Glossary
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.
Channel: 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.
Facies: 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.
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.
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
A glossary of over 900 terms related to geology by WebRef.org
The Online Encyclopaedia of Sedimentary Structures and Processes from Oxford Brookes University.