DATE
CLASS
STUDY
GUIDE
PloteTectonics
Use words in the box to fiIl in the blanks.
CONTINENTAL
DRIFT
20:1 Continents
in Motion
rock
1915
Pangaea
ignored
movement
separated
1or 6 q t
^l:u l l l l l 4^+
L E s^^
^-r^^-t:uullLrlrcrrt
s
scientists
AIfred Wegener
continentaitirift
fossiis
l'l i{
n
ne-{at-Jcif;L-.
called
part of .
Al4rot
named
, a meteorologist
rhishypothesis involved
landmass,had.
l.r-nb"^r
named
an idea in which continents. once
&.";ls
, similar
rli"nt[g
proposed a hypothesis
and moved apart. Evidence for this idea
included the fit ofpresent day
and ancient
gC
, fqk
structures.
that existed on the different continents. The original "supercontinent"
by Wegener. The early continental drift idea was generally
because neither Wegener nor other t r-i'ehlr'q+s
of his day could explain how,
when, or why tlne "l>l:Jtei4levrt
of continents
occured.
2O=2Fossil,Climate,and RockClues
joined
Southern
Australia
structure
Northern
swamps
reptile
equator
South Pole
land bridge
glaciation
Antarctica
Appalachian
Glossopteris
Scandinavia
Lystrosaurus
'evroence
More -9
for the movement of continents continued to
L
, a small doglike
i.l
fef*le_
#'c.r.-. The fossil ggrn 6fe:,*t^./€JA
Antarctica. Since no evidence of u
, were found
ta{c\g-
lancl
time of the tropical
effectson fi.vecontinentsin the
\wtttryP1
in the
d**'*
--QJa€45--.
/lr[,#/-orn
similar age and *!-u.{ui
and
India, and
was found, Wegener believed
iair"e
Further
evidence from the
Hemispherethat occurredat the
Hemisphere supported continental drift.
This evidence indicates that southern continents were nearer ths
northern continents were nearer tne
%taaJaf
4d.{nkrtl"'o;
when it was noticed that,the
South Africa
was found in Africa,
thrs
this evrdence
evidence rndicated
indicated that
that the
the landmasses
landmasses were
were once
ott""
Sla.iq+ia'a
found. Fossils of
)o.i
&JqL
,,oa
than they are today. More evidence came to light
mountain belt in the northeastern United States is of
as mountainsin Greenlandand 2qn"linn
rn
DATE
CLASS
20:3 Magnetic
Clues
drift
basalt
minerai
map
pole
time
magnetic
America
continents
The study of magnetismin ancient rocks is called
rt':
.l;zecl,
fleo,-.rgnJirrrl
whenthey form in rocks,suchas
then line up with the magnetic
Plg
Lgl*
,,
, and zrine.n4l
glarns
pole appeared to have migrated through
. This apparent movementwas called.
notedthatboth
Iron-bearing minerals become
. When paleomagnetism data was plotted on a
, the location of the
*iw-
magnetized
paleomagnetism
polar wandering
*qJn,
f*Lf
|^g
. It was
and Europe had similar polar-wandering paths. This couldbe e:rplaineil
if the two c-r+lrtn<$t1>
had rotated next to each other as in the continental ,,l.rilL
hypothesis,
PLATE
TECTONICS
2O:4Datafromthe Sea Floor
200
depth
1953
older
ridge
trenches
With the invention of the precision A"fU
discovered.the ,a.riJ. -ece<"r-.,
1960's by the
mid-ocean
magnetism
record.eri1
ridge system and deep sea
GL.rnr
were the youngest and were increasingly
No sea-floor rocks older than
Zef-)
magnetometer
Glomar Challenger
i?5 3
, oceanographers
he""l.*S
. Data collected in the
indicated
rocks near the mid-ocean
ol.lCf
on either side of the ridge.
million years were found. In addition to the variation