Sedimentary rocks - Earth & Space

texture

the way something feels

sediment

small pieces of rock that are moved & deposited by water, wind, glaciers, & gravity

lithification

physical & chemical processes that transform sediments into sedimentary rocks

cementation

process of sedimentary rock formation that occurs when dissolved minerals precipitate out of groundwater & either a new mineral grows between sediment grains or the same mineral grows between & over the grains

bedding (1)

horizontal layering in sedimentary rocks

graded bedding (1)

particle sizes become progressively heavier & coarser towards bottom layers

cross-bedding (1)

depositional feature that forms as inclined layers of sediment are carried forward across a horizontal surface

clastic sedimentary rock

formed from abundant deposits of loose sediments that accumulate on Earths surface

clastic

rock & mineral fragments produced by weathering & erosion

porosity

% of open spaces between grains in a mineral

evaporite

layers of sedimentary rocks that form when concentrations of dissolved minerals in a body of water reach saturation due to the evaporation of water; crystal grains precipitate out of solution & settle to the bottom

what occurs during erosion

rocks are broken into pieces & pieces are removed from the immediate area

bedding (2)

the primary feature of sedimentary rocks, horizontal layering & can range from millimeters to several meters thick

formed like a snowball (bedding)

the more rock, the more pressure, the stronger the rocks

graded bedding (2)

when the particles become lighter & finer toward the top layers, often formed by landslides occurring underwater

cross-bedding (2)

formed as inclined layers of sediment are deposited across a horizontal surface, formed by water & wind

graded bedding vs cross bedding

graded - when particles become finer & lighter towards top layers

cross - when inclined layers of sediment are deposited across a horizontal surface

how the two types of ripple marks form

back and forth movement of wave action on shore that pushes the sand on the bottom into symmetrical ripple marks

when a current flows in one direction it pushes bottom sediments into asymmetrical ripple marks

coarse-grained

gravel-sized

conglomerate & breccia

high-energy flows of water

medium-grained

sand

sandstone

stream & river channels, beaches, deserts

fine-grained

slit, mud

slit stone, shale

slow-moving waters

medium-grained clastics

have high porosities, the connected pore space allows sandstone to hold more reservoirs of oil, natural gas, and groundwater

fine-grained clastics

have very low porosities, can form a barrier to the movement of groundwater & oil

type of environments in which fine-grained rocks form

fine-grained rocks form in environments with slow moving water, such as ponds, swamps, & deep ocean

Biochemical sedimentary rocks - what forms them

remains of once living animals & plants

Biochemical sedimentary rocks - where they form

shallow water environments swamps & coastal areas

Biochemical sedimentary rocks - how organic limestone forms

use calcium carbonate in seawater to make shells, calcium carbonate precipitates out of water & crystalizes between grains calcium sediment during lithification

Biochemical sedimentary rocks - how coal forms

thick layers of organic material accumulate, layers are buried & compressed & lithified into coal