Chapter 1 - Introduction To Geology Flashcards
Give four examples of how geology affects our everyday lives
1) Natural events - earthquakes…
2) Economics and politics - minerals and energy resources are not equally distributed
3) our role as decision makers
4) consumers and citizens - we enjoy a standard of living that is directly dependent on consumption of Geologic materials
What is geology
Study of the Earth
Principle of uniformitism
Processes we see today have been operating throughout time. To understand and interpret evidence preserved in rock we must first understand present processes and their results
Relative dating
Layers in piles of rock that show us records of the sequence of past events
Earth as an open system
With many interacting subsystems that involve the transfer of energy and materials from one area to another
Hydrosphere
All Earth’s water such as ice, lakes and snow
Geosphere
Solid Earth from core to surface composed principally of rock and unconsolidated cement
Catastrophism
Theory believing that earths features with permanent and had been produced by a few great upheavals
According to recent studies, how old is the Earth
4550 million years old
What is an open system
Both energy and matter flow into and out of the system
Atmosphere
Mixture of gases that surround the Earth
Biosphere
All of the organisms as well as any organic matter not yet decomposed
What is a rock
A coherent, naturally occurring solid consisting of an aggregate of minerals
Coherent rocks
A rock holds together and must be broken into separate pieces and not a pile of an attached grains the can move around
Naturally occurring rocks
Manufactured materials like concrete and brick do not qualify
What is a crystal and what is a grain
Crystal is a piece of a mineral that grew into its present shape and A grain is any fragment or piece of mineral, Rock glass
Give two ways rocks are held together, and an example of each
1) natural cement - Mineral material the precipitates from water and fills the spaces between grains… And example is Clastic rocks
2) interlocking crystals - rocks who’s crystals interlock with one another… Example is crystalline rocks
Clastic rocks
Rocks whose grains are stuck together by cement
How can rocks best be classified
By how they form
Igneous rocks
Form by the solidification of molten rock
Sedimentary rocks
Form either by the cementing together of fragments broken off pre-existing rocks or by the precipitation of mineral crystals out of water solutions
Metamorphic rocks
Form when pre-existing rocks change into new rocks in response to a change in pressure and temperature conditions
Name for physical characteristics of rocks
1) grain size - in some rocks all the grains are the same size while other rocks contain a variety of different sized grains
2) composition - The proportion of chemicals as well as the assemblage of minerals the developed in rock
3) texture - The arrangement of grains in a rock
4) layering - defined either by bands of different compositions of textures or by the alignment of in inequaint grains so that they train parallel to one other
Bedding and foliation
Bedding is layering in sedimentary rocks, while The layering in metamorphic rocks is called foliation
