Geology

Science

builds and organizes knowledge in the form of testable explanations and predictions about the universe.

Hypothesis

A testable statement that can be proven or disproven through experimentation.

Theory

a hypothesis that has been tested many times and has an established body of evidence for support

Scientific Laws

ideas consider absolutely correct and if not, then the universe as we know it would not exist. They are true, universal, simple, absolute, and eternal. Examples: Newton’s law of motion.

Law

A statement based on repeated experimental observations that describes some aspect of the universe.

Scientific Method

A sequence of steps for systematically analyzing scientific problems in a way that leads to verifiable results

1st Step In the Scientific Method

Recognize the problem

2nd Step in the Scientific Method

Collect Data

3rd Step in the Scientific Method

Hypothesis

4th Step in the Scientific Method

Test Hypothesis

5th Step in the Scientfiic Method

Change hypothesis

6th Step in the Scientific Method

Report/Share Results.

Geocentric model

This model is an ancient astronomical theory that positions Earth at the center of the universe, with all celestial bodies, including the Sun, Moon, planets, and stars, moving in circular orbits around it.

Heliocentric model

This model is an astronomical theory that places the Sun at the center of the solar system, with Earth and other planets orbiting around it.

Circumference of Earth:

Eratosthenes calculated it by comparing the angles of the sun’s rays at two different locations.

Tool for Studying the Universe

Telescope

Big Bang Theory

The theory that the universe began 13.8 billion years ago from an extremely hot and dense point.

Element Formation

Nuclear Fusion in stars gives us the first 26 elements, supernovas are required to make the heavier elements

Solar System Formation

1. Planets are isolated 2. Orbits are elliptical to circular & in nearly the same plane. 3. Planets & moons travel along orbits in same direction, the direction the sun rotates

Nebular Theory

The theory that gravity pulled gas and dust into a rotating disk, forming the Sun and planets.

Dwarf planet

A non-satellite body that lacks certain criteria like clearing its orbit but it orbits around the sun, has a round shape, and has enough mass

Small solar system body (SSSB)

A non-satellite body meeting only the first criteria which orbits around the sun.

Terrestrial planets

Closest to the sun, too hot for light gases, leaves heavy minerals, dense rocky planets.

1st Terrerstrial planet

Mercury

2nd Terrestrial planet

Venus

3rd Terrestrial planet

Earth

4th Terrestrials planet

Mars

Jovian Planets

Farthest from the sun, mostly gas masterial, small rocky cores, mostly H and He, commonly as ice.

1st Jovian Planet

Jupiter

2nd Jovian Planet

Saturn

3rd Jovian Planet

Uranus

4th Jovian Planet

Neptune

Direct Methods For Studying Earth’s Interior

Core, Uplifted Pieces of Earth’s Interior, Meteorites

Indirect Methods For Studying Earths Interior

Density, Seismic Waves, Geothermal gradient

Differentiation

The Separation of (earth) materials based on density. It generates heat and the earth has iron-nickel core surrounded by a magnesium silicate mantle.

Compositional layers

It is based off the composition.

Inner most layer for Compositional

Core

2nd Layer for Compositional

Mantle

Outer Layer for Compositional

Crust

Mechanical layers

It is based on mechanical properties

Inner most layer for Mechanical

Inner Core

2nd layer for Mechanical

Outer Core

3rd layer for Mechanical

Mantle

4th layer for Mechanical

Asthenosphere

Outer most layer for Mechanical

Lithosphere

Most abundant element on the whole earth

Iron

2nd most abudant element on the whole earth

Oxygen

3rd most abudant element on the whole earth

Silicon

Rocks of crust layer

Granodiorite, basalt, gabbro

Rocks of mantle

Periodotite, Garnet periodotite

Elements of earth’s core

Iron and nickel

Magnetic Field

Region affected by the earth’s magnet. It is generated by the rotation of the fluid outer core around the inner core.

Magnetic Direction

The direction the compass points toward magnetic north

Declination

The angle between the direction a compass needle points and true north to

1st Continental Drift Evidence

Obvious fit of continents

2nd Continental Drift Evidence

Climate belts seem to match across continents

3rd Continental Drift Evidence

Distribution of fossils

4th Continental Drift Evidence

Alignment of Ancient Mountain Belts and Rock Types

Hypothesis of Continental Drift

Convection

Paleomagnetism

A record of Earth’s past in Igneous Rocks. Example: Magnetite

Magnetic Declination

Magnetic pole does not equal geographic pole

Magnetic Inclination

The angle between magnetic field and horizontal field = 0 degrees at magnetic equator and 90 degrees at magnetic north pole

Interpreting the Paleomagnetic Record

Continents Drift and the Paleopoles Records line up

Hypothesis for sea floor spreading

Sediment thickens above older crust, earthquakes along the central rift due to the crust splitting at Mid-Ocean ridges, heat flow at mid ocean ridges, ocean crust consumed.

1st observation for Sea Floor spreading

Magnetomter measures strength of total magnetic field

2nd Observation for sea floor spreading

Ocean crust is symmetric

3rd Observation for sea floor spreading

A symmetric pattern of polarity stripes develops and age of oceanic crust varies with location

DSDP 3 Test

Drilled through sediments and into basalt, determined age of oldest sediment at each site using fossils, age vs distance from ridge proved seafloor spreading

Magnetic reversals

Earth’s magnetic field polarity suddenly reverses periodically

Mineral Definition

Homogeneous, naturally occurring, solid, crystalline structure, definable chemical composition, generally inorganic

Polymorphs

Different minerals with the same composition but different atomic arrangement. They exist as the presence of a mineral can tell a lot about the conditions of formation

Polymorphs example

Graphite

Types of mineral formations

The form by freezing of a liquid and precipitation, solid state diffusion and biomineralization

Types of crystals for mineral growth

Euhedral, subhedral, anhedral

Physical Properties of Minerals

Color, Streak, Luster, Hardness, Density, Habit, Cleavage/Fracture.

Identification of Minerals

Physical properties, optical properties, chemical analysis, x ray diffraction

7 Physical properties to identify minerals

Color, streak, luster, hardness, density, habit, cleavage or fracture

Subclasses of silicates

Nesosilicates, inosilicates, phylosilicates, tectosilicates

Model of Silica tetrahedron

1 Silicon 4 Oxygen in a pyramid shape

The Theory of Plate Tectonics

a theory explaining Earth's geology, including rock distribution, earthquakes, volcanoes, fossils, and geographic features.

What is buoyancy and how does apply to the lithosphere and asthenosphere?

Buoyancy is the force that allows the lithosphere to float on the asthenosphere due to differences in density.

The lithosphere is less dense and rigid, while the asthenosphere is more ductile and denser, enabling the movement of tectonic plates across the Earth's surface.

Why is oceanic lithosphere less buoyant than continental lithosphere?

The continental lithosphere is about 150 km thick, with a 35-40 km thick granitic crust, making it less dense and more buoyant, so it floats higher. In contrast, the oceanic lithosphere is 7-100 km thick, with a 7-10 km thick basaltic crust, which is denser and less buoyant, causing it to sink lower.

Active Margin

Margins near plate boundaries are "active."

Passive Margin

Margins far from plate boundaries are "passive."

Cratons

A portion of a continental plate that has been relatively undisturbed since the Precambrian Era.

Shield vs. Platform

Shield - exposed part of the craton/ Platform - covered (by sediment)part of the craton

describe how lithosphere is created or destroyed

Mid-Ocean Ridges (MoRs)- Sea-floor spreading opens the axial rift valley

• Rising asthenosphere melts, forming mafic magma.

• Pooled magma solidifies into oceanic crustal rock.

• Pillow basalt—magma quenched at the sea floor.

• Dikes—preserved magma conduits

• Gabbro—deeper magma

Be able to sketch, label, the three different types of plate boundaries

(Extensional, Transform, and Convergent)

Be ready to draw and label a diagram of a mid-ocean ridge, OR subduction zone. (you can find a subduction zone in " Convergent Boundaries")

mid ocean ridge, (MoRs)

Be able to sketch and label them on your diagrams for the different types of plate boundaries

Divergent/Extensional

Sea-floor spreading, rift valleys, volcanic activity, minor earthquakes

Transform

Faults, earthquakes, no volcanism

Convergent

Subduction zones, mountain building, volcanic arcs, earthquakes

Extensional or Divergent Boundaries

Sea-floor spreading causes plates to move apart./• Magma wells up to fill the gap/.• Magma cools, adding material to each plate./• The ocean basin expands in width.

Be ready to give at least one example of each type of plate boundary

Divergent/Extensional Boundaries

The Red Sea

Transform

San Andreas Fault

Convergent

Himalayas

What are hot spots

Areas of intense volcanic activity from mantle plumes.

Mantle Plumes

Stationary columns of hot mantle rising to surface.

Core-Mantle Boundary

Layer where mantle plumes may originate.

Plate Movement

Tectonic plates shift over stationary hot spots.

What are the three (3) potential mechanisms driving plate tectonics

• Ridge-push—elevated MOR pushes lithosphere away.

• Slab-pull—gravity pulls a subducting plate downward.

• Convection in the asthenosphere adds or subtracts.

Definition of a rock

A coherent, naturally occurring solid that consists of an aggregate of minerals or, less common, a body of glass

Describe and be ready to sketch/label the rock cycle

Igneous rock.

• Most COMMON rock type on earth - all mantle, ocean crust, and most of the continental crust/

• Formed from the freezing and consolidation of magma and/or lava