Depositional Environments

Trace Fossils

  • Used for dating sedimentary rocks and recording organismal behavior.

  • Indicate depositional environment, climate conditions, water depth, current energy, temperature, and precipitation.

Sedimentary Structures

  • Bioturbation: Organism burrowing that disrupts sediment structure.

  • Bioturbation Index (BI): Measures bioturbation levels from 0% (absent) to 100% (complete).

Depositional Environments

  • Locations where sediments accumulate (terrestrial, transitional, marine).

  • Depositional facies: Unique sediment characteristics.

Environment Types

  • Terrestrial: Fluvial, desert, glacial.

  • Transitional: Delta, beach, barrier island.

  • Marine: Continental shelf, slope, deep ocean, evaporite.

Specific Environments

  • Fluvial Systems: River systems (meandering, braided, anastomosing streams) with floodplains.

  • Desert Systems: Windy, eolian environments with dunes and alluvial fans.

  • Glacial Systems: Ice-dominated environments transporting large sediments, forming till and outwash.

  • Deltaic Systems: Formed where rivers meet still water, composed of topset, foreset, and bottomset beds.

  • Beach Systems: Sandy, wave-influenced environments (backshore, foreshore, shoreface).

  • Marine Systems: Varying environments from continental shelf to abyssal plains with terrigenous and biogenous sediments.

  • Carbonate Reefs: Biochemical structures in warm, shallow waters (fringing, barrier, atolls).

Paleogeography and Sedimentary Facies

  • Evaluates past geography using rocks and fossils to understand historical environments and ecology.

  • Facies reveal depositional history and geomorphological evolution, affected by diagenesis and erosion.