Geography Quizlet 7, 8, 10, 11 & 21

Malfic rocks contain about ______% silica. Silicic rocks contain about ______% silica?

50% & 70%

If a rock A cuts across rock B, then rock A is ______ rock B.

A is younger than B. This is the principle of crosscutting relationships.

Which is a method of correlation?

All of the above. o What's correlation? The time equivalency of rock formations. A formation is the term associated with a particular rock layer that has characteristics... o What rocks formed at the same time is what correlation is about. o There are three methods for correlation Physical continuity Fossils Similarity of rocks

Describe or explain difference between continuous & discontinuous.

Bowen determined that specific minerals form at specific temperatures as a magma cools. At the higher temperatures associated with mafic and intermediate magmas, the general progression can be separated into two branches. The continuous branch describes the evolution of the plagioclase feldspars as they evolve from being calcium-rich to more sodium-rich. The discontinuous branch describes the formation of the mafic minerals olivine, pyroxene, amphibole, and biotite mica.

The last era is the Cenozoic Era.

Cenozoic means "recent life". Mammal fossils common in rocks of this era. Age of Mammals Began 65 million years ago. Divided into 2 periods: Tertiary and Quaternary, which are then subdivided into epochs.

Multiple Choice picture

Coal needs a swamp. Oil needs microscopic marine organism. Natural gas needs a structural trap.

Giant magmas are associated with

Convergent plate boundaries

Most earthquakes at convergant plate boundaries are

shallow focus

The point within the earth where seismic waves originate is called:

Focus and epicenter

An igneous rock made of pyroclasts has a texture called:

Fragmental

Which of the following is not true of tsunami

High wave high height in deep water

Most earthquakes at divergant plates boundaries are

shallow focus

The first era is the Precambrian Era

It is the longest era. Very few fossils exist in early Precambrian rocks. Some early Precambrian rocks contain fossils of bacteria and algae. Later Precambrian rocks contain fossils of primitive worms, sponges and corals.

Mount St. Helens:

Last erupted violently in 1980. Is part of the Cascade Range, Had a revival of dome growing in 2004.

What is a type of coal?

Lignite, Bituminous, Anthracite.

The third era is called the Mesozoic Era

Mesozoic means "middle life". Contains fossils of more complex organisms such as reptiles and birds. Age of Reptiles (Dinosaurs). Lasted 180 million years. Divided into 3 periods: Triassic, Jurassic and Cretaceous.

What factors can increase reserves of earth resources:

New discoveries and price control.

Units of Geologic Time

One of the largest units of geologic time is the era. There are four geologic eras. Eras have been further subdivided into periods and the periods are divided into epochs. Largest to smallest: eon, era, period, epoc

One gas typically not released during a volcanic eruption is:

Oxygen

Paleozoic Era is the second era

Paleozoic means "ancient life". It lasted 325 million years. Contains a wide variety of fossils of marine life and land plants and animals. Age of Amphibians. Divided into 7 periods: Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian

S waves are

S waves are the second wave to come in a earth quake and can only travel through solids. They are slower than p waves. The propagate in a up and down way.

Name a shield volcano, composite volcano, and a cone volcano:

Shield= Kilauea. Composite= Mount Rainer, Fujiyama, Mount Vesuvius. Cinder Cone=Cerra Negro.

Describe the difference between a: dike and sill, Batholiths and plutons.

Sills: form when magma intrudes between the rock layers, forming a horizontal or gently-dipping sheet of igneous rock. The Whin Sill (top left image) in N. England provided a defensive cliff-line on which the Romans built Hadrian's Wall. Dykes: form as magma pushes up towards the surface through cracks in the rock. Dykes are vertical or steeply-dipping sheets of igneous rock. This example, (bottom left image) in the Channel Islands, shows several criss-crossing dykes of different ages. Batholiths: are large, deep-seated intrusions (sometimes called Plutons) that form as thick, viscous magma slowly makes its way toward the surface, but seldom gets there! Dartmoor (bottom right) forms part of a large batholith that extends under Cornwall and beyond. a pluton is a body of intrusive igneous rock (called a plutonic rock) that is crystallized from magma slowly cooling below the surface of the Earth. Plutons include batholiths, stocks, dikes, sills, laccoliths, lopoliths, and other igneous bodies. In practice, "pluton" usually refers to a distinctive mass of igneous rock, typically several kilometers in dimension, without a tabular shape like those of dikes and sills. Batholiths commonly are aggregations of plutons.

Oil accumulates when the following conditions are met:

Source rock where oil forms, permeable reservoir rock. impermeable oil trap.

The Richter scale measures

The magnitude of an earthquake. uses a scale of 1 to ?, strongest one has been a 9.5 magnitude. used to describe the amount of energy released in an earthquake.

P waves are

Travel through solids and liquids. Travels faster through denser materials and travels faster than S waves. P wave propagate in a compressing and expanding way.

Geological processes operating at present are the same processes that have operated in the past is the principles of

Uniformitarinism

The geothermal gradient is, on the average, about

Uppercrust 30 degreesC/km

What is our current eon, era, period and epoch?

We live in the Holocene (sometimes called Recent) epoch, Quaternary period, Cenozoic era, and Phanerozoic eon.

The major difference between intrusive igneous rocks and extrusive rocks is

Where they solidify

A geologist could use the principle of inclusion to determine the relative age of

Xenoliths

A change in magma composition due to melting of surrounding country rock is called:

assimilation

The difference in texture between intrusive and extrusive rocks is primarily due to:

different rates of cooling and crystallization

Which is not an extrusive igneous rock?

granite

The Mercalli scale measures

measures earthquake damage, the level of intensity of the earthquake, and the effect of the event on people.

Describe the differences between the continuous and the discontinuous branches of Bowens reaction series.

refer to page 285