Geology exam 2

What are the four stages of coal formation?

(1) accumulation of plant remains in an oxygen-poor environment, (2) formation of peat and lignite from the partial decomposition of plant matter, (3) formation of bituminous coal after deep burial and increased temperatures, and (4) formation of anthracite coal as further heat and pressure metamorphoses bituminous coal.

What are fossils?

(remains of past life) help interpret past environmental conditions and are important time indicators.

What are the four processes that form sedimentary rocks?

1. Weathering 2. Transport 3. Sedimentation 4. Lithification

How many soil orders are there?

12

How many soil series are there?

19,000

How many hierarchical categories are there?

6

What percent of land do sedimentary rocks cover?

75%

What are some soil conservation efforts?

Construct Terraces on steep slopes to slow runoff, increase infiltration, leave crop residues on field.

What are the agents of metamorphism?

Heat, Pressure, Differential stress, and chemically active fluids.

What letters are involved with the horizons?

O,A,E,B,C

What two components does soil have?

Organic matter and air.

What are the controls of soil?

Parent Material, Climate, Plants and animals, time, topography

What is the impact of human activity on soils?

Providing Food, Fiber, and other basic material

What is recrystallization?

Recrystallization is when the minerals in a metamorphic rock have been rearranged WITHOUT melting.

What happens during metamorphism?

Rocks change physically or chemically

What are marine environments?

Shallow Marine Layer, and Deep Marine layer

What are the common types of foliated rocks?

Slate, Phyllite, Shist, Gneiss

What are the types of sedimentary structures?

Strata, and Beds

What are chemically active fluids?

Surround mineral causing recrystallization

What is metamorphic grade?

The degree to which a rock changes

What is laminae?

The thin layers in shale

What are bedding planes?

These are flat surfaces along which rocks tend to separate or break.

What are biochemical sedimentary rocks?

They consist of shells-shells survives and lithified, fossiliferous limestone formed by coral reefs

What are foliated textures?

are Variations of foliation are dependent on the grade of metamorphism and mineralogy of parent rock.

What are chemical sedimentary rocks?

are formed when ions in solution precipitate into chemical sediments

What are joints?

are fractures created by expansion of rock masses, contraction during crystallization of magma, and from tectonic forces of mountain building.

What are sedimentary rocks?

are products of mechanical and chemical weathering and are formed by the process of weathering, transport, deposition, and lithification.

What are ripple marks?

are small waves that are lithified in the sedimentary rocks and suggest air or moving water.

What are porphyroblastic textures?

are unusually large grains in a fine-grained matrix.

What are graded beds?

are where particles in a bed gradually change from coarse at the bottom to fine at the top.

What influences the rates of weathering?

by rock characteristics and climate.

What are clastic sedimentary rocks?

clastic sedimentary rocks, chemical sedimentary rocks, and organic sedimentary rock.

What are conglomerates?

consist of poorly sorted, rounded gravel-size particles, ranging in size from large boulders to pea-size.

What is limestone?

consists of 10% of the total volume of all sedimentary rocks and it is composed primarily of calcite (CaCO3).

What is shale?

consists of sedimentary rock consisting of silt- and clay-size particles.

What is foliation?

describes planar arrangement of mineral grains or crystals within a rock.

What are metamorphic textures?

describes the size, shape, and arrangement of the mineral grains within a rock.

What are the processes of chemical weathering?

dissolution, oxidation, hydrolysis

What is nonfoliated?

do not show any foliated textures

What are organic sedimentary rocks?

form from the carbon-rich remains of organisms

What are evaporites?

form when restricted seaways become over-saturated and salt deposition starts.

What are continental environments?

have a nature of sediment strongly influenced by climate.

What is the most important agent?

heat

What are conglomerates?

indicate a high-energy environment where coarse materials settle out and fine materials remain suspended.

What are mud cracks?

indicate sediment was alternately wet and dry.

What do sedimentary structures aid in interpreting?

interpreting Earth's history.

What is cementation?

involves the crystallization of minerals among the individual sediment grains from ions carried in solution in groundwater.

What is Soil?

is a combination of mineral and organic matter, water, and air.

Chemical weathering

is a complex process that breaks down rocks and the internal structures of minerals.

What is schist?

is a medium- to high-grade metamorphism, it is medium- to coarse-grained and it has parallel alignment of platy minerals of muscovite and biotite dominant.

What is gneissic texture?

is a result of ion migration in high-grade metamorphism.

What is carbonaceous shale?

is a sign of low-energy, organic-rich environment like a swamp or lagoon.

What is humus?

is a source of nutrients, enhances soil's ability to hold water.

What is coal?

is an organic sedimentary rock and is a major energy source.

What is diagenesis?

is chemical, physical and biological changes that take place after sediments are deposited.

What is breccia?

is composed of poorly sorted, angular gravel-size particles. It is angular because they did not travel far from their source.

What is phyllite?

is degree of metamorphism between slate and schist, has platy minerals larger than slate, smaller than schist, distinguished from slate by glossy sheen and wavy surface, fine-grained, visible crystals of muscovite and/or chlorite and exhibits rock cleavage. Both slate and phyllite exhibit rock cleavage.

What is slate?

is fine-grained/low-grade, foliated, composed of minute chlorite and mica flakes, appears dull and closely resembles shale, and has excellent rock cleavage.

What is an exfoliation dome?

is formed after continued weathering causes slabs to separate and peel off.

mechanical weathering

is physical forces that break rock into smaller and smaller pieces without changing the rock's mineral composition.

What is schistosity?

is platy minerals that are discernible with the unaided eye (It exhibits a planar or layered structure)

What is dolostone?

is rock composed of dolomite, a calcium-magnesium carbonate mineral.

What is salt crystal growth?

is sea spray or salty groundwater that penetrates crevices and pore spaces in rock.

What is the soil profile?

is soil horizons that show vertical differences in soil that divide it into zones or layers in other words it is a vertical section through all the soil horizons.

What is sandstone?

is the ability to split into thin layers along well-developed, closely spaced planes.

What is the carbon cycle?

is the movement of carbon along all four of Earth's major spheres.

What is lithification?

is the process by which unconsolidated sediments are transformed into solid sedimentary rocks.

Texture and Structure

is the proportions of different particle sizes in a soil. influences how easily a soil can be cultivated, and how susceptible it is to erosion.

What is regolith?

is the term for the layer of rock and mineral fragments on Earth's surface.

What are transitional environments?

is the transition zone between marine and continental environments.

What does biological activity have to do with weathering?

is weathering by the activity of plants, animals, or humans.

What is spheroidal weathering?

is weathering that attacks edges from two sides and corners from three sides. Sharp edges gradually wear down and become rounded.

What is frost wedging?

is when liquid water expands upon freezing (typically, water expands around 9% upon freezing).

What are the two types of weathering?

mechanical and chemical

What is chert?

microcrystalline quartz

What is compaction?

occurs as sediments are buried, the weight of the overlying material compresses the deeper sediments.

What is sheeting/unloading?

occurs when large masses of exposed igneous rock erode in concentric slabs. Erosion removing the overlying bedrock

What is precipitation?

rain, snow, sleet, or hail that falls to the ground.

What is rock or slaty cleavage?

rocks that split into thin slabs when hit with a hammer.

What is soil taxonomy?

s a method of classifying the many different types of soil on Earth.

What is metamorphism?

s a process that leads to the changes in the mineralogy, texture, and sometimes chemical composition of the parent rock.

What does environment of deposition or a sedimentary environment mean?

s the geographic setting where sediment is accumulating characterized by a particular combination of geologic processes and environmental conditions.

What is cross-bedding?

s where layers are inclined to the horizontal. They develop as characteristics of sand dunes, river deltas, and certain stream channel deposits.

What is arkose?

suggests a dry climate with little chemical alteration of feldspar.

What does particle shape have to do with the rock environment?

tells about environment of transport and the distance or time in transportation

What is gneiss?

which is medium- to coarse-grained banded metamorphic rocks and is granular and elongated minerals predominate.