Minerals, Rocks, and Soil
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Bedrock Geology Glossary from the Roadside Geology of Minnesota, Richard W
Minnesota Bedrock Geology Glossary From the Roadside Geology of Minnesota, Richard W. Ojakangas Sedimentary Rock Types in Minnesota Rocks that formed from the consolidation of loose sediment Conglomerate: A coarse-grained sedimentary rock composed of pebbles, cobbles, or boul- ders set in a fine-grained matrix of silt and sand. Dolostone: A sedimentary rock composed of the mineral dolomite, a calcium magnesium car- bonate. Graywacke: A sedimentary rock made primarily of mud and sand, often deposited by turbidi- ty currents. Iron-formation: A thinly bedded sedimentary rock containing more than 15 percent iron. Limestone: A sedimentary rock composed of calcium carbonate. Mudstone: A sedimentary rock composed of mud. Sandstone: A sedimentary rock made primarily of sand. Shale: A deposit of clay, silt, or mud solidified into more or less a solid rock. Siltstone: A sedimentary rock made primarily of sand. Igneous and Volcanic Rock Types in Minnesota Rocks that solidified from cooling of molten magma Basalt: A black or dark grey volcanic rock that consists mainly of microscopic crystals of pla- gioclase feldspar, pyroxene, and perhaps olivine. Diorite: A plutonic igneous rock intermediate in composition between granite and gabbro. Gabbro: A dark igneous rock consisting mainly of plagioclase and pyroxene in crystals large enough to see with a simple magnifier. Gabbro has the same composition as basalt but contains much larger mineral grains because it cooled at depth over a longer period of time. Granite: An igneous rock composed mostly of orthoclase feldspar and quartz in grains large enough to see without using a magnifier. Most granites also contain mica and amphibole Rhyolite: A felsic (light-colored) volcanic rock, the extrusive equivalent of granite. -
Lecture 13: Earth Materials
Earth Materials Lecture 13 Earth Materials GNH7/GG09/GEOL4002 EARTHQUAKE SEISMOLOGY AND EARTHQUAKE HAZARD Hooke’s law of elasticity Force Extension = E × Area Length Hooke’s law σn = E εn where E is material constant, the Young’s Modulus Units are force/area – N/m2 or Pa Robert Hooke (1635-1703) was a virtuoso scientist contributing to geology, σ = C ε palaeontology, biology as well as mechanics ij ijkl kl ß Constitutive equations These are relationships between forces and deformation in a continuum, which define the material behaviour. GNH7/GG09/GEOL4002 EARTHQUAKE SEISMOLOGY AND EARTHQUAKE HAZARD Shear modulus and bulk modulus Young’s or stiffness modulus: σ n = Eε n Shear or rigidity modulus: σ S = Gε S = µε s Bulk modulus (1/compressibility): Mt Shasta andesite − P = Kεv Can write the bulk modulus in terms of the Lamé parameters λ, µ: K = λ + 2µ/3 and write Hooke’s law as: σ = (λ +2µ) ε GNH7/GG09/GEOL4002 EARTHQUAKE SEISMOLOGY AND EARTHQUAKE HAZARD Young’s Modulus or stiffness modulus Young’s Modulus or stiffness modulus: σ n = Eε n Interatomic force Interatomic distance GNH7/GG09/GEOL4002 EARTHQUAKE SEISMOLOGY AND EARTHQUAKE HAZARD Shear Modulus or rigidity modulus Shear modulus or stiffness modulus: σ s = Gε s Interatomic force Interatomic distance GNH7/GG09/GEOL4002 EARTHQUAKE SEISMOLOGY AND EARTHQUAKE HAZARD Hooke’s Law σij and εkl are second-rank tensors so Cijkl is a fourth-rank tensor. For a general, anisotropic material there are 21 independent elastic moduli. In the isotropic case this tensor reduces to just two independent elastic constants, λ and µ. -
Earth Materials Summary
GRADES 3–4 OVERVIEW EARTH MATERIALS GOALS The Earth Materials Module consists of four sequential investigations dealing with observable characteristics of solid materials from the earth—rocks and minerals. The focus is on taking materials apart to ○○○○○ find what they are made of and putting materials together to better ○○○○○○○○○○○ understand their properties. The module introduces fundamental OVERVIEW CONTENTS concepts in earth science and takes advantage of the students’ Goals 1 intrinsic interest in the subject matter and in the physical world FOSS and National Science around them. Education Standards 2 FOSS EXPECTS STUDENTS TO Science Background 3 • Develop an interest in earth materials. Working in Collaborative • Gain experiences with rocks and minerals. Groups 8 • Understand the process of taking apart and putting together Encouraging Discourse 9 to find out about materials. Guiding FOSS Investigations 10 • Use measuring tools to gather data about rocks. Assessing Progress 11 • Collect and organize data about rocks. Integrating the Curriculum 12 • Observe, describe, and record properties of minerals. FOSS for All Students 13 •Organize minerals on the basis of the property of hardness. The FOSS Teacher Guide • Investigate the effect of vinegar (acid) on a specific mineral, Organization 14 calcite. The FOSS Investigation Folio • Use evaporation to investigate rock composition. Organization 15 • Learn that rocks are composed of minerals and that minerals Scheduling the Earth cannot be physically separated into other materials. Materials Module 16 • Compare their activities to the work of a geologist. Safety in the Classroom 17 • Acquire vocabulary used in earth science. Earth Materials Module • Exercise language and math skills in the context of science. -
Earth Materials
Grade 4 Science, Quarter 1, Unit 1 Earth Materials Overview Number of instructional days: 10 (1 day = 45 minutes) Content to be learned Science processes to be integrated • Identify the four basic materials of the earth • Use physical properties to describe, compare, (water, soil, rocks, air). and sort objects. • Describe, compare, and sort rocks, soils, and • Make, record, and analyze observations and minerals by similar and different physical data. properties. • Cite evidence to support classification of • Record and analyze observations/data about objects. physical properties. • Identify and determine the uses of materials • Cite evidence to support why rocks, soils, or based on their physical properties. minerals are or are not classified together. • Support explanations using observations and • Determine and support explanations of the uses data. of earth materials. Essential questions • In what ways can we identify, describe, sort, • How can we use earth materials? and classify earth materials? Bristol-Warren, Little Compton, Portsmouth, Tiverton Public Schools, C-1 in collaboration with the Charles A. Dana Center at the University of Texas at Austin Grade 4 Science, Quarter 1, Unit 1 Earth Materials (10 days) Written Curriculum Grade-Span Expectations ESS1 - The earth and earth materials as we know them today have developed over long periods of time, through continual change processes. ESS1 (K-4) INQ –1 Given certain earth materials (soils, rocks or minerals) use physical properties to sort, classify, and describe them. ESS1 (3-4) –1 Students demonstrate an understanding of earth materials by … 1d identifying the four basic materials of the earth (water, soil, rocks, air). 1a describing, comparing, and sorting rocks, soils, and minerals by similar or different physical properties (e.g., size, shape, color, texture, smell, weight, temperature, hardness, composition). -
Sediment and Sedimentary Rocks
Sediment and sedimentary rocks • Sediment • From sediments to sedimentary rocks (transportation, deposition, preservation and lithification) • Types of sedimentary rocks (clastic, chemical and organic) • Sedimentary structures (bedding, cross-bedding, graded bedding, mud cracks, ripple marks) • Interpretation of sedimentary rocks Sediment • Sediment - loose, solid particles originating from: – Weathering and erosion of pre- existing rocks – Chemical precipitation from solution, including secretion by organisms in water Relationship to Earth’s Systems • Atmosphere – Most sediments produced by weathering in air – Sand and dust transported by wind • Hydrosphere – Water is a primary agent in sediment production, transportation, deposition, cementation, and formation of sedimentary rocks • Biosphere – Oil , the product of partial decay of organic materials , is found in sedimentary rocks Sediment • Classified by particle size – Boulder - >256 mm – Cobble - 64 to 256 mm – Pebble - 2 to 64 mm – Sand - 1/16 to 2 mm – Silt - 1/256 to 1/16 mm – Clay - <1/256 mm From Sediment to Sedimentary Rock • Transportation – Movement of sediment away from its source, typically by water, wind, or ice – Rounding of particles occurs due to abrasion during transport – Sorting occurs as sediment is separated according to grain size by transport agents, especially running water – Sediment size decreases with increased transport distance From Sediment to Sedimentary Rock • Deposition – Settling and coming to rest of transported material – Accumulation of chemical -
Geomorphic Processes
CHAPTER GEOMORPHIC PROCESSES fter learning about how the earth was forces continuously elevate or build up parts born, how it evolved its crust and other of the earth’s surface and hence the exogenic Ainner layers, how its crustal plates processes fail to even out the relief variations moved and are moving, and other information of the surface of the earth. So, variations remain on earthquakes, the forms of volcanism and as long as the opposing actions of exogenic and about the rocks and minerals the crust is endogenic forces continue. In general terms, composed of, it is time to know in detail about the endogenic forces are mainly land building the surface of the earth on which we live. Let forces and the exogenic processes are mainly us start with this question. land wearing forces. The surface of the earth is sensitive. Humans depend on it for their Why is the surface of the earth uneven? sustenance and have been using it extensively and intensively. So, it is essential to understand The earth’s crust is dynamic. You are well its nature in order to use it effectively without aware that it has moved and moves vertically disturbing its balance and diminishing its and horizontally. Of course, it moved a bit faster potential for the future. Almost all organisms in the past than the rate at which it is moving contribute to sustain the earth’s environment. now. The differences in the internal forces However, humans have caused extensive operating from within the earth which built up damage to the environment through over use the crust have been responsible for the of resources. -
Chapter 2 the Solid Materials of the Earth's Surface
CHAPTER 2 THE SOLID MATERIALS OF THE EARTH’S SURFACE 1. INTRODUCTION 1.1 To a great extent in this course, we will be dealing with processes that act on the solid materials at and near the Earth’s surface. This chapter might better be called “the ground beneath your feet”. This is the place to deal with the nature of the Earth’s surface materials, which in later sections of the chapter I will be calling regolith, sediment, and soil. 1.2 I purposely did not specify any previous knowledge of geology as a prerequisite for this course, so it is important, here in the first part of this chapter, for me to provide you with some background on Earth materials. 1.3 We will be dealing almost exclusively with the Earth’s continental surfaces. There are profound geological differences between the continents and the ocean basins, in terms of origin, age, history, and composition. Here I’ll present, very briefly, some basic things about geology. (For more depth on such matters you would need to take a course like “The Earth: What It Is, How It Works”, given in the Harvard Extension program in the fall semester of 2005– 2006 and likely to be offered again in the not-too-distant future.) 1.4 In a gross sense, the Earth is a layered body (Figure 2-1). To a first approximation, it consists of concentric shells: the core, the mantle, and the crust. Figure 2-1: Schematic cross section through the Earth. 73 The core: The core consists mostly of iron, alloyed with a small percentage of certain other chemical elements. -
Rocks and Soil Materials
Science Benchmark: 04:03 Earth materials include rocks, soils, water, and gases. Rock is composed of minerals. Earth materials change over time from one form to another. These changes require energy. Erosion is the movement of materials and weathering is the breakage of bedrock and larger rocks into smaller rocks and soil materials. Soil is continually being formed from weathered rock and plant remains. Soil contains many living organisms. Plants generally get water and minerals from soil. Standard III: Students will understand the basic properties of rocks, the processes involved in the formation of soils, and the needs of plants provided by soil. Shared Reading Getting to Know Rocks and Soil We live on a rocky world! Rocks are all around us. We live on rocks even though we can’t always see them. These rocks are sometimes hidden deeply beneath our feet, and sometimes they are exposed on Earth’s surface so we can see them. On mountaintops, where the soil is very thin, rocks often poke through. All rocks are made of mixtures of different minerals. Minerals are the building blocks from which rocks are made. People who study rocks make observations of rocks they discover. They identify the different minerals in the rocks they find. How can they do this? Each mineral has a certain color (or colors), appearance, shape, hardness, texture, crystal pattern, and possibly a smell that sets it apart from another. As scientists test each mineral's characteristics, they are able to tell which minerals are in the rocks. Rocks can change over a period of time. -
Sedimentary Rock Formation Models
Sedimentary Rock Formation Models 5.7 A Explore the processes that led to the formation of sedimentary rock and fossil fuels. The Formation Process Explained • Formation of these rocks is one of the important parts of the rock cycle. For millions of years, the process of deposition and formation of these rocks has been operational in changing the geological structure of earth and enriching it. Let us now see how sedimentary rocks are formed. Weathering The formation process begins with weathering of existent rock exposed to the elements of nature. Wind and water are the chisels and hammers that carve and sculpt the face of the Earth through the process of weathering. The igneous and metamorphic rocks are subjected to constant weathering by wind and water. These two elements of nature wear out rocks over a period of millions of years creating sediments and soil from weathered rocks. Other than this, sedimentation material is generated from the remnants of dying organisms. Transport of Sediments and Deposition These sediments generated through weathering are transported by the wind, rivers, glaciers and seas (in suspended form) to other places in the course of flow. They are finally deposited, layer over layer by these elements in some other place. Gravity, topographical structure and fluid forces decide the resting place of these sediments. Many layers of mineral, organics and chemical deposits accumulate together for years. Layers of different deposits called bedding features are created from them. Crystal formation may also occur in these conditions. Lithification (Compaction and Cementation) Over a period of time, as more and more layers are deposited, the process of lithification begins. -
Plate Tectonics and the Cycling of Earth Materials
Plate Tectonics and the cycling of Earth materials Plate tectonics drives the rock cycle: the movement of rocks (and the minerals that comprise them, and the chemical elements that comprise them) from one reservoir to another Arrows are pathways, or fluxes, the I,M.S rocks are processes that “reservoirs” - places move material from one reservoir where material is temporarily stored to another We need to be able to identify these three types of rocks. Why? They convey information about the geologic history of a region. What types of environments are characterized by the processes that produce igneous rocks? What types of environments are preserved by the accumulation of sediment? What types of environments are characterized by the tremendous heat and pressure that produces metamorphic rocks? How the rock cycle integrates into plate tectonics. In order to understand the concept that plate tectonics drives the rock cycle, we need to understand what the theory of plate tectonics says about how the earth works The major plates in today’s Earth (there have been different plates in the Earth’s past!) What is a “plate”? The “plate” of plate tectonics is short for “lithospheric plate” - - the outermost shell of the Earth that behaves as a rigid substance. What does it mean to behave as a rigid substance? The lithosphere is ~150 km thick. It consists of the crust + the uppermost mantle. Below the lithosphere the asthenosphere behaves as a ductile layer: one that flows when stressed It means that when the substance undergoes stress, it breaks (a non-rigid, or ductile, substance flows when stressed; for example, ice flows; what we call a glacier) Since the plates are rigid, brittle 150km thick slabs of the earth, there is a lot of “action”at the edges where they abut other plates We recognize 3 types of plate boundaries, or edges. -
Relative Age-Dating
Relative Age-dating -- Discovery of Important Stratigraphic Principles Roger Steinberg, Assistant Professor of Geology, Del Mar College, Corpus Christi, TX Background Physical Geology and Historical Geology are the two introductory level Geology classes taught at most colleges and universities. Physical Geology is the study of Earth materials (minerals, rocks, sediment and soil) and the processes that affect those materials, including processes associated with oceans and shorelines, rivers, glaciers, groundwater, the wind, downslope movement and tectonic forces. Historical Geology is the study of the Earth through time, emphasizing the origins of and changes in the Earth's surface and subsurface, atmosphere, biosphere, and hydrosphere (water). Historical Geology is, as the name implies, essentially a history class. As in any other history class, we wish to know what happened, and when those particular events occurred. Of equal importance to learning these facts is an understanding of how we know what we claim to know about the history of the Earth. I believe it is critically important to establish that all of our geological knowledge about the Earth and its history has a firm, scientific foundation, and is based on important principles and concepts. In piecing together the history of the Earth, geologists rely on several key principles that allow us to determine the ages of rocks and the timing of significant events. There are two very different approaches to age-dating geological materials and events. Actual age-dating is the determination of the precise, numerical age of rocks and the geologic events that have affected those rocks for a particular area. It is often considered to be synonymous with radiometric age-dating, in which the occurrence and radioactive decay of natural, radioactive isotopes within minerals and rocks can be used as a type of very accurate clock to determine their age, although not all actual age-dating methods are radiometric. -
Structural Geology –Practice Questions and Answers Revised November 2008
Structural Geology –Practice Questions and Answers Revised November 2008 1. Terms used to describe surfaces across which there has been perceptible displacement are many. However, most geologists would prefer one of the falling terms: (a) joints, (b) fractures, (c) cracks, or (d) faults. What term best describes a surface across which there has been perceptible displacement? 2. Force is a term common to physics. Its classical expression is Force = mass * acceleration. However geologists are more concerned with the intensity of force or more succinctly the stress. Stress is defined as ______________________ . 3. Stresses produce strains in Earth materials. What are strains? 4. There are two end-member varieties of faults: dip-slip and strike-slip. The displacement along a strike-slip fault is _________________ to the strike of the fault. 5. The orientation of a plane in space is expressed by its attitude; a term consisting of two components, strike and dip. Define strike. Define dip. 6. Though many beds are upright others are not. For example, an overturned bed is one that has been rotated more than __________ degrees. 7. A dip-slip fault consists of the dipping fault surface and hanging and footwall blocks. The hanging wall block lies ____________ the dipping fault surface. 8. In the following illustration what block is the White Pine located on? What block is the Maple located on? What kind of fault is illustrated? 9. The footwall block lies ___________ a dipping fault surface. 10. What do you call a three dimensional surface separating Earth material of differing aspect? 11. In a dip-slip fault, if the hanging wall block moved up relative to the footwall block, then the fault is classified as a ____________________ .