Geoscience midterm

What defines a natural disaster according to the lecture notes?

an event like a landslide striking a city.

Which culture recorded the earliest writings on fossils, earthquakes, and gemstones?

Ancient Greece.

What is an example of a non-geologic hazard according to the lecture?

A) use of poor construction materials resulting in a cracked foundation

B) volcanic eruptions Sending lava flows toward a city

C) a volcano erupting occurring in the desert

Use of poor construction materials resulting in a cracked foundation.

states that processes shaping Earth today have also operated in the past

Uniformitarianism.

the accepted age of the Earth?

4.6 billion years.

scientific hypothesis

A tentative explanation used to explain observed activities.

percentage of the Earth is covered by oceans

71%.

What role does the atmosphere NOT play according to the lecture?

Lessening the effects of weathering on the geosphere.

Which sphere of Earth is the most extensive?

Geosphere.

What is the accepted age of the universe's formation?

13.7 billion years.

From what elements was the debris of the Big Bang primarily made?

Hydrogen and helium.

Which Earth materials help in interpreting the Earth's interior?

Meteorites, kimberlite pipes, and slivers of crustal and mantle rocks.

What is planetary differentiation?

Separation of materials based on density.

What is the age of the oldest radiometrically dated rocks on Earth?

4 billion years.

What allowed the crust to form as the exterior of Earth?

Materials that make up the crust are less dense and rose to the top.

What provides the most information about the Earth's interior?

Seismic energy waves.

Why is the inner core solid despite the high temperature?

The immense pressures in the core keep it in a solid state.

Which layer of the Earth is the thinnest?

Crust.

Which layer of the Earth is the thickest?

Mantle.

What is the asthenosphere?

A soft, low-velocity layer in the upper mantle.

What generates the Earth's magnetic field?

The outer core.

What defines the texture of a rock?

The size, shape, and/or arrangement of minerals in a rock.

What process converts sediments into rock?

Lithification.

Which characteristics are used to determine the processes that created a rock?

Texture and composition.

What is an example of an alternative transition in the rock cycle?

Sedimentary rocks weather into sediments, which become lithified into sedimentary rocks.

Where are the youngest mountain ranges found today?

The circum-Pacific belt and southern Europe/Asia.

What is a platform in geology?

A part of the craton covered by a thin layer of sedimentary rocks.

What is the density and rock type of continents?

2.7 g/cm³ and granite.

What is the density and rock type of ocean basins?

3.0 g/cm³ and basalt.

Which rock is the most buoyant on the Earth's mantle?

Rock A.

What is the term for a flooded margin of the continent?

Continental shelf.

Where might one expect to see a deep-ocean trench?

Mountain ranges.

What describes Earth's origins through time?

Historical geology.

What is the composition of the crust predominantly made of?

Granite.

What is the primary source for most volcanism?

Rift zones.

In what environment are most sedimentary rocks formed?

In bodies of water.

Which rocks are likely to experience brittle deformation?

Quartzite.

How is seismic energy released during an earthquake?

P waves are released first.