Assignmen 1-2 - rock cycle rock classification PDF

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[Assignment 1-2 PHY-103 Stephene Merritt Southern New Hampshire University

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Abstract For this assignment I was asked to define a mineral and describe its properties and characteristics. I proved knowledge of the three different types of rocks as well as how they are formed. I analyzed the rock cycle and its various stages to obtain a clear understanding of how the rock cycle functions and why it is so critical to life on earth. I defined soil and listed its physical properties, as well as giving examples of each different type of soil and why it is classified as such. Keywords: Minerals, Rock Formation, Rock Cycle, and Soil definition and classification. What is A mineral? [For our first question, the formal definition of a mineral is a substance that must meet the following criteria. A substance must be Naturally Occurring, meaning it is not man made. For example, steel is not a mineral because it is an alloy produced by humans. A substance must be inorganic meaning it is not made from an organism. Fossil Fuels for example are not a mineral because they are made up of tropical tree foliage and other organic material that was once living compressed over time. A substance must also be in a Solid state of matter. It must remain solid at standard temperatures and pressures. The substance must also have a definite chemical composition. This means all occurrences of that mineral have a chemical composition that varies with a specific limited range. The last feature is that the substance must have an ordered internal structure, atoms must be arranged in a systematic and repeating pattern.

[Physical Properties of Mineral]1 There are approximately 4000 minerals, that we know of. Each has its own set of unique physical properties. for my example I will be using the mineral Talc. Talc is a clay mineral, composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening agent and lubricant; is an ingredient in ceramics, paint, and roofing material; and is

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a main ingredient in many cosmetics. It occurs as foliated to fibrous masses, and in an exceptionally rare crystal form. It has a perfect basal cleavage and an uneven flat fracture, and it is foliated with a two-dimensional platy form. It is the softest known mineral and is assigned a firmness of 1 on the Mohs Hardness Scale. [Rock Types.]. [There are three main rock groups: Igneous, Sedimentary, and Metamorphic. For this part of the assignment I am going to be concentrating on metamorphic rock family. Metamorphic Rock arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock is subjected to heat and pressure, causing profound physical or chemical change. The protolith may be a sedimentary, igneous, or existing metamorphic rock. the four main agents responsible for this change are heat, pressure, fluids, and strain all capable of acting and interacting in an almost infinite variety of ways. Most of the thousands of rare minerals known to science occur in Metamorphic Rock. [Amphibolite]. Amphibolite is a coarse-grained metamorphic rock that is composed of green, brown, or black amphibole minerals and plagioclase feldspar. The amphiboles are usually members of the hornblende group.] (Google,2020) [Rock Cycle]. [The Rock Cycle is an idealized cycle of processes undergone by rocks in the earth's crust, involving igneous intrusion, uplift, erosion, transportation, deposition as sedimentary rock, metamorphism, remelting, and further igneous intrusion. The stages of the Rock Cycle are as follows: Melting- Metamorphic rocks underground melt to become magma. When volcanos erupt magma flows out of them (when magma is on the earth's surface it is called lava). As the lava cools it hardens becoming Igneous Rock. Certain types of Igneous Rock such as Pumice, Obsidian, and Peridotite are formed this way.

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Weathering and Erosion- Igneous, sedimentary, and metamorphic rocks on the surface of the earth are constantly being broken down by wind and water. Wind carrying sand wears particles off rock like sand paper. Rushing river water and crashing surf rub off all the rough edges of rocks, leaving smooth river rocks or pebbles behind. Water seeps into the cracks in mountain rocks, then freezes, causing the rocks to break open. Transportation- Eroded rock particles are carried away by wind or by rain, streams, rivers, and oceans. Deposition- As rivers get deeper or flow into the ocean, their current slows down, and the rock particles (mixed with soil) sink and become a layer of sediment. Often the sediment builds up faster than it can be washed away, creating little islands, and forcing the river to break up into many channels in a delta. Compaction and Cementation- As the layers of sediment stack up (above water or below), the weight and pressure compact the bottom layers. Dissolved minerals fill in the small gaps between particles and then solidify, acting as cement. After years of compaction and cementation, the sediment turns into Sedimentary Rock such as Limestone, Sandstone and Coal. Metamorphism- Over exceptionally lengthy periods of time, Sedimentary or Igneous Rocks end up buried deep underground, usually because of the movement of tectonic plates. While underground, these rocks are exposed to high heat and pressure, which changes them into Metamorphic Rock such as Marble, Slate, and Amphibolite. This tends to happen where tectonic plates come together: the pressure of the plates squishes the rock that is heated from hot magma below. (Merritt,2020) [What Is Soil?]

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Soil is defined as the upper layer of earth in which plants grow, a black or deep brown material typically consisting of a mixture of organic remains, clay, and rock particles. The physical properties of soil are color, texture, structure, porosity, density, consistence temperature, and air. The color of soil plays an important part in showing specific properties like organic matter, water, and redox conditions. Soil texture, structure, porosity, density, and consistence are related with types of soil particles and their arrangement. There are two types of soil particles-primary and secondary. [Properties of Soil] There are significant differences in physical, chemical, and mineralogical properties of these fractions. Soil texture shows the relative content of particles of diverse sizes, such as sand, silt, and clay in the soil. It is a fundamental property of soil and is not easily altered. There are 12 texture classes ranging from sand to clay. Soil structure is defined as the way individual particles of sand, deposit, and clay are assembled in different geometric patterns. Soil texture and structure regulate porosity, density, compactness, retention, and the movement of water and air in the soil. Soil temperature influences life processes of soil biota including plants. Soil air is kept in soil pores; its composition is variable, and it holds higher carbon dioxide and moisture and lower oxygen concentration then atmospheric air. Soil air has a distinguished role in the respiration of plant roots and microorganisms and the transformation of mineral and organic matter. [Classifications of Soil] Soil can be classified into 3 main types, Type A, Type B, and Type C. Type A soil is cohesive and has a high unconfined compressive strength of 1.5

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tons per square foot or greater. Examples of Type A soil include clay, silty, sandy clay, and clay loam. Type B soil has a medium unconfined compressive strength between 0.5 and 1.5 tons per square foot. Examples of Type B soil include angular gravel, silt, silt loam and soils that a fissured. Type C soil is the least stable. Type C soils are granular soils which particles do not stick together, and water sinks in easily. Type C soils have low unconfined compressive strength of 0.5 tons per square foot or less. Examples of this type of soil include Gravel and sand.

[SHORTENED TITLE UP TO 50 CHARACTERS] References Google, (2020). Mineral and Their Properties. Pages From 1 - 10. Google,(2020). Foundations of Earth Science . City Name: Publisher Name: Pearsons

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