Earth History

Question 1

Continental crust

Answer 1

Composed of variety of rock types
Much thicker
Lower density (2.7g/cm^3)
Silica-rich rocks such as granite

Question 2

Supercontinents

Answer 2

Large landmasses that contain all or nearly all of the existing continents
Pangaea most recent

Question 3

Rodinia

Answer 3

Earliest well documented supercontinent formed during Proterozoic eon

Question 4

Gondwana

Answer 4

By end of Precambrian many fragments of rodinia reassembled to produce large landmass located in Southern Hemisphere. Sometimes considered a supercontinent.

Question 5

Formation of Pangaea

Answer 5

During Paleozoic era
Collisions of N.America, Europe, Siberia + other smaller crystal fragments forming s larger northern continent called Laurasia
Gondwana migrated northward and collided with Laurasia to form Pangaea

Question 6

Stromatolites

Answer 6

Limestone mats built by lime accretions bacteria

Question 7

Cambrian explosion

Answer 7

Huge expansion in biodiversity during beginning of Paleozoic era, Cambrian period

Question 8

Oceanic crust

Answer 8

Dense (3.0g/cm^3)
Homogenous layer of basaltic rocks derived from partial melting of the rocky, upper mantle
Thin

Question 9

Cratons

Answer 9

Thin crustal fragments collide and accrete to form larger crustal provinces which assemble into larger blocks called cratons. Core of modern continent and mostly formed during Precambrian