Understanding Metamorphic Rocks and Earthquake Dynamics

Metamorphic Rock Formation

Processes transforming existing rocks without complete melting.

Complete Melting

Total melting of rock, forming magma.

Realignment of Minerals

Minerals orienting preferentially under stress.

Segregation of Minerals

Layering of minerals with different compositions.

Solid-State Rearrangement

Atoms reorganize to form new minerals.

Foliation

Layering in metamorphic rocks due to pressure.

Schistosity

Foliation characterized by large mica crystals.

Regional Metamorphism

Metamorphism occurring over large areas, high pressure.

Dynamothermal Metamorphism

Another term for regional metamorphism.

Contact Metamorphism

Metamorphism due to heat from nearby magma.

Quartzite

Non-foliated metamorphic rock from sandstone.

Marble

Non-foliated metamorphic rock from limestone.

High-Grade Metamorphic Rock

Rock formed under high temperature and pressure.

Gneiss

High-grade metamorphic rock with banding.

Foliated Rock Order

Slate, phyllite, schist, gneiss by grade.

Differential Stress

Unequal stress causing mineral alignment.

Compression Direction

Force applied inward, creating foliation.

Clay Recrystallization

Clay transforms into mica under heat.

Mineral Grains Orientation

Foliated rocks have grains aligned in patterns.

Protolith

Original rock from which metamorphic rock forms.

Phyllite vs Schist

Schist has larger mica crystals than phyllite.

Nonfoliated Rock Classification

Based on mineral composition, not texture.

Common Protolith for Slate

Shale is a common precursor to slate.

Sandstone

A sedimentary rock composed of sand-sized grains.

Shale

A fine-grained sedimentary rock formed from clay.

Limestone

A sedimentary rock primarily made of calcium carbonate.

Basalt

A dark, fine-grained igneous rock formed from lava.

Metamorphism

Transformation of rocks due to heat and pressure.

Foliated Rocks

Metamorphic rocks with layered or banded appearance.

Nonfoliated Rocks

Metamorphic rocks without a layered texture.

Differential Stress

Unequal forces acting on a rock body.

Slate

Fine-grained, foliated metamorphic rock from shale.

Diagenesis

Physical and chemical changes in sedimentary rocks.

Thermal Metamorphism

Metamorphism caused by high temperatures, not pressure.

Phase Change

Mineral structure changes without altering chemical composition.

Pressure Solution

Dissolution of minerals under pressure, affecting rock structure.

Recrystallization

Mineral grains change size and shape without melting.

Regional Metamorphism

Metamorphism affecting large areas under high pressure.

Contact Metamorphism

Metamorphism due to proximity to molten rock.

Mountain Belt Metamorphism

Metamorphism occurring in tectonically active mountain regions.

Igneous Pluton

A large body of intrusive igneous rock.

Sedimentary segment

Part of rock cycle involving sediment formation.

Hydrothermal fluids

Hot water that facilitates metamorphic changes.

Metamorphic grade

Classification based on temperature during metamorphism.

Exhumation

Process bringing buried rocks to the surface.

Low-grade metamorphic rocks

Formed at temperatures between 250 to 400 degrees C.

Compressional pressure

Stress causing rock grains to elongate perpendicular to stress.

Rock cycle

Continuous process of rock transformation between types.

Lithification

Process of turning sediments into sedimentary rock.

Solid-state diffusion

Movement of atoms in solid rock during metamorphism.

Intermediate-grade metamorphic rocks

Formed at temperatures between 400 to 600 degrees C.

High-grade metamorphic rocks

Formed at temperatures between 600 to 850 degrees C.

Pressure solution

Metamorphic process causing grain warping without melting.

Erosion

Wearing away of rock material by natural forces.

Uplift

Raising of rock layers to higher elevations.

Compression

Type of stress that can cause rock deformation.

Subduction

Sinking of one tectonic plate beneath another.

Tensile stress

Stress that stretches rock in opposite directions.

Phase change

Transformation of minerals into different structures.

Temperature

Primary factor determining metamorphic grade.

Hornfels

Nonfoliated metamorphic rock from shale.

Rock cycle pathway

Sequence: igneous → metamorphic → sedimentary.

Dynamothermal metamorphism

Occurs during continental collision with heat and stress.

Contact metamorphism

Metamorphism near magma bodies.

Compression

Stress that squeezes rocks together.

Tension

Stress that pulls rocks apart.

Strike-slip fault

Fault with horizontal movement of crust.

Left-lateral strike-slip fault

Fault where far side moves left.

Anticline

Upward arching fold in rock layers.

Syncline

Downward bending fold in rock layers.

Basin

Depressed area with younger rocks in center.

Dome

Upward bulging structure with older rocks in center.

Shear stress

Stress that causes sliding past each other.

Volcanism

Process of magma reaching the Earth's surface.

Burial

Process of sediment being covered by additional layers.

Uplift

Raising of rock layers to the surface.

Weathering

Breaking down of rocks at Earth's surface.

Exhumation

Process of rocks being brought back to surface.

Dome

Circular fold with oldest sediments in center.

Basin

Circular fold with youngest sediments in center.

Anticline

Linear fold with older rocks in center.

Syncline

Linear fold with younger rocks in center.

Strain

Change in shape due to applied stress.

Stress

Force per unit area acting on rocks.

Tension

Stress that stretches rocks apart.

Compression

Stress that pushes rocks together.

Flux melting

Melting due to addition of water at boundaries.

Igneous rock

Rock formed from crystallized magma.

Craton

Stable interior part of a continent.

Shield

Exposed Precambrian rocks on craton surface.

Platform

Cratonic area covered by younger sedimentary rocks.

Monocline

Fold with one limb that is steeper.

Plunging fold

Fold with a tilted hinge line.

Plastic deformation

Permanent change in shape under slow stress.

Brittle deformation

Fracture or break of rocks under stress.

Dip-slip fault

Fault with vertical movement of rock blocks.

Normal fault

Fault where hanging wall moves down.

Thrust fault

Reverse fault with low-angle slope.

Strike-slip fault

Fault with horizontal movement of rock blocks.

Plunge

Angle of a line relative to horizontal.