Earth Science Quiz

Geology Introduction

• Geology is the study of the Earth.

• Science is a systematic process of observation, experimentation, and analysis to understand the natural world.

Kola Superdeep Borehole

• The Kola Superdeep Borehole was a very deep drilling project.

• The project aimed to reach the Earth's mantle but was ultimately unsuccessful in achieving the goal. It was anticipated to be too expensive and dangerous in the future.

Crustal Differences

• Continental crust is thicker and less dense than oceanic crust.

• Oceanic crust is thinner and denser than continental crust.

Earth in Context: Scientific Method

• Scientific Method: A systematic approach to understanding natural phenomena, involving observation, hypothesis formulation, experimentation, and analysis.

• Geocentric Model: A model of the solar system placing Earth at the center.

• Heliocentric Model: A model of the solar system placing the Sun at the center.

Milky Way and Universe

• The Milky Way galaxy is vast, containing billions of stars.

• The approximate number of stars in the Milky Way is billions.

• The estimated number of galaxies in the universe, using Hubble, is large.

• The estimated number of galaxies in the universe, using James Webb, is also large (likely larger).

Doppler Effect

• The Doppler Effect describes how the wavelength of a wave (like light) changes depending on the relative motion of the source and the observer.

Big Bang Theory

• Key Points: The universe began from a hot, dense state and has been expanding and cooling ever since.

• Element Creation (besides Hydrogen and Helium): Most elements are created by nuclear fusion within stars.

• Early Universe Composition: Primordial hydrogen and helium were the primary components of the early universe.

Nebular Theory

• Nebular Theory: The prevailing model explaining the formation of our solar system, proposing cloud collapse and accretion.

Solar System Planets

• Our solar system's planets (order from the Sun): Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

Differentiation of Earth's Interior

• Earth's interior layers differentiated based on density, forming a layered structure.

• Earth Formation: Layers formed due to density differences during Earth's early molten stage.

• Moon Formation: The leading hypothesis is that a Mars-sized object collided with the early Earth, the debris coalesced to form the Moon.

Earth's Magnetic Field

• Earth's magnetic field is crucial for shielding the planet from harmful solar radiation.

• Mechanism of Magnetic Field: Generated by the movement of molten iron in Earth's outer core.

Earth's Atmosphere

• Earth's atmosphere is primarily composed of nitrogen and oxygen.

Minerals and Glass

• Glass: A non-crystalline solid, not a true mineral.

• Silica: Composed of silicon and oxygen.

Earth's Interior Variations

• Pressure and temperature increase with depth within Earth.

• Geothermal Gradient: The rate at which temperature increases with depth in the Earth.

Crust, Mantle, and Core

• Earth's layers: Crust, Mantle, and Core.

• Thickness of each layer: Information on exact thicknesses is not needed at this level.

Moho

• Moho: The boundary separating the Earth's crust and mantle.

Asthenosphere and Lithosphere

• Asthenosphere: A zone of the upper mantle that exhibits ductile behavior due to high temperature and pressure.

• Lithosphere: A rigid outer layer of the Earth encompassing the crust and part of the upper mantle.

Plate Tectonics: Wegener's Contribution

• Alfred Wegener: Proposed the continental drift hypothesis based on observations of continental shapes, fossil distribution, and paleoclimate data.

Wegener's Observations

• Fit of Continents: Continents seem to fit together like puzzle pieces.

• Paleoclimate Data: Evidence of past climates across different continents.

• Fossil Distribution: Matching fossil types across continents.

• Matching Geologic Units: Similarities between rock formations on different continents.

Pangea

• Pangea: A supercontinent that existed millions of years ago.

Paleomagnetism

• Paleomagnetism: The study of past Earth's magnetic field recorded in rocks.

Seafloor Spreading

• Seafloor Spreading: The process of new seafloor creation at mid-ocean ridges and moving away from the ridge.

Geographic vs. Magnetic Poles

• Geographic poles are defined by Earth's spin axis, while magnetic poles reflect Earth's magnetic field.

Bathymetry

• Bathymetry: Mapping the ocean floor.

Seafloor Age

• The age of seafloor rock increases as you move away from a mid-ocean ridge (newest at the ridge).

Magnetic Reversals

• Magnetic Reversals: Changes in the Earth's magnetic field polarity (North and South poles interchange).

Plate Tectonic Theory

• Plate Tectonic Theory: A unifying theory describing the movement of Earth's lithospheric plates.

Oceanic Crust vs. Earth

• Oceanic crust is relatively young compared to the Earth as a whole due to the process of seafloor spreading.

Plate Boundaries

• Divergent: Plates move apart (e.g., mid-ocean ridges).

• Convergent: Plates move together (3 types: ocean-continent, ocean-ocean, continent-continent collisions)

• Transform: Plates slide past each other (e.g., San Andreas Fault).

Plate Movement Rates

• Average rate of plate movement.

Continental Margins

• Active continental margin: Continental margins near plate boundaries (more active).

• Passive continental margin: Continental margins further from plate boundaries (less active).

Hot Spots

• Hot spots: Areas of volcanic activity associated with mantle plumes.

Triple Junctions

• Triple junctions: Points where three tectonic plates meet.

Ridge Push vs. Slab Pull

• Ridge push: Gravitational force pushing plates apart at mid-ocean ridges.

• Slab pull: Gravitational force pulling plates into subduction zones.

Chapter 3: Minerals: Introduction

• Elements: Fundamental building blocks of matter.

• Atomic Number vs. Atomic Weight: Atomic number represents the number of protons, while atomic weight reflects the average mass of an atom.

• Ions: Charged atoms formed by loss or gain of electrons.

• Cations: Positively charged ions.

• Anions: Negatively charged ions.

• Chemical Bonds: Interactions holding atoms together in molecules including; Ionic, covalent, metallic, and van der Waals bonds.

• Molecule vs. Compound: A molecule is the smallest unit of a substance, while a compound is a substance formed from multiple elements.

• Definition of a Mineral: A naturally occurring, inorganic, solid substance with a definite chemical composition and ordered atomic arrangement.

Polymorphs

• Polymorphs: Minerals with the same chemical composition but different crystal structures.

Minerals: Identifying Properties

• Methods of mineral identification: Color, Streak, Luster, Hardness, Specific Gravity, Crystal Habit/Form, Cleavage, Fracture, and Special Properties (like taste or magnetism).

Identifying Minerals: Challenges and Considerations

• Limitations of using color in mineral identification.

Hardness Scale

• Mohs hardness scale: A scale ranking mineral hardness.

Mineral Groups

• Mineral Groups: Major categories of minerals (e.g., silicates, oxides, sulfides, halides, carbonates, native metals).
• Most common within continental crust are silicates.

Silica Tetrahedra

• Silica tetrahedra: Basic structural units in most silicate minerals built from silicon and oxygen atoms.