Lecture note 1
Earth Science is the study of the Earth and its neighbors in space
the four basic areas of Earth science study are: geology, meteorology, oceanography and astronomy.
Geology deals with the composition of Earth materials, Earth structures, and Earth processes. It is also concerned with the organisms of the planet and how the planet has changed over time. Geologists search for fuels and minerals, study natural hazards, and work to protect Earth's environment
Meteorology is the study of the atmosphere and how processes in the atmosphere determine Earth's weather and climate
Oceanography is the study of Earth's oceans - their composition, movement, organisms and processes.
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6 billion years ago from the collapse of a giant cloud of gas and dust, called a nebula
Lecture note 4. Plate tectonics
Earth is composed of several layers. On the outside is the relatively cold, brittle crust. Below the crust is the hot, convecting mantle. At the center is the dense, metallic inner core.
One way scientists learn about Earth’s interior is by looking at seismic waves. Seismic waves travel outward in all directions from where the ground breaks at an earthquake
Scientists also learn about Earth’s interior from rocks from outer space
Crust and lithosphere
Earth’s outer surface is its crust; a thin, brittle outer shell made of rock. The outermost, brittle, mechanical layer is called the lithosphere. The difference between crust and lithosphere is that lithosphere includes the uppermost mantle, which is also brittle.
two very different types of crust: oceanic crust and continental crust.
Oceanic crust is thin, between 5 to 12 kilometers thick (3 - 8 miles). made of basalt lavas Beneath the basalt is gabbro. The basalt and gabbro are dense. Sediments cover much of the oceanic crust, primarily rock dust and the shells of microscopic sea creatures, called plankton.
Continental crust is much thicker than oceanic crust, around 35 kilometers (22 miles) thick on average. Continental crust is made up of many different rocks of all three major types: igneous, metamorphic, and sedimentary. The average composition of continental crust is about that of granite. Granite is much less dense (2.7 g/cm3) than the basalt and gabbro of the oceanic crust..
Oceanic lithosphere is about 100 kilometers thick. Continental lithosphere is about 250 kilometers thick.
Made of rock and extremely hot
Scientists know that the core is metal for two reasons: The first is that some meteorites are metallic and they are thought to be representative of the core. The second is that the density of Earth’s surface layers is much less than the overall density of the planet
. Continental drift
continents move around on Earth’s surface and that they were once joined together as a single supercontinent.
Relative motion of plates defines the three types of plate boundaries:
• Divergent plate boundaries: the two plates move away from each other.
• Convergent plate boundaries: the two plates move towards each other.
• Transform plate boundaries: the two plates slip past each other.
Lecture note 5. Earthquakes and Volcanoes
There are four types of stresses that act on materials
A deeply buried rock is pushed down by the weight of all the material above it This is called confining stress
Compression is the stress that squeezes rocks together. Compression causes rocks to fold or fracture. Compression is the most common stress at convergent plate boundaries
Rocks that are being pulled apart are under tension (also called extension). Tension causes rocks to lengthen or break apart. Tension is the major type of stress found at divergent...