Sedimentary Rocks Flashcards

Flashcards on Sedimentary Rocks

What are Sedimentary Rocks?

Rocks formed from broken pieces of other rocks (clasts).

Where do clasts come from?

Weathering of other rocks

What moves clasts to low areas?

Wind, water, gravity, or ice

What percentage of the Earth's surface do sedimentary rocks cover?

70% of Earth's surface

What percentage of the Earth's crust do sedimentary rocks make up?

8% of the crust

Where can sedimentary rocks be found?

Construction sites

What building materials are sedimentary rocks used to make?

Cement and stone

What fossil fuels do sedimentary rocks contain?

Coal, oil, gas

What can fossils found in sedimentary rocks tell us?

Past life and time periods

What are layers in sedimentary rocks called?

"Beds" or "strata"

What do horizontal layers in sedimentary rocks indicate?

Calm conditions

What do changes in layers of sedimentary rocks show?

Changes in environment

What is one engineering problem with sedimentary rocks?

They can slide along flat layers (bedding planes)

What can the sliding of beds along bedding planes cause?

Landslides

How do fossils help scientists?

Understand past life and time periods

What conditions form parallel bedding?

Calm water, fine particles settle

What forms cross bedding?

Moving water or wind

How are particles arranged in graded bedding?

Heavier particles settle first, lighter ones on top

What processes turn sediment into rock (diagenesis)?

Compaction, cementation, and crystallization

What happens during compaction?

Pressure pushes particles together

What happens during cementation?

Minerals fill in the spaces and glue particles together

What happens during crystallization?

New minerals grow due to pressure/temperature changes

What are detrital sedimentary rocks made from?

Made from solid particles (e.g. sand, mud)

What are chemical sedimentary rocks made from?

Made from dissolved materials that form crystals or shells

What is mudstone/shale made of?

Tiny particles, very common, from still water

What is sandstone made of?

Sand grains, second most common

What is conglomerate made of?

Big round pebbles

What is breccia made of?

Big sharp pebbles

What is limestone made of?

Made of calcite from shells or water

What is dolostone?

Like limestone but with magnesium

What are evaporites made of?

Salt and gypsum from evaporated water

What is chert?

Hard rock made of micro quartz, forms in marine settings

What is coal made of?

Made from plant material, goes through stages: peat → lignite → bituminous

Name one big sedimentary basin in Canada.

Western Canada Sedimentary Basin

What sedimentary rock is used at Niagara Falls and why?

Limestone base used for tunnels and power plants