Early. Geologists (2015) Sukonmeth Jitmahantakul. Friday, 20 February 15

Transcription

1 Early Geologists (2015) Sukonmeth Jitmahantakul

2 Key persons Nicholas Steno provides the basic principles of superposition, original horizontality, and original lateral continuity. John Strachey, Giovanni Arduino, Johann Lehmann, Georg Fuchsel, and Peter Simon Pallas recognize the general age relationships and nature of major groups of rock assemblages in Europe. Abraham G. Werner publishes the first textbook of mineralogy, but errs in his belief that basalt was an oceanic deposit. James Hutton perceives the immensity of geologic time and understands the relation between processes of the present and of the geologic past.

3 Key persons William Smith demonstrates the use of fossils for correlating strata. Georges Cuvier conceives the theory of catastrophism and stipulates that life on Earth underwent periodic extermination, followed by reappearance of entirely new life forms. Charles Lyell explains the relative age of inclusions of one rock in another, and how rocks that cut into and across other rocks can also be used to determine relative geologic age. Charles Darwin and Alfred R. Wallace conceive of natural selection as a mechanism for evolution.

4 Nicolas Steno Niels Stensen Danish scientist (anatomy) Three basic principles of historical geology & stratigraphy : I. Superposition II. original horizontality III. original lateral continuity

5 Principle of Superposition

6 The principle of superposition states that in any sequence of undisturbed strata, the oldest layer is at the bottom, and successively younger layers are successively higher.

7 Principle of Original Horizontality

8 The principle of original horizontality states that sediment is deposited in layers that are originally horizontal.

9 Principle of Original Lateral Continuity

10 The principle of original lateral continuity states that a rock layer extends continuously in all directions until it thins out or encounters a barrier.

11 Principle of original lateral continuity

12 British geologist John Strachey used the principle of superposition and original lateral continuity to decipher the strata of coal-bearing rock formations in England

13 Giovanni Arduino Italian geologist Father of Italian Geology He divided the history of the Earth into 4 periods: Primitive, Secondary, Tertiary and Volcanic or Quaternary

14 Neptunism vs Plutonism

15 Neptunism Abraham G. Werner ( ) was a professor at the Freiburg Mining Academy in Germany. He published the first great mineralogy textbook. All rocks were deposited or perpetuated from a great ocean that once enveloped the entire planet. Neptunists named after Neptune, the Roman god of the sea His universal ocean = hot, steamy, and saturated with all the dissolved minerals -> Primitive rocks Primitive rocks formed the cores of mountain ranges.

16 Neptunism Subsidence and cooling of the primitive ocean to resemble the ocean of today. -> the deposition of fossil-bearing rock strata above the primitive rocks, called transition rocks Alluvium of sand gravel and clay rested on the transition rocks Failed to explain what had become of the immense volume of water that once covered Earth Lava flows were deposited in the same manner as limestones and shales. Basalt was sedimentary!

17 Plutonism or vulcasism after Pluto, the Roman god of the underworld after Vulcan, the ancient Roman god of fire and volcanoes Fire (heat) was the key to the origin of primitive igneous rocks (not from water). Originally proposed by Abbé Anton Moro ( ) James Hutton correctly stated that rocks such as the lava and granite formed in the bowels of the Earth of melted matter poured into rents and opening of the strata. Today, limestone are considered to have resulted explained by the neptunists.

18 Scottish geologist Father of Modern Geology Hutton s Unconformity James Hutton studying present processes (weathering, erosion, deposition of sediment, volcanism, etc.) provides the means of interpreting ancient rocks. His idea became established as the principle of uniformitarianism. Theory of the Earth (1785)

19 Uniformitarianism

20 Uniformitarianism Geologic processes are uniform through all time. Uniform = the physical and chemical laws that govern nature. Earth s history may be deciphered by observing events today and assuming that the same phenomena have operated in the same way throughout geologic time. Uniform, But The geologic past actually was sometimes quite unlike the present. i.e. oxygen-rich atmosphere, meteorite bombardment, volcanism In the past, the rates of change and intensity of processes often varied from those we are accustomed to seeing today, and that some events of long ago simply have no modern counterpart.

21 Actualism John Playfair (1802) The facts of geology can and should be explained by in terms of the sort of physical processes that actually happen. If it looks like a duck and it quacks like a duck, it s a duck.

22 Unconformity

23 Siccar Point, Scotland Hutton s unconformity

24 William Smith Father of English Geology Principle of fossil succession First nationwide geological map (1815)

25 Catastrophism

26 Georges Cuvier French vertebrate palaeontologist reconized that certain large grouping of strata were often separated by unconformities he often observed a dramatic change in animal fossils concluded that the history of life was marked by frightful catastrophes involving flooding of the continent and crustal upheavals Catastrophism =/= Uniformitarianism

27 Principle of Cross-cutting Relationships

28 Sir Charles Lyell Scottish Geologist Principle of Geology (1830) Charles Darwin carried a copy of the first volume with him on his famous voyage a board the H.M.S. Beagle.

29 Principle of cross-cutting relationships

30 Inclusions

31 Evolution How Organism Change Through Time

32 Charles Darwin English naturalist and geologist On the Origin of Species (1859) Alfred R. Wallace a comparatively young naturalist.