Rock Formation & Continental Drift

• Igneous rocks form from cooled, crystallized molten rock, like granite and basalt.
• Sedimentary rocks form through the compaction and cementation of sediments.
• Metamorphic rocks form when pre-existing rocks are changed by heat and pressure.
• Lithification, which is compaction plus cementation, is a key process in rock formation, along with melting composition and changes in pressure and temperature.

Evidence for Continental Drift

• Matching fossils and rock formations across different continents support the idea of continental drift.
• The fit of continents, suggesting they were once joined as Pangaea, is another piece of evidence.
• Past climate evidence, such as glacial striations, also supports continental drift.
• Paleomagnetism, the study of Earth's magnetic field in rocks, provides further evidence.
• Seafloor spreading, which occurs at mid-ocean ridges when tectonic plates separate and create new ocean floor, supports the theory as well.

Mineral Characteristics

• A mineral is a naturally occurring, inorganic solid with a definite chemical composition and a crystalline structure.
• Luster refers to how a mineral reflects light, described as metallic, glassy, silky, or pearly.
• Roughness is a texture, not a form of luster.
• Hardness measures a mineral's resistance to abrasion or scratching.
• Color is the least reliable property for mineral identification.
• Streak is the color of a mineral in powder form.

Plate Boundaries and Stresses

• At divergent boundaries, plates move apart, creating new crust, exemplified by the Mid-Atlantic Ridge.
• At convergent boundaries, plates collide, leading to subduction or mountain building, such as the Himalayas and trenches.
• At transform boundaries, plates slide past each other, like the San Andreas Fault.
• The types of stress are compressional, tensional, and shear.

The Rock Cycle and Wilson Cycle

• The rock cycle involves a continuous transformation of rocks through igneous, sedimentary, and metamorphic stages.
• Magma cools and crystallizes into igneous rocks.
• Igneous rocks undergo weathering and erosion to form sediments.
• Sediments are lithified into sedimentary rocks.
• Sedimentary rocks undergo heat and pressure to become metamorphic rocks.
• Metamorphic rocks melt to form magma, restarting the cycle.
• The Wilson Cycle involves the cyclical opening and closing of ocean basins due to plate tectonics.

Earth Layers

• The outer core is liquid and responsible for Earth's magnetic field.
• Solid layers include the lithosphere, mantle, asthenosphere, and inner core.
• The crust is solid.
• The mantle is solid, consisting of the lithosphere (solid), asthenosphere (ductile), and lower mantle (solid).
• The outer core is liquid.
• The inner core is solid.

Plate Tectonics

• Convergent boundaries occur where plates move toward each other, resulting in subduction or mountain building.
• Continental vs. continental boundaries form when two continents collide, building high mountain ranges upward.
• Continental vs. ocean boundaries result in oceanic crust subducting under continental crust due to its higher density, forming mountains and volcanoes.
• Ocean vs. ocean boundaries involve subduction, where the older, denser plate is forced beneath the other, creating volcanic island arcs and trenches.
• Topographic features include volcanic arcs, trenches, and mountains.

Volcanoes and Lava

• Shield volcanoes are broad, gently sloping mountains formed by non-explosive eruptions of low-viscosity basaltic lava.
• Stratovolcanoes (composite volcanoes) are steep, conical volcanoes formed by alternating layers of explosive eruptions and solidified lava flows, often associated with andesitic lava.
• Cinder cone volcanoes are small, steep-sided volcanoes created by explosive eruptions that eject pyroclastic materials, forming piles of ash and volcanic rocks around the vent.
• Lava domes (volcanic domes) are steep, dome-shaped structures formed by the slow extrusion of highly viscous lava that piles up near the vent.
• Fissure volcanoes erupt lava from long cracks in the Earth’s crust, creating vast, flat fields of basaltic lava.
• Caldera volcanoes are large, circular depressions formed when a volcano collapses after a massive eruption, often filling with water to form crater lakes.
• High viscosity lava is rhyolitic, leading to explosive eruptions.
• Low viscosity lava is basaltic, resulting in gentle eruptions.

Seismic Waves

• Primary (P) waves are the fastest, compressional waves that travel through solids and liquids.
• Secondary (S) waves are slower, shear waves that only travel through solids.
• Surface waves cause the most damage and move along Earth's surface.

Earthquakes

• The Moment Magnitude Scale measures the energy released by an earthquake.
• The focus is the point on the fault where the earthquake originates.
• The epicenter is the point on Earth’s surface directly above the focus.

Mineral Groups and Uses

• Silicate minerals are the most common minerals on Earth, including quartz and feldspar.
• They are used in construction materials, electronics, and more.

Tectonic Activity Locations

• Active margins are areas along tectonic plate boundaries with high earthquake and volcanic activity.
• Passive margins are stable areas with little tectonic activity.

Big Bang Theory

• Evidence for the Big Bang Theory includes Cosmic Microwave Background Radiation (CMBR) and the redshift from distant galaxies.

Doppler Effect and Cosmic Understanding

• The Doppler Effect, specifically redshift, indicates galaxies are moving away, which helps estimate their speed and distance.

Goldilocks Zone

• The Goldilocks Zone is the habitable zone around a star where liquid water can exist on a planet’s surface.

Key Terms

• Lithification is the process by which loose sediments are transformed into solid rock.
• Plate tectonics describes the lithosphere as broken into dynamic plates that move along the asthenosphere.
• Metamorphism is the process of changing existing rocks into new rocks with different textures and minerals.
• Viscosity is a measure of a substance's resistance to flow.
• Seismic waves are vibrations that travel through the Earth, caused by earthquakes, volcanic eruptions, and other events.
  • P waves are the fastest, compressional waves that travel through solids and liquids.
  • S waves are slower, shear waves that only travel through solids.
  • Surface waves cause the most damage and move along Earth's surface.
• Divergent boundaries are where plates move away from each other, creating new crust. An example is the Mid-Atlantic Ridge.
• Convergent boundaries are where plates collide, leading to subduction or mountain building, like the Himalayas and trenches.
• Transform boundaries are where plates slide past each other, exemplified by the San Andreas Fault.
• The rock cycle is the process by which the three main types of rocks change into one another.
• The liquid layer of the Earth is the outer core, which is responsible for the planet's magnetic field.
• The solid layers of the Earth include the lithosphere, mantle, asthenosphere, and inner core.
  • The crust is the outermost solid layer, relatively thin compared to other layers.
  • The oceanic crust is thinner and denser, forming the ocean floors.
  • The continental crust is thicker and less dense, forming the continents.
  • The mantle is below the crust, made of semi-solid rock that flows slowly over time.
  • The upper mantle includes the asthenosphere (partially molten) and lithosphere (solid).
  • The lower mantle is more solid and dense with high pressure and temperature.
• The core is the innermost part of the Earth, mostly made of iron and nickel.
  • The outer core is liquid and generates Earth's magnetic field.
  • The inner core is solid and extremely hot.
• Paleomagnetism is the study of the Earth’s magnetic field in rocks.