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Geology review 1


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What is crystal form?
Crystal form and symmetry: The typical geometric shape of crystals of a given mineral. Most mineral specimens do not show their crystal form because they are either crystalline aggregates or they are broken or they are both.
Give an example of the earth interacting or in equilibrium.
Humans are part of the biosphere. When we build seawalls or clear land, we cause other parts of the system to respond. A seawall prevents wves from reaching areas behind the wall but may cause the beach to the seaward side of the seawall to experience significant erosion. (see pg 275 of book)
What is Geology?
The science that examines Earth, its form and composition and the changes it has undergone and is undergoing.
What is the difference between physical geology and historical geology?
PG studies the earth's composition, structure and the processes that shape it while HG is the study of the history of the earth and the history of life on earth.
What is the State of Dynamic Equilibrium of the four major components of the earth?
Dynamic Equilibrium (changeable balance) such that any significant change in any one of the four parts will result in a change in all of the others, but not necessarily of the same order of magnitude.
What is Earth Science?
Earth Science is the scientific study of earth and its major systems.
What are the four major components of the earth?
GEOSPHERE: - rocky substance of the earth
HYDROSPHERE: The earth's water
(97%in oceans, also rivers, glaciers, lakes, etc.)
BIOSPHERE: All living organisms on earth
ATMOSPHERE: The gaseious envelope arounmd the earth
What is Historical Geology?
HISTORICAL GEOLOGY is the history of the earth and of life on earth.
What are the crust, mantle and core's bacis features?
CRUST: granitic composition
MANTLE: Dense Iron Silicates about 1800 miles thick
CORE: OUTER CORE:molten iron and nickel about 1800 miles thick, about size of the moon.
INNER CORE: Solid iron and nickel
What is physical geology?
PHYSICAL GEOLOGY is the study of earth composition, structure and the processes that shape it (wind, erosion)
What is the biosphere?
All living organisms on earth.
What happens to a crystal when crystals merge to form a CRYSTALLINE AGGREGATE?
Most crystals in nature are merged with other crystals to form a crystalline aggregate, ie: a rock.
What is the hydrosphere?
The Earth's Water
What is the theory of plate tectonics?
The motion and interaction of rigid, interlocking plate-like segments composed of the outer 100 km (62 miles) of the Earth. This results in the deformation of these plates which is accompanied by such "tectonic" activity as earthquakes, volcanism and the formation of mountain ranges.
Explain the concept of the earth as a system.
The earth is a dynamic body with many separate, interacting parts or spheres. They interact and are interdependents and therefore a system. The parts are linked.
How are metamorphic rocks formed?
Formed by recrystallizing igneous or sedimentary rocks without melting them, due to heat and pressure deep underground.
What is the geosphere?
What are its three major subdivisions?
The Geosphere is the rocky substance of the earth, ie. crust, mantle, core. It is the main part of the earth.
What are deep-ocean trenches?
An elongate-depression in the seafloor produced by bending of oceanic crust during subduction.
What is the asthenosphere?
The asthenosphere lies beneath the lithosphere. It behaves as a "plastic" solid (easily deformable) because it is very lose to its melting point (liek a redhot horseshoe is bendable). It is like "grease" that is between the plates so they can move.
What is an element?
A substance that cannot be decomposed into simpler substances by ordinary chemical or physical means.
What is the hydrosphere's verious components?
97% is in the Oceans
Also, rivers, lakes, glaciers, etc.
What is the basic premise of the rock cycle?
"Rocks in flux." These processes recycle rocks from one type to another and therefore the substance of any rock has existed as other rocks in the past.
What is the Atmosphere?
The gaseous portion of a planet; the planet's envelope of air. One of the traditional subdivisions of Earth's physical environment.
How are sedimentary rocks formed?
Sed. rocks are formed from sediments derived from other rocks by seathering and erosion.
-SHALE- most common compacted mud)
-LIMESTONE-used for cement
What is the lithosphere?
The lithosphere consists of the crust plus the uppermost mantle down to about 100 km (62 miles). This behaves as a single rigid unit and is divided into "plates."
What are the three types of plate boundaries?
What does the atmosphere consist of? What are it's most abundant components?
78% Nitrogen
21% Oxygen
1% Argon
Carbon Dioxide
Water Vapor
What is the continental shelf?
The gently sloping submerged portion of the ocntinental margin, extending from the shoreline to the ocntinental slope.
How are igneous rocks made?
Igneous rocks are formed by the cooling and solidification of molten rock (magma).
- basalt lava - most common
- granite - cools more slowly
What are the oceanic ridges?
A continuous mountainous ridge on the floor of all the major ocean basins and varying in width from 300 - 3000 miles. The rifts at the crests of these ridges represent divergent plate boundaries.
What is a rock?
Rocks are consolidated (solid) mineral aggregates. Most rocks are made of more than one kind of mineral. This mineral matter can consist of crystals, particles and even fossils (shells).
What is the difference between continental and oceanic crust as far as their thickness, composition, height, relative to sea level and relative amount of the Earth's surface is concerned?
What is a mineral?
What are the basic components of the hydrologic cycle?
What is breakage?
The way a mineral breaks is often useful in identifying it. The two basic types are: CLEAVAGE Breakage along flat surfaces in a preferred direction
FRACTURE:Breakage not along flat surfaces.
What are the two most abundant elements in the EARTH'S CRUST?
1. Oxygen (almost 1/2 of the
Earth's crust.
2. Silicon
What happens if a crystal's form is not interfered with?
What is the hydrologic cycle?
The continuous transfer of water on earth from one respository to another. Example: from the sea to air (evaporation) then from air to land (precipitation) and finally from the land back to the sea.
How does geologic time enable us to use ordinary, observable processes to explain most of what we see on earth? (uniformitarianism)
Over such long periods of time, many seemingly insignificant natural processes can produce major results. Therefore,most of the earth's geological features can be explained in terms of ordinary, observable processes acting over geologic time spans.
What physical properties are useful in identifying minerals?
Specific Gravity
What powers the hydrologic cycle?
The energy from the sun powers the hydrologic cycle.
What are the components of the hydrologic cycle?
Infiltration (a portion soaks into the ground)
drains downward into lakes, streams,oceans, etc.
Transpiration - some of the water is absorbed by
How do the lithosphere and asthenosphere relate to the theory of plate tectonics?
The lithosphere is the crust that slides around on the "grease" of the asthenosphere.
What is geologic time?
Spans of time encompassing a vast scale. It ranges from thousands to billions of years.
What is the continental slope?
The steep gradient that leads to the deep-ocean floor and marks the seaward edge of the continental shelf.
What causes some minerals to exhibit the property of CLEAVAGE whereas others do not?
Cleavage is breakage along flat surfaces. It is caused by atomic bonds that are weaker in one or more directions. Not all minerals have cleavage.
What is a crystalline solid?
Crystallization is a process in which random arrange ments of atoms are transformed into orderly arrangements. Such material is said to be "crystalline". This leads to the formation of a "crystal."
How to tell if a mineral has cleavage?
Flat surfaces (continuous or stepped)
Mirror-like reflectance (it flashes)
What are volcanic island arcs?
A chain of volcanic islqnds generally located a few hundred kilometers from a trench where there is active subduction of one oceanic plate beneath another.
What are the three major categories of rocks?
What is a convergent boundary?
A convergent boundary is where two plates are colliding and one is forced down beneath the other into teh mantle where it is recycled. This generates powerful quakes, volcanic activity and mountain building. This is mostly occuring in deep ocean trenches and leads to a formation of volcanic island arcs, continental volcanic arcs and complex moutains.
How do crystals form and grow?
By adding atoms to their outer surface (growth by accretion).
What is a transform boundary?
A boundary where 2 plates are sliding past one another along a transform fault. This causes earthquakes and deformation but it neither creates nor destroys lithosphere.
What is a divergent boundary?
A divergent boundary is wehre two plates are pulling apart and moving in opposite directions. This creates new lithosphere as magma intrudes into the cracks formed when the plates pull apart. This occurs along the central part (axis) of mid-ocean ridges.

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