Paleogeography and Systems Tracts

Scales of Study

Sedimentology is performed on a number of scales from single grains to tectonic and hydrologically-driven global sea-level cycles.

Clast

Deposit/rock

Environment/facies

System/facies association/architectural element

Systems tract

Increasing scale and complexityBasin

Eustatic

Sedimentology

Stratigraphy

Clast

Deposit/rock

Environment/facies

System/facies association/architectural element

Systems tract

Increasing scale and complexityBasin

Eustatic

Sedimentology

Stratigraphy

Scales of Study

Systems Tract

A systems tract consists of genetically-related (time-equivalent) depositional systems.

Types of Systems Tracts

Systems tracts are divided into four categories: falling-stage, lowstand, transgressive, and highstand, depending upon their relationship to relative base-level change.

Low

stan

dH

ighs

tand

Ancient Systems Tracts

Systems tracts can be recognized in the ancient record by their facies associations.

Paleogeographic Reconstruction

Systems tracts are a new way to look at the older concept of paleogeographic reconstruction, which involves regional facies analysis.

Regional Correlation

Paleogeographic reconstruction is based on correlation of data from numerous localities in the form of measured sections, logged wells, or both.

Hanging a Section

The stratigraphic succession of a basin can be “hung” on different horizons to distinguish the impact of different depositional events.

Sequence Stratigraphy

A stratigraphic sequence consists of sediment deposited during a single cycle of sea-level fluctuation and is identified, in part, by the presence of systems tracts representing different phases of that cycle.

Clastic Sequence Carbonate Sequence