plate tectonics test

What are the three types of plate boundaries?

Convergent, divergent, and transform.

What is the primary driver of plate tectonics?

Convection in the mantle.

What is the composition of the Earth's crust?

Made of oxygen and silicon, with continental crust being thicker and more buoyant than oceanic crust.

What are the characteristics of oceanic crust?

Thin (~7 km), more dense, and younger than continental crust.

What is the composition of the mantle?

Intermediate composition, mostly iron, magnesium, aluminum, silicon, and oxygen silicate compounds.

What is the temperature range of the mantle?

From +1000 degrees C at the upper mantle to 2890 km depth.

What is the outer core primarily made of?

Mostly iron and nickel, and it is in a molten state.

What is the temperature of the outer core?

About 3700 degrees C.

What is the inner core like?

Solid, unattached to the mantle, suspended in the molten outer core, and has a temperature of ~6000 degrees C.

Who proposed the theory of continental drift?

Alfred Wegener.

What evidence supports the theory of continental drift?

Continental shapes fitting together, matching fossils on different continents, matching rocks and mountain ranges, and climatic clues.

What is seafloor spreading?

The process by which new oceanic crust is formed at mid-ocean ridges and older crust is recycled back into the mantle.

What did Harry Hess contribute to the understanding of seafloor spreading?

He studied mid-ocean ridges and proposed that the ocean floor is young at ridges, where magma rises and spreads.

What is the significance of magnetic reversal in seafloor spreading?

It provides a record of the Earth's magnetic field changes, which is captured in the stripes of oceanic crust.

What is the lithosphere?

The rigid outer part of the Earth, consisting of the crust and upper mantle, about 100 km thick.

What is the asthenosphere?

The upper mantle layer that behaves like plastic rock and can flow due to deformation.

What is the depth range of the inner core?

From 5150 km to 6370 km.

What is the evidence for the age of oceanic crust?

The youngest crust is found at mid-ocean ridges, with older crust being pushed away.

What are climatic clues that support continental drift?

Evidence such as glaciers found in warm places and coal deposits in Antarctica, indicating past connections.

What is the role of density in Earth's interior?

Density differences help explain the behavior of materials; warmer materials are less dense and rise, while colder materials are more dense and sink.

What is the significance of the 'striped' pattern of magnetic orientation on the ocean floor?

It provides evidence for seafloor spreading and shows symmetrical mirror-image patterns on both sides of mid-ocean ridges.

What are the two types of crust?

Continental crust and oceanic crust.

What geological features are formed by plate tectonics?

Mountains, trenches, earthquakes, and volcanoes.

What is the relationship between plate motion and tectonic features?

Plate motion causes collision, separation, or scraping of the plates, leading to various tectonic features.

What drives plate motion?

Lithospheric plates are moved by hot mantle convection, causing the lithosphere to slide over the asthenosphere.

What happens to material in the mantle during plate motion?

Material in the mantle rises towards the lithosphere, cools, and then sinks back down to the mantle.

What is a divergent plate boundary?

A boundary where two plates move apart, causing volcanic activity as hot molten material rises.

What are some examples of divergent boundaries?

Ocean ridges, such as the one formed in Iceland as the North American and Eurasian plates diverged.

What is a convergent plate boundary?

A boundary where two plates move towards each other, leading to various geological features depending on the types of plates involved.

What occurs at a continental-continental convergent boundary?

Neither plate can sink, so they push against each other, causing the crust to buckle and crack, forming mountain ranges like the European Alps and Himalayas.

What happens at a continental-oceanic convergent boundary?

The oceanic plate sinks under the continental plate, leading to subduction, volcanism, and the formation of features like the Andes Mountains.

What occurs at an oceanic-oceanic convergent boundary?

One oceanic plate subducts under another, creating a trench and volcanic island arcs, as well as causing tsunamis and earthquakes.

What is the Ring of Fire?

A region around the Pacific Plate characterized by high volcanic and earthquake activity, formed by convergent boundaries where the Pacific Plate is subducted.

What is a transform plate boundary?

A boundary where plates slide past each other, resulting in shear force and the formation of fault lines, such as the San Andreas Fault.

What are hotspot volcanoes?

Volcanoes formed by hot mantle plumes breaching the surface in the middle of tectonic plates, not at plate boundaries.

What is a hotspot?

A fixed point where magma flows through the crust, forming a chain of volcanoes as tectonic plates move over it.

What are the characteristics of the continental shelf?

The extended perimeter of each continent, which is underwater during interglacial periods but was part of the continent during glacial periods.

What is the continental slope?

The descending slope that connects the seafloor to the continental shelf, considered part of the continent.

What is the continental rise?

A gentle slope with a smooth surface made by the buildup of sediments from erosion, located between the continental slope and abyssal plain.

What are abyssal plains?

Flat or gently sloping areas typically considered part of the ocean floor, found between the continental rise and mid-oceanic ridge.

What are mid-ocean ridges?

Underwater mountain ranges formed by plate tectonics, responsible for seafloor spreading.

What is a trench in oceanography?

A long, narrow topographic depression on the ocean floor formed at subduction zones, such as the Mariana Trench.

What is a submarine canyon?

A narrow deep canyon carved into the continental shelf by erosion.

What is a seamount?

A mountain rising from the ocean floor that does not reach the surface, formed from extinct volcanoes.

What is a guyot?

A flat-topped seamount, also known as a tablemount, formed by erosion.

What is a coral reef?

A structure formed in tropical shallow waters, which can be classified as fringing, barrier, or atoll reefs.

What is the difference between fringing, barrier, and atoll reefs?

Fringing reefs are close to the shore, barrier reefs separate the shore from the reef creating a lagoon, and atolls are coral islands surrounding a lagoon with the original island submerged.

What are the two main components of the Earth's core?

The inner core (solid, made of iron and nickel) and the outer core (liquid, made of iron and nickel).

What is the primary characteristic of the Earth's mantle?

It is the thickest layer, made of hot and semi-solid rocks, and contains most of Earth's mass.

What is the asthenosphere?

The soft part of the upper mantle where tectonic plates float and move.

What does the lithosphere consist of?

The lithosphere consists of the crust and the top of the mantle, which is rigid and solid.

Compare oceanic crust and continental crust in terms of thickness, composition, density, and age.

Oceanic crust is thinner, made of basalt (denser), more dense, and younger. Continental crust is thicker, made of granite (less dense), less dense, and older.

How does density affect the movement of materials in the Earth's interior?

Warmer materials are less dense and rise, while colder materials are more dense and sink.

What causes convection currents in the mantle?

Convection currents are caused by heat rising and cooling, then sinking into the mantle.

What is sea floor spreading?

Sea floor spreading occurs at mid-ocean ridges where new crust forms from rising magma, pushing older crust away.

What evidence supports Alfred Wegener's continental drift theory?

Evidence includes fossils, rock layers, the fit of continents, climatic clues, and seafloor spreading.

Who proposed the theory of seafloor spreading and how did he support it?

Harry Hess proposed the theory and used sonar/radar to map the ocean floor, providing evidence for Wegener's theory.

What is magnetic reversal and how does it relate to seafloor spreading?

Magnetic reversal refers to the flipping of Earth's magnetic poles over time, with new ocean crust showing matching magnetic stripes on both sides of ridges.

What happens at a subduction zone?

Denser plates go under less dense plates at a convergent boundary, causing volcanoes, earthquakes, and trenches.

What occurs at divergent boundaries?

Plates move apart, forming mid-ocean ridges and rift valleys, with a tensional force.

What are the characteristics of convergent boundaries?

Plates move towards each other, potentially forming mountains, trenches, and volcanoes, with a compressional force.

What happens at transform boundaries?

Plates slide past each other, which can cause earthquakes.

What is the difference between a rift and a ridge?

A rift is where land splits apart on continents (e.g., in Africa), while a ridge is where new crust forms underwater (e.g., mid-ocean ridges).

What is a hot spot?

A hot spot is a fixed point where magma rises through the crust, leading to the formation of a chain of volcanoes as tectonic plates move over it.

What is the Ring of Fire?

The Ring of Fire is an area around the Pacific Ocean known for its high volcanic and earthquake activity, primarily due to subduction zones.

What is the significance of the Mid-Atlantic Ridge?

It is an example of a divergent boundary where new oceanic crust is formed.

What geological features are formed at convergent boundaries involving oceanic and continental plates?

Subduction zones, which can lead to the formation of volcanoes and trenches.

What evidence indicates that tectonic plates are in motion?

Fossils of the same species found on different continents, similar rock formations across oceans, and occurrences of earthquakes and volcanoes.