Geology 1020 Exam study guide
Geology 1020 Exam study guide Geol 1020
Popular in Intro to Earth History
verified elite notetaker
verified elite notetaker
verified elite notetaker
verified elite notetaker
verified elite notetaker
verified elite notetaker
Popular in Geology
This 8 page Study Guide was uploaded by Melanie Notetaker on Monday October 17, 2016. The Study Guide belongs to Geol 1020 at University of Colorado at Boulder taught by Stephen Mojzsis in Fall 2016. Since its upload, it has received 112 views. For similar materials see Intro to Earth History in Geology at University of Colorado at Boulder.
Reviews for Geology 1020 Exam study guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/17/16
Geology Midterm Review Sheet 21 questions on Midterm Radioactivity (Lectures 6, 7, 8) o Provide actual ages of rocks. To date a rock containing radioactive material, geologists measure the quantities of two components of the rock: the amount of the material produced by radioactive decay and the amount of radioactive material that has not yet decayed. o Radiometric dating allows us to estimate the ages of rocks within thousands or millions of years. o The spontaneous breakdown of certain kinds of atoms into one or more atoms of different elements, accompanied by a release of energy and subatomic particles. o You have a mineral that was crystalized in an igneous rock. It has no daughter atoms when it first forms, so it only has parent atoms. Once it is crystalized, the mineral becomes "closed" and the products of radioactive decay begin to accumulate. Over time, more and more daughter products accumulate. o 3 most common radioactive substances that we use to determine the ages of things Uranium Thorium Potassium o 3 kinds of radioactivity (Lecture 8) Alpha decay During Alpha decay an atom spits out two protons and two neutrons from its nucleus. o Alpha decay usually happens in larger, heavier atoms Beta decay A neutron sends its electron packing, literally ejecting it from the nucleus at high speed. The neutron turns into a proton! Beta decay increase an atom’s electron count by 1 Can be stopped by WOOD Capture of a beta particle (e^- into proton) D/N ratios (parent and daughter ratios) o It is enclosed within a mineral, decay that leads to daughter product thus giving us DEEP TIME! o To calculate D/N after any subsequent number of t1/2, simply double the previous value and add one. D = Daughter N = Parent o Radioactivity decay is the transformation of the material o Half-life: t1/2 the time it takes for half of the parent atoms to decay to the daughter (1/2)/ (1/2) = 1 (3/4)/ (1/4) = 3 (7/8)/ (1/8) = 7 (15/16)/ (1/16) = 15 (31/32)/ (1/32) = 31 0 = 0 1 = 1 2 = 3 3 = 7 4 = 15 5 = 31 Different rock types o Sedimentary A rock formed by the consolidation of loose sediment or by precipitation of minerals from a watery solution. o Igneous Rocks formed by the cooling of molten material inside and outside of the Earth’s interior o Metamorphic Rock formed by metamorphism. Rocks that change because of intrusion from magma and/or subduction into the mantle that causes the original rock to change its shape and chemical composition caused entirely by heat and/or pressure. Rock cycle o The endless pathway along which rocks of various kinds are changed into rocks of other kinds. Geologic time scale o Look up scale when taking the exam. Allowed internet during exam, Google the time scale or bring book. Fossilization process o Types of fossils (lecture 19) Replacement Rare in plants Not common in animals Cast Formed when a mold is filled in Mold A negative image of the organism Impression Extremely common in plants and animals Trace Fossilized nests, burros, footprints o INDEX FOSSIL is useful for dating or correlation strata. o Fossils are the only evidence of pre-existing life o Not all of like has an equal chance of being preserved You cannot fossilize bacteria or algae Plate tectonics o What are they? The movement and interactions of lithospheric plates Lithospheric plates o Outer most shell of the Earth. It is broken up into a series of moving plates. What divides these plates are convergent, divergent, and transform boundaries. o Where are they? Lithosphere Earth’s outer rigid shell, situated above the asthenosphere and consisting How old are the continental crust vs oceanic? o Oceanic crust Dominates the crustal surface area of Earth, but is thinner and younger on average than continental crust because it is slowly formed at ocean spreading centers (ridges) and recycled at subduction zones. The average age of oceanic crust is ~75 Ma (million years) o (with an age range of 0 – 250 Ma) Oceanic crust is composed of basalt formed from the upwelling of asthenosphere that decompresses (like the Pepsi can experiment) to generate magma! o Continental crust A layer of granitic, sedimentary and metamorphic rocks thus forming continents and continent shelves that are areas of continental rocks under sea-level. It is less dense than the mantle and “floats” on top of the mantle. The average age of the continental crust is ~2 billion years. Most continental rocks formed 2.5 billion years ago. Convergent boundaries are where new continental crust is formed. Composed mostly of granite Different types of plate boundaries o Divergent plate boundaries Oceanic plates that are moving away from each other o Convergent plate boundaries Plates are moving towards each other and colliding with each other resulting in formation of a mountain ridge and subduction of a tectonic plate o Transform plate boundaries The plates are moving against each other (sliding) Different layers of Earth’s interior o Core Inner core is solid Outer core is a hot molten metal The central part of the Earth below a depth of 2900 kilometers. Thought to be about 80% iron (Fe), with a small percentage of nickel and other dense metals (gold, platinum, and uranium) o Mantle The zone of Earth’s interior between the core and the crust, extending from depths of approximately 40 to 2900 kilometers. It is composed of dense ultramafic silicates and divided into concentric layers. o Crust The outermost layer of the lithosphere, consisting of felsic and mafic rocks less dense than the rocks of the mantle below. o Atmosphere The envelope of gases that surrounds the Earth Relative vs. Absolute time o Block diagrams of rocks in layers Be able to give history of a diagram o Absolute ages estimates 1. Mythological estimates 2. Salts in the ocean 3. Rates of sediment accumulation 4. Earth’s temperature 5. Meteorites o What is the difference between relative vs absolute age? The intrinsic age vs. the comparative age Things you can use to determine the age of rocks/earth o Verves (sediments in rock at lake bottom), tombstones, ancient monuments, oral traditions, tree rings o Relative used fossils as markers o Absolute used measured by radiometric dating in millions of years Unconformity o A surface between a group of sedimentary strata and the rocks beneath them, representing an interval of time during which erosion, rather than deposition, occurred. Non-conformity o An unconformity separating bedded sedimentary rocks above from crystalline rocks below. Disconformity o An unconformity above rocks that underwent erosion before the beds above the unconformity were deposited. The strata above and below a disconformity are horizontal. Cross-section problems o You will be given a cross section of layers of rocks, you will need to label the youngest rocks to old rocks. Carbon isotopes o Most common carbon isotope is Carbon-12 with 6 protons and 6 neutrons and atomic weight of 12 o Carbon-13 is the next heaviest and stable with 6 protons and 7 neutrons and atomic weight of 13 o Carbon-14 has 6 protons and 8 neutrons with an atomic weight of 14 Carbon cycle o if CO2 goes down, O2 goes up o if O2 goes down, CO2 goes up o More organic carbon burial = left-over HEAVY carbon in atmospheric CO2. Plants want the lighter carbon and leaves heavy carbon in the atmosphere. o With increasing burial of organic matter, or increasing FLUX (input) into sedimentary reservoir, CO2 level goes DOWN o Blag model: shows the increasing rate of carbon 13. This shows the growth of the first forest on the earth. At the peak of the burial, there was a large increase of oxygen. After this peak there was an extinction of all creatures on earth. Organic matter burial o Rapid burial of organic matter cuts it off from oxygen, therefore no feedback to CO2! o If the carbon never decreased, the atmosphere would be similar to Venues (atmosphere is at the boiling point of Lead) o If there is a new mountain range formed, the climate will become colder because of the burial of Carbon in the sediments. We trace this because of the isotope burial o If the ratio in the atmosphere is balance than the atmosphere is steady. o Burial rate of carbon exceeds weathering rate, there is an increase of heavier carbon in the atmosphere. It is getting colder. o More organic carbon burial = left-over HEAVY carbon in atmospheric CO2. o With increasing burial of organic matter, or increasing FLUX (input) into sedimentary reservoir, CO2 level goes DOWN Density o What is density? The mass of a given volume of any substance Subduction o Descent of a slab of lithosphere into the asthenosphere along a deep- sea trench o What kind of plates can be subducted? Ocean, ocean Continental, continental Ocean, continental o Subduction zone A region where subduction of the lithosphere occurs Convection o Changes in density Heated which makes it less dense o Know the difference between the cause and the effect o Rotational flow of a fluid resulting from an imbalance in its density. Convection often occurs because the fluid below is heated and becomes less dense than the fluid above, or because the fluid above is cooled and becomes denser than the fluid below. Evolutionary theory o Basis: groups of organisms have the capacity to change with time if there is natural diversity with change o Not survival of the fittest o Just good enough to live long enough to pass along traits to the next generation Selective pressure Cladistics o Categorizing species by traits Relationship found in dog’s vs wolves DNA o Deoxyribonucleic acid, the molecule that carries chemically cooled genetic information and is passed from generation to generation o DNA gives instructions for grow and development o Hox genes are known in developmental timing. They can turn on and off in development. In evolution, these genes can change the aging of mammals, change the length of an insect o Heritability o Statistic used in breeding and genetics works that estimates how much variation in a phenotypic trait in a population is due to genetic variation among individuals in that population. o The proportion of observed variation in a particular trait (as height) that can be attributed to inherited genetic factors in contrast to environmental ones o Able to be passed from parent to child before birth Origin of life theories o It started from a single cellular organism that evolved into multi cellular organisms. o It could have begun from a meteorite hitting the Earth cause a warm area in the crater left over from the impact of the meteorite. Different kinds of life (Big Tree) o Bacteria A group of prokaryotes that forms one of the three domains of organisms Prokaryotes are small ancient cells with no nucleus Humans and animals are most like bacteria The oldest life cells o Archaea Lack nucleus, controlled by a single loop of DNA Morphologically similar to bacteria o Reproduce by smaller means o Mainly using flagella Distinguished from bacteria o Structural difference: lack peptidoglycan in their cell walls Different membrane lipid bonding o Ribosomal RNA Archaea are phylogenetically more similar to Eukarya than Bacteria Found in: Hot springs Hypersaline lakes Black smokers o The hot springs of Yellowstone National Park, USA, were among the first places Archaea were identified and classified. o Each pool has slightly different mineral content, temperature, salinity, etc., so different pools may contain different communities of archaea’s and other microbes. o Microbiologists immerse microscope slides in the boiling pools onto which some Archaean’s might be captured for study. o Eucarya (Eukaryotes) Have a different cell structure than any of the other domains of life Animals Are motile Body plan becomes fixed as they develop Are heterotrophs Vertebrates – backbones Invertebrates – no backbone Plants Multicellular eukaryotes Sexual reproduction Modular and indeterminate growth Fungi Unicellular - yeasts, molds Multicellular- fruits forms such as mushrooms Differentiated from plants, bacteria and protists Chitin in their cell walls Similarities with animals Are heterotrophs - acquire food by absorbing dissolved food Protists Complex group, a paraphyletic group of eukaryotes whose members are not plants, animals, and fungi. Oxygen and Carbon isotopes o Carbon isotopes can be used to determine the amount of carbon found in the ocean floor (14C/13C/12C) o Oxygen isotopes can be used the same way that carbon isotopes are used (16O/18O) Extremophiles o Organism in Bacteria and Archaea that live in a low diversity of life because there are extreme conditions Found in Bacteria and Archaea o They live in extreme environments and/or conditions
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'