Here are the principal geological terms used in the descriptions of the units.

Bioturbation: Reworking of soil or other sediment by a living organism such as a worm.

A linear, commonly concave-based depression through which water and sediment flow and into which sediment can be deposited in distinctive, often elongated bodies. Channels can occur in a variety of morphologies, e.g., straight, meandering or braided.

Clay: Fine-grained sediments less than 0.0039 mm in size.

Conglomerate: A coarse-grained sedimentary rock composed of rounded fragments which may vary in size from pebbles to boulders.

The overall characteristics of a rock unit that reflect its origin and differentiate the unit from others around it. Mineralogy and sedimentary source, fossil content, sedimentary structures and texture distinguish one facies from another.

Graded bedding: Type of bedding shown by sedimentary deposit when particles become progressively finer from bottom to top.


Lamination: A fine layer (~ 1 mm thick) in strata, also called a lamina, common in fine-grained sedimentary rocks such as shale, siltstone and fine sandstone. A sedimentary bed comprises multiple laminations, or laminae.

Limestone: A sedimentary rock type composed mostly of calcium carbonate, that formed by chemical precipitation from sea water or by accumulation of fossils with carbonate shells.

Lithofacies: A mappable subdivision of a stratigraphic unit that can be distinguished by its facies or lithology: the texture, mineralogy, grain size, and the depositional environment that produced it.

Marl: Sediment composed of clay mixed with calcium carbonate.

Cross bedding: Bedding that was inclined when originally deposited; it formed by variable current or wave action, or by wind (sand dunes). The beds slope downwards in the direction the water or wind was moving.

Palaeosol: A soil exhibiting features that are the result of some past conditions and processes.

Palustrine: Describing material deposited in or growing in a marsh.

Sandstone: A type of sedimentary rock that contains a large quantity of weathered quartz grains.


More glossaries:

The Schlumberger Oilfield Glossary

An Abbreviated Glossary of Geological Terms from the Geological survey of the Newfoundland and Labrador.

A glossary of over 900 terms related to geology by

The Online Encyclopaedia of Sedimentary Structures and Processes from Oxford Brookes University.