Liam Murphy - GEOL200 - Lab Assignment 04 [Marked]

Liam Murphy 3540040 GEOL 200 - Introductory to Physical Geology Lab Assignment #4 August 3, 2021 Part One Following the procedure outlined below, examine and describe samples 41-48 from the Athabasca University Rock Samples Kit. For each rock, describe the texture as foliated (giving the type of foliation) or nonfoliated. Determine grain size, identify the minerals that are large enough for identification, and describe the basis for your identification. Determine the name of the rock, and identify a likely precursor, using Table 7.1 in the Plummer textbook (15th ed.)(p. 163) if necessary. Indicate whether the rock exhibits a low, medium, or high degree of metamorphism. Remember to describe the basis for your identification of the minerals in the rock samples (that is, the diagnostic properties of the visible minerals). | Sample 41 Sample 42 Texture: Foliated Texture: Non-foliated Gneissic/ Granofelsic Lustrous Grain Size: Fine - Medium grained (< 20mm) Grain Size: Medium grained (2 - 20mm) Minerals: Hornblende Minerals: N/A Minor Quartz Contents Plagioclase ¢ Identification: Lustrous texture, brittle and hard. Coal (Anthracite) Identification: Dark in colour with little Quartz content. Shows a “salt and pepper” look, with a Precursor: Bituminous Coal / @ weak foliation structure. Amphibolite Metamorphism: Low Degree L\S h\. Precursor: . Basalt or Gabbro : Yro \U?M ‘{ 5 Metamorphism: Medium - High Degr Low temp, High pressure L Liam Murphy Unit 5: Metamorphic Rocks GEOL 200 ' ; Lab Assignment #4 Athabasca University Page 1 of 7 August 39, 2021

Samgle43 P SNy ' Samglé44 Texture: Non-foliated Texture: Non-foliated Crystalline Texture . Granofelsic Texture Grain Size: Medium grained (2 - 20mm) Grain Size: Fine Grained (<2mm) Minerals: Fine Calcite Grains, Dolomite, Aragonite. Minerals: Quartz. Identification: Consists of Calcite, Aragonite, and Identification: Small interlocking graind of quartz. Sugary Dolomite minerals. This rock will fizz when appearance and a vitreous lustre. introduced to HCI. Quartzite Marble Precursor: Quartz Whfi OQ Precursor: Limestone / ha‘ac‘\—w‘_( J S—Q SKM Metamorphism: Low — High Degree | Metamorphism: Low-— MDegree Will form at low degree and adjust LK Faal owA_ composition as degree increases. g Sample 45 S : Sample 46 i Texture: * *' Foliated ’ Texture: Foliated oy + Schistosity Earthy Luster it e D | A Grain Size: - Medium — Coarse Grained Grain $|ze- Fine Grained 4‘ '«v, Minerals: Bictite 3 4 4 Mme,ral&:..‘ GV pfay, other sheet silicates. Muscovite Amphibole Identifi catlon. Splits easily into thin flat sheets, generally less than 1cm. T Identification: Visible platy minerals that have obvious Slate - planar alignment. Alternating layers of i » light and dark minerals. Precursor: Shale Schist Metamorphism: Low Degree Precursor: Shale \WM MM,&.‘ s et 5 Metamorphism: Me rade l“ 1 Liam Murphy Unit 5: Metamorphic Rocks GEOL 200 Lab Assignment #4 Athabasca University Page 2 of 7 August 31, 2021

By identifying the Gneiss banding one would be able to correctly distinguish between Granite and Gneiss. e. Conglomerate and Metaconglomerate; L] e £ A conglomerate is rock comprised of various sized grains (small and large). A metaconglomerate is a conglomerate rock that has gone through some phase of metamorphism and experienced differential pressure in some way therefore flattening and large sized grains. By identifying the flattened grains within the rock s imen one would bk able to identify between a conglomerate and a metaconglomerate. a/‘ M& h( 3 M 1‘00 Within a sandstone the grains of sand can be visible to the naked eye. Once the sandstone has gone through a metamorphism process the grains of sand are welded together making the sand no longer visible to the naked eye and not having a grainy texture and a lot harder, Through a visual inspection one could identify a sandstone via the small particles of sand, but quartzite is incredibly strong and will scratch glass, that is another identifier. oS {oo Sandstone and Quartzite; mts Bl ot Was Suced 2. What grade of metamorphism does the presence of chlorite indicate? Explain why chlorite cannot occur in a gneiss. S . Low-grade metamorphism. ‘/ Gneiss is a high-grade metamorphic rock and therefore would not contain any chiorite. 3. Under what conditions would you expect blueschist metamorphism to occur? High pressure, 5 e Low temperature, Vi e Blue amphibole (glaucophane, riebeckite),"} ‘WAWM 5 i o Lawsonite T e "( 3 £ »d®Y I e S { 4. What is the metamorphic product of coal? ‘\ \\ 5} )L + Anthracitgcoal. ALY ~) C\W \ L i ’_z ; 5. Figure 4.2 (next) shows sketches of hand specimens and low power microscopic views of 18 samples of various rock types. The essential minerals are labelled in the microscope views. The small grains shown with dots in the microscopic view are not visible in the hand specimens, but the larger crystals would probably be visible. Study the texture and composition represented in each sketch, and identify each rock. The rocks include igneous, sedimentary, and metamorphic specimens. (Note: You may need to review the assignments for Units 3 and 4 to complete this question.) i # ¥ oo % TR viek 4 Texture Texture - Foliated, fine grained rock. Foliated texture = Satiny luster caused by tiny mica grains. Layers generally greater than 1cm. Composition . «}-Composition - Micas b Micas and Amphiboles (dark layers) - Chilorite crystals. Feldspar and Quartz (light layers) 1 Protoliths may be a mud stone or slate. i B N BAAR gy Tyo@ Identification: _ Gngiss \ - *|identificatioht * . Phylite n _ \0“{ or Uist M0 MY ALY A !; ’5 .4 ~ ¢ "o Liam Murphy Unit 5: Metamorphic Rocks GEOL 200 Athabasca University Page 4 of 7 Lab Assignment #4 August 3, 2021

Texture Texture - Non-foliated - Foliated - Granular texture. Composition Composition - Quartz minerals - Quartz mineral - Calcite bands - Sugary appearance E Interlocked crys:als/ Identification: Wollastonite « & Identification: Quarzite C% CM(}S S % OVLQ Texture Texture - Coarse Varying Textures - Vesicular Texture - Non-Foliated - Rough - Minerals Cemented together Composition Composition - Forms from a viscous lava. - Coarse Biotite - Frothy Volcanic glass. G Muscovite i - Quartz Identification: Pumice [/ - Orthoclase Feldspar Identification: ~ ~ Pegiyatite Q ot . ( .~y V Texture Texture - Non-foliated - Foliated - Black to brown colour g - Medium Grained Composition Composition - Organic material. - Biotite - Peat - Muscovite - Wood Y - Quartz R - Garnet Identification: Charcoal O r ? '00" 0( \/ Identification: Mica Schist I8 0L eS D, ;'_WO\)(iYap('); Coa’r( i * wollaston : ety Qsvon \S & M M)\O—Q\» CwS \'03 v ‘4\3 Unit 5: Metamorphic Rocks GEOL 200 Lab Assignment #4 Athabasca University Page 5 of 7 § ; ! August 314, 2021

Composition Identification: Very fine grained Limestone Non-foliated ' Dull lustre Calcium Carbonate o Calcite o Aragoni Micrite Composition Identification: Texture Texture Foliated Conchoidal fracture. Displays Gneissic Banding Glassy Texture Non-Foliated Composition Dark Volcanic Glass Quartz i Mica Composition Clay Rhyolite Felsic and Mafic layer: Identification: Obsidian / Identification: Texture Texture Non-foliated Coarse grained Granofelsic Texture Calcite Aragonite Dolomite Marble ‘/ N % 262 +f v Liam Murphy i Unit 5: Metamorphic Rocks GEOL 200 Lab Assignment #4 Athabasca University Page 7 of 7 August 34, 2021