Geol 106 exam 2 practice

What was Hutton's interpretation of the Siccar Point rocks?

Hutton's interpretation of the Siccar Point rocks was that they provided evidence for deep time, showing that Earth had undergone immense geological changes over long periods.

4.5 billion years ago, Earth's surface was a molten ocean.

a. True b. False

True

The rounded pillow of the rock in Barberton Hill (South Africa) is the result of

formed under water in an ocean approximately 3.5 billion years

__________

ago

pillow lava

Crystals of

_______________

survive from the earliest stages of Earth?

zircon

Primitive meteorites contain water.

True or False

True

500 Ma since Earth's birth, our planet's surface was mostly composed of

rocks.

True or False

. False

The Archean atmosphere can best be described as ____.

a. Oxygen-rich

b. Nitrogen-rich

c. Ozone-rich

d. Oxygen-deficient

d. Oxygen-deficient – The Archean atmosphere lacked oxygen and was mostly composed of gases like methane, carbon dioxide, and nitrogen.

3.5 billion years ago, granite was dominating on Earth's surface

True or false

False

Which rock is lighter, basalt or granite?

Granite is lighter than basalt because it has a lower density and is more silica-rich.

Why were stromatolites essential in shaping Earth's atmosphere?

Stromatolites were essential in shaping Earth’s atmosphere because they were among the first life forms to perform photosynthesis, releasing oxygen and contributing to the gradual oxygenation of the atmosphere.

Why did the oceans change from green to blue?

The oceans changed from green to blue because oxygen produced by photosynthetic microorganisms reacted with dissolved iron in the water, causing iron to precipitate out as iron oxide. This removed the greenish hue (caused by iron) and made the water clearer and bluer.

Iron-rich sediment layers were deposited in the ancient ocean seafloor.

true or false

True

The expansion of the continents stopped 1.5 billion years ago.

True

The USA and Canada formed the heart of Rodinia, 1 billion years ago.

True

What split Rodinia apart?

a. Marine microorganisms

b. Volcanic eruptions!!!!!

c. A meteor impact

b. Volcanic eruptions

What are heterotrophic organisms?

Heterotrophic organisms are organisms that cannot produce their own food and must obtain nutrients by consuming other organisms.

What are prokaryotic organisms?

Prokaryotic organisms are single-celled organisms that lack a nucleus and membrane-bound organelles

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

Granite-Gneiss Complexes and Greenstone Belts

What does the appearance of red beds in the geologic record indicate about the atmosphere?

The appearance of red beds in the geologic record indicates that the Earth's atmosphere had become rich in oxygen.

A complete _____ involves rifting of a continent and the opening of an ocean basin with passive continental margins on both sides.

Wilson cycle

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

magnetosphere

Before the appearance of cells capable of sexual reproduction, ____.

evolution was comparatively slow

Besides iron, banded iron formations contain

chert

By ____ years ago, much of Greenland, central Canada, and the north central United States formed one large craton.

1.8 billion

Earth differentiated during the ____.

Hadean

Granite-gneiss complexes are typical in what age of rocks?

Archean

Organisms are composed of many elements. Which is the least abundant of these?

calcium

Shield areas of continents are found in modern ____.

tectonically inactive regions

The Archean atmosphere can best be described as ____.

oxygen-deficient

The earliest atmosphere of Earth was ____.

blown into space by solar wind

The Ediacaran fauna include representatives of the modern phyla ____.

Annelida, Arthropoda, and Cnidaria

The exposed part of the North American craton is the ____.

Canadian shield

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

process of photosynthesis by bacteria

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

North America, Greenland, NW Scotland, and the Baltic Shield

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

2.0 billion years old

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

4.0 billion years

The oldest well-documented stromatolites occur in the ____.

Archean

The Precambrian comprises what percent of geologic time?

88 percent

The prevailing model for the formation of greenstone beds in the Archean is ____.

the closing of a back-arc basin

Time divisions in the Precambrian are based on ____.

absolute dates

What are small molecules composed of multiple amino acids called?

proteinoids

What term describes molecules that are intermediate between inorganic compounds and living organisms?

protobionts

_______ is an informal term that encompasses all geologic time from 4.6 to 4.0 billion years ago.

Hadean

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

Rodinia

Continental growth during the Early Proterozoic development of Laurentia was related to____ of Archean age cratons.

accretion

Continents are cored by large areas of exposed ancient rocks called_____ which are tectonically inactive regions.

cratons

Early gases that had begun to accumulate around Earth during the Early Archean were lost because of a lack of a(n)_________

magnetosphere

Early organisms played a role in the accumulation of free oxygen through the process of__________

photosynthesis

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

Proterozoic

Sandstone-carbonate-shale assemblages were deposited along_______continental margins during the Proterozoic.

passive

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

shallow

All known Proterozoic animals were soft-bodied.

True or False

True

Archean and Proterozoic greenstone belts formed in similar tectonic settings. True or False

true

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

True or False

true

Organisms are composed of simple monomers.

True or False

false

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

True or False

true