Sedimentary Petrology

Sedimentary Petrology

A scientific discipline that studies all kinds of sedimentary rocks, focusing on their composition, characteristics, and origins.

Sedimentary Rocks

Rocks that form at low temperatures and pressures from deposition by water, wind, or ice; characterized by layers and distinctive textures and structures.

Weathering

The chemical alteration, physical, and biological breakdown of rock during exposure to the atmosphere, hydrosphere, and biosphere.

Mechanical Weathering

Weathering that requires physical force or stress without changing the composition of the rock.

Chemical Weathering

Breakdown of minerals through chemical reactions with water, soluble chemicals, or gases in the air.

Erosion

The process of moving rock and soil, involving agents like gravity, ice, organisms, water, and wind.

Transportation

The process by which sediment is moved from one place to another, influenced by agents such as ice, water, and wind.

Diagenesis

The physical, chemical, and biological processes that transform sediments into sedimentary rock.

Siliciclastic Rocks

Sedimentary rocks formed from the products of mechanical weathering.

Chemical Rocks

Sedimentary rocks formed through direct precipitation from solution.

Biochemical Rocks

Rocks formed by biogenic and chemical processes, often consisting of organic materials.

Compaction

A diagenetic process that reduces pore space and increases density of sedimentary rocks under pressure.

Cementation

The process where minerals precipitate from groundwater and fill the spaces between sediment grains, binding them together.

Stratification

The layering that occurs in sedimentary rocks due to deposition over time.

Graded Bedding

Bedding characterized by a gradual change in grain size from bottom to top.

Fossil Fuels

Natural substances, such as coal and petroleum, formed from decayed organic matter and have economic significance.

Walther's Rule

States that the different types of sedimentary rocks are formed beside each other in space but can be found stacked on top of each other in a crustal profile.

Alluvial Fan

A fan-shaped deposit formed when a stream loses energy and drops sediment at the base of a mountain.

Fluvial Environment

A river system where sediment is transported in solution, suspension, or along the bottom.

Meandering Channels

Channels with a single, winding course that deposits sediments at the inner sides of bends.

Braided Channels

Channels characterized by multiple thalwegs and bars due to high sediment loads.

Glacial Environment

Regions occupied by glaciers that transport various sizes of sediment as they move.

Maroon

A term referring to glacially-deposited materials, usually unsorted.

Delta

Depositional bodies formed at the point where a river meets a lake or sea.

Reefs

Wave-resistant structures formed primarily from corals in marine environments, contributing to sedimentary rock formation.

Turbidite

Sediments deposited by sediment-laden currents flowing down submarine canyons.

Foliation

A planar fabric visible in metamorphic rocks due to the alignment of minerals.

Metamorphic Facies

Domain of Pressure-Temperature space characterized by specific mineral assemblages.

Sedimentary Structures

Physical features that form in sediment during or shortly after deposition, affecting the final appearance of the rock.

Organic Sedimentary Rocks

Sedimentary rocks formed from the accumulation of plant or animal debris, typically rich in carbon.

Chemostratigraphy

A branch of stratigraphy that uses geochemical signatures to identify and correlate sedimentary rock layers.

Petrography

The study of rocks through microscopic analysis to determine their mineral composition and texture.

Lithification

The process by which sediment transforms into sedimentary rock, typically through compaction and cementation.

Fossilization

The process of preserving remains or traces of organisms in sedimentary layers over geological time.

Carbonate Rocks

Sedimentary rocks primarily composed of carbonate minerals, such as calcite or dolomite.

Ooids

Small, spherical grains composed of concentric layers of calcium carbonate, typically formed in shallow marine waters.

Lamination

Thin layers of sedimentary rock, often indicative of specific depositional environments.

Diagenetic Features

Structures in sedimentary rocks that result from the processes of diagenesis, such as compaction and cementation.