ESC LAB Midterm

Dip

Angle of incline (0-90) degrees

More Physical Properties of Minerals

* Texture *magnetism *Specific Gravity *taste *Odor *effervesces With HCl

Physical Properties of minerals to describe them

* shape *luster *Color *Hardness *Streak *Cleavage

5 things that define a mineral

*Inorganic *naturally Occurring *Solid *Definite Crystalline Structure *Definite Chemical Composition

Hardness Scale

10. Diamond 9. Corundum 8. Topaz 7. Quartz 6. Orthoclase 5. Apatite 4. Fluorite 3. Calcite 2. Gypsum 1. Talc 6.5 is streak plate 2.5 is fingernail

Syncline

A fold with concave side upward Cross-section would show the youngest rocks in the middle

Anticline

A fold with convex size upward Cross-section would show the oldest rocks in the middle

Metamorphic grade

A measure of how much the rock was metamorphosed. Slate is produced through low grade metamorphism Gneiss is produced through high grade metamorphism Slate was metamorphosed at lower Temperatures (T) and Pressures (P), while Gneiss was metamorphosed at higher T & P

Luster

A reflective property of mineral surfaces

Metamorphic Rocks

A rock that has been altered in form due to heat, pressure , and or hydrothermally. has not been melted (is derived from protoliths)

Minerals

A solid inorganic substance of natural occurrence. Most mineral specimens are irregular grains, very few display their characteristic crystal habit.

Hotspots

An area of unusual volcanic activity Not associated with plate boundaries Plumes do not move

Hinge line

An imaginary line that all beds are "bent" around

Three types of deformation

Brittle *faults *joints Elastic Ductile *folds

Streak

Color of powdered mineral which is tested by rubbing the mineral across a porcelain streak plate

Rock cycle sediment

Compaction and cementation-> Sedimentary Rock

Strike

Compass direction (0-360)degrees

Mantle

Contains more than 82 percent of Earth's volume Physical properties vary with depth Behaves rigid in some areas and ductile in others

Parts of Lithosphere

Continental Crust Oceanic Crust Uppermost SOLID mantle

Intrusive igneous rock

Cool at depth. Means they cool at slower rates and therefore have larger crystals

Changes in metamorphic rocks form

Crystal Shape/size - this is called Recrystallization Rock/Mineral shape - high Temp allows rock to act ductile , allowing rock to be deformed by high Pressure Mineralogy - different minerals can form in the rock due to metamorphism.

Aphantic

Crystals are too small to see shows very fast cooling volcanic from lava

Fracture

Describes the inability of a mineral to break in a consistent way and therefore not along cleavage planes

Breakage

Determined by cleavage and breakage Cleavage: is the tendency of the mineral to break along flat planes of weaker bonding *Cleavage Planes 0+ Fracture: Cleavage is absent and mineral breaks irregularly

Convection cells

Drag and move the lithosphere plates

Crust

Earths relatively thin, rocky outer shell. Can be divided into continental crust and oceanic crust

Shape: Crystal Habit

Every mineral has a crystal form. The crystal form is the shape that a crystal will take if it grows unimpeded

Effervesces with HCl

Fizz or give off bubbles

Shield volcanoes

Formed by non-violent Basaltic lava flows Travel large distances before cooling Mainly under-water

Modern evidence of Plate Techtonics

GPS Earth's magnetic Field Paleomagnetism Distribution of earthquakes along plate margins Age dating sediments on either side of the ridge Thickness of sediments also increases away from ridge

Gneissic Banding

Gneissic Banding refers the alternating layers of light and dark minerals Mineral size is medium to coarse (visible to eye) Represents high grade metamorphism

Transport and Deposition

Grains are transported by wind or water, variable distances. Deposition occurs in various location and is directly related to the energy of the environment.

Earthquakes

Ground shaking caused by the sudden and rapid movement of one block of rock slipping past another along fractures in Earth's crust called faults he energy generated by an earthquake radiates outward in the form of seismic waves from the source of the quake, called the hypocenter, or focus.

Rock Cycle Sedimentary rock

Heat and pressure --> metamorphic Rock weathering and erosion-> sediment

Hot Spots

Injection of magma

Volcanic Hazards

Lava flows Lahars Pyroclastic flows Bombs Toxic gasses Acid rain

Divergent Plate boundary

MOR Sea Floor Spreading Upwelling of Molten Material Ocean-Ocean Continent-Continent

What are two types of sediment rocks

Made up of grains there are two types of sedimentary rocks : Chemical (biochemical) (formed through solution) Clastic (detrital) (or debris of any kind)

Core

Made up of iron-nickel alloy. Can be divided into liquid outer core and solid inner core

Where do different types of igneous rocks form

Mafic: oceanic crust is created at divergent boundaries. Hot Spots also tend to be mafic Felsic: A magma chamber that pushes itself through a continental plate tends to be felsic Intermediate: Volcanic Arcs

Rock cycle Metamorphic Rock

Melting---> Magma weathering and erosion-> sediments

Identifying Metamorphic Rocks

Metamorphic Names reflect chemistry and texture Two things to know to name rock: Texture type Mineral types present

How do rocks form

Molten Rock cools and igneous rocks are formed Metamorphic rocks are formed when pre-existing rocks are changed by temperature and pressure When loose grains/sediments undergo lithification, the result is sedimentary rock

Phyllite texture

No visible mica grains Glossy/bright sheen Wavy to wrinkled foliation of mica grains Weak slaty cleavage Represents low to medium grade metamorphism

regional metamorphism

Occurs over large areas due to tectonic processes Pressure involved is moderate to high Temperature involved is low to high Associated with batholiths (only because these are associated with regional tectonics), rock burial (subduction), folding, orogenesis, etc. caused by tectonics

Three types of seismic waves

P waves S waves Surface waves

Seven Major plates

Pacific Eurasian African Australian North American South American Antarctic

epicenter

Point on Earth's surface directly above an earthquake's focus

Rate formula

Rate = Distance/Time

Two types of Metamorphism

Regional Metamorphism Contact metamorphism

Dip- Slip Faults

Result of brittle deformation Dip-slip faults separate rocks into two "blocks" - Hanging wall - Footwall Normal Faults result in a lower hanging wall Reverse faults result in a lower footwal

Non foliated textures

Rocks that have no obvious layering main texture types:1 Crystalline (e.g. Marble) Microcrystalline (e.g. Hornfels Sandy (e.g. Quartzite) Glassy (e.g. Anthracite)

Magnetism

Some minerals are magnetic. This ranges from weakly to strongly magnetic

Taste

Some minerals exhibit a specific taste

convergent plate boundary

Subduction Zones Volcanic Arcs Island Arcs Ocean-Ocean Ocean-Continent Continent-Continent

Vesicular

Texture Contains vesicles (gas bubbles trapped in lava) Formed from depressurization of the magma. Often looks like a sponge

Glassy

Texture Looks like glass. Very rapidly cooling forms from volcanic glass no crystals present

Phanertic

Texture Visible crystals, shows slow cooling 1-10mm

Porphyritic

Texture two distinct crystal sizes Large ones and small ones Generally due to a change in the rate of cooling

Pegmatitic

Texture Very large crystals shows very slow cooling (plutonic)

Cleavage

The ability of a mineral to break or come apart in consistent way * breakage is along atomic planes *cleavage is consistent with crystal symmetry and may be one to multi-directional from one mineral to another

What do grains tell us about sedimentary rock

The grains of a sedimentary rock give us a story of origin of the grains and what type of environment the rock formed in

Lithification

The hardening of sediment through compaction and cementation This forms the rock

Geothermal gradient

The rate of temperature increase with depth within the Earth. Varies from place to place

Seismogram

The recordings made by seismographs. used to determine the time and location of earthquakes

Specific Gravity

The specific Gravity of a mineral is a comparison of its weight with the weight of equal volume of water. Specific gravity measures the density of a mineral

Luster: metallic

There are two types of metallic minerals: metallic and Sub-Metallic

Surface Waves

Transmitted along the surface

S waves

Travel through Earths interior Slower than p waves Only travel through solids

P waves

Travel through the earths interior have the greatest velocity travel through solids, liquids and gases

Strike Slip Faults

Two possible motions along a strike-slip fault - Left-Lateral (sinistral) -Right-Lateral (dextral) If you stood along the fault, the block that is coming towards you shows the motion of the fault

Composite Volcanoes

Usually Andesitic or Rhyolitic Steep slopes, and violent eruptions Sometimes called "Stratovolcanoes"

Cinder Cones

Usually basaltic with high gas content Gas escapes first, and launches pyroclastic material into the air Material accumulates to form the cone After gas escapes, basaltic lava flows are common

Luster: Metallic vs Non- Metallic

Usually, we begin by separating the metallic and Non-Metallic minerals. Minerals can be further divided into sub-categories based on luster. some minerals exhibit both metallic and non-metallic properties.

Evidence for direction and rate of plate motion

Volcanic islands created by hotspots allow us to track the rate and direction of plate movement. Youngest at the hotspot cool -> dense -> subside -> erosion -> Seamounts

Color

Wavelengths of visible light are absorbed or reflected by the mineral Some minerals change color or have various forms of different color Sometimes color is determined by trace elements You CANNOT rely on color when it comes to mineral identification

Conchoidal

a smooth, curved breakage in all directions

Luster: Non-Metallic

adamantine resinous glassy/vitreous pearly greasy/oily silky dull earthy

Three types of folds

anticlines synclines monoclines

Types of magma

basaltic (Mafic) -low viscosity andesitic (intermediate) -Moderate Viscosity rhyolitic (felsic) -high viscosity

extrusive igneous rock

cool at the surface they cool at faster rates and have smaller crystals

Rock cycle Magma

cooling--> Igneous Rock

3 main types of plate boundaries

divergent convergent transform

Sedimentary rock

formed from the accumulation and consolidation of sediment usually in layered deposits

Igneous Rock

formed through the cooling and solidification of magma or lava

5 types of properties looked for in grains of sedimentary rock

grain size Grain shape Sorting Fossils Chemical Properties

Seismographs

instruments that detect and record seismic waves

Weathering

is the process of breaking down rocks and minerals into smaller pieces by water, wind, and ice. This creates grains

Law of Orginal Horizontality

layers of sediment are originally deposited horizontally under the action of gravity. Metamorphic rocks typically keep the bedding orientation if they come from

Schistosity

minerals (e.g. mica) and/or linear alignment of prismatic minerals (e.g. tourmaline or hornblende) Minerals are visible Rock is covered in scaly/glittering layer of shiny minerals Can have wavy foliation Represents medium to high grade metamorphism

what is a rock

naturally occurring solid aggregate of one or more minerals or mineraloids

Protoliths

parent rocks Include: Igneous Sedimentary Metamorphic rock types

Foliation

refers to the layering and parallel alignment of mineral crystals. Foliation forms perpendicular to pressure

4 types of Foliation textures

slaty cleavage phyllite texture schistosity gneissic Banding

Sedimentary Structures

structures formed during or shortly after disposition some created by water others created by things such as footsteps

Grain sorting

tells us how far grain traveled and energy level of transportation Degree of uniformity of grain size: *well sorted: -grains are all the same size -low energy transportation -slow river -long travel time *poorly sorted: -Grains are different sizes - High energy transportation - I.e. debris slide, gravity flow -short travel time

Grain Shape

tells us how far the grain has traveled Rounded= more travel time Angular= less travel time

Grain size

tells us how far the grains traveled before deposition smaller the grain size, the further the grain has traveled Biggest to smallest: Gravel Sand Silt Clay

Pyroclastic

texture fragments of volcanic glass, ash, cinders, volcanic bombs

types of igneous rocks

ultramafic- rare, primitive, mantle derived mafic- Mg and/ or Fe rich, more dense, oceanic crust intermediate- mix of mafic and felsic felsic- Al and/or Si rich, less dense, continental crust

Rock Cycle Igneous Rock

weathering and erosion-> sediment Heat and pressure --> metamorphic Melting---> magma

How are sedimentary rocks formed

weathering- Transport and Deposition Lithification

Parts of Mantle

• Asthenosphere Upper mantle Lower mantle

Convergent deformation

• Folding and Faulting: Uplift Reverse Faults (Dip Slip) Thrust Faults (Dip Slip)

Parts of Core

• Inner Core Outer Core

Transform Plate boundaries

• Slide past one another Leaky transforms Transpression and Transtension (more in later classes)

transform Deformation

• Slide past one another Leaky transforms Transpression and Transtension (more in later classes) the formation of mini basins and ranges

Divergent Deformation

• Thinning of the crust• Subsidence Normal Faulting (Dip Slip) Spreading Upwelling of Molten Material Ocean-Ocean, Continent-Continent

Slaty Cleavage

•If it has slaty cleavage, it is Slate Slaty Cleavage refers to the way the rock breaks into tabular sheets, roughly oblique to perpendicular in respect to the foliated crystals (usually mica) No visible mica grains Slate usually does not have a sheen to it (though may have a dull sheen) - why would it have no to dull sheen? Represents low grade metamorphism

Layers of earth

•It was due to the variations in travel times of P and S waves that scientists were able to provide evidence for the division of Earth's interior into three compositionally distinct layers Crust Mantle Core

Contact Metamorphism

•Occurs locally, next to igneous intrusions, or from hydrothermal fluids from intrusions Pressure is low to moderate Temperature is moderate to high

Block Diagrams

● Representation of 3-D space in a 2-D image Used to show regional or local deformation Shows strike and dip symbols on the surface Axes of any folds Faults