Geology & the Geosphere Educational Posters, Charts & Maps
for the science classroom and home schoolers.

Like the pieces of a giant jigsaw puzzle, slabs of rocky crust known as tectonic plates fit together to form the Earth's outer shell. The puzzle changes as the plates slide over the hotter, softer rocks beneath them. Moving by mere inches annually, they reshape continents and oceans basins over the millions of years by colliding, separating and scraping past one another with relentless force. These interactions set off earthquakes, fire up volcanoes, and wrinkle the Earth's crust into mountains, valleys, and deep-sea trenches.

Most earthquakes occur near plate boundaries, where rock grinds past rock. Friction keeps the plate edges from sliding smoothly. The longer they remain stuck, the more strain builds and the more violent the snap and resulting vibrations – the earthquake.

Subduction Zones are when one plate dives beneath another plate. Oceanic plates subduct under continents and perhaps under other oceanic plates as well, forming trenches that mark their descent. Where continental plates run into each other, they buckle, creating ranges such as the Himalaya.

Transform Faults occur when tectonic plates shift past each other horizontally - a distinct type of strike-slip fault. The San Andreas Fault is a slow creep with frequent small jumps and rare big ones.

Volcanoes are magma rising to the surface from insie the Earth mainly at subduction zones and spreading centers. The edge of the Pacific Basin – the 30,000 mile long Ring of Fire– is especially volatile, with about 70 percent of the world's more than 500 historically active volcanoes.

Hot spots are the scrattering of places where magma burns through a tectonic plate. Each hot spot likely marks the top of a plume of semimolten rock that rises many hundreds of miles inside the Earth. As a plate slowly passes above, the plume melts into it, creating a chain of volcanoes such as those in the Hawaiian Islands.

Spreading Centers are where the tectonic plates move apart allowing magma to rise in the resulting rift. Under the oceans this process has created the 46,600-mile-long Mid-Ocean Ridge system, segmented by faults, that snake around the globe. On land the process is creating the East African Rift System

Geosphere: Rock Cycle

Poster Text: In the rock cycle, rock is neither created nor destroyed, but is continually recycled. Rock changes both physically and chemically, and is redistributed and transformed. Under the crust of the Earth is a circulating layer of liquid molten rock known as magma. When magma cools and solifies underground or above ground it becomes igneous rock. Igneous rock, through heat and pressure can be transformed into metamorphic rock. Once rocks are ... on the surface of the Earth, weather and erosion produce sediment. The sediment is transported and deposited in layers, which undergo compaction to become sedimentary rock. Sedimentary rock can also become exposed to the same process that created it. Some rock becomes magma again through tectonic areas known as subduction zones. It is at these zones that one tectonic plate is pushed down under another....

Geosphere: Plate Tectonics

Poster Text: The earth upon which we stand may seem solid and still, but in fact is in constant motion. That motion is explained in the theory of plate tectonics. The outermost layer of the Earth, the lithosphere, contains the continental crust and oceanic crusts. Those crusts are divided into separate land masses know as plates. These plates are floating on a molten layer of magma and rock called the ... and moving toward each other due to ....

Volcanoes

Volcanoes are openings in a planet's surface where hot, molten (melted) rock, ash and gas escape from below the surface.

• more natural phenomena posters
• mountain posters

Earth Processes Poster Series

volcanoes, earthquakes, plate tectonics, faults & folds, erosion & weathering, glaciers, rocks & minerals

Earthquakes

• more natural phenomena posters

Minerals are naturally occurring substances formed through geological processes. A mineral has a characteristic chemical composition, a highly ordered atomic structure and specific physical properties; in comparison a rock is an aggregate of minerals and may not have a specific chemical composition. Minerals range from pure elements and simple salts to very complex compositions of silicates with thousands of known forms. The softest mineral is talc, the hardest mineral is diamond (April Birthstone).

The study of minerals is called mineralogy. Mining is the extraction of valuable minerals or other geological materials from the earth.

Examples pictured above: gold, diamond, sulpher, copper, sphalerite, pyrite, chalcopyrite, cinnabar, stibnite, galena, fluorite, corundum, quartz, hematite, rutile, cassiterite, agate, amethyst, magnetite, calcite, rhodochrosite, malachite, azurite, dolomite, ... wulfenite, barite, celestite, anglesite, gypsum, apatite, turquoise, garnet, tourmaline, topaz, beryl, spodumene, orthoclase, analcite, scolectiz.

Meteorites are natural objects originating in outer space that survives impact with Earth's surface.

Most meteorites are stony, about 5% are iron-nickel alloys, and about 1% are a stony-iron combination.

• astronomy - space phenomena