Chapter 15Chapter 15

Rocks & FossilsRocks & Fossils

The primary reason people The primary reason people study rocks isstudy rocks is

They tell a story.They tell a story.

What kind of rock appears to What kind of rock appears to be made of particles bonded be made of particles bonded

together by natural cements or together by natural cements or of solids that settled from of solids that settled from

water solutions?water solutions?

Sedimentary RocksSedimentary Rocks

Sedimentary rocks have Sedimentary rocks have been known to form in days. been known to form in days.

What famous eruption site What famous eruption site demonstrates the rapid demonstrates the rapid

formation of sedimentary formation of sedimentary rocks?rocks?

Mount St. Helens in Mount St. Helens in Washington StateWashington State

Sedimentary rocks Sedimentary rocks characteristically form layers characteristically form layers

called what?called what?

stratastrata

Sedimentary rocks are Sedimentary rocks are classified in two basic ways. classified in two basic ways.

What are they?What are they?

1. Clastic – fragmental – made up of parts from other rocks

2. Nonclastic – chemical – came from dissolved minerals

Three kinds of clastic Three kinds of clastic rocks are:rocks are:

1. Conglomerate – pebbles & gravel

2. Sandstone – sand

3. Siltstone or shale – silts & clays

How is breccia different than How is breccia different than conglomerate rocks?conglomerate rocks?

The fragments are sharp The fragments are sharp and angular instead of and angular instead of

rounded like a rounded like a conglomerate.conglomerate.

This is a material in which This is a material in which something else is enclosed something else is enclosed

or embedded.or embedded.

MatrixMatrix

Nonclastic or Nonclastic or chemical chemical

sedimentary rocks sedimentary rocks form from minerals form from minerals dissolved in what?dissolved in what?

waterwater

When minerals in water When minerals in water become supersaturated, become supersaturated,

the mineral may crystallize the mineral may crystallize out of solution, settling as out of solution, settling as

a solid to the bottom to a solid to the bottom to form a what?form a what?

precipitateprecipitate

Halite deposits Halite deposits occasionally occur deep occasionally occur deep underground as vertical underground as vertical

cylindrical masses called cylindrical masses called what?what?

Salt domesSalt domes

What is any trace or What is any trace or remains of a living remains of a living

organism that has been organism that has been preserved by natural preserved by natural

means?means?

fossilfossil

Fossils that extend Fossils that extend through several layers of through several layers of sedimentary rock strata sedimentary rock strata have been found. What have been found. What

are they called?are they called?

Polystrate fossilsPolystrate fossils

What three natural What three natural materials are known as materials are known as

fossil fuels?fossil fuels?

• Coal

• Oil (petroleum)

• Natural gas

When found, oil is When found, oil is usually associated with usually associated with

what kind of rock?what kind of rock?

Sedimentary Sedimentary rockrock

The fossil fuels are The fossil fuels are often found with fossils often found with fossils

of what creatures?of what creatures?

Sea-living creaturesSea-living creatures

Evolution believe that oil Evolution believe that oil formed over millions of formed over millions of

years. When do creationist years. When do creationist believe that oil formed?believe that oil formed?

Formed quickly Formed quickly during or shortly after during or shortly after the Genesis Flood.the Genesis Flood.

Information and images on this PowerPoint come from Space & Earth Science, Third

Edition, 2005 BJU Press,

Greenville, South Carolina