Chapter 1 - Chapter 1: An Introduction to Geology Geology:...

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Chapter 1: An Introduction to Geology I) Geology: science that pursues an understanding of planet Earth A) Physical geology: the materials composing earth and seeks to understand the processes that  operate beneath and upon its surface B) Historical geology: understand the origin of Earth and its development through time II) History of geology A) Aristotle 1) Arbitrary pronouncements 2) Rocks were created under the “influence” of the stars 3) Earthquakes occurred when air crowded into the ground, heated by central fires, and  escaped explosively B) James Ussher: catastrophism 1) Earth’s landscapes have been shaped by great catastrophes 2) An attempt to fit the rates of Earth processes to the then-current ideas on the age of Earth C) Hutton: uniformitarianism 1) Physical, chemical, and biological laws that operate today have also operated in the geologic  past a) To understand ancient rocks must first understand present-day processes and their  results b) Forces that appear small could over long spans of time produce effects that were just as  great as those resulting from sudden catastrophic events 2) Carefully cited verifiable observations to support ideas 3) Doctrine should not be taken too literally—some geologic processes are not currently  observable but evidence that they occur is established 4) Acceptance of uniformitarianism meant acceptance of very long history of Earth 5) Rock record contains evidence that shows Earth has experienced many cycles of mountain  building and erosion III) Geologic time A) Relative dating: events placed in their proper sequence or order w/o knowing their ages in years 1) Done by applying principles like law of superposition: in layers of sedimentary rocks or lava  flows they youngest layer is on top and oldest is on the bottom 2) Establishes sequence of rock layers but not their numerical ages B) Fossils are basis for the principle of fossil succession 1) fossil organisms succeed one another in a definite and determinable order, so any time  period can be recognized by its fossil content 2) Allowed geologists to identify rocks of the same age in widely separated places and to build  the geologic time scale C) Earth is 4.5 billion years old IV) Development of new scientific knowledge involves basic logical processes that are universally  accepted A) Constructing a hypothesis/model: tentative explanation
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1) Best if it can explain a given set of observations 2) Extensive research is conducted by proponents of opposing models and results are made  available to wider scientific community B) Hypothesis must pass objective testing and analysis 1) Requires that predictions be made based on the model being considered
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This note was uploaded on 04/02/2008 for the course GLG 201 taught by Professor Libarkin during the Spring '07 term at Michigan State University.

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Chapter 1 - Chapter 1: An Introduction to Geology Geology:...

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