Vocabulary
The age of a rock compared to other rocks.
relative age.
When you visit Panited Dersert in Arizona what color rocks you see.
Grey, red, green, blue, and even purple.
Eras are subdivided into units of geologic time called ------.
Periods
Geoligists study what.
Rock layers, and fossils
What year was volleybal invented.
The age of rock given as the years sinced the rock formed.
Absolute Age
Sedimentary rocks usually form in ---------- layer.
Horizontal
Geologists time begins with a long span of time called Precambrian. What percent does time cover the Earth.
88 Percent
Mass extinction killls most species, what era was this.
The Permian.
when was track started in.
In Greece 776 BCE
The preserved remains or traces of an organism thet lived in the past.
fossil
Geologists use -------- what dating.
Radioactive
Scientists frist developed the geologic time scale by studying rock layers and ---------- --------.
index fossils
What era was the frist brids evolve.
The Jurassic
When was goat show invented.
Early 1900
Era
What is a extrusion.
It is a younger rock that covers it.
Scientists placed rocks by -------------.
Relative age
Scientists hypothesize that the mass extinction occurred when the -------- struck Earth.
Asteroid
When was 4-H founded.
1902
The geologic principle that states that in horizoltal layers of sedimentary rock each layer is older than the layer above it.
law of superpostion
Scientists use the half-life ratio to calculate the age of the ----.
Rock
What does Mesozic Era mean.
It mean middle.
What is a amphibian.
It is an animal that lives on land and water.
When was basketball invented.
December 21, 1891