Earth and Environmental Science - Energy, Plate Tectonics, and Climate (Video Notes) - Practice Flashcards

Flashcards covering energy concepts, heat transfer, plate tectonics, crust formation, subduction, metamorphism, the geologic cycle, and climate systems based on the provided video notes.

What is energy in Earth systems and what does the First Law of Thermodynamics state about its creation or destruction?

Energy is the capacity to do work or cause change; it exists in many forms and cannot be created or destroyed, only transformed or transferred.

Name two broad ways energy can move or change form in Earth systems as described by the First Law examples.

Energy can be transferred (moved from one object/place to another without changing form) or transformed (changed from one form to another).

What is kinetic energy?

Energy of motion; examples include flowing rivers, wind, and moving tectonic plates.

What is thermal energy?

Heat energy due to the motion of particles; examples include heat from Earth’s core and volcanic activity.

What is gravitational potential energy?

Energy due to position in a gravitational field; examples include water in a dam, landslides, and tides.

What is chemical energy?

Stored in chemical bonds; examples include fossil fuels, photosynthesis, and chemical weathering.

What is elastic potential energy?

Stored when objects are stretched or compressed; example: stress build-up in rocks before an earthquake.

What is radiant energy?

Energy in electromagnetic waves (including visible light); example: sunlight.

What is nuclear energy?

Released from atomic nuclei (fission/fusion); example: radioactive decay inside Earth.

What are Earth's energy sources?

Solar energy, Geothermal energy, and Radioactive decay.

What provides a constant internal heat source and drives mantle convection?

Radioactive decay of isotopes in the mantle and crust (e.g., U-238, Th-232, K-40).

What is the geothermal gradient?

Temperature increases with depth in the crust; typical crustal gradient is about 25–30°C per km; heat flows from the core to the surface.

What are the three main methods of heat transfer?

Conduction, Convection, and Radiation.

How does conduction transfer heat?

Direct contact; high-energy particles collide with cooler neighbors, moving heat from hot to cold.

How does convection transfer heat?

Heat transfer by movement of fluids due to temperature and density differences; mantle convection drives plate motion.

What is radiation?

Transfer of energy through electromagnetic waves; does not require a medium (can travel through vacuum).

What is the geotherm gradient?

Temperature gradient in the Earth, with heat flowing outward from the interior; crustal gradient ~25–30°C per km initially, decreasing with depth.

What is isostasy?

Gravitational equilibrium between Earth’s crust and mantle; crust 'floats' at a level dependent on thickness and density (continental vs oceanic).

What is plate tectonics?

The unifying theory that explains movement of Earth's lithospheric plates and processes at their boundaries (earthquakes, volcanism, mountain building, ocean basin formation).

Who proposed continental drift and what was the idea?

Alfred Wegener (1915); continents were once joined in a supercontinent called Pangaea and drifted apart.

What evidence supports continental drift?

Fit of the continents, identical fossils (e.g., Mesosaurus), similar rock types/mountain ranges (Caledonian Appalachians), and climatic evidence like glacial striations and tillites.

What limitation did Wegener have?

He lacked a convincing mechanism for how continents moved; later seafloor spreading provided the mechanism.

What is seafloor spreading?

Magma rises at mid-ocean ridges, creates new oceanic crust as it cools, and pushes older crust outward on both sides.

What is magnetic striping on the seafloor and what causes it?

Alternating stripes of normal and reversed magnetism in newly formed basalt; caused by periodic reversals of Earth's magnetic field as rocks solidify.

What does age of the sea floor reveal?

Rock age increases with distance from mid-ocean ridges, supporting seafloor spreading.

What are the three plate boundary types and their key features?

Divergent (spreading, ridges), Convergent (subduction, trenches/volcanic arcs), Transform (lateral sliding; significant earthquakes).

What distinguishes oceanic crust from continental crust?

Oceanic crust: 5–10 km thick, more dense, basalt/gabbro, relatively young; Continental crust: 25–100 km thick, less dense, granite/diorite, very old.

What happens at subduction zones?

Dense oceanic crust sinks beneath less dense continental crust, forming deep trenches and volcanic arcs; water lowers mantle melting point leading to magma.

What metamorphism occurs in subduction zones?

Regional metamorphism under high pressure and variable temperatures (basalt → greenschist → blueschist → eclogite); contact metamorphism near magma intrusions.

What is the age and composition difference between oceanic and continental crust in terms of rocks and density?

Oceanic crust: basalt/gabbro, high density (~3.0 g/cm3); Continental crust: granite/diorite, lower density (~2.7 g/cm3).

What drives mantle convection and plate movement?

Heat from interior (including radioactive decay) causes mantle convection; ridge push and slab pull also contribute.

What is the role of ridge push and slab pull in plate movement?

Ridge push: rising mantle at mid-ocean ridges pushes plates apart; Slab pull: sinking dense slabs pull the rest of the plate downward.

What is the role of water in subduction zone melting?

Water released from hydrous minerals lowers the mantle wedge melting point, generating magma and volcanic arcs.

What is the geothermal gradient in the crust and how does it vary with depth?

Crustal gradient ~25°C/km in the upper crust, decreasing with depth (toward ~0.5°C/km beyond ~200 km).

What is the difference between felsic and mafic rocks?

Felsic rocks (granite, diorite) are silica-rich and less dense; Mafic rocks (basalt, gabbro) are richer in Fe/Mg and denser.

What is the Greenhouse Effect?

Greenhouse gases absorb infrared radiation and re-emit it, warming the Earth's surface and lower atmosphere.

Which gases are considered greenhouse gases in climate discussions?

Water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3).

What is albedo and how does it affect climate?

Albedo is the fraction of incoming solar radiation reflected by a surface; high albedo surfaces (ice, clouds) reflect more; low albedo surfaces (oceans) absorb more, influencing climate.

What is the Earth’s energy budget?

About 30% of solar radiation is reflected; ~70% is absorbed (roughly 47% by land/ocean and 23% by the atmosphere) and later radiated back to space.

What is terrestrial radiation?

Heat emitted from the Earth’s surface and atmosphere; long-wavelength infrared radiation with lower energy.

What is the Coriolis effect?

Deflection of moving air and water due to Earth's rotation, causing wind and surface currents to bend; stronger toward the poles.

What drives surface ocean currents and what pattern do they form?

Driven mainly by wind; density differences, Coriolis effect, and landmasses create circular gyres (clockwise in the Northern Hemisphere, counterclockwise in the Southern).

What is thermohaline circulation?

Deep-ocean circulation driven by temperature and salinity differences; cold, salty water sinks and warm, less salty water rises; forms the global conveyor belt.

What is the global conveyor belt and how long does a complete cycle take?

A continuous circulation of deep and surface currents driven by thermohaline processes; takes about 1,600 years to complete one full circuit.

What role do ocean currents play in climate regulation?

They redistribute heat from warmer to cooler regions, helping to moderate global temperatures.

What is the Coriolis effect’s influence on wind and currents?

It deflects moving air and water to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, shaping wind patterns and ocean current directions.

What are major climate drivers in Australia?

ENSO (El Niño–Southern Oscillation) and IOD (Indian Ocean Dipole), with neutral phases also possible.

What happens during El Niño in terms of Pacific winds and Australia’s rainfall?

Trade winds weaken/reverse; warm water shifts east toward South America; Australia receives less moist air, leading to reduced rainfall and higher temperatures.

What happens during La Niña in terms of Pacific winds and Australia’s rainfall?

Trade winds strengthen; more warm water piles near Australia; moister air increases rainfall and can reduce daytime temperatures in summer.

What is the Indian Ocean Dipole (IOD) and its phases?

A climate pattern in the Indian Ocean with neutral, positive (warm water toward Africa, drier Australia), and negative (warm near Indonesia, wetter Australia) phases.

How do ENSO and IOD interact to influence Australian climate?

They can work together to intensify drought or rainfall, or oppose each other; seasonal forecasts consider both.

What is a typical fossil fuel energy source and how is it related to energy forms?

Fossil fuels store chemical energy, which can be burned to release thermal and kinetic energy (heat and motion).

What is a key piece of evidence for past plate movements from glacial deposits?

Glacial striations and tillites found in now-tar regions indicate past glaciation and continental positions differing from today.

What rock types are typical of oceanic crust vs continental crust?

Oceanic crust: basalt (extrusive) and gabbro (intrusive); Continental crust: granite and diorite.

What happens to older oceanic crust in the context of plate tectonics?

Old oceanic crust is recycled back into the mantle at subduction zones, balancing the creation of new crust at ridges.

Why are tectonic plates constantly moving, even if slowly?

Driven by mantle convection, ridge push, and slab pull as heat and density differences cause slow, persistent motion.