Exam 19: Precambrian Earth and Life History

The rapid rate of plate motion was probably the most important factor in rapid continental growth in the Late Archean.

The Precambrian history of Earth is difficult to determine for all but which of the following reasons?

What are two examples that demonstrate the difficulty of adopting absolute minimal criteria for deciding whether or not something is alive?

Ophiolites are abundant in Archean age rock sequences.

The presence of thick sections of carbonate and sandstone indicates that Archean continents had well-developed shelf environments.

What two processes,which began during the Archean,can account for the introduction of free oxygen into the atmosphere?

Most of the Precambrian is divided into the following two eons _______ and _______,with the earlier part of the time interval being the _______.

What are banded iron formations composed mainly of?

Continents are cored by large areas of exposed ancient rocks called ____________________,which are tectonically ____________________ regions.

Rocks associated with the Wopmay orogen document the oldest complete Wilson cycle.

Sandstone-carbonate-shale assemblages occur along continental rift margins and intracratonic basins.

The Grenville orogeny occurred between ______ to ______ billion years ago

Material such as chitin may have formed semi-durable chitinous exoskeletons.

Sandstone-carbonate-shale assemblages are restricted to the Proterozoic.

The earliest atmosphere of Earth was ____.

Sandstone-carbonate-shale assemblages comprise ______ percent of the Proterozoic rock record and indicate ____________________ tectonics.

During the Archean,how long was the length of a day on Earth?

Besides the origin of life itself,what was the most significant biological event of the Archean?

What are small molecules composed of multiple amino acids called?

The rate of plate motion was probably slower in the Archean.