Relative aging, fossils, natural disasters

Create 3 Venn diagrams comparing different types of erosion. You must include 3 different facts for each one. Worth 27 points. Example: Wind 3 facts Water 3 facts

Rocks breaking down into smaller pieces

Water that moves over Earth’s surface Causes sheet erosion Moves downhill Forms rills and gullies

Erosion creates valleys, waterfalls, flood plains, meanders, oxbow lakes Deposition creates alluvial fans, deltas, add soil to flood plain

Underground water Chemical weathering-water combines with CO2 to form carbonic acid, breaks down limestone Forms caves, stalactite (roof) and stalagmite (floor)

Continental glaciers-covers much of continent, island Valley glaciers-long, narrow glacier from snow and ice in mountain valley

Plucks rocks Breaks rocks Drags rocks which scratches bedrock Deposits sediment when it melts- till, moraine, kettle

Energy comes from wind blown across water’s surface Break apart rocks on shore Abrasion-headland, arch, cave Deposit sediment-beaches, spits, sandbars, barrier beaches

Deflation-wind removes surface materials, Dust Bowl Abrasion-Polishes rock, little erosion Deposits-sand dunes, loess- sediment that is finer than sand

Soil Loose, weathered material on Earth’s surface in which plants can grow.

Soil Formation Rock broken down by weathering Sediment mixes with materials on surface Soil horizon-layer of soil that is different in color and texture

Soil Layers Topsoil- crumbly, dark soil that is a mixture of humus, clay, and other minerals Subsoil-Clay, other particles, little humus

Living Organisms in Soil Humus-formed from organic material Litter-layer of dead plant leaves Decomposers-break down organic matter to form humus Earthworms, and other burrowing animals mix soil

Importance of Soil Fertility-ability for plants to grow depend on nutrients in soil Dust Bowl-loss of topsoil, devastating Soil conservation by farmers

Fossils Preserved remains or traces of living things

How fossils form Living things die and are buried in sediments Sediments harden into rock and preserve shapes of organisms Sedimentary rock

Molds and casts Most common Mold-hollow area in sediment in shape of organism Cast-sold copy of the shape of organism

Petrified Fossils Minerals replace all or part of an organism Petrified wood

Carbon Films Extremely thin coat of carbon on rock Carbon from organism left behind in shape of organism

Trace Fossils Provide evidence of activities of organisms Footprints Trails Burrows

Preserved Remains Organism trapped in tar, or amber Rancho La Brea tar pits Freezing in Siberia Protects organism from decay

 Age compared to the age of other rocks  Absolute age-number of years since rock formed

 In horizontal sedimentary rock layers, the oldest layer is at the bottom and each higher layer is younger than the layers below it.

 Extrusion- lava that hardens on the surface ◦ Always younger than the extrusion below it  Intrusion- Magma that hardens into igneous rock ◦ Always younger than the rock layers around and beneath it  Faults-Break in Earth’s crust ◦ Younger than rock it cuts through  Unconformity- Gap in geological record ◦ Rock layers lost because of erosion

 Tell relative ages of the rock layers in which they occur

 Atoms of one element break down to form atoms of another element  Half-life- time it takes for half of the radioactive atoms to decay  Carbon-14- measure amount of Carbon-14 left in organism to determine absolute age