ESCI 110 Intro to the Earth
Dr. Steven B. Newman
Exam 1 Study Guide
Use this as an outline to focus your study on topics we covered in class. This outline is NOT intended to
be a complete guide to everything we have covered in class.
Chapter 2 Minerals
-Basic building blocks of solid earth; Four criteria—solid, inorganic (no carbon-hydrogen
bonds); naturally occurring; definite chemical composition.
-Made of elements (either alone or bonded together). Some bonds stronger than others.
-Mineral identification based on certain physical properties
-crystal structure
-cleavage (tendency to break on flat planes)
-fracture (absence of cleavage)
-hardness (resistance to scratching); Mohs Scale (talc =1, diamond = 10)
-color
-streak (color of mineral scratch mark on unglazed porcelain)
-luster (how light is reflected—metallic, earthy, pearly, etc.)
-others (reaction to acids, taste, feel, magnetic properties, etc.)
-Rock-forming minerals (silicates)
-92% of all minerals found
-based on silicate ion (SiO4)—silicon-oxygen tetrahedron
-Mafic silicates—dark in color due to iron and magnesium content
-Felsic silicates—light in color due to feldspar and silica, little iron or Mg
-Non-silicates (only 8% of minerals)
-includes ores such as malachite, sphalerite, galena, gold, silver
-Carbonates (CaCO3 as major ion) include limestone, marble
-Evaporites (minerals left when solutions evaporate): halite, gypsum
-Hazardous minerals
-vermiculite (produces asbestos fibers when heated)
-asbestos itself is a mineral which can produce carcinogenic fibers
-radon gas from decay of uranium
-silicosis (from exposure to silicon and quartz dust) and black lung
(from exposure to coal dust)
Chapter 3 Rocks
-Rock Cycle begins with magma and proceeds through sedimentary and metamorphic
rocks. Eventually destroys rocks and starts them over again.
-Three types of rocks: igneous, sedimentary, metamorphic
-Igneous rocks: from magma (intrusive, below ground) or lava (extrusive, at
the surface.
-Can be coarse grained (slow cooling) or fine grained (rapid cooling). Classified
by their grain and composition. Basaltic (mafic) igneous rocks are darker.
Principal type is basalt. Granitic (felsic) igneous rocks are lighter. Principal
type is granite (very hard rock—used in tombstones).
-Sedimentary rocks: formed from weathered or eroded pieces of existing rocks.
Can be detrital (clastic): conglomerate, breccia, sandstone, siltstone, shale (in
order of decreasing particle size). Can also be chemical (from bits of material
due to chemical reactions); most common is limestone. Bioclastic sed. Rocks
such as chalk, or coquina also exist. Travertine is dissolved and resolidified
limestone found in caverns (where you find stalactites and stalagmites—which is
which?)
-Metamorphic rocks: formed by heat and pressure on existing rocks. Often
realigns crystal elements in the rock to give a banded structure (foliation). Most
common types are slate, schist and gneiss (from shale), quartzite (from
sandstone) and marble (from limestone—not banded).
Chapter 6 Plate Tectonics
-Theory of Continental Drift: proposed in 1915 by Alfred Wegener. Used fossil
rock, and glacial evidence along with good fit of continents to propose a supercontinent
(Pangaea) some 250 million years ago, that began to break apart. Not accepted at first
due to lack of mechanism for movement.
-Earth’s internal structure
-Crust: 4-70 km thick (thinnest under oceans)
-Upper mantle and crust make up the lithosphere
-Asthenosphere: mantle below the crust. Rock is not quite solid or liquid, but
more like a plastic layer. Lithosphere “floats” on this layer.
-Outer core: liquid layer below the mantle.
-Inner core: solid iron and nickel at earth’s center. About 2400 km diameter.
-Additional evidence for continental drift: paleomagnetism, drifting of magnetic poles
through time, alignment of magnetic elements in rock to old polar locations, pole
reversals, sea floor spreading and age of rocks away from Mid-Atlantic Ridge.
-Theory of Plate Tectonics: crust composed of approx. 20 plates that float on the
asthenosphere. Creates boundaries where plates adjoin.
-Divergent boundary: plates spread apart. New crust created. MidAtlantic Ridge is prime example.
-Transform boundary: plates slide past one another. Many strong earthquakes
are found at transform boundaries. San Andreas fault is an example.
-Convergent boundaries: plates collide. Three types:
-oceanic-oceanic: one plate slides (subducts) below the other. Creates
strings of volcanoes in the ocean (island arcs): Japan, Phillipines, etc.
-oceanic-continental: oceanic plate subducts below continental plate.
Creates strings of volcanoes on the continent (volcanic arcs). Cascades
in California, Oregon and Washington are examples.
-continental-continental: plates smash together, creating large mountains,
like the Himalayas.
-Hot spots: magma plums near center of plate pokes through to crust and
creates a volcanic islands. As plate moves, new islands form. This is how
the Hawaiian Islands formed. Hawaii is still active over the spot.