Chapter 22

Question 1

Zircon

Answer 1

A very stable material that commonly occurs (in small amounts) in granite.

Question 2

Asteroid

Answer 2

Metallic or silica rich object 1 to 950 km in diameter

Question 3

Meteorites

Answer 3

Small asteroid or fragment of asteroid that fell to

Earth

Question 4

Differentiation

Answer 4

When heavy materials sink towards the center of a planet and lighter ones go towards the surface

Question 5

Precambrian shield

Answer 5

A core of Archean and Proterozoic rocks in today’s continents

Question 6

Canadian shield

Answer 6

A Precambrian shield that is in North America. Much of it is exposed in Canada hence the name

Question 7

Microcontinent

Answer 7

A small piece of continental crust

Question 8

Laurentia

Answer 8

Ancient continent that was fully formed 1.8’billion years ago. Assembled from the core of modern day North America.

Question 9

Cyanobacteria

Answer 9

Tiny threadlike chlorophyll have filaments of this

Question 10

Stromatolites

Answer 10

Large mats or mounds of Cyanobacteria

Question 11

Banded iron formations

Answer 11

Deposits which are alternating bands of chert and iron oxides. Formed by locally high concentrations of oxygen in seawater

Question 12

Red bed

Answer 12

Sedimentary rock that is younger than 1.8 billion years and are rusty red in color

Question 13

Amino acids

Answer 13

Building blocks of proteins

Question 14

Hydrothermal vent

Answer 14

Hot water vent that is on the ocean floor. All nutrients and energy necessary for life is present here

Question 15

Prokaryote

Answer 15

Organism composed of a single cell

Question 16

Eukaryote

Answer 16

Organism composed of cells that contain nucleus.

Question 17

Varangian glaciation

Answer 17

Glaciation 800-700 million years ago that led to extinction of a group of possible eukaryotes, the acritarchs

Question 18

Ediacara fauna

Answer 18

Fossils of soft bodied organisms, found in the ediacara hills of southern Australia