Exam 19: Precambrian Earth and Life History

The oldest well-documented stromatolites occur in the ____.

What are the two major rock types that characterize Archean shield areas?

Glacial deposits, as well as striated and polished bedrock, indicate that two major episodes of glaciation took place during the _______________.

The large Proterozoic landmass known as Laurentia was composed of ____.

The increase in atmospheric oxygen during the Proterozoic was most related to the ____.

What are prokaryotic organisms?

Briefly explain the difference between the tectonic setting of shield areas during the Precambrian and since the onset of the Phanerozoic.

Earth differentiated during the ____.

Time divisions in the Precambrian are based on ____.

The Precambrian comprises what percent of geologic time?

Some Paleoproterozoic-age rocks and associated features provide excellent evidence for widespread glaciation.

The oldest eukaryotes in the fossil record are at least how old?

The assemblage of sandstone-carbonate-shale is probably indicative of ____________________ (in depth)water shelf environment.

Modern eukaryotic cells that contain organelles and mitochondria support the theory of endosymbiosis.

Before Earth had a differentiated core, the solar wind would have stripped any gases from the surface because of the lack of a(n)_____.

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

The oldest rocks (not minerals)on Earth are_____ old.

Between 1.3 and 1.0 billion years ago, the Grenville orogeny occurred in the supercontinent __________.

Archean and Proterozoic greenstone belts formed in similar tectonic settings.

Archean rocks in South Africa have yielded more than 50% of the world's ____ since 1886.