Metamorphic and Sedimentary Rock Identification Lab Solutions

CIV185 metamorphic/sedimentary rock ID lab – Solutions Key Takeaways and Common Mistakes 1) 12-2 p.m. Lab Only: Stop #4) The metamorphic rock outside the Clara Benson Building is gneiss, which was commonly incorrectly identified as quartzite. Gneiss is characterized as a foliated rock with banded formations, while quartzite is a non-foliated rock. Although quartzite may sometimes contain veins, these veins are typically much narrower and linear in shape than the foliated layers in gneiss rocks. Figure 1. Foliated vs non-foliated metamorphic rock formations 2) 12-2 p.m. Lab Only: Stop #8) The stone comprising most of the exterior of Knox College is sandstone. This was commonly misidentified as shale. Sandstone has a unique rough texture, similar to sandpaper, while shale is much finer-grained and therefore feels smooth to the touch. 3) 4-6 p.m. Lab Only: Stop #3) This sedimentary rock should be identified as concrete due to the presence of both rounded and angular rocks (natural breccia only contains angular rocks). The pasty, cement material binding the rocks together can only be used as to identify this rock as anthropogenic in nature. 4) 4-6 p.m. Lab Only: Stop #8) The floors of the Hart House are composed of travertine tiles. This rock was commonly misidentified as limestone or greywacke. Although travertine is a type of limestone, it can be specifically characterized by its vein patterns, caused by dissolved minerals which are percolated up through the limestone by water geysers or mineral springs. Figure 2. Travertine (left) vs Limestone (right)

CIV185 metamorphic/sedimentary rock ID lab - Solutions One of the numbered “rocks” is not a natural rock at all, but a fragment of brick. Bricks are usually a mixture of sand and clay, and then baked at 900 – 1000 °C. In this respect, brick is similar to natural rocks formed by contact metamorphism , a situation where and intruded magma heats up the surrounding country rock. For example, when an igneous magma intrudes a limestone, the limestone is heated, mineralogical changes occur, resulting in a rock type called skarn . A broader term, hornfels , applies to any type of rock that experienced contact metamorphism. METAMORPHIC ROCK TABLE One of the numbered “rocks” is not a natural rock at all, but a rounded fragment of concrete collected on the shore of Lake Ontario. Concrete is a mixture of sand and rock held together with hydrated portland cement. SEDIMENTARY ROCK TABLE Particle/grain size Composition Comments Rock Name ID# Detrital Coarse (> 2mm) The gravel-sized particles can be of any rock type, and often held together with CaCO 3 or SiO 2 based cements. Rounded particles Conglomerate* 5 Angular particles Breccia* N/A Texture Grain size Comments Parent Rock Rock Name ID# Non-foliated Medium to coarse Variable colors, fizzes with dilute HCl Limestone Marble 3,4 Variable colors, hardness of 7 Quartz sandstone Quartzite 21 Fine Dense, dark colored, formed by contact metamorphism Variable Hornfels N/A Anthropogenic Clay/sand Brick 38 Foliated Fine Breaks along planes, but denser than parent rock. Shale Slate 12 Breaks along planes that are wavy, glossy Slate Phyllite N/A Medium to coarse Abundant micas Phyllite Schist 19 Compositional banding Variable Gneiss 23

Bound with hydrated portland cement, anthropogenic Could be rounded or angular particles Concrete* 36 Medium (1/16 - 2mm) Predominantly quartz White, tan, red or brown, feels like sandpaper Sandstones* Quartz sandstone 8 Quartz with other rock fragments, mica, clay Dirty-looking, feels like sandpaper Graywacke 25 Fine (1/256 - 1/16mm) Quartz and clay minerals Feels gritty when ground between your teeth Mudstones* Siltstone N/A Very fine (<1/256mm) Clay minerals and clay-sized minerals Feels smooth when ground between your teeth, splits in layers, sometimes fossils Shale 28 Chemical/ Biochemical/ Biological Very fine grained CaCO 3 , fizzes with dilute HCl Powdery, shells of microscopic plants/animals Chalk N/A Al 2 (Si 2 O 5 )(OH) 4 Soft, hardness 1.52 Kaolin 1 Fine to very fine grained CaCO 3 , fizzes with dilute HCl Sometimes fossils present Limestone 26 Medium to fine grained (Ca,Mg)CaCO 3 , fizzes with dilute HCl when powdered Sometimes fossils present Dolostone 37 Fine to very fine grained CaSO 4 •2H 2 O Evaporite, hardness = 2 Gypsum stone N/A Medium to fine grained CaSO 4 Dehydrated gypsum hardness = 3.5 Anhydrite stone 11 Medium to very fine grained Carbonaceous material Black, bituminous (soft), anthracite (hard). Coal 27 Very fine grained Amorphous to poorly crystalline SiO 2 Conchoidal fracture, hardness = 7 Chert 13 *Keep in mind that any of the detrital sedimentary rocks may or may not be cemented together with CaCO 3 . If CaCO 3 cement is present, they will “fizz” when in contact with dilute HCl.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Stop #1 (inside) : On the first floor of the Earth Sciences department, a series of boulders line the hallway. One, an amphibole-calcite rock, is a matter of debate, as to whether it is metamorphic or igneous in origin. The other is definitely metamorphic; list its name below. Stop #2 (outside) The old (now closed off) southeast corner entrance to the : Bancroft Building is surrounded by ornately carved sedimentary rock, complete with a polished red granite pillar. List the name of the type of sedimentary rock in the space below. Stop #3 (inside) On the first : floor of the Ecology & Evolutionary Biology department, an exhibit case displays a fossilized palm tree. List the geologic epoch from when this tree was alive. Stop #4 (outside) The east entrance to the : Clara Benson Building is lined with a garnet polka- dotted metamorphic rock. List the name of the type of metamorphic rock. Stop #5 (inside) : Just inside the north entrance to the Ramsay Wright Laboratories are a pair of comfortable couches. Have a seat, and look back at the top of the entrance. During what geologic epoch did these tusks originate? Stop #6 (outside) Tucked in between : Ramsay Wright Laboratories and Sydney Smith Hall sits Zoo Woods , one of three ecosystem plantings on campus. You can read more about Zoo Woods at the entrance, where a plaque is mounted to a boulder. What type of metamorphic rock does the boulder consist of? Stop #7 (inside) : Inside the northeast entrance to the Lash Miller Chemical Labs the walls and stairwell are lined with polished slabs of metamorphic rock. List the type of metamorphic rock in the space below. Stop #8 (outside) : The windows and trim of Knox College consist of smooth Queenston Limestone (technically a calcitic dolostone) quarried near Niagara-on-the-Lake . The rest of the bui lding stone is sedimentary and rough in texture. List the type of sedimentary rock here → Iron Skarn Quartz Sandstone Eocene Pleistocene Gneiss Marble Gneiss Sandstone Metamorphic and Sedimentary Rock Mini Field Trip – 12 – 2 p.m.

Stop #1 (inside) : On the first floor of the Earth Sciences department, a series of boulders line the hallway. One, an amphibole-calcite rock, is a matter of debate, as to whether it is metamorphic or igneous in origin. The other is definitely metamorphic; list its name below. Stop #2 (outside) : Below the white pine tree sit two boulders. One consists of a banded gneiss, the other is a conglomerate. What type of mineral cement binds the pebbles and sand? Stop #3 (outside) : The exterior panels just to the left of the entrance to 215 Huron St. consist of angular pebbles bound together. Are these panels varieties of natural breccia, or concrete? Stop #4 (outside) : Next to the Student Commons is the Fields Institute . On the exterior, the first floor of the Fields Institute is clad with square tiles of Wiarton Limestone . Although sold commercially as “limestone” these tiles are technically dolostone, and date from the middle Silurian period. In the space below, list an approximate numeric age for these rocks (in units of years before present). Stop #5 (inside) : To the north of the fountain here, you can enter the Bahen Centre , take a right turn, and walk down the terrazzo ramp that leads into the Koffler Student Service Centre . Terrazzo is a type of concrete where the surface is ground down until you can see the rock used to make the concrete. Here a white portland cement was used (without sand) to bind together white, tan, and gray limestone chips. Upon entering the Koffler Centre , the flooring changes to travertine tiles. Travertine is the name for a type of sedimentary rock that forms in layers around hot springs as calcite precipitates out of solution. Just inside the St. George St. exit of the Koffler Centre , travertine steps ascend a staircase to the former Health and Wellness Centre (since moved). What type of metamorphic rock is used to construct the banister (sides and rails) of this staircase? Stop #6 (outside) : Outside the northwest corner of the Galbraith Building sit two large boulders. One is called the Rock of Ajax (a pun on an old Christian hymn from the late 1700s called Rock of Ages , also the title of a 1980s Def Leppard hit single). The Rock of Ajax commemorates veterans of World War II who studied engineering at U of T’s former Ajax campus. The other boulder houses a plaque celebrating the 125 th anniversary of the founding of the university’s School of Practical Science (today’s Faculty of Applied Science and Engineering). What type of metamorphic rock do these boulders consist of? Stop #7 (outside) : Here a series of magnificent pillars support the perimeter of Convocation Hall . What type of sedimentary rock do these pillars consist of? Stop #8 (inside) : The exterior of Hart House is built primarily of sandstone blocks, but with limestone trim along corners and around windows and doorways. Inside the main level of Hart House, what type of sedimentary rock was used for the floor tiles? Iron Skarn Calcite Concrete ~430 million years ago Marble Gneiss Marble Sandstone Travertine Metamorphic and Sedimentary Rock Mini Field Trip – 4 – 6 p.m.

2024_CIV_185_Lab_metamorphic and sedimentary_rock_ID_Solutions (1)

Related Documents