GMOA Notes

This is a work in progress, and eventually I will finish it. Sorry it is taking so long.

These are notes that cover Geology, Meteorology, Oceanography, and Astronomy.

Introduction
Earth's four spheres

Hydrosphere - dynamic mass of liquid that is always on the move
 * Oceans - the most prominent feature of the hydrosphere
 * 71% of Earth's surface is covered by ocean which is 97% of Earth's water
 * Only 3% is fresh water - streams, lakes, glaciers and underground supplies
 * Water Cycle - constantly recycles water

Atmosphere
 * Provides us with the air we breath
 * Protects us from the sun's intense heat and radiation
 * Protects us from space

Biosphere
 * Includes all life on Earth
 * Interacts and influences the other 3 spheres

Lithosphere
 * Earth's rigid outer layer called the crust and the upper mantle called the asthenosphere
 * Solid earth consists of 4 layers:
 * core
 * inner, solid core
 * outer, liquid core
 * mantle
 * lithosphere
 * Divisions of Earth's surface
 * continents
 * ocean basins

Sciences

Sciences involved in better understanding the earth integrate chemistry, physics, and biology into the following sciences:

Meteorology - the study of:
 * the atmosphere
 * weather and climate

Geology - the study of the Earth, and is broken into
 * Physical geology
 * minerals
 * rocks
 * Earth processes - mountain building, earthquakes, volcanoes, etc.
 * Historical geology - Earth's origin and it's past
 * physical
 * biological

Oceanography - study of the Oceans
 * Composition and movement of seawater
 * Seafloor topography and sea life

Astronomy - the study of the universe
 * Earth is a tiny object in a vast universe
 * to understand Earth helps us to understand other planets and vice versa

Resources and Environmental Issues

Environment
 * Physical environment (abiotic)
 * water
 * air
 * soil
 * rock
 * Biological - living environment (biotic)

Resources
 * Important environmental concern
 * Include:
 * water
 * soil
 * minerals
 * energy
 * Two broad categories of resources
 * Renewable resources
 * can be replenished
 * Examples: plant (lumber) and wind energy
 * Nonrenewable Resources
 * Fixed quantities
 * Examples: fuels and metals

Environmental Problems
 * Local, regional, and global
 * Human-induced and accentuated
 * Urban air pollution
 * Acid rain
 * Ozone depletion
 * Global Warming
 * Natural Hazards
 * Earthquakes
 * Landslides
 * Floods
 * Huricanes
 * World population pressures - in 30 years population increased from 4 to 7 billion
 * US makes up 6% of that but uses 30% of the annual mineral and energy resources
 * Alternate energy sources needed

Scientific Inquiry

Scientific Inquiry - scientific knowledge is gained through the following systematic steps called the scientific method, (PI-HE-RAC)

Gather facts through observation then ask why?
 * Problem - state the problem
 * Information about the problem
 * Hypothesis (untested best guess as to why)
 * Experimentation
 * Record and Analyze results
 * Conclusion - accept or reject hypothesis

Goal of science is to discover patterns in nature and use knowledge to predict what will happen under certain circumstances
 * Theory - tested and confirmed
 * Law - no known deviations have ever been found

Minerals
A mineral is a naturally occurring crystalline solid with a definite but not fixed chemical composition and ordered atmomic arrangement.

Chemistry and Mineral Terms

Chemistry Terms:


 * Chemical Property - characteristics of a material, which depends upon how the material reacts with other materials


 * Periodic Table - list of all known elements


 * Element - matter made up of atoms that are essentially all the same and cannot be subdivided by ordinary chemical methods


 * Atom - smallest part of an element


 * Nucleus - central part of an atom made up of protons and neutrons


 * Protons - subatomic particles with a positive charge


 * Electrons - subatomic particles with a negative charge


 * Neutrons - subatomic particles with a charge of 0


 * Atomic number - the number of protons in an atom (above element symbol on periodic table)


 * Atomic mass - the number of protons plus the number of neutrons (below element symbol on periodic table)




 * Isotope - change in the number of neutrons in an atom. Example, and isotope of sodium may have 10 or 12 neutrons


 * Electron Configuration - how the electrons are arranged around the atom in energy levels
 * 1st energy level has 2 electrons
 * all other energy levels have 8 electrons




 * Ion - change in the number of electrons
 * Atoms are most stable with 8 electrons in the outer energy level
 * Will share, lose, or gain electrons to achieve this


 * Ionic bonding - transfer of electrons
 * example - Sodium and Chlorine


 * Lewis Electron Dot Structure - Short hand for showing "chemistry" activity in the outer level by showing the number of electrons in the outer energy level




 * Covalent bonding - sharing of electrons. VERY STRONG BOND
 * example - bond between Hydrogen and Oxygen


 * Metallic bonding - electrons do not belong to any particular nucleus, they float between nuclei
 * example - two metals touching for a long time can "weld" to each other by metallic bonding. You can increase the speed of this by adding heat.

Mineral Terms:


 * A mineral is a naturally occurring crystalline solid with a definite but not fixed chemical composition and ordered atomic arrangement
 * Size of the ion is important because ions that are within 10% of the same size may be substituted in many minerals. This is why minerals of the same type have different chemical compositions.
 * examples - Si,Al; Fe,Mg; Na, Ca


 * Mineral formation
 * Melting - Volcanic activity
 * Evaporation - Salt water: Halite, Gypsum
 * Biological activity - sulfur producing bacteria
 * Oxidized - comes into contact with oxygen: Limonite
 * Leached - as water moves through the soil it dissolves elements. A leech line forms due to mineral formation where the water stops: bauxite
 * Metamorphic processes - formed by heat and pressure. Examples: graphite, chlorite, diamonds. Alters chemical composition and structure, called recrystallization


 * Mineral Types
 * Native minerals - contain one element
 * examples - graphite, C; Copper, Cu; Sulfur, S
 * Sulfides and Sulfates - contain Sulfur and other elements
 * Silicates - contain silicon and other elements
 * Oxides - contain oxygen and other elements
 * Carbonates - contain CO and other elements
 * will effervesce in the presence of an acid
 * Phosphate - contains PO and other elements


 * Physical Property - is controlled by the chemical properties of a material...how its bonded can determine the hardness and the type of impurities that are present in its change in color


 * Color - reflected light; very poor indicator of the true color due to impurities


 * Streak - true color of the mineral found by powdering it. This is found by scratching the mineral across a streak plate.


 * Hardness - the resistance to scratching


 * Cleavage - the tendency for a mineral to break along flat smooth planes that reflect light
 * This is controlled by a weakness in structure, may break where bonds are longer or fewer
 * predictable pattern, not random
 * 1 perfect - stacks like sheets of paper, example: mica
 * 2 perfect - break in two directions and is very clear, example: calcite
 * 3 cubic - breaks into perfect cubes, example: halite
 * none - no repeating faces
 * conchoidal fracture - concentric circles are around breaks, irregular fracture pattern, example: quartz


 * Magnetism - minerals that contain iron and are polarized, example: magnetite


 * Taste - how they taste: bitter, sweet, salty


 * Luster - appearance
 * metallic - look like metal
 * nonmetallic - look earthy


 * Density = mass/volume


 * Specific gravity - how heavy something is in air compared to how heavy it is in water


 * Radioactivity - the breakdown of atoms in the nucleus

Mineral Key
This is not a full table of minerals.

Igneous Rocks and Volcanoes
Rock Cycle
 * the rocks of the crust are classified into 3 types according to their origin
 * Two of the three types are formed by processes deep in the earth's crust and tell us about conditions within the crust
 * There are:
 * Igneous rocks - solidify from a melt or magma. If it cools fast small crystals form, if it cools quickly large crystals form
 * Metamorphic rocks - pre-existing rocks that are changed by heat and pressure within the crust.
 * Sedimentary rocks - weathered rock fragments of older rocks deposited in layers near the earth's surface by wind, water, or glaciers then cemented together by various agents. Records conditions on the Earth's surface.
 * the interactions among the forces that produce these three rock types can be illustrated by the rock cycle.

The Rock Cycle

Igneous Rocks
 * formed by the crystallization of magma
 * magma is a natural, hot melt composed of a mutual solution of rock forming minerals (mainly silicates) and some volatiles (maybe steam), that are held in a solution by pressure. Magma probably originates near the bottom of the crust.
 * magma that reaches the surface before solidifying is called lava.
 * two types of igneous rock
 * extrusive - reach the surface, small crystals, are called volcanic rocks, and cooled on the surface
 * intrusive - doesn't reach the surface, large crystals, called Plutonic rock, cooled below the surface

Volcanism - Volcanic Activity
 * Volcanoes are important because they provide clues about the earth's inaccessible interior.
 * Studying magma, gases and rocks we can determine chemical conditions, temperatures, and pressures within the crust and mantle.
 * Two factors control the violence of volcanic eruptions:
 * The amount of gas in the lava or magma - the greater the amount of gas, the more violent the eruption.
 * Viscosity - the resistance to flow, this determines how easily the gas escapes.
 * Two factors influence viscosity:
 * Temperature
 * Silica Content
 * Gases - most of the gas released from a volcano is steam, which is water vapor. The other gases that are released are Hydrogen Sulfide, Carbon Dioxide, and Hydrochloric Acid.
 * Rocks - chemical analysis shows that silica is the most abundant component in most volcanic rocks.
 * The amount of silica can vary from 45% to 65%. This accounts for the difference in the appearance, mineral content, and behavior of the parent lava.
 * Mafic rocks are silica poor (45% or less silica) and are typically dark in color. The parent lava has a low viscosity.  The minerals included in these rocks are augite, olivine, chromite, and magnetite, which make up dark colored rocks.  The most common mafic rock is basalt.  The lava tends to flow easily (hotter), not as viscous, and is low in silica.
 * Felsic rocks are silica rich (65% or more silica). The minerals included are quartz, potassium feldspar, and muscovite, this produces light colored rocks.  The most common felsic rock is granite.  High in silica, very viscous and explosive.
 * Intermediate rocks have a chemical composition between mafic and felsic. They are medium to dark grey in color.  Andesite is the most common.  Lava is sluggish and explosive.

Volcano Types
 * There are three types of volcanoes that differ in size, shape, and composition.
 * The three types are:
 * Shield volcanoes - mafic in composition, very fluid and nonexplosive magma. The form a broad gently sloping cone (looks like a shield), and are the largest volcanoes on the planet.



This image is from


 * Hawaiian Islands - have quiet eruptions, basalt lava flows from central vent. They are an example of intraplate volcanism, and have formed over a hotspot.
 * Two types of basalt flows:
 * Aa - blocky lava that looks like rubble, cools quickly.
 * Pahoehoe - ropy lava that looks smooth, cools slower than aa.


 * Cinder Cones - very steep slopes of loose rock fragments ejected from the central vent. They are the smallest type of volcano and erode easily.  Mainly made up of pyroclastic material.  Can be found on shield volcanoes.
 * Pyroclastic material or tephra can be any size and is classified by size.
 * Dust, ash - finest particles
 * Cinders - are 2-4mm in size
 * Bombs and blocks - molten blobs become streamlined during flight, solidify, and fall to the ground to form a lens shaped pyroclast.
 * These erode easily and can be found on shield volcanoes.



Cinder Cone Source


 * Composite Volcanoes - also called stratovolcanoes, are made up of alternating layers of andesitic lava and ash. They are the most explosive type of volcano.
 * Lava is very viscous and is felsic in composition which causes the vents to be blocked easily.
 * Plugs cause gas pressure to build up until the pressure is greater that the plug and an explosion results
 * Not as steep as a cinder cone volcano
 * Very violent eruptions
 * Found along converging plate boundaries, which accords to the Theory of Plate Tectonics



Composite Volcano Diagram Source

Calderas
 * a large basin-shaped depression formed by the inward collapse of a volcano after an eruption (example: Crater Lake, OR). They usually exceed 1 km in diameter and fill with rain water or snow melt to form a crater lake.
 * The three stages of caldera formation are:
 * Magma drawn off from eruption
 * No lava weight to support the volcano
 * The volcano collapses inward