Exam 19: Precambrian Earth and Life History

The increase in atmospheric oxygen during the Proterozoic was related to what?

Early organisms played a role in the accumulation of free oxygen through the process of ____________________,which combines carbon dioxide and ____________________ to make organic molecules,and ____________________ is given off as waste.

How did Laurentia evolve?

The iron in banded iron formations was primarily in which iron-bearing minerals?

The oldest stromatolites are 4.1 billion years old.

Shield areas of continents are found in modern ____.

The heat reservoir of the early history of Earth was generated by all but which of the following?

Stromatolites are the first life form with skeletal structure.

The transition from single to multi-celled organisms may have started with cell colonies.

What are the three major units found in greenstone belts from bottom to top,and what type dominates the lower two-thirds? In the upper third?

Both the presence of banded iron formations and red beds are evidence that the atmosphere and hydrosphere changed from oxidizing to reducing in the Proterozoic.

The ____________________ orogen is the earliest that documents a complete ____________________ cycle of opening and closing ocean basins.

What factor(s)led to the enormous scale of banded iron deposition during the Proterozoic?

Proterozoic layered igneous intrusions are the world's major source of chrome and platinum.

Subunits within the shield are delineated by radiometric ages and structural trends.

Most of the volcanism associated with greenstone belts was ____.

The Grenville orogeny was the culminating event of the amalgamation of Laurentia.

The Sudbury Basin was the site of two meteorite impacts that occurred at roughly the same time.

The Ediacaran fauna include representatives of the modern phyla ____.

The formation of the Midcontinent rift was ____________________ in time with the Grenville orogeny.