Catastrophism, Uniformitarianism, and Gradualism Or, how humans have thought about geologic processes Neptunism Abraham Gottlob Werner, 1787 All rocks precipitated from ocean water
Problems? Catastrophism Baron Georges Cuvier, late 18th mid-19th century Researched fossils and
extinction Series of six major catastrophes All of these facts, consistent among themselves, and not opposed by any report, seem to me to prove the existence of a world previous to ours, destroyed by some kind of catastrophe. Problems? James Hutton and Uniformitarianism
The past history of our globe must be explained by what can be seen to be happening now. Plutonism - igneous rocks result from the cooling of hot magma
What kinds of processes did Hutton imagine had shaped the world in the past? Siccar Point Huttons Unconformity Photo credit: Dave Souza, Wikimedia Commons Evidence of mountain-building Charles Lyell
Principles of Geology The present is the key to the past. Much better writer than Hutton; disseminated idea of Uniformitarianism to a much
wider audience Lyell and Darwin Charles Darwin Lyell was one of the first scientists to endorse On the Origin of Species, although he disagreed with aspects of the theory of natural selection Why would Lyells work
have been useful to Darwin? Why is Uniformitarianism a more logical approach to understanding Earth history? Constancy of laws: In order to meaningfully study the past, we must assume the same or similar mechanisms operated then as now. Otherwise, how can we know anything about the past?
Parsimony: Occams razor We know the earth is extremely old (how?) Does Uniformitarianism mean that nature is ALWAYS constant? Geologists do not deny uniformitarianism in its true sense, that is to say, of interpreting the past by means of the processes that are seen going on at the present day, so long as we remember that the periodic catastrophe is one of those processes.
Those periodic catastrophes make more showing in the stratigraphical record than we have hitherto assumed. Ager, Derek V. (1993). The Nature of the Stratigraphical Record, 3rd Ed.. Chichester, New York, Brisbane, Toronto, Singapore: John Wiley & Sons. pp. 8384. From Uniformitarianism/Gradualism to Actualism Uniformitarianism was a huge step in the right direction
Evidence exists that there have been different intensities of geological activity during the past Deccan Traps near Mumbai, India Series of intense volcanic eruptions ~66 mya
TheStringis really a reference to an entry in the string constant table! The strange String semantics should make more sense now. Arithmetic. Opcode. Mnemonic; Description; 96. iadd. Pops two integers from the stack and pushes their sum. iconst_2. iconst_3. iadd....
University Roles in Science, Innovation and HQP in the Canadian Agri-food System. Presentation to Federal-Provincial-Territorial Deputy Ministers. by the Association of Canadian Faculties of Agriculture and Veterinary Medicine. 23 April 2013. Montreal
Modeling the Glutamate Metabolic Pathway in Saccharomycescerevisiaeto Resemble Experimental Data. Anthony Wavrin & Matthew Jurek. Department of Biology. Loyola Marymount University. February 28th, 2013. ... Differential equations that model the dynamics.
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Members who joined the system on or after July 1, 2007, become vested in the system with eight (8) years of creditable service. Employees who joined the system on or before June 30, 2011 are eligible to retire at any...
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