M2 Subtopic 3 Flashcards
These are the geological processes that originate within the Earth and result from the energy stored in its interior. These processes are responsible for shaping the Earth’s surface through the creation and modification of landforms
Endogenic Processes
Endogenic Processes Include:
Metamorphism and Magma Generation and Intrusion
Tectonic Activity
Volcanism
Earthquakes
Isostasy
the thermal energy that was generated during the formation and early evolution of the Earth.
Primordial Heat from Planetary Formation
The process of planet formation involves the collision and aggregation of smaller bodies (planetesimals). The kinetic energy from these collisions was converted into heat
Accretion
As the Earth formed, gravitational forces caused it to compress. The conversion of gravitational potential energy into thermal energy generated significant heat
Gravitational Compression
The decay of short-lived radioactive isotopes (such as aluminum-26) during the early stages of Earth’s formation contributed to the initial heat
Radioactive Decay
also known as gravitational contraction or self-compression, is the process by which a celestial body generates heat due to the conversion of gravitational potential energy into thermal energy
Gravitational Compression
Generated by the movement of tectonic plates
Heat from Friction Due to Plate Movements
One plate being forced under another generates significant friction and heat
Subduction zones
Heat moves through solid materials like rocks; Heat moving from Earth’s hot core to the cooler mantle and crust
Conduction
Heat transfer through the movement of semi-fluid rock in the mantle
Convection
Localized Heat Sources: Areas of volcanic activity not directly associated with plate boundaries.
Hotspots
Conditions Required for Magma Formation
Heat, Pressure, Volatiles
For rocks to melt and form magma, temperatures must be high enough to overcome the bonds holding the minerals together.
Heat
As it increases with depth, it raises the melting point of rocks. However, under certain conditions, a decrease can lead to melting.
Pressure
Primarily water, and carbon dioxide, lower the melting point of rocks.
When they are are introduced into the mantle, they reduce the temperature at which rocks begin to melt, facilitating magma formation.
Volatiles
Processes Leading to Magma Formation
Decompression Melting
Flux Melting
Heat-induced Melting
Occurs when there is a decrease in pressure as mantle rocks ascend. This process is common at divergent plate boundaries, such as mid-ocean ridges, where tectonic plates move apart. As the pressure decreases, the mantle material rises and partially melts, forming basaltic magma
Decompression Melting
Happens when volatiles like water and carbon dioxide are added to the mantle, reducing the melting temperature of the rocks
Flux Melting
occurs when the temperature of the mantle or crust increases due to tectonic processes such as mantle plumes or hotspots
Heat-induced melting
These chambers act as storage areas where magma can evolve before potentially leading to volcanic eruptions
Magma Chambers
When magma cools and solidifies below the Earth’s surface, it forms intrusive igneous rocks
Intrusive Pathway
When magma reaches the surface, it erupts through volcanic vents, forming extrusive igneous rocks like basalt, andesite, and rhyolite
Extrusive Pathways
Formed by low-viscosity basaltic lava that flows easily and spreads widely
Shield Volcanoes
Characterized by alternating layers of lava and pyroclastic material, resulting from explosive and effusive eruptions.
Stratovolcanoes/composite
Large, basin-shaped depressions formed when a volcano collapses following a massive eruption
Calderas
As magma cools, early-forming minerals crystallize and settle out of the melt, removing specific elements and altering the composition of the remaining liquid. This process can create layered intrusions with distinct mineral bands
Fractional Crystallization
Magma can incorporate surrounding rock material as it ascends, altering its composition. It can lead to the formation of hybrid magmas with mixed characteristics.
Assimilation
When magmas from different sources or depths come into contact, they can mix, forming a new magma with intermediate properties. This process can produce complex igneous rock formations with varied textures and compositions
Magma Mixing
Types of Metamorphism
Contact Metamorphism
Regional Metamorphism
Dynamic Metamorphism
Caused by mechanical deformation along fault zones, leading to changes primarily due to pressure. This can create rocks like mylonite
Dynamic Metamorphism
