ERTH2404 MIDTERM LEC 1-5 TEST WITH
COMPLETE SOLUTION
Formation of solar system - ANSWER cloud of elements
flattens to pancake from gravity
rings form
planets and sun form
planetesimals - ANSWER mass flow between sun and disk ceases acceleration
all planets formed - ANSWER same time 4.6Ga ago
inner core - ANSWER 4 solid iron and nickel alloy
outter core - ANSWER 3 liquid iron and nickel alloy
mantle - ANSWER 2 iron and magnesium silicates
crust - ANSWER 1 silicon and oxygen
denser material - ANSWER migrates gradually to centre
inital earth - ANSWER hot, mostly molten
moon - ANSWER less dense than earth not formed at same time
uniformitarianism - ANSWER natural processes behave same way forever,
present is key to past
estimates of earths age - ANSWER theological considerations, sediment
accumulation, cooling rates, radioactive decay, 4.55 billion years
,relative dating - ANSWER task of placing rock units and geological events in
chronological order
stenos rules - ANSWER original horizontality
lateral continuity
superposition
cross cutting relations
original horizontality - ANSWER layers of sediments are always deposited in
horizontal sheets
layers are one after another without interruption
if not horizontal they have been disturbed
Lateral Continuity - ANSWER sediments are deposited in large, continuous
horizontal sheets to the point where they terminate against a solid surface
Superposition - ANSWER in undeformed sedimentary rocks, each layer is
older than the one above it
if layers are folded or inclined at a large angle they have been disturbed after
deposition
unconformities - ANSWER Gaps in rock sequences halts in sedimentation
angular unconformity - ANSWER older layer dip at an angle different from
the younger layer
nonconformity - ANSWER erosion surface is an igneous or metamorphic rock
disconformity - ANSWER erosional surface separating horizontal strata below
from horizontal strata above and where there is a gap in time
,deposition of sequence A in conformable layers - ANSWER ------------------
------------------
--------A---------
------------------
------------------
deformation and metamorphism of sequence A - ANSWER
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\ A /\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
erosion of A Erosional Surface - ANSWER ----------------------------
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\ A /\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
deposition of sequence B - ANSWER |||||||||||||||||||||||||||||||||||||||||||
, |||||||||||||||||| B ||||||||||||||||||||
|||||||||||||||||||||||||||||||||||||||||||
----------------------------
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\ A /\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
forces cause sequence AB to uplift - ANSWER AB rotates 45
erosional event leads to Erosional Surface - ANSWER AB is shaved down flat
deposition of sequence C leads to angular unconformity, layers are no longer
conformable - ANSWER new layer C is added ontop of the 45 degree, cut,
sequence AB
Principle of cross cutting relationships - ANSWER any event that cut or
breaks a rock must be younger than that rock, intrusive, fault
law of included fragments - ANSWER if fragments of one material are found
in another then the included fragments must be older
COMPLETE SOLUTION
Formation of solar system - ANSWER cloud of elements
flattens to pancake from gravity
rings form
planets and sun form
planetesimals - ANSWER mass flow between sun and disk ceases acceleration
all planets formed - ANSWER same time 4.6Ga ago
inner core - ANSWER 4 solid iron and nickel alloy
outter core - ANSWER 3 liquid iron and nickel alloy
mantle - ANSWER 2 iron and magnesium silicates
crust - ANSWER 1 silicon and oxygen
denser material - ANSWER migrates gradually to centre
inital earth - ANSWER hot, mostly molten
moon - ANSWER less dense than earth not formed at same time
uniformitarianism - ANSWER natural processes behave same way forever,
present is key to past
estimates of earths age - ANSWER theological considerations, sediment
accumulation, cooling rates, radioactive decay, 4.55 billion years
,relative dating - ANSWER task of placing rock units and geological events in
chronological order
stenos rules - ANSWER original horizontality
lateral continuity
superposition
cross cutting relations
original horizontality - ANSWER layers of sediments are always deposited in
horizontal sheets
layers are one after another without interruption
if not horizontal they have been disturbed
Lateral Continuity - ANSWER sediments are deposited in large, continuous
horizontal sheets to the point where they terminate against a solid surface
Superposition - ANSWER in undeformed sedimentary rocks, each layer is
older than the one above it
if layers are folded or inclined at a large angle they have been disturbed after
deposition
unconformities - ANSWER Gaps in rock sequences halts in sedimentation
angular unconformity - ANSWER older layer dip at an angle different from
the younger layer
nonconformity - ANSWER erosion surface is an igneous or metamorphic rock
disconformity - ANSWER erosional surface separating horizontal strata below
from horizontal strata above and where there is a gap in time
,deposition of sequence A in conformable layers - ANSWER ------------------
------------------
--------A---------
------------------
------------------
deformation and metamorphism of sequence A - ANSWER
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\ A /\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
erosion of A Erosional Surface - ANSWER ----------------------------
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\ A /\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
deposition of sequence B - ANSWER |||||||||||||||||||||||||||||||||||||||||||
, |||||||||||||||||| B ||||||||||||||||||||
|||||||||||||||||||||||||||||||||||||||||||
----------------------------
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\ A /\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/\/\
forces cause sequence AB to uplift - ANSWER AB rotates 45
erosional event leads to Erosional Surface - ANSWER AB is shaved down flat
deposition of sequence C leads to angular unconformity, layers are no longer
conformable - ANSWER new layer C is added ontop of the 45 degree, cut,
sequence AB
Principle of cross cutting relationships - ANSWER any event that cut or
breaks a rock must be younger than that rock, intrusive, fault
law of included fragments - ANSWER if fragments of one material are found
in another then the included fragments must be older
