Sedimentary structures

Sedimentary structures are features formed during or shortly after sediment deposition, preserved in sedimentary rocks. Their shapes and orientations record processes such as transport, deposition, and deformation.

Sediment: Loose mineral, rock, or biological particles that can be transported and deposited. Sediment is the material whose movement and settling produce many structures.
Bedform: A feature formed on a sediment bed by fluid flow, including ripples and dunes. Bedforms are the moving templates behind many current-generated structures.
Paleocurrent analysis: The reconstruction of ancient sediment-flow directions from preserved geological indicators. Cross-bedding and sole marks provide common directional measurements.
Soft-sediment deformation: Folding, disruption, or movement of unconsolidated sediment before it becomes rock. It modifies or creates structures after deposition, unlike primary flow-built forms.
Sedimentary rock: Rock formed from deposited sediment, accumulated biological material, or minerals precipitated from water. Structures are preserved and studied within these rocks.
Ripple mark: A small ridge-and-trough pattern formed on a sediment surface by flowing water or wind. Ripple geometry records flow conditions and may survive as a rock surface.
Facies analysis: The interpretation of rock characteristics to infer depositional environments and processes. Structures combine with grain size and fossils to distinguish depositional settings.
Tectonic fabric: The planar or linear arrangement of minerals and features produced by deformation of rock. Tectonic fabrics form during rock deformation rather than sediment deposition.
Stratification: The arrangement of sediment into distinct layers or beds. Layering is the broad framework that includes many sedimentary structures.
Cross-bedding: Inclined layers within a larger sedimentary bed, formed as ripples or dunes migrate. Its inclined foresets preserve the direction of bedform migration.

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