds Geology, to obtain a copy of said repot, (doesn’t cost much), but it gives you much additional information/data, a great number of maps and other illustrations data and information for the entire Hudson’s Bay/James Bay Lowlands etc…I am only going to quote a couple of items in this post, of this very large and informative geological/geophysical report, which I consider very important indeed…which as I read the fine print, is allowed, provided one gives the report “credit”, and it is for non commercial use, as noted above…
OFR 6192 Scott, Rainsford…2006
From Aeromagnetic data, and revised terrain maps…
Some features to note:
-" The merging of greenstone belts of Uchi domain and Oxford-Stull domain under the James Bay Lowland;"
Of course, these is a very complex set of Geological factors which cannot be explained easily,
Or ascertained to any degree in one study, however, certain assumptions may be theorized, such as the reason why these 2 distinctive Geological Units have “merged” under the James Bay Lowlands…This MAY indicate some evidence for plate tectonics, more particular “subduction zones” or crustal growths thru “rift”which have “merged” these 2 UNITS together..
Some other potential evidence for this “subduction zone” and crustal growth is stated below, wherein an “INDENTOR” taken to mean an indentation, or a lowering of the James Bay lowlands terrane, as compared to the surrounding rocks, sometimes referred to in Geology as similar to a Graben…additional important data from this statement below is that this “indentor” is flanked on each side by FAULTS…you will see this more clearly if you obtain the full report…
Now the “GRABEN” concept/idea is my opinion, since the geological definition of Graben is
“ an elongated depressed crustal unit, or block, that is bounded by “faults” on it’s sides”…it may or may not be expressed as a “rift valley”….
How my “GRABEN” description importantly relates to the Ni Cu PGEs mineralization is somewhat clear, since some of the World’s largest Ni Cu PGEs deposits like Norlisk in Russia occur within these types of “GRABEN” or “indentors” "low lands" ..At Norlisk it is described by Naldrett as a 3.5 Km thick “volcanic basin” in/near the axis or keel of an anticline formation, that is thought to have brought these deposits to near surface…these Norlisk deposits are world class and account for LARGE portion of Ni Cu and of course PGE’s..Russia being the world’s MAJOR producer of Palladium…you will also notice a number of “DOMES” and anticlines in and around the McFaulds lake area from the Geo maps posted…
- A large indentor-like feature underlies the James Bay Lowland, flanked by faults; -
Debate has grown as to the AGE of these MMS intrusions…The statement from the said report below, may shed some light into this discussion…I have read and that some samples taken from the McFaulds and adjoining areas, area were dated from 2737 to 2696…A;though I previously posted that these rocks were Proterozoic,, or earlier, that was not exactly correct. They are about 200 Million years older… The Archean age ranges from 3.8 to 2.5 Billion years old…the youngest known as late Archean 2.9 to 2.5 Billion years old.. Proterozoic age starts after 2.5 Bill…so the dates quoted in some reports show that some of these intrusive rocks underlying the Paleozoic limestone are of late Archean ages aound 2.7 Billion years old,…some of the surrounding rocks are of early Archean ages 50+ more years older……From reading may publications, and mapping of World MMS Ni Cu PGEs deposits, especially from Prof. Naldrett, it seems that the older the rocks the higher the sulfide content of Ni etc…, since the theory is that the earth’s Mantle, was somewhat more HOT Dynamic and Violent , than it is today, as it is very very slowly cooling…so AGE may be a plus for McFaulds…and interesting side note of these world MMS deposits maps, is that Canada has been unusually blessed with a higher proportion of these deposits , than other countries…
In conclusion, I have believed for some time that the Potential for Large and rich deposits of Ni Cu PGEs at McFaulds is/has been Great!..…As more geological data , interpretation and especially drilling comes forth, I believe again the words of Mr. Nemis “THE RING OF FIRE ( The McFaulds area) WILL BE LARGER THAN VOISEY’S BAY”…the structure and Geology are there, the Ni Cu PGE’s are there, at least proven to exist thru 50 Kms belt of McFaulds, while others potentially to be found and extending Mfaulds further…
from SPQ’s VMS discoveries some 25 Kms away East from NOT’s discovery, to the BMK Ni MS discovery last year 20+ Kms away West of NOT’s discovery….now all that is left is the very important “drilling” to actually outline and “prove” the orebodies…Good luck to all McFaulds Lake Players….
ALL of the above as usual ….In My Considered Opinion…pls do your won D.D….