Stage (geology)

High school (ages 12+)
Environment & Earth

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/stage-geology

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the correlation methods?Biostratigraphy (using index fossils) and geochronology (radiometric dating)
2. What is the paleogeographic reconstruction?Inferred from lithofacies, sedimentary structures, and fossil assemblages within stages
3. What is a geological stage?A stage is a formal unit of rock that was formed during a specific time interval in Earth's history. It is like a chapter in a giant book of Earth’s past, helping geologists organize and talk about the planet’s history.
4. How do scientists know when a stage starts or ends?Scientists mark the start or end of a stage with a special spot in a rock called a boundary stratotype or golden spike. This point shows a clear change in the rock or fossils that marks a new time period.

Chronostratigraphy: The branch of stratigraphy concerned with the age of rock strata and their relationship to time.
Lithofacies: The physical characteristics of a rock unit, such as its composition, texture, and sedimentary structures.
Index Fossil: A fossil from a specific geologic time period used to date and correlate rock layers.
Radiometric Dating: A method of dating geological materials by measuring the decay rate of radioactive isotopes.