GEOL 102 Exam 1 GMU Questions And Answers With Latest Study Quiz

Physical geology vs. Historical geology - Physical geology deals with materials and processes that make up the Earth, Historical geology is applying chronology to events in Earth's past Relative age - Determination that something is younger or older than something else Absolute Age - Precise measurement of how much time has passed since something was created or modified Fossils - Remains, traces, or other indications of life Principal of Original Horizontality - Sediment is deposited in layers that are originally horizontal Principle of Original Lateral Continuity - Rock layers extend in all directions until they thin out, encounter a barrier, or grade laterally into another rock type Concept of Uniformitarianism - The present is the key to understanding the past. Past history of Earth must be explained by what is happening now Principle of Actualism - Natural laws do not change with time Concept of Catastrophism - History of life on Earth is marked by catastrophes. Each calamity extinguishes all life on earth and new animals and plants appear after Principal of Natural Selection - Species evolve over time and the most favorable traits pass on to the next generation and the rest die off. What are the Eon divisions in the Geologic TimeScale - Phanerzoic (541 Ma), Proterozoic (0.541 - 2.5 Ga) , Archean (2.5 Ga - 4.0 Ga) , Hadean(4.0 Ga - 4.6 Ga): Youngest to OldestPrinciple of Superposition - in undisturbed layers of rock, the oldest rocks are on the bottom and the rocks become progressively younger toward the top Principle of Cross-Cutting - younger features cut across older features in rock strata How can radioactive materials be used to determine the ages of geologic samples? - Radiometric dating uses the decay of specific element isotopes to determine the absolute age of a rock What is half-life? - The time required for half of a given amount of an unstable parent to decay to a daughter isotope/element. It is nonlinear. What are the requirements for a material to be a mineral? - Occurs naturally as an inorganic solid/Has specific internal structure/Has specific chemical composition How are minerals defined? - Based on their properties and chemical composition. What are some tests you can do to identify a mineral? - Microscopic analysis or a field test kit(Physical properties) that check color, streak, luster, cleavage, fracture, hardness, crystal shape. Silicate minerals - Silicate minerals contain silicon(Si) and Oxygen(O) and bind together in the shape of a tetrahedron Non-silicate minerals - Carbonates, sulfates, sulfides, chlorides, oxides What are the requirements for a material to be a rock? - Rock is a solid material that occurs naturally and is composed of one or more minerals/organic material How are igneous rocks formed? - Form from solidification of molten rock(magma or lava)/ melting of a rockDo all minerals in igneous rocks crystalize at the same time? - No minerals crystallize from cooling magma in a systematic sequence Intrusive vs. Extrusive Igneous Rocks - Intrusive solidifies underground and Extrusive solidify on the surface where they cool much faster and become fine-grained