Study for first test Flashcards
Silicon-oxygen tetrahedron
All silicates have the same fundamental building block.
One silicon atom in the center and four oxygen atoms at the corners
Silicates
The most common group of rock forming minerals
Gneiss
A metamorphic rock that has corse grained texture minimal amounts of mica and contained minerals that are segregated into bands
Mica schist
A metamorphic rock that has a coarse grained texture is dominated by mica. There can be traces of quartz.
Slate
A metamorphic rock that has a microscopic to very fine grained texture breaks into slabs or sheets and is dull on the surface
Marble
A metamorphic rock that lacks foliation and reacts to hydrochloric acid
Quartzite
A metamorphic rock that lacks foliation, scratches glass and is composed of interlocking quartz grains
Isostasy
The rising and sinking of Earths crust relative to the mantle in response to the redistribution of mass on the surface
Iron produces what colors in minerals?
Brown, yellow or red hues
Copper turns rocks and minerals what color?
Blue or green
Hydrosphere
Dynamic mass of water that is continually moving, evaporating from the oceans to the atmosphere. Precipitating to the land and flowing back to the ocean.
Atmosphere
Earth is surrounded by. Life-giving gaseous envelope. Provides the air that we breathe. Protects from dangerous radiation from sun. This produces effects to the weather and climate.
Biosphere
All life on earth.
Geosphere
Lying beneath the atmosphere and the ocean is the solid earth. From surface to the center of the planet. Largest if the earth spheres.
What are the layers to the Geosphere?
Core- dense inner sphere
Mantle- less dense
Crust- the light and very thin outer skin if earth
Lithosphere
Rigid outer layer that includes the crust and uppermost mantle.
Asthenosphere
Beneath the lithosphere- weak and able to slowly flow in response to the uneven distribution of heat deep within earth.
Geologic time
The span of time since the formation of earth.
Renewable
Which means that they can be replenished over relatively short time spans. Ex: plants and animals
Nonrenewable
Important metals such as iron. Aluminum, and copper. Fixed quantities of these substances
Mineral
Any naturally occurring inorganic solid that possesses an orderly crystalline structure and a definite chemical composition that allows for some variation
Rock
Any solid mass of mineral or mineral like. Matter that occurs naturally as part of our planet
Aggregate
Minerals are joined in such a way that their individual properties are retained.
Limestone
Sedimentary rock. Composed of almost entirely of calcite with most forms being composed of shells or skeletons of past organisms
Obsidian
Composed of no mineral matter. Volcanic rocks. Noncrystalline glassy substance
Coal
Consists of solid organic debris
Atoms
Small particles that can not be chemically split. Protons and neutrons in the nucleus and is surrounded by electrons
Protons and electorns
Opposite charges. Protons +1 and Electrons -1. There are equal amounts of protons and electrons in atoms.
Atomic number
The number protons in the nucleus of an atom. Determines chemical nature.
Chemical bond
Is a transfer or sharing of electrons that allows each atom to attain a full valence shell of electrons
Metallic bonds
Valence electrons are free to move from one atom to another. All atoms sharing the available valence electrons. Ex: copper, gold, aluminum
Luster - physical properties of minerals
Appearance or quality of light reflected from the surface of a mineral. Pg 31
Streak- physical properties of minerals
Color of a mineral in powdered form. Streak is obtained by rubbing it across a streak plate.
Color and ability to transmit light
Both physical optical properties of minerals. Pg 31
Crystal shape or habit
Refers to the common or characteristic shape of individual crystals or aggregates of crystals.
Tenacity - mineral strength
A minerals toughness or it’s resistance to breaking or deforming.
Hardness- mineral strength
A measure of the resistance of a mineral to abrasion or scratching. This property is determined by rubbing a mineral of unkind hardness against one if known hardness.
Mohs scale
Numerical value of hardness can be obtained by using this scale. Which consists if 10 minerals arranged in order from 1 soft - 10 hardest
Cleavage
A weakness in a mineral. Weak bonds. The tendency of a mineral to break along planes of weak bonding
Fracture
Minerals that have chemical bonds that are equally or nearly equally strong in all directions.
Density
An important property of matter is defined as mass per unit volume. Specific gravity is to describe the density of minerals.
Eight elements make up the vast majority of rock forming minerals
Oxygen, silicon, aluminum, iron, calcium, sodium, potassium and magnesium
Silicates
Silicon and oxygen are combined to form the basic building blocks. This is the term for them. Mostly igneous rocks.
Nonsilicates
Less abundant in earths crust than the silicates.
Silicon- oxygen tetrahedron
All silicates have the same fundamental building block. Consists if 4 oxygen atoms surrounding a much smaller silicon atom
Rock cycle
Allows us to see many if the interactions making the many components and processes of the earth system.
Gives understanding to the origins of igneous, sedimentary and metamorphic.
Cross beds
Inclined layers in sediment or sedimentary rocks that reveal the direction of wave or wind transport
Fine-grained texture
Igneous rocks that form rapidly at the surface or as small masses within the upper crust. Crystals are to small to be seen by the naked eye . These usually have voids called vesicles.
Vesicular texture
Common in many fine grained igneous rocks. Left by gas bubbles that formed as the lava solidified.
Coarse-grained texture
When large amounts of magma solidify far below the surface. Heat is lost slowly. Ions have more time to organize into larger crystals. Crystals are roughly equal in size. Are large enough for minerals to be identified with the unaided eye.
Prophyritic texture
Rock that has gone through two stages of cooling. Some of the crystals are too small to see while others are big enough to see. Lava started to cool under the earth surface and then was pushed to the surface. Pg 50
Dark silicates
Minerals made of silicon and oxygen but are rich in iron and/or magnesium and are comparatively low in silva (SiO2). Olivine, pyroxene, amphibole and biotite mica.
Light silicates
Have oxygen and silicon. Have great amounts of potassium, sodium and calcium and are richer in silica. Quartz, muscovite mica, feldspars (most abundant of this mineral group)
Felsic rocks - granitic composition
Rocks composed almost entirely of light colors silicates- quartz and potassium feldspar. Only igneous rocks!
Rhyolite
The extrusive equivalent to granite but is composed essentially of light colored silicates. Usually light pink to light gray in color. Fine grained and frequently contains glass fragments and voids (vesicles)
Basaltic (Mafic) rocks
Contains substantial dark silicate minerals and calcium rich plagioclase feldspar. Darker in color and denser than grantic rocks. No quartz. Magnesium and ferrum. Iron content.
Mechanical weathering
Disintegration- is the physical breaking up of rocks
Chemical weathering
Decomposition- actually alters what a rock is, changing into different substances. Ex: oxidation, carbonic acid
There are three important physical processes break rocks into smaller fragments
Frost wedging, sheeting and biological activity
Metamorphic rock
Produced from preexisting igneous, sedimentary or even metamorphic rocks.
Parent rock
Each metamorphic rock has one. It is the rock they were originally
Contact metamorphism - thermal metamorphism
When a preexisting rock comes in contact with high temperatures. Ex: coming in contact with lava
Regional metamorphism
When a preexisting is subject to high pressure and high temperatures. Large scale deformation. Ex: mountain building
Metamorphic agents
Heat , confining, pressure, differential stress and chemically active fluids
Foliation
Any nearly flat arrangement of mineral grains or structural features within a rock. Characteristic of metamorphic rocks. Rock units deformed mainly by folding. Pg 69
Continental drift
Hypothesis that says the continents and ocean basins had fixed geographic positions
Supercontinent
Alfred Wegner suggested this. Consisting of al Earths landmasses once existed. This landmass was named Pangaea.
Lithospheric plates
Lithosphere is broken into about 12 dozen segments of irregular size.
Divergent plate boundaries
Constructive margins- where two plates move apart, resulting I upwelling of hot material from the mantle to create new sea floor
Convergent plate boundaries- destructive margins
Where two plates move together resulting in oceanic lithosphere descending beneath an overriding plate. Eventually to be reabsorbed into the mantle or possibly in the collision of two continental blocks to create a mountain belt
Olivine
From the dark silicate minerals. Dark colored igneous rock. Abundant in the earths upper mantle. Glassy lister and usually has a granular crystal shapes
Igneous rock
Form as magma or lava cools and crystallizes.
Magma
Is molten rock that is most often generated by melting of rocks in earths mantle. When magma reaches the top it is called lava.
Extrusive / volcanic
When molten rock solidifies at the surface. Igneous rock. Are abundant in western portions of the Americas.
Intrusive / plutonic
And igneous rock that forms under the earth crust. Intrusive rocks remain at the depth unless portions of the crust are uplifted. Ex: erosion
Crystallization
As magma cools the once mobile ions begin to arrange them selves into orderly patterns. The rate if cooling strongly influences the crystal size.
What happens with crystallization when there is slow cooling?
Ions can migrate over great distances. Slow cooling results in the formation of fewer large crystals.
What happens in crystallization when there is rapid cooling ?
The ions lose their motion and quickly combine. Results in a large number of small crystals.
What happens to crystallization when there is no cooling?
The ions can not move at all and are randomly places causing the rock to look like glass.
This can happen in violent volcanic eruptions.
Granite
An igneous rock with a course grain texture. During episodes of mountain building maybe uplifted. Is usually polished and used for tombstones and table tops.
Andesitic (intermediate) rocks
Compositing between granitic and basaltic. Contain a mixture of both light an dark colored minerals. Occurs at volcanic activity typically confined to continental margins. Pg 54
Ultramafic rock
Contains mostly of dark colored minerals. Ex: peridotite. Are rare rocks at earths surface.
Transform plate boundaries - conservative margins
Where two plates grind past each other without the production of lithosphere.
Alfred Wegener- 1915
A German meteorologist and geophysicist write the origins of the continents and oceans. Explained his hypotheses - continental drift. Challenged the long-held assumption that the continents and ocean basins had fixed geographic positions.
Supercontinent
Part of Wegener’s hypotheses. Consisted of all if earths landmasses, named this land mass Pangaea.
Wegener’s hypotheses
200 million years ago. Early part if Mesozoic era this supercontinent began fragment into smaller landmasses. These continental blocks then drifted to their present position over a span of millions if years
What evidence proofs there was a Pangea?
- finding the same types of dinosaur fossils in different continents. These creatures couldn’t swim.
- certain mountain belts in different continents have the same types of rocks. Appalachian mountains, British isles and Caledonian mountains.
- jigsaw puzzle pieces
Evidence - ancient climates
Alfred Wegener also studied ancient climates. He learned evidence for a glacial period that dated to the late Paleozoic had been discovered in Southern Africa, South America, Australia and India. 300 million yrs ago vast ice sheets covered portions of the Southern Hemisphere.
Oceanic ridge system
During ww2 oceanographers were given the chance to use new marine tools to study the sea floors.
This ridge Winds through all the major oceans in a manner similar to the seams on a baseball. Theory of plate tectonics was born
Lithospheric plates
Lithosphere broken into two dozen segments of irregular size and shape. They are in constant motion with respect to one another. Largest plate - pacific plate
Plate boundaries
Where the plates have action or move, cause tension. Plate boundaries were first established by plotting the locations of earthquakes and volcanoes. 3 types of boundaries
Divergent plate boundary- constructive margins
Where two plates move apart, resulting in upwelling of hot material from the mantle to create new sea floor
Convergent plate boundaries - destructive margins
Two plates move together. One plate descends beneath the less dense plate eventually to be absorbed into the mantle. Possibly this collision creates a mountain belt
Transform plate boundaries - conservative margins
Where two plates grind past each other without the production or destruction of lithosphere
