Geololgy Chapter 7, Interlude B - flashcards

Sedimentary rocks

Lithified sediments, forms when rock debris transported by the agents of erosion solidify. Cools deep below the ground

How much of Earth’s surface does sedimentary rocks cover?

75-80%

what important resources do sedimentary rocks provide

oil, natural gas, coal, sand, gravel, salt, clay, ores

Weathering

Break down of rocks

Regolith

Loose material that is the end product of weathering

Erosion

Movement/deposition of sediments

The more chemically weathered a rock is…

the more it will likely undergo mechanical weathering

mechanical weathering

physical breakup of rock, dominant process in cool/dry climates, maintains mineral compositions

chemical weathering

changing the chemical makeup of the rock

mechanical exfoliation

curved plates of rock are stripped from the rock below

geological example of mechanical weathering

Exfoliation domes, Stone Mountain

Frost wedging

splitting or break-up of rock by the pressure of water freezing in cracks, crevices, pores, joints or bedding planes.

What type of environment is chemical weathering most dominant in?

Warm/humid areas

thermal expansion

quartz expands 3 times as much as felspar

abrasion

stones grinding together, gradually gets more flat or spherical

root wedging

roots work their way down into the cracks of the rocks, slowly pushing the rocks away from each other. tree roots break up the rock’s mass allowing water to come in

oxidation

oxygen and a metal binding together, producing rust

hydrolisis

H20 breaks down and reacts with the crystalline structure of the other minerals and changes their composition; it is an acidifying agent

spheroidal weathering

weathering attacks the corners and edges of a rock the quickest, and the faces the rock the slowest, ultimately creating a spherical shape

example of spheroidal weathering

Vedawoo

0 Horizon- A2 Horizon

Topsoil-transition

B horizon

Subsoil- formation of clay

C Horizon

accumulations of silica, carbonates, & gypsum

Lithified sediments

sediments that are compacted under pressure, dewaters (expels water), and solidified (cemented)

strata

stacked-up layers of accumulated sedimentary rock deposits

Conglomerate rocks

formed by river deposits

sandstone rocks

found near beaches or deserts

Shale

formed in oceans, lakes, or swamps

submatrine fan

underwater land slides that happen on the continental slope

Organic rocks

remains of plants

river that runs into the Dead Sea

Jordan River… runs into a desert and then evaporates

Carbonates (biochemical)

forms in warm and most likely shallow marine environments

examples of carbonates

limestones, conquina, ooids, chalk

what do we use limestone for?

creating cement

alluvial fan

triangular shaped deposit of gravel, sand and smaller sediments

sorting

the process by which sediments of similar size are naturally segregated during transport and deposition

How well sorted can an alluvial fan be?

very poorly sorted

vertical ripple marks

caused by uplift of seafloor

Delta

when a stream carries a sediment into a larger body of water, creates conglomerate stones

Lake Bonneville

water levels decreased over time, but delta deposits still stayed

graded bedding

particles grade up to finer particles

as sea levels rise…

sediments move towards the land

as sea levels fall

sediments move owards ocean

transgression

sea level rising over the land

regression

sea level falling off the land and into the ocean

Cause of sea level rise

Interglacial rising: glaciers are melting and forming at a more quicker rate than natural processes can keep up with

How do we preserve sand dunes/sandstone mountains

as groundwater comes up from below, it saturates the bottom on the dunes, but leaves the top of the dunes dry, allowing sand dunes to grow more (accumulation)