Geology 1
Terms
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- Purpose of Geology
- -Understand the origin , operation and evolution of Earth -Find resources -Prevent contamination -Predict sudden movements
- Universe began...
- 13.7 billion years ago as a small, dense mass that began to suddenly expand.
- Stars
- thermonuclear fusion reactors, New Stars are \"born\" from the rmains of past stars and other matter. Finite lifetimes.
- Nebular Theory
- Formed from older material. Slowlyrotating gas gets smaller and faster. Pressure and heat increase. 10% becomes proto-sun (concentrated matter) and fusion begins. Planets form from the rest of the debris. Rocky/metal planets are closest to the sun and gaseous are farther away due to \"solar winds\". Then \"icy\" planets form from frozeen gas. Everything is disk shaped.
- Jovian Planets
- \"Gas Giants\"
- Extrasolar Planets
- other planets that rotate their own sun. Very large with short rotation. 422 discovered.
- How to detect extrasolar planets
- 1. Gravity (wobble) method: detect the gravitational influence of a planet on light coming from a star (dopler effect) Transit (wink) method: detect periodic dimming of star\'s light caused by a planet moving in front of its star during orbit.
- Earth\'s formation
- 4.57 Billion years ago Homogeneous composition Very hot due to collisions, compression and radioactivity (decay of isotopes). After 50 million years Earth reached iron\'s melting point (the Iron Catastrophe) causing convection. Results in layering 4.4 billion years ago.
- Layers of the Earth
- Core (densest, molten the solid layer, 6000 C), mantle (dense, 80% of Earth;s volume), and crust (oceanic or continental).
- Formation of the Moon
- 4.5 billion years ago A Mars sized object hits Earth and the debris coalesced into the Moon. Tilted the Earth\'s Axis. The gravitational pull helps stabilize our tilt. The moon was originally 10x closer.
- Development of Atmosphere
- 1st-Helium and hydrogen (blown away) 2nd- CO2 and Nitrogen (from volcanoes). Colling condenses water vapor and allows for life to form. Cyanobacteria (single celled, 3.8 bya, ocean) consumed CO2 and produced oxygen (photosynthesis). Atmosphere becomes oxygen rich.
- Ozone radiation
- blocking gas in upper atmosphere from atmospheric oxygen.
- Eons
- Primary geological time divisions. Precambrian: 4.5-0.54 Ga (87% of Earth\'s history) Phanerozoic: 0.54 ga- present
- Appearance of life
- multi-cellular/shell creatures= 3.5 GA. Only marine and had hard parts. 500 MA (Vertebrates) 430 MA (plants) 300 MA (insects) 200 MA (Dinosaurs and mammals) 0.5 MA (Homo sapien)
- Eras
- Paleozoic, Mesozoic, Cenozoic.
- Environmental Geology
- the study of interactions between geological processes and society.
- Natural Hazard
- a process in nature that poses a threat to our property of well-being. Results in Natural Disaster (Catastrophe)
- GC or H?
- GC= potential global catastophe (meteorite, volcano) H= Requires human interaction to be dangerous (Earthquakes, tsunami)