Geology Lecture words 2

Terrigenous sediments-

Sediments from land rocks weathered by nature like wind , rain, temperature

Siliciclastic sediments-

sediment made of silicate materials and rock fragments

Biologic sediments –

produced from remains of biological organisms

Authigenic Sediment –

Sediments produced by chemical reactions.

Cosmogenic sediments –

Sediments produced from meteorites.

Lithification –

Process that converts sediment into solid rock by compaction or cementation.

Cementation –

Precipitates that form in the pore space between sediments.

Compaction –

Pressure from the mass accumulation of sediment that squeezes grains together reducing space

Abrasion –

wearing away of rock by grinding action of sediment

Exfoliation –

A physical weathering process in which large flat or curved sheets detach from a rock due to lower overlying pressure.

Temperature-

Alternating warm and cold temperatures Breaks apart rocks

Frost wedging –

A physical weathering process in which the expansion of water in fractures freezes breaks apart rock.

Root Wedging –

A physical weathering process in which root growth into fractures breaks apart rock.

Dissolution –

A chemical weathering process of an acid dissolving a rock.

Bioturbation –

The process of organisms churning and burrowing through sediments

Hydrolysis –

A chemical weathering process where water reacts with minerals creating new minerals

Oxidation –

minerals react chemically with oxygen with the atmosphere

Bedding –

Formation of parallel layers of sediment.

Graded bedding –

Bedding that shows progressive change in grain size from top to bottom.

Alluvial fan –

Fan shaped sediment deposit formed where rushing water slows down

Braided streams –

A stream whose channel divides into a network of interlacing channels

Meander –

A curve or bend in a rivers channel.

Floodplain –

A flat area near river prone to flooding

Oxbow lake –

a crescent shaped lake formed when a river bypasses a meander

Bed load  -

The material a stream carries along its bed by sliding and rolling.

Saltation –

The transport of material in a current that move along in a series of short jumps

Suspended  load –

Material carried suspended in the flow of a current.

Pointbar –

A curved sand deposit along the inside of a channel.