Physical Geology - Answer Sheet - Test 1 : OnLine Section

QuestionAnswerComments
# 1Athe universe is thought to have formed 10-15 billion years ago
# 2Ciron and nickel are concenrated in the core
# 3E
# 4Ethe first 4 are examples of some of the problems that scientists work on
# 5Ca hypothesis is an "educated guess" that needs to be tested
# 6Bminerals are naturally occurring, crystalline solids with a fixed OR variable composition
# 7C
# 8A
# 9B
# 10Cthe mantle is beneath the crust and above the outer Liquid core
# 11Dsee above
# 12Ethe Moho discontinuity separates crust from mantle
# 13Bthe term crust is used to describe the composition of that part of the Earth whereas lithosphere is used to describe the behavior of that part of the Earth - relatively cold and rigid
# 14A radioactive decay releases heat - volcanic activity is driven by the accumulation of such heat. the Earth is a poor conductor and it takes heat from the core a LONG time to reach the surface.
#15BThe lithosphere is a rigid solid
# 16Bconduction is a transfer process accomplished as the atoms increase their rate of vibration as the temperature is increased
# 17Doceanic crust is created at divergent margins or spreading centers
# 18Eoceanic crust has been recycled several times on Earth and consists primarly of basalt which forms at a much higher temperature than the granite which constitutes the continental crust
# 19Baccretion involves addition of material to a continent /// at a divergent margin new sea floor is formed and plates slide past one another at a transform boundary
# 20DThe asthenosphere is hot and plastic and flow can occur
# 21Aabout the same rate as finger nails grow
# 22DLaurasia - the northern hemisphere continents in Pangaea - Gondwanaland - the southern hemisphere continents in Pangaea
# 23Aconvergent boundaries can possess a deep-sea trench, shallow, intermediate to deep earthquakes and volcanic activity
# 24Batomic number - the number of protons in the nucleus : mass number - the number of protons plus neutrons in the nucleus
# 25Cisotopes are atoms of the same element (therefore same number of protons) that differ in mass -- the difference, therefore, is in the number of neutrons
# 26Aionic bonds involve a transfer of electrons whereas covalent bonding involves sharing electrons
# 27Dthe most abundant element in the continental crust is oxygen but oxygen forms anions (has a negative charge). Silicon is the second most abundant element and forms cations (has a positive charge)
# 28DTectosilicates involve the sharing of all 4 oxygens per tetrahedron
# 29APlagioclase feldspar is the most abundant mineral in the oceanic crust and olivine is the most abundant mineral in the mantle
# 30Esee above
# 31BPlagioclases cover a significant temperature range. While olivine, pyroxene, amphibole and biotite are precipating as the temperature decreases the plagioclase is becoming enriched in the element sodium - Na
# 32Erhyolites form by rapid cooling whereas granites form by slow cooling
# 33Cquartz crystallizes about 600 degrees C and is the last rock forming mineral to crystallize from a melt
# 34BWhen melts of the composition of oceanic crust are allowed to cool slowly a coarse grained gabbro can form
# 35Ain general, viscosity (the resistance to flow of a liquid or fluid) increases as the temperature decreases. high temperature melts flow easily compared with low temperature melts and gabbro forms at a higher temperature than any of these rocks
# 36Cthe other minerals formed at higher temperatures and react more rapidly at the Earth's surface with the reactive atmosphere
# 37Bdiamond and graphite are two well known polymorphs - they have identical chemical compostions (both are pure carbon) but differ in structure -- hence the difference in physical properties. 
# 38Awith the exception of quartz, all common silicates exhibit solid solution
# 39DIncreasing pressure favors small volumes (material compresses) and smaller volumes mean that the mass is packed more tightly - hence the higher density
# 40Bthe longer the time for growth, the larger the minerals tend to be....rapid cooling leads to very small crystals
# 41Aeach of the common mineral assemblages forms at a different temperature -- olivine and Ca-rich plagioclase form at high temperatures than alkali feldspar and quartz
# 42Athe Aleutian islands are an island arc - formed where once piece of oceanic crust is subducted beneath another
# 43BB is a spreading center - formation of new oceanic lithosphere - basalts form at speading centers
# 44Dstratovolcanoes are andesitic - andesitic volcanism accompanies subduction - where a piece of oceanic lithosphere (more dense) is subducted beneath continental crust or oceanic crust
# 45Ba sill is "parallel" to the enclosing structure whereas a dike cuts across the enclosing structure
# 46Bhigher temperatures and water promote the rates of chemical reactions
# 47AQuartz has a density of about 2.6 g/cc - the others are higher
# 48Bthe boundary between Europe and Asia
# 49Awhere the Juan de Fuca plate is subducted beneath North America
# 50Cwithin the Pacific Plate

The average was a 33 or 66%


Use the following scale to give you an idea as to how I would evaluate your performance on this one exam:

84 - 100 : Very Good
70 - 83 : Good
58-69 : OK
50 - 57 : Not So Good
<50 ????