The Earth's Geologic Events

What Does the Timeline Really Look Like? Plotting Geologic Events on a Timeline

Purpose

In this activity, you will gain an appreciation for the span of geologic time and the relative recency of most of the earth's major historical events.

Introduction

Many people, not just students, have difficulty grasping the magnitude of the time that has passed since the Earth formed. It is also a common misconception that major biological and geological events occurred at regular intervals over this long time period. This is often because of the way the geologic time periods are depicted on charts such as the one below. This exercise illustrates when major events occurred relative to each other, the long periods of "quiet" between these events and the relative quiescence of the first 4 billion years of Earth's history.

Supplies

Graph paper
Tape
Pencils with erasers
Calculator

PART 1

Instructions

In this activity you will use 100 consecutive squares on graph paper to plot several geologic events. (GRID SIZE OF GRAPH PAPER IS OF YOUR OWN CHOOSING - WORKS WITH ALL SIZES AS LONG AS YOU HAVE ONE HUNDRED SQUARES IN A ROW TO WORK WITH.) You may need to tape more than one sheet of graph paper end-to-end to get 100 squares in a row.

1. Draw a straight line under 100 consecutive squares on the graph paper.

2. Above the line, place arrows pointing to the spot on the line that you think corresponds to the location of the time period of the mentioned activity.

Earth and Moon form

Oceans form

Hydrologic (water) cycle begins (weathering and erosion started then)

Grenville Orogeny (formation of the Green Mountains in VT)

Massabesic Gneiss

Simple sea life

Bronson Hill Anticline (first collision and folding that created New Hampshire's first 'land')

Concord Granite injected & cooled

Mt Washington/Chocorua/Monadnock rocks formed

Ossipee ring dike & dinosaurs

Dinosaurs extinct

PART 2:

1. For background information, Geologic Time (the total age of the Earth) is 4.6 Billion years.

2. Calculate the value of one square in years.

3. Now plot the location of the following events by placing arrows below the line pointing to the spot on the line that you think corresponds to the location of the time period of thementioned activity. (Times are given in billions (bya) or millions (mya) of years before the present. Therefore, you will be measuring back from the present each time you plot a point.)