Chapter 29 Studying the Past Paleontology Fossils Let’s talk about the types……… The study of...
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Transcript of Chapter 29 Studying the Past Paleontology Fossils Let’s talk about the types……… The study of...
Chapter 29 Studying the Past
• Paleontology
• Fossils
• Let’s talk about the types………
• The study of life that existed in prehistoric times
• Preserved remains of a plant or animal
• Original remains
• Replaced remains
• Original and unchanged remains of a plant or animal preserved in a rock – Amber is an example (animals caught in sticky tree sap
• Minerals in groundwater replace the decaying plant or animal – like petrified wood!
• Cast
• Mold
• A copy of the original fossil
• A depression in a rock of the original fossil
• Trace fossils • Impressions such as footprints, tracks, burrows or bite marks
Relative Time
• Relative dating
• Strata -
• Placing events in a sequence in which they occurred
• Layers of the Earth
Basics…..
• Law of Superposition • The oldest layers of rock will be on the bottom and the youngest strata or layers will be on top
• Principle of Cross Cutting Relations
• The igneous intrusion that cuts across layers of rock is always younger than the layers it cuts
• Law of Embedded Fragments
• The fossils or fragments of rock that are embedded in a layer are OLDER - because they existed before
• Correlation • The matching of rock layers
• Correlation • The matching of rock layers
• Unconformity • A missing layer in the rock strata
Absolute Time
• Radioactive Decay
• Half-Life
• Radiocarbon Decay – Carbon – 14 dating
• The decay of radioactive isotopes, emitting tiny particles
• The time it takes ½ of a radioactive atoms to decay
• Using the isotope Carbon 14 to date organic material; half life of c-14 is 5,730 years