The Lithosphere and Plate Tectonics

Flashcards covering the structure of the lithosphere, plate tectonics, mountain formation, and earthquakes.

What are the three types of Lithosphere?

Oceanic Lithosphere, Continental Lithosphere, Subducted Lithosphere

What is the typical thickness range of the Oceanic Lithosphere?

50-140km thick

What is the typical thickness range of the Continental Lithosphere?

40-250km thick

What is the typical thickness of the Subducted Lithosphere?

Up to 400km thick

What is Sima?

Mafic rock rich in iron and magnesium that forms the oceanic crust.

What is the density of oceanic crust compared to continental crust?

Oceanic crust is denser at around 3g/cm3, while continental crust is around 2.7g/cm3.

What are cratons?

Highly stable and old sections of continental crusts.

How are Igneous rocks formed?

Formed by the cooling and recrystallisation of magma, either intrusively or extrusively.

How are Sedimentary rocks formed?

Formed through the accumulation and deposition of different sediments.

How are Metamorphic rocks formed?

Formed through cycles of elevated temperatures and high pressures that alter the physical and chemical properties of the rock.

What are tectonic plates?

Rigid crusts of continental and oceanic plates that float on the liquid asthenosphere.

What is a Divergent boundary?

Plate boundaries that are formed as two tectonic plates move away from each other.

What is the Mid-Atlantic Ridge?

An underwater mountain range formed by the separation of the North American, Eurasian, and African plates.

What is the East African Rift?

A rift formed as the African plate splits into the Nubian and Somalian plates.

What is a Convergent boundary?

Formed by two plates colliding together creating a subduction zone or a continental collision zone.

How are the Andes Mountains formed?

Through the subduction of the oceanic Nazca plate underneath the continental South American Plate.

How are the Himalayas Mountains formed?

Through the collision of the Indian plate to the Eurasian plate.

What is a Transform boundary?

Boundaries that neither create nor destroy tectonic plates, instead, two plates grind against each other.

What is the San Andreas Fault?

A transform fault formed between the north-westerly moving Pacific-plate and the south-easterly moving North American plate.