9 Distinguishing quartz from a very clear colourless calcite crystal ANS Quartz

9 distinguishing quartz from a very clear colourless

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9. Distinguishing quartz from a very clear colourless calcite crystal ANS: Quartz will have conchoidal fracture when broken off, meaning smooth curved breakage along its surface. Calcite crystal on the other hand, will have three directional cleavage, breaking off along three edges (but not at 90 degrees). Another difference we can use to distinguish quartz from calcite is that if we put acid on calcite, it will have a chemical reaction producing carbon dioxide, whereas quartz will not. 10.Igneous intrusive structures (dykes, sills, etc.) and Mt. Royal A dike is a vertical tabular intrusion which tends to cut through pre-existing layers of rock, whereas a sill is a horizontal tabletop-shaped tabular intrusion. When magma is injected between layers and dome upward, we get a laccolith. This is essentially what Mt. Royal is, a igneous intrusive structure formed as a laccolith. In Mt. Royal, we are able to see many dikes and sills. Over time, erosion and exhumation has helped erode layers of exterior rock to reveal the igneous intrusive structure that is Mt. Royal. 11.Depositional environments: formation of sedimentary rocks ANS: Terrestrial environments: -Glacial environments: ice carries and drops sedimentary rocks everywhere, so we get unsorted and unstratified clasts all mixed together, ranging from clay size to boulder size -Mountain stream environments: Fast moving water carries large clasts, the large clasts settle out to form gravel and boulder beds, and further
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downstream, water would carry finer sediments (mud and sand). This produces breccia and conglomerate. -Alluvial-fan environments: Mountain fronts, fall down at the end of streams at high velocity, sediments get dumped, and because of this, they are fairly well rounded arkose and conglomerate -Fluvial environments: Transports mud, silt, gravel and sand. Coarser sediments settle on the bed of the channel while lighter finer sediments get deposited on the banks or on the floodplain. River sediments -> siltstone, sandstone, shale -Lake environments: No great movement in water, only fine clay makes it to the center of the lake bed while coarser sediments settle on the outlets. Lake environments -> shale -Delta deposits: Contains three components, relatively horizontal topset beds ( gravel accumulates), relatively sloped foreset beds ( gravel and sand ), then relatively horizontal bottomset beds ( silt ). Coastal and Marine Environments: -Marine delta deposit: Large delta, more complex than lake delta, all variety of sediments -Coastal beach sands: Well sorted silt and clay (from waves coming back and forth over them) -Shallow marine clastic deposits: fine-grained and well-sorted silt -> siltstone, mudstone -Shallow-water carbonate environments: Lagoons, quiet water protected by reefs, lots of organisms and shells -> limestone -Deep-marine deposits: only fine clay and plankton for sediment  mudstone, chalk, bedded chert (turbidity -> allows for thin alternation of shales and sandstone) 12.Lahars ANS: Lahars are essentially flows of water mixed with volcanic ash and debris which appear to be like wet concrete. They tend to occur when volcanoes are capped with ice and snow. When the ice and snow melts, or if it rains, any ash
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