Decomposition and disintegration of rock by natural agents.
Wearing away and transportation of rock and soil by natural agents.
Downslope movement of rock and soil under the influence of gravity.
Breaking of rock into smaller pieces by natural forces without changing its compostition.
Water freezing and expanding in cracks.
Rock breaks along parallel cracks to form layers (sheets). Caused by expansion of rock as the weight of overlying rocks is removed by erosion.
Caused by the force generated by plant roots growing in cracks.
Process where rocks change into minerals that are more stable on Earth's surface.
Reaction of a mineral with water to form a hydrated mineral, typically clay minerals.
Reaction of a mineral with oxygen to form an oxide or hydroxide mineral
Dissolving away of rock by water, especially acidic water, to form ions in solution
Decomposed and disintegrated rock. The mineral part of the soil.
A mix of mineral matter from weathering, and organic matter from biological activity.
Regolith, Humus, Water, Air
The four main ingredients of soil.
Dark-colored organic matter. Formed by decay of plants, animals, and animal wastes.
Almost entirely organic matter. Dark brown to black. Upper part if recognizable organic debris (leaves, twigs, etc) Lower part is unrecognizable grains of decomposed, humus-rich organics.
Mostly mineral matter plus as much as 30% humus. Also dark colored. Most clay and soluble minerals (calcite & gypsum) have been removed by downward moving water.
Zone of minerl accumulation. Shades of red, orange, brown due to iron oxides. Mostly clay, quartz, and some soluble minerals removed from the topsoil.
Weathered parent material. Weathered rock or sediment from which the mineral part of the soil comes, i.e. regolith. The first part of the soil to form.
The rock formation that lies beneath soil.
Sediments deposited on top of the bedrock by water, wind, and ice.
Loose materials transported and deposited by erosion.
Rock formed when sediment is turned into stone.
Materials from land that consist of particles.
Formed by inorganic precipitation of dissolved salts.
Fromed by organic precipitation of dissolved salts.
A reduction in volume due to weight of overlying sediments squeezing out air and water.
Binding of particles by minerals deposited by water moving through pores.
Crystallization and Recrystallization
Formation of a mass of interlocking crystals. Due to direct precipitation (crystallization), or growth around previously formed crystals or shells.
Horizontal layers deposited one atop another. Each layer = an episode of sediment deposition, followed by a break during which sediment consolidates before more is laid on top of it.
A stack of sets of tilted strata in which the direction and angle of tilt can vary from set to set. Forms from migration of a slope on which sediment is deposited.
Wave-like ripples caused by waves, currents or wind disturbing sediment.
A network of cracks dividing the surface into polygons. Formed when sediment dries out, shrinks, and cracks open.
Local concentration of a foreign mineral
Local concentration of a mineral cement.
Similar to a nodule, but hollow and lined with crystals.
Evidence of prehistoric life, such as bones, teeth, shells, petrified wood, and tracks.
Made of cemented and/or compressed particles.
Made of interlocking crystals
Made of cemented shells.
Made of organic hydrocarbons formed from plants
Coarse-grained, Mix of smoothe, rounded quartz gravel and sand. Forms from beaches, sandbars, and dunes.
Medium-grained, Mostly quartz and feldspar, froms from beaches, sandbars, and dunes.
Very fine-grained, thinly layered, soft,rumbly, and easily weathered, mostly tiny bits of clay and quartz, most common sedimentary rock, forms from mud deposited in nonturbulent conditons, often deep water.
Made of calcite, texture can be crystalline, bioclastic, or clastic, grain size varies from coarse to very fine
Made of dolomite, same textures and grain sizes as limeston. Forms when brine moves through calcite sediment and turns it into dolomite.
Made of microcrystalline quartz. Very fine-grained, hard, dense, and durable, breaks like glass to form a sharp edge. Sometimes bioclastic, typically occurs as nodule in carbonate rocks, but can also be in layers, forms in the ocean, shallow to deep sea.
Inorganic, precipitates formed from hypersaline water. Form in hot, dry climates where water is shallow and evaporation rates are high, which concentrates salts. Usually form along sea coasts, or in desert salt lakes.
Burnable geologic deposits of organic hydrocarbons
an organic textured rock formed from plant debris
Formation of Coal
Plant debris is deposied in stagnant water, a swamp or bog, where it can't completely decay. This forms organic peat- a low grade fuel. Next, the peat is deeply buried under more sediments, which heats and compresses it. This drives off volatiles and concentrates carbon to form coal.
Brown coal. Low grade, Most volatiles, lowest % carbon, lowest energy yield.
Soft Coal, Medium grade, less volatiles, more carbon, higher energy yield.
Hard Coal, highest grade, least volatiles, most carbon, highest energy yield, forms when lower grade coal is heated and compressed during formation of mountains. Rarest type.
Rocks formed by recrystallization without melding due to heat and pressue deep underground.
Chemically Active Fluids
Brines in the pores that act as a chemical catalyst. Greatly speeds up the process by making it easier for atoms to move from one mineral grain to another.
Atoms moving from one mineral grain to another.
A preferred crystal alignment
A random crystal alignment that lacks layers, bands, or rock cleavage.
Cased by effects of a magma intrusion. A portion of the surrounding rock is changed.
Recrystallization of a vast volume of rock due to widespread heating and compression.
Very fine-grained, closely spaced even layers, very good rock cleavage, mostly mica and quartz.
Visibly crystalline, layers typically uneven, uneven rock cleavage, mostly play minerals, such as mica.
Visibly crystallin, banded, no rock cleavage, mostly feldpar and quartz, dark bands are ferromagnesian silicates.
Visibly crystallin, sometimes has bands of color, mostly calcite or dolomite, forms from limestone or dolostone
Visibly crystalline, granular "sugary" look, made of quartz, forms from sandstone.