Chapter 6
Section 3 – Sedimentary Rocks
Objectives:
-Distinguish among the three types of sedimentary rocks and how
they form
-Discuss different features typical of sedimentary rocks
Sedimentary Rocks – form from sediments that harden or are cemented
together
Cementation – The process by which minerals precipitate out of solution to
fill the spaces between sand grains, pebbles or other rock particles and bind
the fragments together
Three Types of Sedimentary Rocks:
Clastic Sedimentary – form from fragments of other rocks
Shale (Silt), Sandstone (Sand), Conglomerate (Pebbles)
1. A river moves
sediment into a lake.
2. Particles are sorted by size. The
largest gravels are the first to be
deposited, followed by sands, and
then silt and clay.
Sands and
Gravels
Conglomerate
Sands
Silt and
Clay
Sandstone
Shale
Chemical Sedimentary - form from mineral grains that fall out of solution
(Precipitate), evaporation, or by chemical action
Limestone
Organic Sedimentary – form from the remains of plants and animals
Coal, Limestone
Stratification – arrangement of visible layers
Fossils – remains, impressions, or any other evidence of plants and animals
preserved in rock
9) Bituminous Coal – soft and lightweight
Shiny to black dull
Organic Sedimentary
10) Conglomerate – contains rounded pebbles (gravel) cemented together
Clastic Sedimentary
11) Dolomite – contains fine-grained rock
Brown or gray
Clastic Sedimentary
12) Limestone – fine-grained rock
Light to medium gray, red
Organic/Chemical Sedimentary
13) Coquina – form of limestone composed entirely of shells (calcium
carbonate)
Organic Sedimentary
14) Sandstone – contains fine or course-grained quartz sand (gritty)
Porous – air can pass thru
Permeable – water can pass thru
White, gray, yellow, red
Clastic Sedimentary
15) Siltstone – fine grained sand (gritty)
White, gray, yellow, red
Clastic Sedimentary
16) Shale – fine grained, layered
Impermeable – water unable to pass thru
Scratches easily
Yellow, red, gray, green, black
Clastic Sedimentary