Atoms - Neutrons (n)- Protons (p)- Electrons (e)
1) Atom: the minimum unit an element can be divided into
that still retains its chemical properties
parts of the atom
protons (p)
Atomic #: C=6
nucleous
+ neutrons
# p = # e
__________________
Z = Atomic Mass #
C14
neutral
electrons (negative)
atom
Atoms of a given element have a constant # of protons
2) Atoms of the same element have = number of protons
Isotopes same element = number of protons and different
number of neutrons
C Isotopes = 6 protons
E.g. 6C12
6C13
6C14
6n
7n
8n
3) Ions: charged
cation (Atom - e-) lost e-!
anion (Atom + e-) gained + e-!
covalent share e-
Bonding: ionic
oppositely charged ions attracted
metallic e- move freely around aggregate of ions
van der Waals: weakest
4) Periodic Table of the elements: elements in the same group -> similar chemical properties given by their atomic structure
5) Chemical compound: combination of 2 or more elements
defined properties & proportions
different from those of indiv. element.
Minerals General
Definition natural
inorganic
solid
element or compound
definite composition
regular internal crystal structure
macroscopic scale
microscopic scale
Amorphous
Identification chemical composition
arrangement of its crystal structure
Physical properties: crystal form & habit (related to crystal
structure)
hardness
luster
fracture
cleavage
specific gravity
streak
magnetism
color
acid test
Hardness Mohs Scale from 1 to 10
1. Talc, 10 diamond
Mineral Groups (on the basis of their anions)
clays (expansive), micas
Silicates
Quartz
most common feldspar (most abundant):
orthoclase, plagioclase.
minerals
Ferromagnesian: biotite, olivine, hornblende
Halides: halite, fluorite
Carbonates: dolomite, calcite
Non
Sulfates: gypsum
Silicates
Sulfides: pyrite, chalcopyrite, sphalerite, galena
Oxides: hematite, magnetite
Native elements: Ag Cu, Au (C= diamond), S
Silicates' structures are based in the silicate tetrahedron unit: one Si atom surrounded by 4 oxygen atoms
Rocks
Rock
solid
def.
cohesive or poorly consolidated
aggregate: 1 or more minerals
naturally occurring inorg. or organic matter
physical properties suitability to our
purposes
imprint of its latest history
Classes based upon their origin: Igneous, Sedimentary and Metamorphic
no poral space
Igneous Rocks:
little or no water
structurally strong Igneous Rocks
magma: molten silicate mat. + crystals + H2O + gas
high T
solidification (cooling) + crystallization of magma => Igneous Rocks
Factors controlling grain size: TIME
space
abundance of nutrients
Plutonic Rock: slow cooling of magma
Large
Igneous
at depth
crystals
Rocks
granite
Pegmatite ( grainsize > 1 inch)
Volcanic Rocks: quick "freezing" of magma
small
at the surface
crystals
+
lava
glass
Examples: obsidian, basalt
Sedimentary Rocks: surface processes
- Low temp
Sediments
loose accumulations ( of min. & rocks)
transported by
wind
e.g.
water
sand,
ice
mud,
gravity
chem. sed.
deposited
Sedimentary rock: solid cohesive mass formed after compaction and cementation
(LITHIFICATION) of sediments
Clastic sedimentary rocks
Formation
mechanical
weathering
of
processes
erosion
Sed. Rock.
transport
accumulation
(burial)
compaction
(percolating H2O)
cementation
Classification = grainsize
clay = less than 1/256 mm, SHALE
MUDSTONES
silt = 1/256 to 1/16 mm, SILTSTONE
sand = 1/16 to 2 mm, SANDSTONE
gravel = more than 2 mm, CONGLOMERATE
Poral space depends on rounding and sorting
Not structurally strong, unless cemented
Accumulation occurs if Gravity > transportation force
Bedding or Layering: cyclic transport - deposition
They are good identifiers of sedimentary origin
Chemical sedimentary rocks
Precipitation from solutions
limestones
seawater
freshwater
mineral = calcite = CO3Ca
Evaporitic deposits
rock salt (evaporation)
mineral = Halite =
Cl Na
Organogenic: Skeletons - Shells
organic debris
Coquina =
+
inorganic precipitates
Coal = plant debris
Metamorphic rocks
1) Formed under the influence of heat &/or pressure &/or fluids
2) Metamorphism: the process
recrystallization
neomineralization
P
deformation - stretch
compression
in solid
folding
(plastic) state
3) Sources of P & T: P burial
tectonic differential = directed stress
T thermal gradient
intrusion of magma
Contrast between Regional & Contact metamorphism
Local source of To magma proximity = Contact Metamorphism.
Large scale source of P & To mountain building = Regional Metamorphism.
Directed stress foliation (platy minerals)
Foliated texture = minerals arranged in parallel fashion
slate - phyllite - micaschist - gneiss
Gneiss as a textural term: Alternating bands of dark and
light minerals
Metamorphic grade
Temperature attained during metamorphism, as indicated by the
new minerals which grow in the rock.
SED.R.
MET. ROCK
shale
=> slate
=> phyllite =>
micaschist =>
gneiss
clay
muscovite muscovite
biotite
garnet
minerals
chlorite
garnet
biotite
feldspar
=========================================================>
Arrow indicates increasing metamorphic grade
(chemical composition remains constant)
Non foliated rocks and their protoliths (rock sources)
Parent rock Met. rock
sandstone =======> quartzite
limestone ========> marble
granite ==========> orthogneiss
basalt ===========> amphibolite
Important Concept: THE ROCK CYCLE
ROCKS AND MINERALS - REVIEW TOPICS
1. Know the definitions of all the terms mentioned in the "Terms to
remember" section of your text. They are
defined throughout the chapter and ordered alphabetically in the text Glossary
2. Physical properties of minerals.
3. Classification of minerals in groups. Examples of at least one mineral
of each group.
4. Know how to classify igneous rocks. Concepts involving all new vocabulary.
5. Know texture, minerals and type of magma for
GRANITE and BASALT. Remember that the oceanic crust is basaltic in composition
and the continental crust is granitic in bulk composition.
6. Bowen Reaction series: continuous and discontinuous.
(If not covered in class, we may see it later, with volcanism)
7. Classification of sedimentary rocks: Clastic and Chemical
Sed. Rocks. Composition. Examples.
8. Agents and changes related to metamorphism. Classification
of Metamorphic rocks. Factors prevailing
in Regional Metamorphism and Contact Metamorphism.
9. The concept of metamorphic grade.
10. Terms: foliation, schistosity, slate,
phyllite, schist, gneiss.
11. Common metamorphic equivalents to sedimentary
or igneous rocks.
12. The Rock cycle: processes to go from one rock type
to the other.