Bedding Structures in Sedimentary Rocks

Vocabulary flashcards covering sedimentary rock stratification, bed forms, graded beds, and surface markings.

Stratified

A property of sedimentary rock meaning that it is formed in distinct layers.

Strata

Horizontal layers in which sediment is laid down.

Bedding planes

Boundaries between each layer of strata formed when a region experiences a change in depositional environment or material.

Bed forms

Formations created when water or wind flows over loose sediment, whose shape and texture depend on flow velocity and sediment size.

Ripples

A type of bed form that forms due to the flow of water.

Asymmetrical ripples

Ripples that form when water is flowing in only one direction.

Symmetrical ripples

Ripples that form when water waves oscillate back and forth.

Dunes

A type of bed form produced due to the action of wind.

Cross bedding

A bed form created during the process of forming ripples or dunes, where sediment piles up and slips down the slip face as it moves downstream.

Graded beds

Bed forms where the sediment becomes finer towards the top of the strata, formed due to a sudden period of high energy movement.

Turbidite currents

Currents created when sediment avalanches over the edge of a continental shelf, causing heavy sediment to settle out first and finer silt to settle on top.

Bed surface markings

Features occurring due to alterations on the surface of the Earth that are preserved within sedimentary layers.

Mud cracks

A type of bed surface marking formed when the surface of the Earth dries out, indicating past alternating wet and dry conditions.

Fossils

A type of bed surface marking preserved within sedimentary layers that provides evidence of past life.