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University of Mississippi *

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101

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Geology

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Oct 30, 2023

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GEOL 101 Geology - is the science to study and understand the planet Earth - GEO = EARTH - Logos = discourse Physical Geology : Material composing Earth and geological processes - Water flow rate - Types of rocks - Erosion rate Historical Geolog y: Origin of Earth and its development through time - Erosional history - Predicted future Geology and humans are not mutually exclusive - Humans can fundamentally change geological processes - Geology (or Nature) can fundamentally change our ways to life STUDY OF GEOLOGY THROUGH TIME Written record of geology goes back more than 2300 years 17th and 18th Century: Catastrophism was the leading thought 1795: James Hutton published “Theory of the Earth” - Uniformitarianism Principle of Uniformitarianism “The present is the key to the past” James Hutton, “father” of modern geology Slow, Gradual observable change - erosion, movement of tectonic plates Catastrophic events - meteorite impacts, large volcanic eruptions Geologic Time

GEOL 101 Uniformitarianism required us to think of the Earth as VERY old Geologists are now able to assign fairly accurate dates to events in Earth history - Absolute Dating - Relative Dating The Earth is 4.6 BILLION years old SCIENCE Science is a body of knowledge. But it is also a process of acquiring new knowledge through observation, measurement, and experimentation. Scientific Method: The method by which scientists work to answer scientific question or observations Hypothesis: an EDUCATED statement that provides an explanation for a phenomenon and that is testable. Hypothesis MUST BE TESTABLE - cannot test validity of ghosts, spirits, vampires, etc… or personal subjective questions. We can not prove the validity of a hypothesis - we can only falsify it Some ideas are so overwhelming (like this class) well-supported that to reject them at present is unreasonable Theory - A well-tested and widely accepted view that the scientific community agrees best explains certain observable facts A theory is also not proved but it makes predictions that are consistent with the underlying hypotheses SCIENTIFIC LAWS are the logical (mathematical) extensions of scientific theories

GEOL 101 Tuesday - 8/29 The 3 kind of rock: ● Igneous Rock ○ Cooling and solidification of molten rock ● Sedimentary Rocks - Grand Canyon ○ Sediments are derived from weathering of preexisting rocks ○ Sediments will lithify into sedimentary rocks ○ Accumulate in layers at Earth’s surface ● Metamorphic Rocks ○ Formed by “changing” preexisting igneous, sedimentary, or other metamorphic rocks ○ Driving forces are heat and pressure ALL ROCKS CAN BE ALL ROCKS Chapter 3 A mineral is a 1.) Naturally occurring 2.) Inorganic (generally) 3.) Solid substance 4.) Specific chemical composition 5.) With an orderly arrangement of atoms and crystalline structure A mineral is NOT a ROCK. A rock is a solid composed of one or more minerals. Atoms are chemical bonded with other atoms.

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GEOL 101 1. Precipitate out of fluids: reach saturation 1. Precipitate out of fluid: slowly moving groundwater (geodes) 2.Crystallization of Molten Rock - Similar to water freezing - When the magma is hot, the atoms are mobile, when the magma cools, the atoms slow and begin to chemically bond - Generates a mosaic of intergrown crystals 3. Deposition as a Result of Biological Processes: secrete skeleton from water Mineral Properties Minerals have an unique specific and observable physical and chemical properties, which are the basis of mineral identification ● Luster ○ Appearance of a mineral in reflected light ■ 2 basic categories: ● Metallic: looks like metal ● Non metallic: dull & glassy ● Color ○ Some minerals have wide variety of colors ○ Some minerals have a single distinctive color e.g. Sulphur ○ Therefore, NOT DIAGNOSTIC ○ Impurities in the mineral can change the color of the mineral (these are all the same mineral) ● Streak ○ Color of a mineral in powdered form ○ For some minerals, the powder color of a mineral is different from mineral color.

GEOL 101 ● Hardness ● Cleavage ● Specific Gravity ● Reaction to acid ● Crystal Form Ability to transmit light 1. Transparent: light passes through, objects on the other side can be seen 2. Translucent: light passes through, objects on the other side can't be seen 3. Opaque: light does not pass through