Ages of Rocks
The number of years since the rock formed--radioactive dating used to determine it.
What is Absolute age of rock?
Fossils in minerals replace all or part of an organism.
What is petrified fossils?
This period is considered the " Age of Humans".
What is the Quaternary period?
Lava that hardens on the surface. Rock layers below are always older.
What are Extrusions?
What is 4.6 Billion years old?
What is Relative age of rock?
What is a carbon film?
This Era is the "Age of Reptiles".
What is the Mesozoic Era?
What is intrusion?
During this period mass extinction occurred. 90% of Ocean and 70% of land species died out.
What is the Permian period?
This Law states that in horizontal sedimentary rock layers, the oldest layer is at the bottom and each layer above is younger than the layer under it.
What is Law of Superposition?
Provides evidence of the activities of ancient organisms.
What are trace fossils?
This era is the "Age of Marine life".
What is tthe Paleozoic Era?
Scientist that study, collect and classify fossils.
Who are Palenontologist?
Hollow area in the sediment which shows the shape of an organism or part of one.
What is a mold?
Gaps in the geologic record where some rock layers have been lost because of erosion.
What is Uncomformity?
This time covers about 88% of Earth's history.
What is the Precambrian Time?
This Era was the "Age of Mammals".
What is the Cenozoic Era?
The time between Precambrian and present, Include Paleozoic, Mesozoic, and Cenozoic______.
What are Eras?
This Period had flowering plants and reptiles. At the end of this period another mass extinction. Wiped out dinosaurs and half of the plants and animal species.
What is the Cretaceous Period?
Finding certain fossils in different layers can tell scientists the relative ages of the rock layer in which they occur.
What are index fossils?
Eras are divided into these.
What are periods?
In what Era was the Triassic and Jurassic Period when it was the age of Reptiles and Dinosaurs.
What is the Mesozoic Era>
A solid copy of the shape of an organism, usually mineral or compacted sediment.
Wha is a cast?
The period when earth cools, mammals widespread, whales and dolphins evolve. Big Ice Age.
What is the Neogene Period?