Answers to in-class questions:

Week 1:
Chondrule: Small spheres (or round blobs) of rock that crystallized from tiny droplets of magma that were floating in the solar nebula (cloud of gas and dust) from which the sun, planets, moons, asteroids, and comets formed. The textbook definition is incorrect.

Chondrite: A meteorite that is made up of chondrules that have been packed together with dust grains, rock and mineral fragments and organic molecules that were floating in the solar nebula. The most important things about chondrites is that they have a “solar” composition for non-volatile elements and are the only meteorite that never experienced whole-rock melting.

Accretion: The process whereby the solid particles in the solar nebula stuck together to build bigger rocks, asteroids, and eventually (in some cases) planets.

Differentiation: The separation of materials with different densities into layers – specifically in this case, the separation of rock and metal to form a core, mantle, crust structure.


Week 2:

The 3 types of plate boundaries are convergent, divergent, and transform
Convergent: a trench (if subduction is occurring) or a folded mountain belt (if two continents are colliding) occurs at the boundary; oceanic crust is destroyed
Divergent: a rift valley or a midocean ridge occurs at the boundary; oceanic crust is created
Transform: a fault occurs at the boundary; oceanic crust is neither created nor destroyed

Subduction is the process whereby a piece of oceanic lithosphere descends into the mantle at a convergent plate boundary.

Cation:  An atom that has lost one or more electrons and so has a positive charge

Anion:  An atom that has gained one or more electrons and so has a negative charge

Polymorph:  One of many possible mineral structures which corresponds to a single chemical formula.  Examples:  Graphite and diamond are both polymorphs of C.  Kyanite, Sillimanite, and Andalusite are all polymorphs of Al2SiO5.  Quartz, Tridymite, Coesite, and Stishovite are all polymorphs of SiO2.

Iron (Fe) and Magnesium (Mg) easily subsitute for each other in minerals such as olivine, pyroxene, amphibole, biotite, etc.   That's why the chemical formula for olivine is written (Mg, Fe)2SiO4 - with the Mg and Fe in parentheses separated by a comma.


Week 3:

Hematite is the mineral with a red-brown streak
Calcite is the mineral that effervesces in dilute hydrochloric acid (HCl)
Plagioclase feldspar is the mineral that has striations on cleavage planes
You determine the hardness of a mineral by trying to scratch objects of a known hardness, such as a penny or a piece of glass.  If your mineral scratches that object, then your mineral is harder than that object.  If your mineral doesn't scratch that object, then it is softer than that object.
A partial melt is a magma that forms when minerals in a rock begin to melt, but don't completely melt, creating a mixture of mineral grains surrounded by magma.  That magma is referred to as a partial melt.


Week 6:  We did two exercises - The one on Bowen's reaction series is a pdf - CLICK HERE TO FIND IT

Mechanical weathering only breaks material down into smaller pieces, whereas chemical weathering alters the chemistry of the original rocks and minerals.