In person lab 1- Minerals and Rocks-2 redone

GEOL 102 History of the Earth S23 Name: Emanuel Moreno In person lab 1: Minerals & Rocks Purpose: Minerals are the building blocks of our world, and rocks are made of up minerals. These are materials that both make up the Earth around us and are important resources used in our everyday lives. By learning to identify a few key minerals and rocks through practicing minerals and rocks in person, and understanding the context of how and where they form, you can approach the world from a very different perspective, eyes wide open to the “how” and “why” of your surroundings. This lab is based on one by Madeline Marshall, Albion College Tasks: ◻ Work to explore and identify the minerals, igneous rocks, sedimentary rocks, metamorphic rocks, and tell a story of the rock cycle. ◻ This should be a review for you based on your work in Geology 100, but please ask lots of questions! Due: end of your lab period Part A: Minerals 1. Complete this blank Bowen’s Reaction Series with the range of temperatures that these minerals crystallize at, and the mineral names themselves. 2. Then, review the physical properties outlined below. Examine the minerals for this lab and use the physical properties, along with the minerals reference table to identify them all. 1A – Biotite 2A – Muscovite 3A – Plagioclase Feldspar 4A – Quartz 5A – Potassium Feldspar 6A – Pyroxene 7A –Olivine 8A – Amphibole 9A – Calcite 10A – Pyrite 3. Add the appropriate number of the sample to the names you placed on the Bowen’s diagram. 1

GEOL 102 History of the Earth S23 4. There are two samples that aren’t part of Bowen’s Reaction Series, because they don’t form through igneous processes (in volcanoes or magma chambers). Identify these two minerals by name below, and note 1 key identifying characteristic of each (how did you figure it out?): Calcite – 9 rhombohedral cleavage Pyrite – 10 brassy yellow color Most common minerals can be identified by their physical properties, which result from the internal arrangement of atoms in the mineral. These properties include: ● Color : fairly obvious, but can vary widely and is generally not to be trusted as the only criterion 2

GEOL 102 History of the Earth S23 variable (rhombohedral) HCl acid, rhombohedral construction Black to dark green 2 cleavage planes at 90º 5-6 Jewelry (Ca,Na) (Mg,Fe,Al) (Si,Al)2O6 Pyroxene Black to dark green 2 cleavage planes at 120º 5-6 Usually relatively long crystals Jewelry NaCa2(Mg,Fe,Al) 5(Al,Si)8O22(OH) 2 Amphibole White to pink 2 cleavage planes at 90º 6 Often blocky crystals Ceramics, glass KAlSi3O8 Potassium feldspar White to gray 2 cleavage planes at 90º 6 Striations on surfaces Ceramics, glass (Na,Ca)AlSi3O8 Plagioclase feldspar Green to gray or brown fractures 6.5 Granular, commonly light green Furnace bricks, gemstone (Fe,Mg)2SiO4 Olivine Colorless to variable fractures 7 Glassy, can form hexagonal crystals Glass, electronics, jewelry SiO2 Quartz Dark red to green fractures 6.5-7.5 crystals cubic or dodecahedra Gemstone, abrasives Fe3Al2Si3O12 Garnet Part B: Igneous Rocks Magma and Lava are often used cavalierly in everyday speech, but those terms actually refer to pretty different things. Magma is molten material inside the earth, and when this intrusive material crystallizes into rock, the crystals will be large due to the gradual cooling process. Lava has been erupted onto the surface of the earth (sometimes on land, sometimes at the ocean floor), and when this extrusive material crystallizes into rock, the crystals will be tiny due to the rapid cooling or quenching process as it hits much cooler air or water. 1. Identify the samples of igneous rocks. Utilize the identification chart below to help. B1 – basalt B2 – pumice B3 – andesite B4 – andesite B5 – diorite B6 – granite B7 – rhyolite B8 – andesite 2. Place their names and the corresponding sample numbers on the diagram below showing both location of formation within or above the Earth AND the range of compositions . ( There is a one rock type seen in two different samples; include both #s .) 4

GEOL 102 History of the Earth S23 Diagram above modified from Fig. 1, Caricchi, L., & Blundy, J. (2015). The temporal evolution of chemical and physical properties of magmatic systems.   Geological Society, London, Special Publications ,   422 (1), 1-15. *Note: in Note: in reality, the felsic, intermediate, and mafic systems would all be found in different locations largely based on their plate tectonic settings. 5 Felsic (cool, viscous, explosive) Mafic (hot, fluid, non-explosive) Ultramafic Intermediate (moderate, gaseous, sticky)

GEOL 102 History of the Earth S23 Sedimentary rocks comprise ~70% of all rocks exposed at the Earth’s surface, and they are not only volumetrically significant but also economically important. We’ll be digging ( ☺ ) into a lot more sedimentary rocks in a few weeks, but for now we’re just going to cement ( )your 😐 knowledge of two key sedimentary rocks. 1. Identify sedimentary #1 in person. Siltstone 2. What category of sedimentary rock does this sample belong to? Inorganic land derived. 3. Identify sedimentary #2. Conglomerate 4. What category of sedimentary rock does this sample belong to? Inorganic land-dervived 5. Within sedimentary #2, check out the component grains more closely – what do you think they are, and why? ( Feel free to ask if you need some guidance, but at least make a preliminary hypothesis .) I believe that it is fragments of pebbles or potentially little shells due to the shapes. 7

GEOL 102 History of the Earth S23 Part D: Metamorphic Rocks When heat and/or pressure are applied to either igneous or sedimentary rocks, they are transformed into metamorphic rocks. These forces can be from a variety of ultimate sources, and one of the key culprits is the process of mountain-building – pre-existing rocks are squashed together, thrust up, faulted over each other, sometimes pushed deeper into the Earth, and sometimes heated too. The pre-existing rocks might be anything from a shale to a granite! More intense metamorphism is typically deeper within the Earth, while lower-grade metamorphism occurs closer to the surface. Because it’s such a large-scale process (think about the Rocky Mountains in North America!), this is referred to as regional metamorphism . Regionally metamorphosed rocks can be framed as being of different “grades” – essentially, how squashed did they get? The more squashed (higher grade), the more defined the foliation is. For example, gneiss has full-on color (compositional) banding, while slate has the platy layers of mild foliation due to mineral alignment. Alternatively, rocks can be metamorphosed if they come into contact with extreme heat – such as if magma is injected through fractures in rocks at the Earth’s surface. Contact metamorphism can alter various “parent” rocks, often sedimentary, and essentially fuse all the grains together so intensely that you can no longer discern the boundaries of individual grains (it appears to be a uniform mass). 1. Identify each of the metamorphic samples. Use the concept of foliation, and referring to the identification chart below, also bring in what you now know about the typical colors/appearances of the minerals present in each type of metamorphic rock. ( As you are working on this, ask questions if you need help narrowing down your ideas! ) D – 1 ½ marble D – 1 2/2 marble D – 2 Quartzite D – 3 shist D – 4 Slate D – 5 Genisis 2. On the Regional Metamorphism diagram below, add the names and sample numbers of the appropriate rocks to where you might be likely to find them within a mountain (consider metamorphic grade, which often increases with depth). 8

GEOL 102 History of the Earth S23 c 10

GEOL 102 History of the Earth S23 Part E: The Rock Cycle While we may discuss each of the three major rock types independently, they are all interconnected (and often have many of the same minerals) through the Rock Cycle – you may have guessed that most Earth systems in this course are cycles! With your partners, your wrap-up for this lab is to tell a short story : Imagine a granite that formed intrusively – perhaps the magma chamber crystallized slowly and entirely, and was then uplifted as a mountain (like Yosemite in California!). Outline, diagram, and discuss how the original magma (begin there!) could travel through the rock cycle, following the diagram below. There are multiple possible routes, so use your imaginations (and new geological knowledge). Short Story- Deep under the surface of the Earth, granite's birth began as molten. In a large subterranean cavern, magma gradually solidified. Over the ages, it slowly pushed its way through the nearby rocks to become granite. The granite bulk was raised over time, reaching the sky, as tectonic forces took their course. The view of Yosemite was made clear by the appearance of a mountain. Which goes completes the life cycle. -Magama in formed in a chamber deep beneath the earth -The formation of granite shows the formation of an igneous rock -Plates uplift creating mountains -The rocks eroding create sediments - They then turn into sedimentary rocks over time with heat and preassure 11