•AT 41J86NWee28 BUCKLES48 BUCKLES 010 GENERAL NOTES ON ROCKS FROM QUIRKE LAKE PROPERTY In the accompanying reports on the individual sections the name of the rock as logged will be found following the sectin number. The true name for the rock will be found underlined near the end of each report. A number of points concerning the nomenclature require special mention. The names given during logging are to all intents accurate; with the exception of the quartzites which, with the exception of K2512, belong truly to the greywacke group. This is caused by the presence of altered argillaceous material as a matrix. The definition of greywacke presupposes that the rock consists of fragments of quartz, possibly feld spar and of rock in an argillaceous matrix. Sub-greywacke is a greywacke in which the argillaceous material is present in small amount. Sandstones and their metamorphic equivalents have no argillaceous matrix, the cement usually being quartz or rarely carbonate. The variation between the various members of the series K2511, K2513, K25H, K2515, K2516, K2518, K2523 can be seen to be essentially a variation in the ratio of quartz to matrix. The Huronian sediments have all suffered very low grade metamorphism, the degree being shown by the amount of recrys tallization of the argillaceous material. The clay minerals have gone over to sericite, the FeMg clastic fraction of the clay to chlorite© and in a few cases it is possible to see incipient combination of the two to form new biotite. At no; ;. y point has the biotite stage of metamorphism been attainedf^^fy^. ~ r-© © V- © ©""VjS.©^V © i"t"©(©"©-*©©i^S-- . j^X/r^V©i " QMii ill : ^^i^^O'^^^^^*™ ,:' B ..l J ' ^i '-M . • -•.'•' - - ••.'.(••" V.TLv:- life f. \ S m--tifyft". - 2 - © Sf-:!-©?©.."1: © © ||; These rocks are remarkably free of introduced material and although ||5 many of them have been intensely deformed most of the minerals in l;; fractures could be derived from primary constituents. This is ;! especially true of the carbonates which are present in some of ?; the rocks and which in general have the tendancy to become mobile under stress. The pyrite which is fairly common has obviously recrystallized but its distribution does not suggest introduction but rather the recrystallization of some primary constituents. Other accessory minerals are notably absent. Of the Pre-Huronian rocks K2519 and K2520 are true andesites as logged. The granite, diorite and granodiorite are really all granites, admittedly of different character and degree of alteration, giving them a great differ3nce in appearance in hand specimen. It would be impossible to say how they are related. K2523 logged as granodiorite is a sediment of greywacke composition, and I would suggest that it is related to the Huronian sediments and not pre-Huronian as suggested. K2506. DDH-Q309. Banded greywacke and argillite Coarse phase Approx. Calcite matrix jr© Quartz ;x: fragments V;, Plagioclase ^ r Pyrite in irregular patches --•':**r-"'--. '.'. - '-. ^ ' * •IfeS"-,'-,. -. '. Few graJ ns'sericite ;' Fine phase . Sericite 20# to Quartz and Feldspar #0?S to Rock is banded coarse and fine more or less alternating. The fragments in the coarse are of silt size, angular and up to 1/10 mm. diameter, with quartz predominant and not over 10^ feldspar. No argillaceous material in matrix which consists of calcite. This phase is really only a silty limestone. Meta~ morphism has not been sufficiently intense to cause reaction between the constituents. The fine grained phase consists of a gradation between mainly sericite with a little fine silt to mainly fine silt with sorr.e interstitial sericite and is therefore a graded bedded silty argillite showing low grade met amor phi srri. There has been considerable contortion of the original bedding. Rock is a banded silty argillite and limestone. K2507. DDH-Q309 Argillite probably a greywacke Approx. Cataclastic quartz grains Sericite Chlorite Calcite in veinlets and corroding quartz Few grains plagioclase Rock consists of very badly mashed up (cataclastic) grains ;, of quartz up to 5 nun. diam. in a matrix of sericite and ©rchiorito;i-© © -r ©© © © "© .- :© ::- © - - ••''^••:.^- !\-.':-^l^^i:^'^l^i^^^^ - 4 - The matrix shows signs of flowage, developing a mullion like structure-around, the quartz, and dragging broken fragments off the larger grains. The deformation has been particularly intense as it is unusual for quartz grains to be so considerably broken up when imbedded in such a soft matrix. Metamorphism is a low grade. Sufficient to cause sericite to form from the original argillaceous material but not advanced encugh to form biotite with the sericite and chlorite. The rock is a true greywacke, intensely deformed. K2508. Banded limestone and argillite Approx. Cataclastic quartz Calcite Chlorite vSericite Small amount of biotite The rock consists of badly mashed up quartz which was probably originally of sand size but has been reduced by deformation to a mush of cataclastic fragments in a carbonate matrix. The quartz is accompanied by chlorite and sericite showing flowage structure. In places there is a tendency to the formation of biotite in very small amount from some of the chlorite. The carbonate has obviously recrystallized which would be expected with deformation sufficient to brecciate the quartz. The chlorite and sericite have therefore been streaked out along with the quartz. The rock was probably a sandy limestone carrying a ,© : - 5 - small amount of argillaceous material in the matrix and during deformation the components have segregated. Rock is a highly deformed sandy limestone. K2509 Banded limestone and calcite veinlet Approx. Calcite 90^ Quartz ) ) 10/0 Feldspar) Rock consists wholly of fine grained calcite with a small amount of fine silty quartz and a few grains of plagioclase. The dark bands almost ur.detectable in thin section seem to be the result of a fine dusting of carbonaceous material. The rock appears to be ^.deformed. The v jinlvit consists mainly of calcite although there are a few grains of quartz up to l mm. in diameter. In places the walls have a lining of fine grained quartz. The quartz in the veinlet has been much corroded by the calcite and it looks somewhat as if it were originally a quartz veinlet replaced by calcite. The rock is a slightly silty limestone. K2510. Granite boulder in pebble conglomerate. Granite Pebble composition: Approx: Quartz Fresh microcline Sericitized plagioclase about obligoclase-andesine - 6 - Green biotite altering to chlorite Carbonate Few grains epidote, some zircon Pyrite and black opaque material Coarse grained granitic, the plagioclase is badly sericitized, the microcline remarkably fresh. The quartz is strained and almost cataclastic. All the minerals are shot through with stringers of Carbonate with which the opaques are associated. The rock is a ^ranodiorite. Matric composition : Approx: Quartz 60fo Plagioclase (sericitized) Micrclinec. Chlorite and sericite Carbonate The matrix consists of almost the same material as the pebble with the exception of biotite. The quartz and feldspar grains are quite coarse, of sand size, and of fairly uniform coarseness of grain (about l mm.}. All are well rounded to sub rounded. These are set in a matrix of sericite and chlorite with some carbonate replacing the matrix particularly at the borders of the pebble. The rock is a conglomerate with a sandy and argillaceous matric having a tendency cowards being arkosic. This might be s-vJ!?W? * j©lVX"y*--'' - 7 " K2510 (Cont©d) called a coarse greywacke. Metamorphism has been low grade, still in chlorite stage as there is no sign of biotite in the matrix and possibly the chlorite in the pebble is retrograde. There is no sign of interchange of material between the pebble and matrix. Any apparent "reaction" rim around the pebble may probably be the coating of carbonate. K2511. Quartzite, probably arkose or grit Approx. Quartz (slightly cataclastic) Microcline) Plagioclase ) Sericite and chlorite I 5fo Biotite The rock looks rather like the matrix of K2510 and consists of coarse quartz grains with minor amounts of feldspar, all of which are still showing the original sedimentary roundness. The grains have been slightly deformed with a tendancy to the formation of cataclastic texture. The matrix is mainly a mixture of chlorite and sericite which are beginning to go over to biotite so that the metamorphism is slightly more advanced than in K2510. This shews also in the very slight reaction between the matrix and the quartz grains around the borders of the latter. The rock would properly be called sub greywacke (grit requires ^... .... - 8 - angular grains) and does not have sufficient feldspar to be truly arkosic. Because of the presence of the argillaceous matrix and the lack of recrystallization of the quartz it is definitely not a true quartzite. K2512. Fine grained white quartzite Approx. Quartz 95# Microcline) ) less than 5^ Plagioclase ) Sericite and chlorite very small amount This is probably a phase of the same rock as K2511. It is almost wholly made up of grains of quartz with a few grains of feldspar of fairly uniform grain size about 2mm. diameter. There is a very little recrystallized argillaceous material, but insufficient to be significant. The grains have been cataclastically deformed so that although there has been no recrystallization of the quartz the rock has the appearance of a true quartzite. One could call the rock a cataclastically deformed sandstone but quartzite would be accurate enough within the definition of the term without splitting hairs. K2513. Quartzite Approx. Quartz * 40# ;iv ' -' ./j". -* . * f|^. ' © . - 9 - ttv.: . ;v Plagioclase slightly sericitized I . 15* .^v Microcline fresh 'S Sericite and chlorite ) •c . j 40?5 Biotite ) Pyrite Ankerite ? Limonite The grains of quartz and feldspar are rounded to subangular and have been somewhat cataclastically deformed. These are set in a matric of sericite and chlorite which is in process of going over to biotite.