Introduction to Geology - Lecture notes - Geol 1109 Jan 14 PDF

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Geology 1109

Jan. 14.15

Science: Knowledge or a system of knowledge covering general truths or the operation of general laws, especially as obtained and tested through the scientific method Scientific Method: a systematic approach to problem solving through systematic observation and experimentation Hypothesis: A tentative explanation based on data collected by experiment and observation or by serendipity Theory: A hypothesis that has survived repeated examination and still holds up - Established set of ideas that can be used to make predictions and create models (technology) Scientific Law: Considered absolutely correct based on current knowledge (generally involves equations); laws of gravity, thermodynamics, motion - There are no laws in geology because it is over great amounts of time and the earth is too complex Paradigm: The umbrella under which we operate (science, plate tectonics, evolution, earth shape) Geology: The ‘science of the earth’, which includes but is not limited to the study of the materials, processes, products and history of the earth Geologists conduct Basic and applied scientific research in order to increase our understanding of the Earth system and they apply their knowledge to benefit human society Geologists are a combination of scientist and historian putting together geologic histories to understand Earth processes Modern geological research involves an integration of many research areas, hence the term, “Geoscience” Geoscience Specialties Geophysics: prediction of earthquakes and volcanic eruptions, petroleum exploration, etc. Hydrogeology: Exploring groundwater reserves and managing drinking water supplies, etc. Mineralogy: investigating the composition of minerals in rocks Structural Geology: plate tectonics, mapping, petroleum exploration, ore deposits etc. Geochemistry: assessment of soil contamination, pollution, climate change etc. Paleontology: the history of life and ancient life; change through time Scientific Method via inductive reasoning the ‘bottom up’ approach

Testing a hypothesis:

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Experiment Numerical simulation Examining results of natural processes to deduce nature’s experimental conditions Meteorite Impact at K-T boundary: TOP DOWN APPROACH - Alvarez et al. (1980) observed high Iridium concentration at K-T boundary AND Iridium occurs in high concentration in meteorites meteorite impact hypothesis study: what’s found at modern impacts Shocked quartz: typically found in meteorite craters today, occurs at K-T boundary  also finds glass spherules: result from strong volcanic eruptions OR meteorite impacts today. Glass spherules are found at many K-T boundary sites - Meteorite impact crater found in subsurface on Yucatan Peninsula that dates to K-T boundary - *K stands for cretaceous - Science can never prove anything… can only disprove…scientific knowledge is always open to reassessment History of Geology Georges Cuvier (1769-1832) - Prominent French zoologist and paleontologist Catastrophism: Earth’s history could be explained by a series of catastrophes (specifically floods), caused by supernatural processes; why? Needed to create a lot of change in a very short period of time James Hutton (1726-1797) (grandfather of geology) Uniformitarianism: Present geological processes have been operating throughout Earth’s history, and can be used to explain past geologic processes “The present is the key to the past” - Opposite from catastrophists because: o He believed the Earth was very old, perhaps 100s of millions of years o He ignored the catastrophists Sir Charles Lyell (1797-1875) (father of geology) - Won the majority of geologists over to Uniformitarianism with his 3-volume Principles of Geology (1830-1833) - Believed in a STEADY – STATE EARTH wherein the kinds of rocks, the processes, and living organisms have never changed Geologists concede that Earth’s processes have operated at different rates at different times, and… Not all kinds of events that occurred in the geologic past have been duplicated within human history

Todays Uniformitarianism = ACTUALISM While the natural laws have been constant, the rates and intensities of change have varied through time “The present is a key to the past”...