Geology Handouts

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Lecture 1 - Introduction to Geology
- study of the earth, its origin, history, materials, processes and resources Geology as a discipline: a. relevance of time, b. issue of scale, c. complexity of replicatingnatural systems in the laboratory Main Branches:

1. Physical - study of Earth materials and processes> Volcanology, Seismology, Environmental Geology, Engineering Geology, Mining Geology, Petroleum Geology, Mineralogy, Petrology, Geomorphology, Geophysics, Geochemistry, Planetary Geology 2. Historical - study of Earth origin and evolution> Paleontology, Stratigraphy, Geochronology Basic Concepts:

1. Catastrophism 
sudden, worldwide catastrophes are the agents of change that alter the physical features of the Earth over timewidely accepted by theologians in the early 1800s due to similarity with Biblical events suchas Noah’s Flood 2. Uniformitarianism

proposed by James Hutton (The Father of Modern Geology)
The present is the key to the past.”
advocates the idea that the Earth is continuously modified by geologic processes that havealways operated throughout time (at different rates), and that by studying them we canunderstand how the Earth has evolved through time

Lecture 2 – The Planet Earth 
FORMATION OF THE EARTH – offshoot of the formation of the Universe Formation of the Universe: Big Bang Theory
Formation of the Solar System: Nebular Hypothesis
contends that the Universe originated from a cosmic explosion (origin unknown) that hurledmatter in all directions 15 and 20 billion years ago first proposed by the Belgian priest Georges Lemaître in the 1920sEdwin Hubble justified Lemaître’s theory through observations that the Universe iscontinuously expanding; galaxies are moving away from each other  THE NEBULAR HYPOTHESIS

the solar system originated from a single rotating cloud of gas and dust, starting 4.6 billionyears ago, which contracted due to gravity the idea was first proposed by Immanuel Kant and Pierre Simon de Laplace in the 18thcentury THE NEBULAR MODEL

The Big Bang produced enormous amount of matter: rotating cloud of gas and dust.The rotating gas-dust cloud began to contract due to gravity. Most of the mass becameconcentrated at the center, forming the SUN. The remaining matter condensed to form the planets.

mostly made up of hydrogen, the principal product of the Big Bang  sun’s center became compressed enough to initiate nuclear reactions, consequentlyemitting light and energy (sun became a star) a middle-aged star 

composition depended on distance from the sun
planets nearest the sun contained high-temp minerals (e.g. iron) while those that are far away contained lower-temp materials (e.g. methane and ammonia, and some thatcontained water locked in their structures) * Mercury, Venus, Earth, Mars - inner or terrestrial planets (nearest the sun) - rocky composition: largely silicate rocks and metals (Si, Fe, O) * Jupiter Saturn Uranus Neptune - giant or Jovian planets (outer planets; far from the sun) - lack solid surfaces: in gaseous or liquid form

- composition: light elements (H, He, Ar, C, O, Ni)
* Pluto - neither a terrestrial or Jovian planet
- similar to the icy satellites of the Jovian planets
1. Planets’ revolution = counterclockwise direction.
2. Planets’ rotation direction the same as direction of revolution except for Venus, which rotatesin a retrograde direction. 3. Uranus and Pluto rotate about axes that are tipped nearly on their sides. 4. Orbital Speed of the Earth = 30 km/s

- started as “dust ball” from the nebular gas and dust brought together by gravity (accretion),which was heated (heating) and eventually segregated into layers (differentiation) as it cooled- when cooling set in, the denser elements (e.g., iron) sank while the lighter ones floated out intothe surface, creating a differentiated Earth CONSEQUENCES OF THE HEATING & DIFFERENTIATION OF THE EARTH

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