Lec 1: Deep Geological Time - Deism, Neptunism, Vulcanism, World Machine Flashcards
Thomas Burnet (1635-1715)
1684 - The Sacred Theory of the Earth
- > God did it right
- > calculated Noah, saw Ocean not big enough
- > Earth originally had a perfect featureless crust (paradise of Eden). Water rose from below, creating Oceans where it spewed, and mountains where the crust was upturned
- > Newton suggests non-literal bible; have super long days to allow this process to happen
- > Burnet spurns Newton; such long day/night incompatible with life, and would make the ancients lives crazy long
Abraham Gottlob Werner (1749-1817)
- > all rocks come are precipitate from aqueous solution
- > known as “Neptunist Theory”
- > 5 distinct stages in geological history, of different types of rocks & different types of life, explains rock strata, agrees with Genesis
- > fails to explain insoluble rocks like granite, and veins of rock that cross strata bounds
Neptunist Theory
Attributed to Werner, rocks formed from crystallizing minerals in the oceans. (think Neptune, the sea god)
- > 5 stages
- > correlated intelligent creator
Two problems:
- > Granite insoluble
- > basalt really far from volcanoes
1) Primitive rocks (e.g. granite) crystallize from chemical solution
2) Transition strata (some precipitate chemically, some mechanically) appear, and fish
3) Water recedes, secondary rocks (basalt, chalk) from fine particles torn by receding torrents, mammals.
4) Large waves/winds create transported (alluvial, derivative) strata (clay, pebbles)
5) Local coal deposits ignite, local lava deposits.
James Hutton (1726-1797)
Scot who disagreed with Werner. MECHANIZATION OF NATURE.
- > world as an eternal machine: “no vestige of a beginning, no prospect of an end”, justified by the idea that God was a master artisan and would make a machine that would never break or need maintenance. Also similar to Newton’s gravity, runs forever unsupervised.
- > founded the “Vulcanist” theory (as opposed to Werner’s Neptunist).
Published in “The Theory of the Earth”
- > but did not comment on creation
- > so hard to read, needed Playfair’s Illustrations of the Huttonian Theory of the Earth (1802)
He only found evidence (unconformities, esp granite) afterwards
->notably, Siccar Point
Hutton’s World Machine (Vulcanism)
- > process & driver?
- > advantages
1) Never ending swap of continent and ocean
2) Each stage starts the next.
3) Driven by Earth’s heat, fusing sedimentary rock
Stage 1: Rivers and waves break down rocks
- > forms soil
- > washes erosion into ocean
Stage 2: Strata of sediment build up
- > weight generates pressure, mobilizing lower layers
- > heat at subsurface + pressure generates
Stage 3: Heat of melting sediment causes expansion
- > uplift
- > old oceans replaced by continents
- > old eroded continents now oceans
Advantages:
- > VS Neptunism, argued water was erosive, which alone could not explain folding seen in strata
- > was not a past event that magically happened, continues imperceptibly right now
Archbishop Ussher (1600’s)
Said the Earth was created in 4004 BC by counting generations in the Bible.
Charles Lyell (1797-1875)
Wrote “Principles of Geology”
->Most historically significant supporter of Hutton. Said that Hutton was the first to observe that granite must be produced by heat & pressure, and that unconformities indicate multiple cycles of uplift & erosion. Mistakenly though Hutton based his theories on field-work, but the theory actually preceded his expeditions.
->past laws of nature continued today, unchanged in rate and intensity.
(more stuff in card in Lec4)
