Ch. 6 Earth Science 9

Sedimentary rock can form from changes in igneous rock; igneous rock can form from changes in sedimentary rock

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The composition of a sedimentary rock depends upon the composition of the rocks and living things its sediments came from.

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Over millions of years silt washed into a lake formed layers of sedimentary rock. What type of rock was likely formed?

A type of detrital sedimentary rock called siltstone was the likely product of this process.

What is cementation?

Cementation occurs when water soaks through rock, picking up atoms and molecules released from minerals during weathering. This solution of water and dissolved materials moves through open spaces between sediments. Minerals are deposited between the pieces of sediments, holding the particles together like glue, making a detrital sedimentary rock.

Classifying sedimentary rock

Cementation-minerals such as Quartz, Calcite, and Hematite act as cement for large sediment Classified by their composition- detrital, chemical, organic

Compare and contrast conglomerates and breccia.

Conglomerates and breccia are both detrital sedimentary rocks formed with large sediments. While the sediments that make up conglomerates are rounded, breccia is formed from sharp, angular sediments.

How do detrital, chemical, and organic sedimentary rocks differ from one another?

Detrital rocks form by compaction and cementation of rock fragments and bits of minerals, plants, and animals; chemical rocks form from minerals dissolved in solution and deposited after evaporation; biochemical rocks form from the remains of once-living things compacted and cemented together.

Describe how detrital sedimentary rocks are classified.

Detrital sedimentary are classified according to the size and shape of their sediments.

Chemical sedimentary rock

Dissolved minerals come out of solution -Limestone, Calcium carbonate in ocean water. -Rock salt, water that is rich in salt evaporates to leave Halcite

sedimentary rock

Forms when sediments are compacted and cemented together or when minerals form from solutions.

Common detrital sedimentary rocks

Gniess, Granite, Limestone- Cementing materials are usually Quartz and Calcite

compaction

Process that forms sedimentary rocks when layers of sediments are compressed by the weight of the layers above them.

Organic sedimentary rocks

Rocks made by the remains of once-living things. -Chalk, made of microscopic seashells. -Coal, made when pieces of dead plants are buried. Then chemically changed by microorganisms and then compacted over millions of years.

cementation

Sedimentary rock-forming process in which sediment grains are held together by natural cements that are produced when water moves through rock and soil.

sediment

Small, solid pieces of material that come from rocks or organisms; earth materials deposited by erosion.

Use the rock cycle to explain why sedimentary rock will never be the only form of rock on Earth.

The rock cycle is a dynamic process with no end and no beginning. Sedimentary rock will never be the only form of rock on Earth because dynamic processes transform sedimentary rock into igneous and metamorphic rock. The formation of new layers of sedimentary rock gradually pushes older layers deeper and deeper where they are exposed to heat and pressure that can result in metamorphosis or even melting. The rock cycle is dynamic and constantly transforming one type of rock into another.

Where do the sediments that make up sedimentary rocks come from?

The sediments that form sedimentary rocks come from weathered minerals and rocks. Sediment can form from igneous, sedimentary, or metamorphic rocks.

Detrital sedimentary rock

Weathering and erosion- rocks are broken down and sediment is left behind Compaction- extreme pressure pressed small sediment together Shape and Size of sediments further classified Sediment size- Clay-shale, Silt-Siltstone, Sand-Sandstone Gravel- Round sediment-Conglomerate, Angular sediment-Breccia

Materials found in sedimentary rocks

can be most any rock or mineral, Common minerals- quartz and feldspar

Formation of sedimentary rock

stacked rock- layers of rock pressed together,