GEOL 101 Lecture 8: Introduction to Geological History Chapter 8 Add

Total Page:16

File Type:pdf, Size:1020Kb

GEOL 101 Lecture 8: Introduction to Geological History Chapter 8 Add GEOL 101 Lecture 8: Introduction to Geological History Chapter 8 Add images • 14 C lab •19th Cent smoke stacks •A-Bomb Geologic Time Scale Relative Dating (Logic) & Absolute (Radiometric) Dating 1 General Rules for Interpreting Sedimentary Rocks • Law of Original Horizontality • Law of Superposition • Law of Cross-Cutting Relationships • The Meaning of Unconformities • Concept of Facies = (Environments of Formation) • Correlation Tools Original Horizontality • Horizontal Beds vs. Vertical Beds Up Up What’s It All Mean? Horizontal Bedding: U.S. Rt. 19, Powell Mtn., WV J.S. Kite Photo 2 GEOL 101 Lecture # General Rules for Interpreting Sedimentary Rocks • Law of Original Horizontality • Law of Superposition • Law of Cross-Cutting Relationships • The Meaning of Unconformities • Concept of Facies = (Environments of Formation) 3 Superposition • Stratified Sediments or Rocks • Younger “Rocks” - Added to Top of a Sequence • Oldest “Rocks” at the Bottom of Sequence Horizontal Bedding: U.S. Rt. 19, Powell Mtn., WV J.S. Kite Photo Superposition • Oldest “Rocks” are at the Bottom. • Younger Rocks are at the top. Youngest Oldest 4 Breached (Eroded) Folds & Age of Rocks. Superposition: Youngest on Top Younger Rocks Older Rocks Where are older rocks exposed at the surface? Younger Rocks General Rules for Interpreting Sedimentary Rocks • Law of Original Horizontality • Law of Superposition • Law of Cross-Cutting Relationships • The Meaning of Unconformities • Concept of Facies = (Environments of Formation) Cross-Cutting Relationships • Younger Intrusions or Faults Cut Across Older Rocks . 5 Fault Parts Cross-Cutting Relationships - Plutons Explain the geological history represented by an outcrop of basalt that is intruded by a dike of rhyolite porphyry. The 5-10 cm of rock that was basalt along the dike is now hornfels. Which rock was there first? Which was there second? What caused the hornfels? 6 General Rules for Interpreting Sedimentary Rocks • Law of Original Horizontality • Law of Superposition • Law of Cross-Cutting Relationships • The Meaning of Unconformities • Concept of Facies = (Environments of Formation) Unconformity • Buried Erosion Surface . Unconformity, Ouray Colorado 7 Unconformity, Ouray Colorado Late Devonian sandstone Elbert Formation ~360 million years old Unconformity: ~1,000,000,000 years missing Precambrian shale, siltstone & sandstone (Uncompahgre formation ~1.5 billion years old) Vince Matthews, Colorado G.S. source for text information. General Rules for Interpreting Sedimentary Rocks • Law of Original Horizontality • Law of Superposition • Law of Cross-Cutting Relationships ) • The Meaning of Unconformities 8 • Concept of Facies = (Environments of Formation Maturity Immature Sediments Mature Sediments Facies Tools to Reconstruct Relative Ages in Earth History • Correlation . Correlation: • Marker Beds –Volcanic Ash –Iridium Layer •(Bolide Impact) . 9 Volcanic Ash Marker Beds Iridium Layer 65,000,000 years old Great Relative Dating Tool: Fossils Trilobite 10 Correlation with Fossils Strata = Layers Stratigraphy = Study of Layered Rocks Stratigraphic Units • Groups • Formations • Members 11 Formation • Smallest Mappable Stratigraphic Unit • (vs. Outcrop) Morgantown Stratigraphy • Monongahela Group • Conemaugh Group • Allegheny Group • Pottsville Group Bits of Local Stratigraphy • Monongahela Group • Waynesburg Formation • Uniontown Formation • Pittsburgh Formation • Pittsburgh Coal - $$$ • Conemaugh Group • Clarksburg Shale • Morgantown Sandstone 12 Local Stratigraphy • Pottsville Group • Connequenessing Formation • Upper Connequenessing Sandstone Crops Out at Coopers Rock Absolute Dating • E.G. Radiometric Dating • * Table 8.3, p. 195 * • Plummer et al. 10th ed • Expect Questions Meadowcroft Rock Shelter, Avella, PA: Occupied How Do we Know That? 17,000 years ago 13 How Do we Know That? Carbon-14 Dating = Radiocarbon Dating Carbon Isotopes Common, Stable Uncommon, Stable Uncommon, Radioactive Cosmic Rays “Zap” a Nitrogen-14 Proton into a Neutron to Form C-14 Beta Capture 14 C-14 Dating • C-14 mixed thru Atmosphere • Plants take in C-14 • Animals Eat Plants • Other Animals Eat Animals ... etc. • All living things include C-14 C-14 Dating • Dead Things Do Not Take in New C-14 (or C-12 or C-13) • C-14 Decays w/ Time • C-12, C-13 Does Not. Carbon - 14 is Radioactive • Decays back into N-14 at Known Rate • Half-Life is 5730 yr N-14 C-14 15 C-14 Dating • In 5730 years (1 Half-Life), Half of C-14 will Decay • In next 5730 years, Half of what was left will Decay –3/4ths will decay in 11,460 yr • 7/8ths will decay in 17,190 yr • etc.... C-14 Dating • <0.1 % of C-14 is Left After 57,000 yr • Most Labs “poop out” at >40,000 to >50,000 yr C-14 Dates • Years Before Present (yr B.P.) • Present = A.D. 1950 • +/- Measurement Error • example: 22,500 +/- 450 yr B.P. 16 What Can C-14 Dating Be Used For? • Dating Dead Things • <100,000 years Bristlecone Pine Tree-Ring Calibration of C14 Dating http://www.sonic.net/bristlecone/Images2.html Dendrochronology Another Absolute Dating Method 17 Carbon - 14 Basic Assumptions #1: Predictable Decay Rate #2: Constant C-14 Production Rate #3: All Living Things have Same Portions of C-14, C-12, & C-13 Obvious Problems w/ C-14 Dating • No Good for Most Minerals • Useless on Really Old Stuff –Find Another Method Problems w/ C-14 Dating • Basic Assumption # 3 : – All Living Things DO NOT have Same % of C-14, C-12, & C-13 • Bottom Waters • Antarctic Ocean Diluted by Glacial Meltwaters 18 Problems w/ C-14 Dating Basic Assumption # 2 : –C-14 not Constant in Atmosphere –Sun’s Cosmic Ray Output not Constant –More C-14 in Past –10,000 yr BP = 11,500 Calendar yr Man’s Impact • Industrial Revolution - Fossil Fuels diluted C-14 • Atmospheric Nuclear Testing increased C-14 Problems w/ C-14 Dating • Biggest Problem = –Stupid Geologist - • 2nd Biggest Problem = –Contamination of Samples • Young Carbon • Old Carbon 19 Geologic Cross Section - Hawaii Highlights of Earth History and Absolute Geologic Time • ~13.7 BY (BY = billion years): Universe forms • 4.55 - 4.60 BY: Earth forms • (Rest of Solar System, too) – Molten Magma Surface, – Methane, Ammonia, Hydrogen Atmosphere – High UV Radiation – Amino Acids etc. Geologic History Zircon Photo: J. Valley • 4.4 BY – Oldest Mineral (Zircon xl) • 3.8 - 4.1 BY – Oldest Known Rocks, Chemical Fossils • 3.5 BY Stromatolites, – Algae - Stromatolites South Africa • 1.8 - 2.0 BY – Oxygen "Crisis" • 1.5 - 1.7 BY – Sex 20 Geologic Time • 600-650 MY (MY = million years) – First Complex Animals Hallucigenia sparsa Anomalocaris canadensis Big Changes • ~551 MY – First Hard-Shelled "Critters" - Trilobites fossils common • ~500 MY – all phylum of higher animals exist, including chordates (vertebrates) 551-245 MY • Paleozoic (=“Old Animals”) Era 21 245 - 65 MY Mesozoic Era Age of Reptiles Allosaurus fragilis, a large Jurassic theropod, one step away from capturing a Dryosaurus altus. www.dinosaursinart.com/allosaurus/ IMAG0009.JPG 65 - 0 MY • Age of Mammals (Cenozoic Era) Horses through Time 22 The Geologic Time Scale • See p. 195 –in Plummer et al, 9th edition • Dates to Know : • 65 MY, 245 MY, 551 MY, 4.5-4.6 BY Question of Time If you plotted all of geologic time on a time line as long as the circumference of the Earth (25,000 mi or 40,000 km), what distance would represent 1 year? Earth Image Source: www.ameritech.net/users/ paulcarlisle/earth.jpg Question of Time • If you plotted all of geologic time on a time line as long as the circumference of the Earth (25,000 mi or 40,000 km), what distance would represent 1 year? • What distance would represent 75 years? • What distance would represent 1 semester (4 months = 0.33 year)? • What distance would represent this lecture? 23 The Whole Earth Time Line • Circumference of the Earth is 25,000 mi (40,000 km) • What distance would represent 1 year? –Figure this out in small groups. –Easiest if we use metric units • Divide Distance by # of Years (4,600,000,000 yr) The Whole Earth Time Line 40,000 km / 4,600,000,000 yr = distance represented by 1 year? 40,000,000 m / 4,600,000,000 yr = 4,000,000,000 cm / 4,600,000,000 yr = 0.87 cm / yr (0.34 inch / year) The Whole Earth Time Line 0.87 cm / yr (0.34 inch / year) X 75 yr = 65 cm (Lifetime = 25.7 inches) X 0.33 yr = 0.29 cm (Semester = ~1/8 inch) 24 Whole Earth Time Line 40,000,000,000,000 microns / (4,600,000,000 yr X 365 day/yr X 24 hr/day) = 0.99 micron / hour This Lecture would be just over 1 micron long on the Whole Earth Time Line. The paper you are writing on is about 100 microns thick 25.
Recommended publications
  • Facies and Mafic
    Metamorphic Facies and Metamorphosed Mafic Rocks l V.M. Goldschmidt (1911, 1912a), contact Metamorphic Facies and metamorphosed pelitic, calcareous, and Metamorphosed Mafic Rocks psammitic hornfelses in the Oslo region l Relatively simple mineral assemblages Reading: Winter Chapter 25. (< 6 major minerals) in the inner zones of the aureoles around granitoid intrusives l Equilibrium mineral assemblage related to Xbulk Metamorphic Facies Metamorphic Facies l Pentii Eskola (1914, 1915) Orijärvi, S. l Certain mineral pairs (e.g. anorthite + hypersthene) Finland were consistently present in rocks of appropriate l Rocks with K-feldspar + cordierite at Oslo composition, whereas the compositionally contained the compositionally equivalent pair equivalent pair (diopside + andalusite) was not biotite + muscovite at Orijärvi l If two alternative assemblages are X-equivalent, l Eskola: difference must reflect differing we must be able to relate them by a reaction physical conditions l In this case the reaction is simple: l Finnish rocks (more hydrous and lower MgSiO3 + CaAl2Si2O8 = CaMgSi2O6 + Al2SiO5 volume assemblage) equilibrated at lower En An Di Als temperatures and higher pressures than the Norwegian ones Metamorphic Facies Metamorphic Facies Oslo: Ksp + Cord l Eskola (1915) developed the concept of Orijärvi: Bi + Mu metamorphic facies: Reaction: “In any rock or metamorphic formation which has 2 KMg3AlSi 3O10(OH)2 + 6 KAl2AlSi 3O10(OH)2 + 15 SiO2 arrived at a chemical equilibrium through Bt Ms Qtz metamorphism at constant temperature and =
    [Show full text]
  • Part 629 – Glossary of Landform and Geologic Terms
    Title 430 – National Soil Survey Handbook Part 629 – Glossary of Landform and Geologic Terms Subpart A – General Information 629.0 Definition and Purpose This glossary provides the NCSS soil survey program, soil scientists, and natural resource specialists with landform, geologic, and related terms and their definitions to— (1) Improve soil landscape description with a standard, single source landform and geologic glossary. (2) Enhance geomorphic content and clarity of soil map unit descriptions by use of accurate, defined terms. (3) Establish consistent geomorphic term usage in soil science and the National Cooperative Soil Survey (NCSS). (4) Provide standard geomorphic definitions for databases and soil survey technical publications. (5) Train soil scientists and related professionals in soils as landscape and geomorphic entities. 629.1 Responsibilities This glossary serves as the official NCSS reference for landform, geologic, and related terms. The staff of the National Soil Survey Center, located in Lincoln, NE, is responsible for maintaining and updating this glossary. Soil Science Division staff and NCSS participants are encouraged to propose additions and changes to the glossary for use in pedon descriptions, soil map unit descriptions, and soil survey publications. The Glossary of Geology (GG, 2005) serves as a major source for many glossary terms. The American Geologic Institute (AGI) granted the USDA Natural Resources Conservation Service (formerly the Soil Conservation Service) permission (in letters dated September 11, 1985, and September 22, 1993) to use existing definitions. Sources of, and modifications to, original definitions are explained immediately below. 629.2 Definitions A. Reference Codes Sources from which definitions were taken, whole or in part, are identified by a code (e.g., GG) following each definition.
    [Show full text]
  • Earth Science Power Standards
    Macomb Intermediate School District High School Science Power Standards Document Earth Science The Michigan High School Science Content Expectations establish what every student is expected to know and be able to do by the end of high school. They also outline the parameters for receiving high school credit as dictated by state law. To aid teachers and administrators in meeting these expectations the Macomb ISD has undertaken the task of identifying those content expectations which can be considered power standards. The critical characteristics1 for selecting a power standard are: • Endurance – knowledge and skills of value beyond a single test date. • Leverage - knowledge and skills that will be of value in multiple disciplines. • Readiness - knowledge and skills necessary for the next level of learning. The selection of power standards is not intended to relieve teachers of the responsibility for teaching all content expectations. Rather, it gives the school district a common focus and acts as a safety net of standards that all students must learn prior to leaving their current level. The following document utilizes the unit design including the big ideas and real world contexts, as developed in the science companion documents for the Michigan High School Science Content Expectations. 1 Dr. Douglas Reeves, Center for Performance Assessment Unit 1: Organizing Principles of Earth Science Big Idea Processes, events and features on Earth result from energy transfer and movement of matter through interconnected Earth systems. Contextual Understandings Earth science is an umbrella term for the scientific disciplines of geology, meteorology, climatology, hydrology, oceanography, and astronomy. Earth systems science has given an improved, interdisciplinary perspective to researchers in fields concerned with global change, such as climate change and geologic history.
    [Show full text]
  • Stage 1А–Аdesired Results
    www.nextgenscience.org STAGE 1 – DESIRED RESULTS Unit Title: Earth’s Place in the Universe Grade Level: 6 Length/Timing of Unit: Teacher(s)/Designer(s): Pascack Valley Regional Science Committee Science State standards addressed (verbatim): ​ MS­ESS1­1 . Develop and use a model of the Earth­sun­moon system to describe the cyclic patterns of lunar phases, eclipses of the sun and moon, and seasons. [Clarification Statement: Examples of models can be physical, ​ graphical, or conceptual.] MS­ESS1­2. Develop and use a model to describe the role of gravity in the motions within galaxies and the solar system. [Clarification Statement: Emphasis for the model is on gravity as the force that holds together the solar system and Milky Way galaxy and controls orbital motions within them. Examples of models can be physical (such as the analogy of distance along a football field or computer visualizations of elliptical orbits) or conceptual (such as mathematical proportions relative to the size of familiar objects such as students’ school or state).] [Assessment Boundary: Assessment does not include Kepler’s Laws of orbital motion or the apparent retrograde motion of the planets as viewed from Earth.] MS­ESS1­3. Analyze and interpret data to determine scale properties of objects in the solar system. [Clarification ​ Statement: Emphasis is on the analysis of data from Earth­based instruments, space­based telescopes, and spacecraft to determine similarities and differences among solar system objects. Examples of scale properties include the sizes of an object’s layers (such as crust and atmosphere), surface features (such as volcanoes), and orbital radius.
    [Show full text]
  • 6. Relative and Absolute Dating
    6. Relative and Absolute Dating Adapted by Sean W. Lacey & Joyce M. McBeth (2018) University of Saskatchewan from Deline B, Harris R, & Tefend K. (2015) "Laboratory Manual for Introductory Geology". First Edition. Chapter 1 "Relative and Absolute Dating" by Bradley Deline, CC BY-SA 4.0. View Source. 6.1 INTRODUCTION To develop a history of how geologic events have acted on the Earth through time, we need to understand what and when geological processes have occurred through Earth's history. Geologists learn about what processes occur on Earth through studying the rock record and observing geologic processes in modern environments. To understand when these processes have acted during Earth's geologic time, geologists make observations about the relationships of rocks to one another in the rock record, using a process called relative dating. Geologists use this information to construct models for how these relationships developed. For example, if the rock record in an area contains sedimentary rocks that are folded, a model to explain those relationships would start with a region where sediments were deposited, followed by lithification of the sediments to form rock, then the rocks would be subjected to tectonic pressures that folded the rocks. Using relative dating techniques, we know those events occurred in that order, but not when they occurred precisely in time. To add specific dates for the events in the model, geologists can use absolute dating techniques to date the rocks (determine their age). Geologists develop models such as this at locations all across Canada, North America, and around the globe. Each location geologists study may only provide information on Earth history from a short window in time; collectively, however, the information in these models can be used to develop our understanding of processes that have acted on Earth since it first formed.
    [Show full text]
  • Sequence Stratigraphy and Geochemistry of The
    Report of Investigations 2007-1 SEQUENCE STRATIGRAPHY AND GEOCHEMISTRY OF THE UPPER LOWER THROUGH UPPER TRIASSIC OF NORTHERN ALASKA: IMPLICATIONS FOR PALEOREDOX HISTORY, SOURCE ROCK ACCUMULATION, AND PALEOCEANOGRAPHY by Landon N. Kelly, Michael T. Whalen, Christopher A. McRoberts, Emily Hopkin, and Carla Susanne Tomsich ASK AL A G N S E Y O E L O V G R U IC S A L L A A N SIC D GEOPHY Published by STATE OF ALASKA DEPARTMENT OF NATURAL RESOURCES DIVISION OF GEOLOGICAL & GEOPHYSICAL SURVEYS 2007 Report of Investigations 2007-1 SEQUENCE STRATIGRAPHY AND GEOCHEMISTRY OF THE UPPER LOWER THROUGH UPPER TRIASSIC OF NORTHERN ALASKA: IMPLICATIONS FOR PALEOREDOX HISTORY, SOURCE ROCK ACCUMULATION, AND PALEOCEANOGRAPHY by Landon N. Kelly, Michael T. Whalen, Christopher A. McRoberts, Emily Hopkin, and Carla Susanne Tomsich 2007 This DGGS Report of Investigations is a final report of scientific research. It has received technical review and may be cited as an agency publication. STATE OF ALASKA Sarah Palin, Governor DEPARTMENT OF NATURAL RESOURCES Tom Irwin, Commissioner DIVISION OF GEOLOGICAL & GEOPHYSICAL SURVEYS Robert F. Swenson, State Geologist and Acting Director Division of Geological & Geophysical Surveys publications can be inspected at the following locations. Address mail orders to the Fairbanks office. Alaska Division of Geological University of Alaska Anchorage Library & Geophysical Surveys 3211 Providence Drive 3354 College Road Anchorage, Alaska 99508 Fairbanks, Alaska 99709-3707 Elmer E. Rasmuson Library Alaska Resource Library University of Alaska Fairbanks 3150 C Street, Suite 100 Fairbanks, Alaska 99775-1005 Anchorage, Alaska 99503 Alaska State Library State Office Building, 8th Floor 333 Willoughby Avenue Juneau, Alaska 99811-0571 This publication released by the Division of Geological & Geophysical Surveys was produced and printed in Fairbanks, Alaska at a cost of $5.00 per copy.
    [Show full text]
  • Geologic Time Scale Essential Questions: 1
    Geologic Time Scale Essential Questions: 1. How does the relative and absolute age of rocks and the fossil record provide evidence to Earth’s geologic history? 2. How is Earth’s geologic history classified? 3. What are some major events in the Earth’s geologic history? Geologic Time Scale Earth Scientists • Geologist – a scientist who studies the Earth’s crust as well as the processes and history that shaped it • Paleontologist – a scientist that studies fossil remains found on the Earth’s surface in order to study primitive life forms such as: plants, animals, fungi, and bacteria Geologic Time Scale Sedimentary Rock Layers Stratigraphy • A branch of geology dealing with the arrangement of sedimentary rock layers or strata • Geologists assume the newest rock layers are on top of the older ones, unless some type of disturbance occurs. • Called the Law of Superposition © KeslerScience.om Geologic Time Scale Sedimentary Rock Layers Relative Age • The strata of sedimentary rocks is important in determining their relative age. • Relative age determines the “relative” order of past events but not the absolute age. • Like saying you’re relatively younger than your grandfather. Quick Action – Geologic Time Scale Sedimentary Rock Layers Determining Relative Age 1. Which is older sandstone or limestone? 2. Which is older mudstone or siltstone? 3. Which is the youngest rock in this strata? 4. Which is the oldest rock in this strata? Geologic Time Scale Sedimentary Rock Layers Relative Age • Strata is sometimes disturbed. • Here we see a fault (E) and an igneous intrusion (D) • See if you can determine the order of the strata in this diagram.
    [Show full text]
  • What We Know About Subduction Zones from the Metamorphic Rock Record
    What we know about subduction zones from the metamorphic rock record Sarah Penniston-Dorland University of Maryland Subduction zones are complex We can learn a lot about processes occurring within active subduction zones by analysis of metamorphic rocks exhumed from ancient subduction zones Accreonary prism • Rocks are exhumed from a wide range of different parts of subduction zones. • Exhumed rocks from fossil subduction zones tell us about materials, conditions and processes within subduction zones • They provide complementary information to observations from active subduction systems Tatsumi, 2005 The subduction interface is more complex than we usually draw Mélange (Bebout, and Penniston-Dorland, 2015) Information from exhumed metamorphic rocks 1. Thermal structure The minerals in exhumed rocks of the subducted slab provide information about the thermal structure of subduction zones. 2. Fluids Metamorphism generates fluids. Fossil subduction zones preserve records of fluid-related processes. 3. Rheology and deformation Rocks from fossil subduction zones record deformation histories and provide information about the nature of the interface and the physical properties of rocks at the interface. 4. Geochemical cycling Metamorphism of the subducting slab plays a key role in the cycling of various elements through subduction zones. Thermal structure Equilibrium Thermodynamics provides the basis for estimating P-T conditions using mineral assemblages and compositions Systems act to minimize Gibbs Free Energy (chemical potential energy) Metamorphic facies and tectonic environment SubduconSubducon zone metamorphism zone metamorphism Regional metamorphism during collision Mid-ocean ridge metamorphism Contact metamorphism around plutons Determining P-T conditions from metamorphic rocks Assumption of chemical equilibrium Classic thermobarometry Based on equilibrium reactions for minerals in rocks, uses the compositions of those minerals and their thermodynamic properties e.g.
    [Show full text]
  • Sediment-Hosted Copper Deposits of the World: Deposit Models and Database
    Sediment-Hosted Copper Deposits of the World: Deposit Models and Database By Dennis P. Cox1, David A. Lindsey2 Donald A. Singer1, Barry C. Moring1, and Michael F. Diggles1 Including: Descriptive Model of Sediment-Hosted Cu 30b.1 by Dennis P. Cox1 Grade and Tonnage Model of Sediment-Hosted Cu by Dennis P. Cox1 and Donald A. Singer1 Descriptive Model of Reduced-Facies Cu 30b.2 By Dennis P. Cox1 Grade and Tonnage Model of Reduced Facies Cu by Dennis P. Cox1 and Donald A. Singer1 Descriptive Model of Redbed Cu 30b.3, by David A. Lindsey2 and Dennis P. Cox1 Grade and Tonnage Model of Redbed Cu by Dennis P. Cox1 and Donald A. Singer1 Descriptive Model of Revett Cu 30b.4, by Dennis P. Cox1 Grade and Tonnage Model of Revett Cu by Dennis P. Cox1 and Donald A. Singer1 Open-File Report 03-107 Version 1.3 2003, revised 2007 Available online at http://pubs.usgs.gov/of/2003/of03-107/ Any use of trade, product or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY 1 345 Middlefield Road, Menlo Park, CA 94025 2 Box 25046, Denver Federal Center, Denver, CO 80225 Introduction This publication contains four descriptive models and four grade-tonnage models for sediment hosted copper deposits. Descriptive models are useful in exploration planning and resource assessment because they enable the user to identify deposits in the field and to identify areas on geologic and geophysical maps where deposits could occur.
    [Show full text]
  • Role of Water in the Formation of Granulite and Amphibolite Facies Rocks Tobacco Root Mountains Montana
    University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 1988 Role of water in the formation of granulite and amphibolite facies rocks Tobacco Root Mountains Montana Linda M. Angeloni The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Angeloni, Linda M., "Role of water in the formation of granulite and amphibolite facies rocks Tobacco Root Mountains Montana" (1988). Graduate Student Theses, Dissertations, & Professional Papers. 8115. https://scholarworks.umt.edu/etd/8115 This Thesis is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. COPYRIGHT ACT OF 1976 Th is is an unpublished manuscript in which copyright SUBSISTS. Any further r e p r in t in g of its contents must be APPROVED BY THE AUTHOR. Ma n s f ie l d Library Un iv e r s it y of Montana Date : t , 9 C B_ THE ROLE OF WATER IN THE FORMATION OF GRANULITE AND AMPHIBOLITE FACIES ROCKS, TOBACCO ROOT MOUNTAINS, MONTANA By Linda Marie Angeloni B.S., University of California, Santa Cruz, 1982 Presented in partial fulfillment of the requirements for the degree of Master of Science University of Montana 1988 Approved by Chairman, Board of Examiners Dean, Graduate School Date UMI Number: EP38916 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted.
    [Show full text]
  • GY 402: Sedimentary Petrology
    UNIVERSITY OF SOUTH ALABAMA GY 402: Sedimentary Petrology Lecture 17: Sandy Fluvial Depositional Environments Instructor: Dr. Douglas W. Haywick Last Time Volcaniclastic Sedimentary Rocks 1. Origin of volcaniclastic sedimentary rocks 2. Classification of volcaniclastic sed. rocks 3. Thin section petrography Volcaniclastic sedimentary rocks Air fall coarse fine Volcaniclastic sedimentary rocks tephra ignimbrite tephra ignimbrite Volcaniclastic sedimentary rocks Parallel laminations Volcaniclastic sedimentary rocks are sedimentary rocks… Channel lag … they follow sedimentary rules Volcaniclastic Petrography Source: Carozzi, A.V., 1993. Sedimentary Petrology. Prentice Hill, 263p. 1993. Sedimentary Petrology. A.V., Source: Carozzi, Vitric\Crystal Tuff quartz rock frag ppl xn 1.5mm vitric fragments Today’s Agenda Sandy Fluvial Siliciclastic Environments •Meandering river dynamics •Sedimentary facies •The model (vertical sections) Meandering Rivers • Sinuous, single channel drainage systems Meandering Rivers • Sinuous, single channel drainage systems • Typically form on low gradient alluvial plains Meandering Rivers • Sinuous, single channel drainage systems • Typically form on low gradient alluvial plains • Sinuosity depends on gradient Meandering Rivers • Are characterized by a distinct suite of facies and processes • Oxbow lakes • Levees • Floodplains • Cut banks • Point bars • Yazoo streams • Cutoffs Meandering Rivers • The channel meanders across the flood plain Meandering Rivers • Deposition occurs on the inside of meander loops (point bar) Meandering Rivers • Large point bars may consist of numerous accretionary ridges Meandering Rivers • Erosion occurs on the outside of meander loops (cut bank) Meandering Rivers • Meandering river channels are asymmetrical (deepest near cut bank) Meandering Rivers • Water velocity is greatest where the channel is deepest resulting in a “corkscrew” flow pattern. http://www.geocities.com/sogodbay/Images/SDK/Inecar03.jpg Meandering Rivers • Vortices can be either singular or complex.
    [Show full text]
  • Module 22A Geological Laws GEOLOGIC LAWS
    Module 22A Geological Laws GEOLOGIC LAWS Geologic Laws ❑ Superposition ❑ Original Horizontality ❑ Original Continuity ❑ Uniformitarianism ❑ Cross-cutting Relationship ❑ Inclusions ❑ Faunal Succession Missing strata ❑ Unconformity ❑ Correlation Law of Superposition ❑ In an undisturbed rock sequence, the bottom layer of rock is older than the layer above it, or ❑ The younger strata at the top in an undisturbed sequence of sedimentary rocks. Law of Superposition Undisturbed strata Law of Superposition Disturbed strata Law of original horizontality ❑ Sedimentary rocks are laid down in horizontal or nearly horizontal layers, or ❑ Sedimentary strata are laid down nearly horizontally and are essentially paralel to the surface upon which they acummulate Law of Original Continuity ❑ The original continuity of water-laid sedimentary strata is terminated only by pincing out againts the basin of deposition, at the time of their deposition Law of Original Continuity Law of Original Continuity Law of Original Continuity NOTE: This law is considerable oversimplification. The last discoveries indicate that the termination is not necessarily at a basin border. Facies changes may terminated a strata. Uniformitarianism ❑ James Hutton (1726-1797) Scottish geologist developed the laws of geology ❑ Uniformitarianism is a cornerstone of geology ❑ Considered the Father of Modern Geology Uniformitarianism ❑ Uniformitarianism is based on the premise that: ➢ the physical and chemical laws of nature have remained the same through time ➢ present-day processes have operated throughout geologic time ➢ rates and intensities of geologic processes, and their results may have changed with time ❑ To interpret geologic events from evidence preserved in rocks ➢ we must first understand present-day processes and their results Uniformitarianism is a cornerstone of geology Uniformitarianism MODIFIED STATEMENT “The present is the key to the past" • The processes (plate tectonics, mountain building, erosion) we see today are believed to have been occurring since the Earth was formed.
    [Show full text]