Pyroclastic Fall Deposits

Flashcards covering essential vocabulary relating to pyroclastic fall deposits and their classification.

Pyroclastic Deposits

Fragments of volcanic material ejected during explosive eruptions.

Density Currents

Gravity-driven flows of particulate material that can occur during volcanic eruptions.

Fall Density Current

A type of pyroclastic flow that results in deposits created primarily by falling volcanic materials.

Geometry of Deposit

The shape and arrangement of volcanic deposits which can indicate past volcanic events.

Isopach Map

A map that shows the thickness of a deposit, helping to analyze eruption dispersal and characteristics.

Convective Fall

A type of fall deposit formed from finer clasts that rise in buoyant volcanic plumes.

Ballistic Fall

A fall mechanism where large clasts from explosive eruptions follow independent trajectories due to gas thrust.

Eruption Magnitude

A measurement of the volume and scale of a volcanic eruption.

Mean Grain Size

Average size of the particles within a volcanic deposit, which decreases with distance from the vent.

Sorting

The distribution of grain sizes within a deposit; well-sorted deposits have grains of similar size.

Plinian Fall

A type of pyroclastic deposit characterized by well-sorted, pumice-rich material.

Phreatoplinian Fall Deposit

A finer-grained deposit formed from phreatomagmatic eruptions, reflecting a higher degree of magma fragmentation.