Paleo Test Review Guide

Hutton’s principal of uniformitarianism states…. Hutton’s principal of uniformitarianism states…. -current geologic processes are the same processes that were at work in the past.

Relative age indicates… Relative age indicates… -one layer of rock is older or younger than another layer. It does not tell an exact numerical age.

The law of superposition states… The law of superposition states… -an undeformed sedimentary rock layer is older than the layers above it and younger than the layers below it.

The principle of original horizontality states… The principle of original horizontality states… -sedimentary rocks left undisturbed will remain in horizontal layers.

A break in the geologic record is an…. A break in the geologic record is an….-unconformity.

Three types of unconformity… Three types of unconformity… -nonconformity, angular unconformity, and a disconformity.

Absolute age is… Absolute age is… -the numerical age of something.

The law of crosscutting relationships states… The law of crosscutting relationships states… -a fault or igneous intrusion is always younger than the rock layers it cuts through.

Four ways to determine absolute age are… Four ways to determine absolute age are… -rates of erosion, rates of deposition, varve count, and radiometric dating.

Radiometric dating is… Radiometric dating is… -using radioactive decay to measure absolute age.

What are isotopes? What are isotopes? -atoms of the same element that have different numbers of neutrons.

What is half-life? What is half-life? -amount of time it takes half the mass of a given amount to decay into its daughter isotopes.

Carbon-14 is an isotope. What is it’s effective dating range? Carbon-14 is an isotope. What is it’s effective dating range? -less than 70,000 years.

The remains of animals or plants that lived in a previous geologic time are called…. The remains of animals or plants that lived in a previous geologic time are called….-fossils

The study of fossils… The study of fossils…-paleontology.

Almost all fossils are found in what type of rock? Almost all fossils are found in what type of rock? -sedimentary rock

What are the five main ways fossils can be formed? What are the five main ways fossils can be formed? -mummification, amber, tar seeps, freezing, and petrification.

The four main types of fossils are… The four main types of fossils are… -imprints, molds & casts, coprolites, gastroliths, and trace fossils.

Index fossils… Index fossils… -occur only in rock layers of a particular geologic age. Can be used to estimate absolute ages of specific rock layers.

What is a geologic column? What is a geologic column? -represents a timeline of Earth’s history. The oldest rocks are at the bottom and the youngest are towards the top.

What are the four main eras? What are the four main eras? -precambrian, paleozoic, mesozoic, cenozoic

The Devonian Period is best known as… The Devonian Period is best known as… -The Age of the Fishes!

What is the leading theory on how the dino’s became extinct? What is the leading theory on how the dino’s became extinct? -meteorite impact hypothesis.

What era is considered the Age of the Mammals? What era is considered the Age of the Mammals? -Cenozoic Era

What are the most common types of fossils you would expect to find dating back to Precambrian Time? What are the most common types of fossils you would expect to find dating back to Precambrian Time?-stromatolites

What are the three periods of the Mesozoic Era? What are the three periods of the Mesozoic Era? -Triassic, Jurassic, and the Cretaceous

The largest unit of geologic time is called… The largest unit of geologic time is called… -an Eon.

The gradual development of new organisms from preexisting organisms is called? The gradual development of new organisms from preexisting organisms is called?-evolution

Large areas of exposed Precambrian rocks found on every continent are called… Large areas of exposed Precambrian rocks found on every continent are called…-shields

Coal deposits found in Pennsylvania, Ohio, and West Virginia can be linked to what period? Coal deposits found in Pennsylvania, Ohio, and West Virginia can be linked to what period? -Carboniferous Period

When and what caused the Appalachian Mountains to form? When and what caused the Appalachian Mountains to form? -End of the Permian period (Paleozoic Era), the collision of the continents forming into Pangea.

The Mesozoic Era is also known as the… The Mesozoic Era is also known as the… -Age of Reptiles

The Cenozoic Era is also called the… The Cenozoic Era is also called the… -Age of Mammals

What mountain ranges were created in the Cenozoic Era? What mountain ranges were created in the Cenozoic Era? -Alps, Himilayas

Mountain ranges created in the Mesozoic Era include… Mountain ranges created in the Mesozoic Era include… -Sierra Nevada’s and the Andes

A decrease in temperatures during the Cenozoic Era resulted in… A decrease in temperatures during the Cenozoic Era resulted in… -new species of animals being developed.

Explain the concept of evolution as brought on by geologic change. Explain the concept of evolution as brought on by geologic change. -figure this one out on your own!

What period and era mark the end of the dino’s? What period and era mark the end of the dino’s? -end of the Cretaceous period, Mesozoic Era.

What method of dating seems to be the most accurate? What method of dating seems to be the most accurate? -radiometric dating.