what are the 3 kinds of north displayed on a map?
true north, magnetic north, and grid north
National Topographic System (NTS)
Canada's official map index system divides into large, numbered blocks based on lat+long designed to locate areas, not points
Universal Transverse Mercator (UTM)
designed to locate points, not areas numeric code only, no number/letter combos uses a decimal system rather than degrees-minutes-seconds 2cm = 1km ex. zone 11 699 100 easting 5657 250 northing
Latitude and Longitude
divide earth with lines W-E = longitude N-S = latitude ex. 114°9'40" W 51°1'40" N
colour
least reliable physical property. felsic = light mafic = dark
lustre
quality of light reflected from a mineral: metallic, vitreous, earthy
hardness
measure of how easily a mineral can be scratched
streak
refers to the colour of a powdered mineral
cleavage
a mineral's ability to split easily along flat points of weakness.
habit
the shape of an unbroken mineral crystal; shape it naturally forms
homogenous
made up of a single material
heterogenous
made up of several materials
biogenic
consisting of the remains of organisms or formed due to the activity of organisms
abiogenic
resulting from non-biological chemical reactions
aggregate of crystals
rock composed of many crystals
aggregate of grains
rock composed of fragments of: rocks, crystals, or fossils that show signs of physical reworking from current transport or erosion
amorphous
does not contain crystals or grains, typically glassy
mineral
a naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition
fossil
any evidence of life in the rock record. includes plant and animal remains as well as traces of biological activities (footprints)
rock
aggregate of mineral crystals, fossils, grains, or a mass of natural glass
Igneous rocks form by
the crystallization of molten magma or lava (intergrown crystals)
intrusive igneous rock
rock that forms below Earth's surface (longer to cool, typically larger crystals)
extrusive igneous rock
rock that forms from the cooling and crystallization above the Earth's surface (less time to cool, typically smaller crystals)
phaneritic texture
coarse-grained, crystals are large enough to be seen by naked eye, formed by slow cooling (intrusive)
aphanitic texture
fine grained, crystals cannot be seen with the naked eye, formed by fast cooling (extrusive)
glassy/amorphous texture
A texture formed when a rock cools so fast it doesn't have time to crystallize
porphyritic texture
an igneous texture consisting of large crystals embedded in a matrix of much smaller crystals
phenocrysts
large crystals in porphyritic rocks (igneous)
vesicular texture
describes a rock containing vesicles caused by gas being trapped during crystallization
mafic rocks (igneous)
dark-colored rocks that are silica poor and iron and magnesium rich. examples: olivine, pyroxene, plagioclase, and amphibole
intermediate rocks (igneous)
examples: plagioclase, hornblende, quartz, pyroxene, biotite, k-feldspar
felsic rocks (igneous)
light colored rocks that are silica rich and iron and magnesium poor. examples: plagioclase, k-feldspar, quartz, amphibole, and biotite
sedimentary rocks form by:
sediments by compaction and cementation, evaporation of water & organic remains
crystalline texture (non-clastic, sedimentary)
a term for the texture of sedimentary rocks in which the minerals form a pattern of interlocking crystals
consist of inter-grown crystals (may resemble igneous rocks)
clastic texture (sedimentary)
a term for the texture of sedimentary rocks in which an aggregate of grains have been subsequently cemented together
chemical vs clastic sedimentary rocks
clastic: deposition and subsequent cementation and compaction of sediment chemical: precipitation of minerals out of a solution (ex. limestone and rock salt)
framework
consists of packed clasts that are partial or in full contact with one another (majority of rock)
matrix
consists of smaller grains that fill spaces between the larger framework grains
cement
bind the framework and matrix to form sedimentary rocks
pore space
non-solid space between grains that is filled with fluid or gas
conglomerate
a sedimentary rock made from small rounded stones that have been cemented together
breccia
coarse sedimentary rock consisting of angular fragments; or rock broken into angular fragments by faulting
sorting
refers to the uniformity of grain size; well sorted sediments will have grains of approximately equal size
planar bedding
horizontal sedimentary beds that are roughly parallel to each other
ripple marks
Small waves of sediment formed by running water or blowing wind
asymmetrical ripples
indicate water or wind flowing in one direction (think river)
symmetrical ripples
indicate water or wind flowing in an oscillatory pattern (think tide/waves)
cross bedding
refers to large scale equivalent of ripple cross lamina (dip towards dominant current direction)
graded bedding
type of bedding in which particle sizes become progressively heavier and coarser toward the bottom layers
a rock is considered dolomitic when:
it reacts WEAKLY with HCl
Metamorphic rocks form from
igneous and sedimentary rocks that undergo a significant change in pressure or temperature. NO MELTING OCCURS
regional metamorphism
formation of metamorphic rock bodies that are hundreds of square kilometers in size *convergent boundaries/mountain ranges
contact metamorphism
formation of a metamorphic rock caused by magma coming into contact with existing rock
foliation
an arrangement of minerals in flat or wavy parallel bands.
metamorphic index minerals (lowest to highest)
chlorite (green) biotite/muscovite garnet (red) kyanite (blue)
porphyroblast
large crystals that form in solid rock by the reorganization of atoms during metamorphism
protolith
the original rock from which a metamorphic rock formed
slate
a metamorphic rock with clean, flat breakage along closely spaced planes due to parallel arrangement of microscopic crystals of clay and mica (slaty texture). Slates are shinier than shales, generally having an egg-shell sheen
phyllite
a metamorphic rock with very closely spaced parallel planes and glossy appearance due to the parallel alignment of microscopic mica crystals (phyllitic texture).Phyllite is shinier than slate because the reflective mica crystals are larger, giving the rock a satin sheen
schist
a metamorphic rock with approximately parallel arrangement of mica crystals large enough to see with the naked eye (schistose texture). To fully name a schist, you must include one to two of its most common index minerals.
gneiss
a metamorphic rock with discrete layers of different mineral content giving the rock a banded appearance (gneissic texture). Typically, the dark bands are composed of hornblende and/or biotite, whereas the light bands are composed of quartz and feldspars
the protolith mudstone/shale can become what after metamorphosis?
slate phyllite schist
the protolith mudstone/felsic igneous rock can become what after metamorphosis?
gneiss
the protolith quartz sandstone can become what after metamorphosis?
quartzite
the protoliths limestone or dolostone (carbonate rocks) can become what after metamorphosis?
marble
if the protolith is a conglomerate what can this become after metamorphosis
metaconglomerate
if the protolith is a mafic igneous rock like basalt or gabbro what can this become after metamorphosis
amphibolite
3 methods of direct preservation that produce unaltered remains
unaltered, desiccation, embedding
unaltered preservation
hard parts remain unchanged (shells, bones, teeth)
desiccation
freezing or mummification under dry (desert) or acidic (bog) conditions
embedding
in wax and amber (desiccation also occurs in this mold)
5 methods of direct preservation that produce altered remains
recrystallization, replacement, permineralization, petrification, and carbonization
recrystallization
minerals change to a more stable form without changing chemical composition. often involves an increase in crystal size and makes shells more dull
replacement
minerals making up a fossil are completely replaced by a new mineral with a different composition
permineralization
pores, or empty body chambers are filled with a mineral
petrifaction
organic tissue of fossil is replaced by a new mineral. note: pores within the tissue are permineralized
carbonization
volatiles like water are removed (often via heat and compaction) leaving a thin, carbon film
what are the 2 methods of indirect preservation?
molds and casts
molds
impressions of remains external: organism stamped into sediment internal: interior of organism is filled with sediment and shell dissolves away, leaving behind an internal mold note: mold is a negative (inverse of original shape)
casts
exact replicas of remains if an external mold is filled with sediment/minerals, a cast is created. note: cast is a positive (same as original shape)
principle of original horizontality
sediments are originally deposited on horizontal or nearly-horizontal surfaces
principle of superposition
rocks that are highest in an undeformed sedimentary structure are the youngest and rocks that are lowest are oldest
principle of cross cutting relationships
the rock that cuts across a structure is younger than the structure it cuts through
unconsolidated sediments
recent deposits that have not yet been cemented or compacted enough to make up rocks, forming sand and gravel deposits rather than sandstone or conglomerate units
alluvium
unconsolidated clastic (or detrital) material deposited by a stream or other body of running water
bedrock
solid rock that underlies soils or other unconsolidated, superficial material
drumlin
hills of sediment (generally a quarter of a mile or more in length) that have been streamlined by glacier flow
esker
ridges made of sands and gravels deposited by glacial meltwater flowing through tunnels within and underneath glaciers, or through meltwater channels on top of glaciers
braided stream
multi-threaded channels that branch and merge to create the characteristic braided pattern
meandering stream
single-channel that winds through a valley
oxbow lakes
a U-shaped lake or pool that forms when a wide meander of a river is cut off, creating a free-standing body of water
shell with 2 valves that are not identical, but each valve is bilaterally symmetrical on itself. often ribbed valve surfaces with wing-like extensions on either side
brachiopod
altered: permineralization *hint this is a bone
dinosaur bone fragment
internal mold shell commonly with 2 identical valves (mirror images) joined by a hinge. has a raised protuberance called an umbo arises near the hinge
bivalve
external mold segmented organism divided into 3 parts; head (cephalon), body (thorax), and tail (pygidium) this particular fossil only shows the head of this organism
trilobite cephalon
this sticky substance that hardens to a crystal-like form is capable of producing unaltered remains through embedding
amber
altered: recrystallization this is an organism that was recrystallized in dolostone
coral in dolostone
unaltered remains shell commonly with 2 identical valves (mirror images) joined by a hinge. has a raised protuberance called an umbo arises near the hinge *hint, not a brachiopod
bivalve shell
altered: petrification *hint, not an animal
wood
altered: dessication *hint, not an animal
walnut