Geology study guide
Popular in Geol 113-2
Popular in Geology
This 6 page Study Guide was uploaded by Katie Thedford on Friday September 23, 2016. The Study Guide belongs to 20841 at Fort Lewis College taught by Allie Jackson in Fall 2016. Since its upload, it has received 28 views. For similar materials see Geol 113-2 in Geology at Fort Lewis College.
Reviews for Geology 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: 09/23/16
Geology- Study Guide Exam #! rd Wed/Sept/23 Ch :1-8 labs: 1-4 What is Geology? o Physical Geology is the study of earth’s material’s and processes. Physical geologists study rock and mineral formation, active erosion, volcanic eruptions, and earthquakes. They also assist in the search for natural resources like oil and natural gas. o Historical Geology is the study of preserved evidence in the earth’s crust and dating. Historical Geologists reconstruct past landforms such as Pangea and look for evidence of past occurrences in such areas. What is the scientific method and how does it differ for geologists? o Geologist’s cant usually use the traditional scientific method as direct observation or experimentation is sometimes not possible o Edited Geologic Method: Question about Phenomenon Attempt to make an observation Creation of multiple hypothesis Test hypothesis or find an inactive or older subject Big Bang Theory? o All matter was compressed into a single point o Exploded 13.7 GA and continues to expand o Hydrogen and Helium were the first elements (nucleosyntheisi) o Stellar Nucleosynthesis and supernovae then formed the heavier elements o Because the universe seems to be expanding the universe is cooling. If it is cooling today it must have been hotter in the past meaning it was too hot for atomic nuclei to form o Background radiation and red shift are two examples of proof Geologic Time Scale? 2 Earth’s Internal Structure? o Differentiation- Density and composition sorting early in earth’s history as it cooled from its original molten state (separation of core from rock) o Layers- Crust Mantle Lithosphere Asthenosphere (layered based on rock strength instead of seismic waves) Outer core (liquid) Inner core (solid) Catastrophism vs. Uniformitarianism; significance James Hutton? o Uniformitarianism- “the present is the key to the past” o James Hutton – known as the father of geology Suggested that the earth was much older than originally stated by the church Stated that processes occurring in the present were the same that had been occurring since the beginning o Catastrophism- the theory that changes in the earth's crust during geological history have resulted chiefly from sudden violent and unusual events. Alfred Wegener and Continental Drift- o Alfred Wagner (1880-1930) Theorized that the continents fit together (Pangea) Published “the origins of continents and oceans” in 1915 o Proof of continental drift: Matching fossils in south America and Africa whose living forms could not have crossed the oceans Matching mountain ranges across oceans 3 Paleoclimate matching (evidence of glaciation where there shouldn’t be) Puzzle piece fit of continents o Mechanisms? All Wegner’s ideas had no supporting mechanisms and Wegner died in Greenland still looking for answers Paleomagnetism: seafloor magnetic anomalies o Renewed interest in the 1950’s came up with the idea of magnetized minerals in rocks o Minerals arrange themselves towards poles while molten and are locked into orientation when cooled Iron minerals archive the magnetic signal when cooled o Apparent polar wandering offers clues that continents where not in the same place over time Seafloor spreading: evidence, importance o Proposed by Harry Hess in the 1960’s o Geomagnetic Reversals Earth’s magnetic field periodically reverses polarity. Dates when polarity of earth’s magnetism changed were determined from lava flows recorded in the ocean crust 4 Driving forces: slab push-pull, convection o Ridge push- The process that results when magma rises at a mid-ocean ridge and pushes oceanic plates in two different directions away from the ridge o Slab pull- the process that results when a dense oceanic plate sinks beneath a more buoyant plate along a subduction zone, pulling the rest of the plate that trails behind it. o Convection- the circulation of particles with a material caused by differences in thermal energy and density even though the mantle is technically a solid o Subduction- the process that occurs when one tectonic plate moves under another tectonic plate Plate boundary types o Divergent boundaries- Found mainly at mid ocean ridges Plates move away from each other Decompression melting occurs in asthenosphere turning it into magma New ocean crust is formed along mid-ocean ridges o Convergent boundaries- Boundary between two colliding plates, often associated with mountain building ocean trenches and volcanic islands Subduction and collision o Transform boundaries – Accommodate lateral movement Definition of a mineral o Mineral resources are useful minerals that are economically recoverable Mineral properties? o Naturally occurring o Solid o Orderly crystalline structure o Definite chemical composition o Inorganic substance Mineral classes? o Carbonates-fizz under acid Calcite o Oxides-oxygen bonded with a metal Hematite o Halides Halite (table salt) o Sulfides- metals bound to sulfide ions Pyrite (fool’s gold) o Sulfates-metal combined with sulfate ion Gypsum o Phosphates o Native elements 5 What is magma? o Magma rises to the surface because it is less dense than surrounding rock o When molten rock reaches the surface it is called lava Describe how fractional crystallization works. What minerals crystallize first and which crystallize last? o Magma does not form crystals all at once o Always a mixture of chemical compounds with different crystallization temperatures o Magma composition changes as different minerals and molecules become removed from the mix or settle Describe the differences between intrusive and extrusive igneous rocks. o When magma cools and crystallizes into rock under the earth’s surface, it forms intrusive igneous rocks (also called plutonic) this rock has larger crystals o When lava cools above the earth’s surface it forms extrusive igneous rock (volcanic) Rock classifications o granite – felsic, intrusive, phaneritic o rhyolite-felsic, extrusive, aphanitic o diorite-intermediate, intrusive, phaneritic o andesite- intermediate, extrusive, aphanitic o gabbro-mafic, intrusive, phaneritic o basalt-mafic, extrusive, aphanitic o obsidian- felsic, extrusive, glassy o pumice- felsic, extrusive, frothy glass? o Tuff- felsic, extrusive, pyroclastic What determines how explosive or calm a volcanic eruption will be? o Gas content or magma composition (viscosity) o Basaltic magma = High temperature, low viscosity – gentle eruptions o Intermediate magma= Medium temperature , medium viscosity – pyroclastic materials ejected o Felsic magma= Low temperature, high viscosity – very explosive be able to describe the type(s) of volcanoes and igneous rocks you would typically find in a specific tectonic setting o cinder cones- basaltic magma (continental rift) o composite cone – intermediate magma (ocean-ocean) o volcanic dome – felsic magma (ocean-continent) o shield volcano- basaltic magma at an oceanic hot spot 6
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'