Sedimentary

Sedimentary Rocks:

• 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, etc. 

• Non Detrital Sediment:Sedimentary rocks that are made up of minerals that have been precipitated from water or been 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 geographical process that occurs when 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 further splitting the rock apart

• Exfoliation: A type of mechanical weathering in which outer layers of rock, approximately parallel to the surface, fracture off. 

• Oxidation: A chemical substance, like a mineral within a rock, reacts with oxygen, typically in the presence of water, causing a breakdown or weathering of the material. 

• Acidation: Rainwater can become acidic due to pollutants in the atmosphere, accelerating chemical weathering processes. Natural Carbonic Acid in RainWater. 

• Hydration: A type of chemical weathering process where water molecules bond with a mineral, changing its structure. This can make the mineral softer and more susceptible to other types of weathering. 

• Lithification: The process of turning sediment into a sedimentary rock, including deposition, compaction, and cementation. 

• Dehydration: The process by which minerals lose water molecules from their crystal structure/removal of water from rock or mineral structures.

• Compaction: Sediment being squeezed together into a coherent mass. 

• Cementation: Sediment being “glued” together via mineralization, typically calcite and quartz from groundwater fluids. 

• Quartz: One of the most common minerals, and is found in many different geologic settings, including the dominant component of sand on the surface of the Earth. Transparent, any color with impurities, no cleavage, hard, forms equant masses. 

• Clay: A soft, fine-grained, natural material with plastic properties that’s made up of clay minerals. 

• Sandstone: A rock primarily made of sand. 

• Shale: A very fine-grained rock with very thin layering (fissile). 

• Limestone: A chemical or biochemical rock made of mainly calcite. 

• Coal:Former swamp-derived (plant) material that is part of the rock record. 

• Detrital Texture: Sedimentary Rock texture that is defined by the size, sorting, and roundness of its grains. 

• Nondetrial Texture: A sedimentary rock texture that is not clastic, or broken, and instead crystalline. 

• How does Bowen’s Reaction Series relate to a mineral’s chemical stability? - Bowen’s Reaction relates to a mineral’s chemical stability by stating that the higher a mineral is on the Bowen’s series, the less stable it is chemically. 

• How do the different types of physical weathering break down rocks? - 

  • Nivation (Frost Wedging): Water seeps into cracks in a rock, freezes, expands, and widens the cracks, eventually breaking the rock apart; most effective in cold climates with frequent freeze-thaw cycles.

  • Plant-Root Pressure: Plant roots grow into cracks in rocks, exerting pressure as they expand and further splitting the rock apart

  • Exfoliation: As pressure is released from deeply buried rocks due to erosion, they expand and crack, forming large, sheet-like fractures parallel to the rock surface. 

  • Stream Rounding: Transport of pebbles in a stream causes them to collide and rub against one another and the stream bed, and the resulting abrasion produces the familiar smooth and rounded shape of river rocks.

• How do the different types of chemical weathering break down rocks? - 

  • Acidation: Rainwater can become acidic due to pollutants in the atmosphere, accelerating chemical weathering processes

  • Oxidation: When minerals in a rock, especially those containing iron, react with oxygen, forming iron oxide (rust) which weakens the rock structure and alters its color.

  • Hydration: Water molecules interact with minerals in a rock, causing them to break down and form new minerals like clay, often changing the rock's texture and composition.

• The steps for making a detrital sedimentary rock.

  • 1. Weathering (Physical/Chemical to break up rock) = SOIL

  • 2. Erosion (Movement by wind, water, or ice.) = SEDIMENT

  • 3. Deposition (Turns the energy off)

  • 4. Diagenesis (Anything happens to sediment after it is deposited). 

• The types of detrital and non detrital sedimentary rocks.

  • Detrital Rocks: Quartz, Clay, Shale, Sandstone, Conglomerate, Breccia, Siltstone, Mudstone 

  • Non Detrital Sedimentary Rocks: Limestone, Dolomite, Chert, Travertine, Coal 

• The processes that can lithify a sedimentary rock.

  •  Diagenetic Processes (Compaction and Dehydration).

• The compositions of detrital and non detrital sedimentary rocks. 

  • Detrital Sedimentary Rocks: Sandstone - Quartz Sand, Shale - Clay

  • Non Detrital Sedimentary Rocks: Limestone - Calcite, Coal - Carbon