Geog 1710 chapter 9-10

magnetic reversal

1.2 million years ago - normal .8 million- reversed .4 Million- normal

Core Volume

1/6 of earths volume

How old is the Earth?

4.6 billion years old

How old is the solar system?

4.6 billion years old

The oceanic crust thickness is about _______, and the average continental crust thickness is ______km.

5 30

Curie point

575 C

Minerals

A mineral is an inorganic (nonliving) natural compound having a specific chemical formula and possessing a crystalline structure

Rock

A rock is an assemblage of minerals bound together, or a mass of a single mineral, or undifferentiated material, or even solid organic material (such as coal)

the inner temperature at the Asthenosphere upper mantle lower mantle outer core

Asthenosphere-400 C upper mantle- 900 C lower mantle -900-4,000 C outer core 4,000- 5,000 C

The youngest epoch in the geologic time scale is

Holocene

three cycles (subsystems)

Hydrologic cycle: transportation and deposition of materials by media powered by solar energyRock cycle: formation of three types of rockTectonic cycle : transportation of heat energy and new materials to the surface

Alfred Wegner

In Origin of Continents and Oceans. Wegener set forth his hypothesis of continental drift in 1915

The principle of buoyancy and balance, when applied to Earth's crust, helps us to explain fluctuations in Earth's outer crust, a property known as

Isostatic adjustment

Which of the following is NOT true of the asthenosphere?

It is beneath the upper mantle.

Two most abundant chemical elements in Earth's crust are

Oxygen silicon

Wegener used ________to name a supercontinent approximately 225 million years ago.

Pangaea

Principle of Superposition

Rock and sediment always are arranged with the youngest bed "superposed"toward the top of a rock formation and the oldest at the base, if there have not been disturbed.

Which of the following is not an example of an age-relationship based on absolute dating?

The Coconino formation in the Grand Canyon is older than the Kaibab formation.

earths magnetism

The fluid outer core generates 90% of Earth's magnetic field, because it is made of liquid molten metallic iron.• Migration of the north magnetic pole (NMP): NMP in 2016 was at 86.4oN,166.3oW.• Magnetic poles and geographic poles are different!

Which of the following statements about Earth's core is not true?

The inner core is believed to be liquid and the outer core solid.

how do we know earths age?

Two facts: -The oldest rock on Earth is about 4.0 billion years old. -The oldest fossil on Earth is about 3.5 billion years old.

How do we know the history of the geomagnetic reversal?

We can see this in the magnetic patterns found in volcanic rocks, especially those recovered from the ocean floors. (googled)

radiometric dating

a method of dating geological or archeological specimens by determining the relative proportions of particular radioactive isotopes present in a sample. (googled)

periodic table

a tabular display of the chemical elements. -look up image

how old is the moon

about the same age as Earth

There are two types of time, which are

absolute and relative

At which of the following locations does subduction occur?

along collision zones between continental and oceanic plates

Convergent plates boundaries are characteristics of

collision zones between plates

Which of the following gives the correct sequence of layers in the Earth, from the surface to the center?

crust, asthenosphere, lower mantle, core

List three types of plate boundaries: ________boundary, ________boundary, and __________ boundary.

divergent convergent transform

Which of the following lists the correct sequence of divisions in the geologic time scale, from largest to smallest?

eon, era, period, epoch

what are exogenic systems

external processes that set into motion air, water, and ice, all powered by solar energy

Since the core's mass is about one third of Earth's entire mass, the volume of the core is also of one third of the Earth's entire volume.

false

The density of material below the Moho is less than that above it.

false

The oceanic crust is less dense than the continental crust.

false

Earth's Interior Density

gets more dense as it gets closer to the inner core

The decay rate is expressed as _______the time required for one half of the unstable atoms in a sample to decay into "daughter" isotopes.

half life

The transportation and deposition of materials by media powered by solar energy is the

hydrologic cycle

Three basic rock types are _________(fire-formed, molten), ________(from settling out), and _________(transformed from any other rock through extreme heat or pressure).

igneous sedimentary metamorphic

Knowledge of Earth's interior is derived from

indirect evidence involving the analysis of seismic waves

what are endogenic systems

internal processes that produce flows of heat and material from deep below Earth's crust

Earth's magnetic field

remain a mystery as to its cause

Several large, linear lakes are formed in East Africa. This is evidence of what process?

rifting

Divergent plate boundaries are characteristics of

sea-floor spreading centers

The Earth's dominant materials are

silica and iron

When geologists or archaeologists dig downward into a unit of rock or sediment, they are digging "back in time". This fact is based on the principle of_________.

superposition

Heat energy and new materials are brought to the surface from the interior by the

tectonic cycle

What is radioactivity?

the emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei. (googled)

daughter isotope

the stable isotope produced by the radioactive decay of the parent isotope. it

What is a half-life?

the time taken for the radioactivity of a specified isotope to fall to half its original value(daughter isotope)

Depth of earthquake focus increases with increasing distance from ocean trench.

true

Earth was once in a molten state, during which materials became sorted based on density.

true

Ocean floor subducts under continents because the ocean floor is denser than continental material.

true

The Hawaiian Islands were formed as a result of a rising plume of magma from the mantle.

true

The Moho mirrors the surface topography, i.e., high places on the surface of the Earth overlies areas in which the Moho descends to greater depths, and vice versa.

true

The age of the sea floor increases with increasing distance from a mid-ocean ridge.

true

The fluid outer core generates 90% of Earth's magnetic field.

true

The magnetic stripes found around mid-Atlantic ridge were due to the magnetic reversal.

true

Uniformitarianism assumes that the same physical processes we see today are a key to understand the processes that have been operating throughout the geologic time.

true

Which of the following gives the correct sequence of layers in the mantle, from bottom to top?

upper mantle, asthenosphere, lower mantle

Which of the following is an endogenic process?

volcanism

Which of the following is an exogenic process?

weathering

Earth's mantle

•Average depth is about 2900 km. •Two parts: lower mantle and upper mantle•Consists of 80% Earth's total volume•Average density is 4.5g/cm3.•The boundary between the uppermost mantle and the crust above is called the Mohorovicicdiscontinuity, or Moho.

Wegener's Four Evidences

•Coastal lines •Fossils •Rock types and mountain belts •Ancient climates

seismic waves

•Seismic waves travel at a higher speed in the cooler and more rigid areas than in the hotter and softer areas.•The plastic zones do not transmit some seismic waves, but absorb them.•Density changes could induce reflection and refraction of seismic waves.

Principle of Uniformitarianism

•The same physical processes active in the environment today have been operating throughout the geologic time.•"The present is the key to the past."•Earthquakes, volcanic eruptions, landslides, mountain-building have been happening over the history of Earth.

Radioactivity dating only can be used to measure relative time.

False

In 1912, German geophysicist and meteorologist, Alfred Wegener first proposed the__________ hypothesis about the Earth's land mass migration.

Continental Drift

Formation of Earth

Earth is thought to have condensed and congealed from a nebula of dust, gas, and icy comets about 4.6 billion years ago.

the two energy sources

Earth's internal heat (radioactive decay) and solar energy (external)

Isostatic

iso = "equal," static = "standstill" The state of gravitational equilibrium between the lithosphere and asthenosphere such that the tectonic plates "float" at an elevation that depends on their thickness and density.

boyancy

less dense than wood

Which layer of planet forms 80% of Earth's total volume, and has an average density of 4.5 g/cm3.

mantle

What is the Holocene?

olocene•Holocene is the youngest epoch in the geologic time scale

The asthenosphere can be described as

plastic-like

Which of the following is incorrectly matched?

radioactive decay heat-exogenic energy source