"Grain Sized" loose rock derived from older rock- CLAY
- How sedimentary rocks are made
- Physical and chemical breakdown of rocks
Removal of weathered material
Action of gravity on large masses of rock or sediment.
Build-up of sediment, soil or rock on other landforms.
Percent of earths surface that is sedimentary rock
Sedimentary rock "hosts.."
gas and oil accumulations, coal, mineral deposits and other resources.
3 Ways Sedimentary Rocks Form
- Detrital Sediments
- Chemical Precipitates
- Organic Accumulations
Examples of Detrital Sediments
- Oolitic Limestone, Sand, Silt
- (Detrital- Held together by cement/matrix)
Examples of Chemical Precipitates
Gypsum, Halite, Limestone
Examples of Organic Accumulations
Coquina, Chalk, Coal, (some limestone)
"Layers" always present in sedimentary rocks. (Sometimes present in volcanic rock)
Small round features (fossil cyanobacteria)
What does the "gray area" deal with?
Organic and Chemical sedimentary rocks.
Process of cementing rocks
Compacting of rocks (Clay)
White Sand is made out of what?
Gypsum - which is used for drywall.
Evaporite minerals that can be extracted from earth by injecting hot water.
Precipitation of quartz, was used for Native American spear points.
Made from pressed plants, 300 or more years left of coal.
Thicker than 1km, accumulation of sedimentary rocks.
Down warping of the crust.
Ocean crust thickness
0 to 15 km thick
0 to 35 km thick
Process that results in changes to the crystallinity or bulk composition of a rock due to heat, pressure, shock or hydrothermal fluids.
Average Geothermal Gradient
25 to 30 C/km
Types of Metamorphic Rocks
- Fault Zones
Occurs during mountain building (roots of the mountain)
Contact with magma chamber
Effects of geothermal gradient.
Contact with hot fluids.
Fault Zones (Metamorphism)
Shearing of minerals and development of new materials. (two plates sliding against one another)
When minerals recrystallize...
They become larger in size and change in orientation. Also, mineral grains change.
All metamorphic rocks have/come from a parent rock.
Marble (Kid rock)
Slate (Kid Rock)
Quartz and Sandstone (Parent)
Quartzite (Kid Rock)
Gneiss (Kid Rock)
Basalt and Gabbro (Parent)
Amphibolite (Kid Rock)
Determined by amount of heat and pressure
High Pressure, Low Heat
Contact (Metamorphic Grade)
Low Pressure, High Heat
Regional (Metamorphic Grade)
High Pressure, High Heat
Texture of Metamorphic Rocks
Foliated, Weakly Foliated, or Non-Foliated.
3 types of Meteorites
- Stony Materials (most common)
- Stony Iron
- Iron-Nickel meteorite
Oldest rocks found on earth
4.4 Ga (Billion years)
Types of Radioactive Decay
- Alpha Decay
- Beta Decay
Loses two neutrons and protons. Helium Ion
An electron released when neutron decays into a proton.
High energy photons (packets of energy)
- Inner Core
- Outer Core
- Upper Mantle
How we know what we know about plate tectonics.
- -Seismic wave behavior and velocities
- -Diamond anvil presses
- -mantle xenoliths
Thickness of crust
0 to 70km thick
Thickness of Mantle
- 2900 km thick
- 75 percent of earths volume.
- Mostly made of peridotite.
Increases with depth except at velocity zone (200 to 250km deep).
- hypothesized centrifugal force separated continents, continental drift hypothesis.
Plate tectonic hypothesis. Convection cells in the mantle drove plate tectonics.
4 Sources of Magma
- Spreading Centers
- Subduction Zones
- Deep Crustal Zones
- Mantle Plumes
Outer Core (Made of)
Mostly Iron and Nickel
Always solid due to pressure.
Very old stable part of continental crust, usually in the middle of a continental plate.
Cores of Cratons that are exposed.
Craton covered by thin layer of sedimentary rock.
Linear belts of mountains at collisional boundaries.
Structural and sedimentary features where crust has been down-warped.
Tectonic plates include
Crust and uppermost mantle
Most common at tectonic plate boundaries.
Types of rock deformation
bend and rebound, causes earthquakes.
Faults and Fracturing
- Creates Folds;
- Strata can be folded
- Stress and strain (compressional forces)
Types of Folds
Low-angle reverse fault (results of compression)
Two tectonic plates rubbing against one another (shearing).
Vertical "drop" in land due to weight. (Explains why mountains have roots)
Emperor Seamount Chain, 43 Million year bend caused by absolute plate motion.