PPT-GY111

Physical Geology Lecture 5 Weathering and Soil Formation Weathering Chemical Weathering Hydration chemical reaction that consumes H 2 O 2KAlSi 3 O 8 2H 2 CO 3 H 2 O Al 2. Evolution of the Continents. Important Terms. Craton: interior of continents made of stable Precambrian and Paleozoic . rocks.. Shield: portion of Craton composed of older Precambrian . rocks.. Platform: portion of Craton made of younger Paleozoic . Solar System. Nebular Hypothesis. Nebular Hypothesis: Solar System was produced by the gravitational collapse of a gas cloud – the remnant of a supernova . explosion.. Concentration of heavy elements in inner . Geological Attitudes & 3D Block Diagram Interpretation. Problem 1: Strike and dip of bedding.. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. Geological “Clocks”. Geologic time determination is subdivided into 2 categories:. Relative Dating: simply determines whether or not an event occurs before or after another event (e.g. a granite dike is younger than the surrounding sandstone since it intrudes across the sandstone in an outcrop).. Types of Rocks. Rock: an aggregate of one or more minerals. Igneous Rocks: crystallize from a magma. Sedimentary Rocks. Clastic: formed by the erosion of pre-existing rocks. Chemical/Biochemical: precipitated from chemical reactions. Geological Attitudes & 3D Block Diagram Interpretation. Problem 1: Strike and dip of bedding.. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. Atoms & Atomic Particles. An atom is the smallest component of an element that can retain the properties of that element. Atoms are composed of fundamental particles:. Protons. Neutrons. Electrons. Earthquake Mechanisms. Brittle Mechanical Model: “stick-slip”. Focal point: 3D point inside the lithosphere where the seismic event occurs. Epicenter: projection of focal point to the map surface . Geological Attitudes & 3D Block Diagram Interpretation. Problem 1: Strike and dip of bedding.. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. 0. 90. 180. 270. Metamorphism. Causes of Metamorphism. Elevated T & P. Fluids (H2O, CO2, CH4, etc.). Directed Stress. Types of Metamorphism. Regional: occur along convergent plate boundaries.. Contact: occurs along margin of a magma intrusion.. Stress & Strain. Stress: a force applied to an area.. Example: tire pressure in psi.. Strain: a change in original shape or volume (produced by stress).. Elastic strain: analogous to a steel spring or rubber band.. Important Terms. Craton: interior of continents made of stable Precambrian and Paleozoic rocks.. Shield: portion of Craton composed of older Precambrian rocks.. Platform: portion of Craton made of younger relatively undeformed Paleozoic sediments..