Sedimentary

Sediment

Pieces of rock that have been weathered and possibly eroded.

Detrital Sediment

Sedimentary rocks made of mineral grains weathered as mechanical detritus of previous rocks, e.g. sand, gravel.

Non Detrital Sediment

Sedimentary rocks made up of minerals that have been precipitated from water or formed through biological processes.

Weathering

Breaking down rocks into small pieces by chemical or mechanical means.

Physical Weathering

The process by which rocks break down into smaller pieces without changing their chemical composition.

Chemical Weathering

Breaking down of mineral material via chemical methods, like dissolution and oxidation.

Frost Wedging

A process where water freezes inside cracks in rocks, causing expansion and mechanical weathering.

Abrasion

A process where friction causes particles of rock to be worn away through scraping, rubbing, or scouring.

Plant Root Pressure

Plant roots grow into cracks in rocks, exerting pressure as they expand and splitting the rock apart.

Exfoliation

A type of mechanical weathering where outer layers of rock fracture off, approximately parallel to the surface.

Oxidation

A chemical reaction where a substance in a rock reacts with oxygen, causing breakdown of the material.

Acidation

A process where rainwater becomes acidic from pollutants, accelerating chemical weathering.

Hydration

A type of chemical weathering where water molecules bond with a mineral, changing its structure.

Lithification

The process of turning sediment into sedimentary rock, including deposition, compaction, and cementation.

Dehydration

The process where minerals lose water molecules from their crystal structure.

Compaction

Sediment being squeezed together into a coherent mass.

Cementation

Sediment being glued together via mineralization, typically calcite and quartz.

Quartz

One of the most common minerals, transparent with no cleavage, found in many geologic settings.

Clay

A soft, fine-grained, natural material made up of clay minerals with plastic properties.

Sandstone

A rock primarily made of sand.

Shale

A very fine-grained rock with very thin layering, also known as fissile.

Limestone

A chemical or biochemical rock made mainly of calcite.

Coal

Former swamp-derived plant material that is part of the rock record.

Detrital Texture

Sedimentary rock texture defined by the size, sorting, and roundness of its grains.

Nondetrial Texture

A sedimentary rock texture that is crystalline and not clastic.

Bowen’s Reaction Series

A series that relates to a mineral’s chemical stability; higher minerals are less stable.

Nivation (Frost Wedging)

Water freezing in cracks of rock, expanding, and eventually breaking the rock apart.

Stream Rounding

The transport of pebbles in a stream causing them to collide and become smooth and rounded.

Diagenesis

Anything that happens to sediment after it is deposited.

Detrital Rocks

Examples include Quartz, Clay, Shale, Sandstone, Conglomerate, Breccia, Siltstone.

Non Detrital Sedimentary Rocks

Examples include Limestone, Dolomite, Chert, Travertine, Coal.

Diagenetic Processes

Processes such as compaction and dehydration that lithify sedimentary rocks.

Detrital Sedimentary Rocks Composition

Sandstone - Quartz Sand, Shale - Clay.

Non Detrital Sedimentary Rocks Composition

Limestone - Calcite, Coal - Carbon.