EAR 110 1st Edition Lecture 3 Outline of Previous Lecture:I. Forces and processes that affect the earth’s materialsII. Energies of EnvironmentsIII. Igneous rocksIV. Other rocks formed in hot or deep conditionsV. The Rock CycleVI. Earth’s 4 spheresVII. Earth and the Solar systemOutline of Current Lecture: I. Case study: Black Hills of DakotaII. Chapter 2: Investigating Geologic Questions IntroductionIII. Evolution of landscapesIV. Determining the Geologic Sequence of Events (i.e. position of layers)V. Types of mapsCh 1: the Nature of Geology continuedCh 2: Investigating Geologic QuestionsI. Case study: Black Hills of Dakotaa. The area has older rocks that were uplifted; younger rocks tilted away from rangeb. Rapid Creek flows through Rapid cityc. In 1972, this was the site of a large flood due to intense thunderstorms in the canyonII. Chapter 2: Investigating Geologic Questions Introductiona. Observe a map of the Mediterranean Sea i. Closed drainage basin –not a lot of inflows into the seaii. Eventually this will lead to salty waters as evaporation exceeds precipitation so the concentration of salts in the water will increase as more water leaves the seathan is coming iniii. Evaporites – elements that remain after all water has evaporated, such as salt and gypsum (used in dry wall)1. Note: salt domes – salt behaves plasticly (able to flow), so eventually it will flow upward under enough pressure and form a domeIII. Evolution of landscapesa. Lithification – process of making rocksb. Landscapes change with time as rocks weather, are uplifted etc. i. Example of weathering: mesa  butteknobs/knolls (hills)flat surfacec. You can infer characteristics about the landscape at the time rocks were madei. Example – Iron (Fe) normally has no charge, however when it is exposed to oxygen it becomes oxidized and becomes red in color (rust); so bands of rock that are red indicate periods the rock was exposed to the atmosphereThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.IV. Determining the Geologic Sequence of Events (i.e. position of layers)a. Principle of original horizontality: when layers are deposited, they are deposited in horizontal layers; if layers are tilted etc, then an event occurred AFTER the rocks were formed; the originally form flat rowsb. Lower layers are deposited first, upper layers later onc. Principle of cross cutting relations: layers must exist before faults; if a fault cuts through layers, then the fault is younger than the layerd. Pieces of older rock can be found inside younger rock if the rock began to weather and then soil formed around it, then was lithifiede. Cross cutting by magma intrusions creates contact effects on the edges of the rock it intruded into; creates contact metamorphismf. Unconformities – separation of two rock massesV. Types of mapsa. Shaded relief maps – have shadows to show dimensionb. Topographic maps – map with elevation contour lines (levels of equal elevation)i. Steep slopes have lines closely spaced togetherc. Satellite images – obtained from the air; can be falsely colored/shaded to categorize features in the imaged. Geologic maps – show the rock type that occurs at the