The Timiskaming Assemblage is a belt of clastic metasedimentary rocks and associated alkalic metavolcanic rocks, centered on Kirkland Lake and extends east of Larder Lake and eventually comes in connection with Temagami. This is rather one of the best studied assemblages of the Southern Abitibi greenstone belt. This foremost assemblage is important for several reasons, one being that it hosts some of the largest archean lode deposits in the world, it's also the youngest archean supracrustal unit of Abitibi greenstone belt, and it occupies a unique position in the tectonic framework of the Southern Abitibi Greenstone Belt that postdates one regional deformation, and predates the second. Much of the metasedimentary rocks or the Temiskaming Assemblage are dominated by Alluvial-fluvial facies association consisting of mainly conglomerates containing distinctive red chest coast and cross-better sandstone. For the most part, these sedimentary rocks are associated with distinctive alkalic, dating 2685 to 2677 million years old metavolcanic rocks. These are rather several outliers of metasedimentary rocks north of the main belt of the Timiskaming Assemblage . These foremost outliers consist of conglomerate bearing red chest clast trough cross-bedded sandstone and alkalic metavolcanic rocks. These observations by OntarioExplorations101 suggest that the outliers belong to the Timiskaming Assemblage. Conglomerates associated with the alluvial-fluvial favors of the Timiskaming Assemblage are most commonly clast supported and have distinctive alkalic metavolcanic and intrusion clast, red chest clasts, and green carbonated clasts. The larger clast type can be derived from metavolcanic rock altered prior 5o deposition of the Timiskaming Assemblage.
The Timiskaming Assemblage of Temagami lies in conformity upon the deformed 2700 million year old Kenojevis South Assemblage. Within the Timiskaming Assemblage there is a distinctive suite of alkalic metavolcanic rocks. These foremost alkalic rocks are commonly amygdaloidal and include pseudoleucite-bearing flows, and trachyte flows, tuff, and agglomerates. Calc-alkalic metavolcanic rocks are known to occur near the base of the unit.
Phenocryst phases in alkalic suite include pseudoleucite, olivine, Augite to aegerine Augite, alkalic-feldspar, hornblende, and biotite. However, not all of these phenocryst types are present in the rock. The Timiskaming Assemblage is moderate to steeply south dipping and south facing assemblage that is cut by numerous faults and shear zones. The average dip within the Timiskaming Assemblage is 060 degrees, but 020 degrees to 045 degrees dips are not uncommon. The most significant mineralization within the Timiskaming Assemblage is gold, which is spatially related to shear zones, quartz veins, and carbonated altered rocks.
The Temagani Greenstone Belt is known for hosting metavolcanic and metasedimentary rocks that strike east to northeast and have folded about the east striking tetapaga syncline. Coeval with the extensions of the volcanic rocks was the emplacement of layered pyrocenenite-gabbro-anorthosite sills of thoelleiitic affinity, a layered dunite-peridotite-gabbro plug of komatiic affinity and diorite and quartz diorite sills of calc-alkalic affinity. The layered gabbro-anthrosite bodies occur in association with coarse grained feldspar megacrystic, iron rich, tholeitiic basalt flows. Intrusives into the belt is also massive to foliated tonolite-trondhjemise-granodiorite island batholith. A massive microline granite stock cuts across all stratigraphic and structural trends. Lamprophyre and pyroxenite dikes cut all archean units, but do not cut the proterozoic units.
Greenschist favors metamorphic conditioned rather prevailed except adjacent to the late granitiods where amphibolite facies conditions were obtained. The development of penetrated foliations varies from indistict to intense. Early foliations have an easterly strike which is parallel to the stratigraphic contacts, the axial planar foliation of the tetapega syncline, and the margins of the Iceland and Strathy-Chambers batholith. Parallel to these earlier foliations are the paired north east arm deformation zone and the Link Lake Shear Zone are interpred to have developed contemporaneously. The later, east to northeast striking Net-Vermilion Deformation Zone and Tasse Shear Zone are charcturized by an oblique sinistral component of slip. The related shear fabric cuts parts of the Strathy-Chambers Batholith, and deflects the earlier East-Striking foliation and the Northerneast-striking shear foliation. Much of the mineralization consists of arsenopyrite, pyrrhotite, chalcopyrite, sphalerite, Galena, and Auriferous pyrites concentration, in both quartz vein, and impregnation habits, are localized within a northeast-striking segment of the Net-Vermilion Deformation Zone South of Strathy-Chambers Batholith, and Shear Zone preprendicular to the Southern Lode of the Strathy-Chambers Batholith in Strathy Township.
The Chambers-briggs Assemblage is rather known to be 2737 million years old that consists of massive, pillows, coarse grained feldspar-Megacrystic tholeitiic basalts at the base, overlaid by calc-alkalic, effusive and pyroclastic andesite flows, coarse grained, resedimented, andesitic debris deposits, and decide and effusive rhyolite, and subaqeous pyroclastic flows. These resedimented debris-flows deposits occur within the northwest part of the greenstome belt. This assemblage is rather capped by units of pyrite-pyrrhotite and chert-magnetite-hematite iron formation. Stratigraphic units on the north limb of the Tetapaga Syncline rather have steep dips and faces to the south, which stratigraphically equivalent rock units on the south limb also have steep dips, but face to the north.
For the most part, two discrete iron formations occur at the top the Chambers-Briggs Assemblage. A thinner unit of chert, Pyrite, pyrrhotite (Sulphide-Facies-Iron-Formation) lies stratigraphically below a thicker unit of Chert-magnetite-Hematite Oxide facies iron formation on the north limb of the Tetapaga Syncline. The oxides-facies-iron formation is interlayered with turbidititic metasedimentary unit. On the north limb of the Tetapaga Syncline, a unit of ultramafic fragments rocks of underlain origin, overlies the oxide facies iron formation. The Chert-Magnetite-Hematite-Chlorite Iron Formation have been the main source of iron ore extraction at the Sherman Iron Mine that are banded. Other areas of mineral distribution include the polymetalic, being, disseminated, and massive base metals sulphide mineralization, enriched in copper, gold, cobalt, platinum, and silver, was also extracted at the Temagami Copper Mine. This had also included other polymetalic mine like the Kanichee Mine, and the Gosselin Mine that contains similar polymetalic metals to that of the Temagami Copper Mine. The mineralization is rather localize along the contact between a diorite intrusion and intermediate, calc-alkalic metavolcanic rock near the top of the Chambers-Briggs Assemblage on the south limb of the Tetapaga Syncline.
Another known assemblage is the wedge shaped Arsenic Assemblage that mainly consists of steeply dipping, south facing, iron rich, massive, pillowed, coarse grained, feldspar metacrystic, and variolitic tholeiitic basal and andesitic to ryholitic effusive flows and fragmental rocks. Vesicularity of flow units increase from zero at th base of the assemblage to consistently greater than 10% at the top of the assemblage. The intermediate to felsic metavolcanic rocks consist of andesitic effusive flows, commonly with flow top breccias and ryholitic fragmental rocks interpreted to have also been deposited as subaqueous pyroclastic flows. The ryholitic rocks have some geochemical characteristics of the high silica ryholites associated with vocanogenic massive base metal sulphide mineralization. Unlike the Chambers-Briggs Assemblage, resedimented andesitic debris flows are not abundant. The intermediate to felsic metavolcanic rocks are overlaid conformity by turbiditic metasedimentary rocks. Regionally continuous sulphide and occur facies iron formation units are not observed in the Arsenic Assemblage, although thin, discontinous, sulphide rich interface units occur at the top of the Assemblage. The contact between the Arsenic and the Chambers-Briggs assemblages is the focus of the oblique, sinistral Net-Vermillion Deformation Zone. Along the western part of this contact, the unit of tholeiitic basalt and parts of the andesitic unit belonging to the Arsenic Assemblage have been structurally removed. This stratigraphic consistent with an early thrust history. The nature of the contact between the clastic metasedimentary rocks of the Arsenic Assemblage and the metavolcanic rocks of the Command Assemblage to the south is unclear.
Much of the Command Assemblage mainly consists of massive and pillowed, iron rich tholeiitic basalt, which the assemblage occurs only in the core of the Tetapaga Syncline. The strike and dip of the flows within this assemblage are poorly constrained because of the absence of distinctive marker units. Also, contact relationships between this and the adjacent assemblages are not well constrained but it does appear to have a correlation with the Timiskaming Assemblage in various ways that can be identify through much of the geology on prospects and mine sites put together by OntarioExplorations101 in Temagami, Ontario, Canada
Still to be continued