Geology Final Questions (175)

A "Rock" is best defined as:

An aggregate (mixture) of one or more minerals or organic solids

"Lithostratigraphy" correlates rocks based on their:

Physical and chemical characteristics (Rock type)

A "periodic" process is one that:

Repeats at regular, predictable intervals

A "Hiatus" in stratigraphy refers to:

The interval of time not represented by strata (the missing time at an unconformity)

The basic fundamental unit of Lithostratigraphy (rock mapping) is the:

Formation

Which 17th-century Archbishop famously calculated the age of the Earth based on Biblical genealogy?

James Ussher

Modern science seeks to explain natural phenomena in terms of:

Natural terms and processes

Which rock type gives us the most information about past surface environments?

Sedimentary

If a geologic process is "episodic," it means:

It happens rarely and at irregular intervals (like a hurricane)

Which cooling history results in a "glassy" texture, such as Obsidian?

Instantaneous cooling (quenching)

What is a "Protolith"?

The parent rock before it was metamorphosed

Modern Geology is often described as a synthesis of:

Uniformitarianism and Catastrophism

What defines "Historical Science" (like Geology) as opposed to "Experimental Science"?

It relies on observation and interpreting past clues rather than controlled lab experiments

What is the currently accepted age of the Earth?

4.56 billion years

If the ratio of Parent to Daughter atoms is 1:1, how many half-lives have passed?

1

If a half-life is 10 million years and the rock is 30 million years old, how many half-lives passed?

3

How much Parent is left after TWO (2) half-lives?

25%

What is the definition of a "Half-Life"?

The time it takes for 50% of parent isotopes to decay into daughter isotopes

Which of the following is NOT part of the definition of a mineral?

Organic

Which physical property is often the LEAST reliable for identifying minerals?

Color

"Felsic" minerals (like Quartz and Feldspar) are characterized by being:

High in Silica, light colored, and lower density

Which mineral group makes up over 90% of the Earth's crust?

Silicates

Sedimentary rocks form through a process called:

Lithification (or Diagenesis)

A sedimentary rock made of rounded pebbles cemented together is called:

Conglomerate

Coal is considered a _______ sedimentary rock.

Biogenic (Organic)

When Sandstone is metamorphosed, it transforms into:

Quartzite

Which pair matches the Intrusive rock with its Extrusive equivalent?

Granite & Rhyolite

What is the difference between "Magma" and "Lava"?

Magma is underground; Lava is on the surface

An "Unconformity" represents:

A gap in the geologic record caused by erosion or non-deposition

Who formulated Superposition, Original Horizontality, and Lateral Continuity?

Nicolas Steno

Which is NOT a characteristic of a good "Index Fossil"?

It lived for a very long period of geologic time (Long range)

In scientific terminology, what is a "Theory"?

A robust explanation supported by a large body of tested evidence

Magnetic patterns are symmetric about mid-ocean ridges because:

New crust forms and spreads equally in both directions, recording the magnetic field

Finding Devonian coral fossils in Canada is evidence that:

Canada was once located between 0° and 30° latitude

Subduction is the process by which:

Oceanic crust is pushed back into the mantle at deep-sea trenches

The term 'magnetostratigraphy' refers to:

Stratigraphic changes in the polarity of rock strata

Who formulated the concept of continental drift?

Alfred Wegener

When igneous rocks cool, iron-bearing minerals:

Align with the Earth's magnetic field

What is paleomagnetism?

The study of the magnetic properties preserved in rocks

Finding Glossopteris fossils in Antarctica suggests:

Antarctica was once located at a lower latitude with a milder climate

The maximum thickness of sediments on the deep-sea floor is approximately:

1.3 kilometers

Guyots (seamounts) are best described as:

Flat-topped, isolated underwater volcanic mountains

Why is oceanic crust much younger than continental crust?

Oceanic crust is destroyed at subduction zones and recycled

Why are apparent polar wander paths from North America and Europe different?

The two continents have moved relative to each other over time

Paleomagnetism cannot determine:

Longitude

During a regression, a vertical stratigraphic sequence shows:

Shallowing-upward facies: limestone > shale > sandstone

The three broad categories of sedimentary environments are:

Continental, transitional, and marine

Which is a transitional depositional environment?

Delta

Glacial deposits are typically characterized by:

A poorly sorted mixture of boulders, pebbles, sands, and mud

In shallow marine environments, which factor is more important than tidal action?

Wave action

Graded bedding in a Bouma sequence (fining upward) is caused by:

Larger, heavier grains settling out first as flow energy decreases

Cross-bedded sandstone is most likely deposited in:

Eolian (wind-blown desert) dune field

Beach-barrier island deposits are characterized by:

Clean, well-sorted sand deposited by waves and longshore currents

A large clast embedded in fine-grained laminated sediment is a:

Dropstone (released from a melting iceberg/glacier)

In a meandering river, the vertical facies sequence from bottom to top is:

Channel ss > point bar ss > levee ss > floodplain shales

A 'sedimentary facies' is:

A body of rock with characteristics recognizable of a specific depositional environment

Continental crust differs from oceanic crust in that it is:

Less dense, thicker, and composed of felsic rock

The asthenosphere is:

The part of the upper mantle that behaves plastically

Ridge push occurs when:

Ascending magma and heat at mid-ocean ridges pushes the lithosphere up and outward

The Taconic Orogeny was caused by:

The collision of Laurentia with an island arc

The Acadian Orogeny resulted from the collision of Laurentia with:

Baltica (forming the Old Red Sandstone continent)

The East African Rift Valley is an example of:

A divergent boundary in the early stages of formation

The bimodal distribution of Earth's elevations is explained by:

Isostasy (differences in density and thickness)

How many major lithospheric plates does the Earth have?

8 to 9

Red beds first appeared ~1.8 Ga because:

Iron was oxidized to ferric oxides (Fe3+)

The mid-continent rift (~1.2 Ga) in North America:

Nearly tore the craton apart but stopped before an ocean basin formed

The Miller-Urey experiment (1953) demonstrated:

Amino acids could be produced under conditions simulating the early atmosphere

The Canadian Shield is significant because it is:

The largest Precambrian shield on Earth

Albedo is:

The amount of solar radiation reflected from the Earth's surface

Chloroplasts originated from:

A cyanobacterium consumed by a larger cell

The faint young Sun paradox is the problem that:

The early Sun's output was only 70%, which should have been too low for liquid water

Red tides are caused by:

Mass blooms of dinoflagellates

Chemical weathering of rocks removes CO2 by forming:

Carbonic acid (H2CO3)

During the Boring Billion, there was:

Relatively stable fossil diversity and no major carbon cycle perturbations

Molecular clock models estimate divergence times by:

Using the mutation rate of genes

A negative feedback in the carbon cycle:

Acts to slow or counteract a change

Carbon isotope fluctuations at 2.3-1.8 Ga reflect:

Changes in organic carbon burial rates

When organic carbon is buried, the ocean and atmosphere become:

Enriched in 13C

The ice-weathering negative feedback helps end glaciation because:

Glaciers decrease weathering, allowing CO2 to build up and warm the climate

Black shales form when:

Organic matter-rich muds accumulate under anoxic conditions

Biomarkers are useful because they:

Can identify specific groups of organisms through preserved organic compounds

Fossils are important for biostratigraphy because:

They provide a means of telling relative time

The first animal trace fossils appear approximately:

560 million years ago

The plant Glossopteris helped reconstruct:

The supercontinent Pangaea

Trace fossils include all EXCEPT:

Petrified wood

Non-vascular plants (bryophytes) include:

Mosses and liverworts

Dinoflagellates are important because:

About half are photosynthetic primary producers

Fungi are primarily:

Decomposers

When did angiosperms first appear and become dominant?

Early Cretaceous (dominant ever since)

Early Earth's atmosphere was produced primarily by:

Volcanic degassing

The Snowball Earth hypothesis proposes:

Most of the world was covered in ice, including the equator

The Great Oxidation Event began approximately:

2.5 billion years ago

How did the planet escape Snowball Earth?

Volcanic CO2 accumulated, enhancing the greenhouse effect

Multicellularity likely began with:

Cells first living colonially

Archaea differ from Bacteria primarily in:

Genes for certain enzymes and ester lipids in cell walls

Which scientist influenced Darwin regarding uniformitarianism?

Lyell

The abrupt appearance of most major animal phyla in the Cambrian is the:

Cambrian Explosion

"Small Shelly Fossils" (SSFs) are:

Tiny skeletal elements that cannot be assigned to living phyla

Most Cambrian animals were:

Benthic marine organisms

Trilobites are index fossils for the ______ and went extinct at the end of the ______.

Cambrian; Permian