Continental Drift Theory
-
Upload
makati-science-high-school -
Category
Education
-
view
784 -
download
0
Transcript of Continental Drift Theory
CONTINENTAL DRIFT THEORY
Alfred Wegener
ACT.3A: REASSEMBLING THE PIECES
LET’S FIT IT!
Assembling a puzzle can reveal a hidden meaning.
Procedure: Choose a page of a magazine with
pictures. Cut the page of a magazine into not
more than 20pcs. Insert the pieces inside the brown
envelope. Trade the envelope with the other
groups. Try to fit the pieces of magazine
together.
ANSWER THE FF. QUESTIONS What evidence did you use to
put the pieces together? What features of the magazine
helped you to connect the pieces perfectly?
How do the lines of prints or texts in the help you to confirm that you have reassembled the magazine page?
How do your pieces serve as a model of CDT?
BRING THE FF.(BY GROUP) List of dominant species of plants and animals found in the continents before and after drifting away from each other
photocopy of the seven continents (letter size)
world map pair of scissors
ACTIVITY 4: DRIFTED SUPERCONTINENT
Tell the possible direction of motion of the continents as they drifted away.
Draw fossils of plants and animals as evidences found in the present continents that will help solve the puzzle in the fitting of the drifted continents.
Reconstruct and describe Pangaea.
Predict what will happen to the world as the continents continuously move.
PROCEDURE: Cut carefully the traces of the seven continents.
Sketch the dominant species of plants and animals found in the continents before and after drifting away from each other.
Put the cut-outs together. Answer: Q13-16.
PROCEDURE: Make sure that you put fitting edges
of the continents side by side to form the supercontinent Pangaea.
Answer: Q17-20 Compare Pangaea with the world
map. Now move one continent relative to
its current location. Observe carefully the direction of its motion as it assumes its current location and position. Record your observation.
PROCEDURE:
Do the same procedure to the other continents. Record your observations.
Answer: Q21
ANSWER: THINKING CRITICALLY: INFERRING
Coal deposits have also been found beneath the ice of Antarctica. But coal only forms in warm swamps. Use Wegener’s theory to explain how coal could be found so near the poles.
refer to Plate Tectonic Theory History PPT
CDT MAP
DRIFTING CONTINENTS
DRIFTING CONTINENTS
Continents were not stationary, but actually moving or drifting away from one another.
TOPOGRAPHIC EVIDENCE Inspection of any global
map will show that the edges of continents such as South America and Africa appear to match.
This apparent jigsaw-like fit is no coincidence - the two continents split apart from one landmass during the Cretaceous period, and oceanic crust developed in between them.
TOPOGRAPHIC EVIDENCE
TOPOGRAPHIC EVIDENCE
Map of a closed Atlantic Ocean showing the rifts that formed when Pangaea was split by a spreading center. The rifts on today's continents are now filled with sediment. Some of them serve as the channel ways for large rivers.
TECTONIC FIT The positions and ages of
tectonic features which occur on the various continental landmasses seem to join up.
Another line of evidence is the alignment of glacial striations (scratches caused by ice) in rocks caused by the movement of ice sheets over the southern continents during the Permian and Carboniferous periods.
STRATIGRAPHIC CORRELATION
Continents which were once part of the same landmass will show similar rock sequences along their margins up until the time when they split apart.
In the African and South American plates, similar freshwater rocks found along the continental margins can be correlated up until the end of the Lower Cretaceous, when continental rifting split the continents apart.
STRATIGRAPHIC CORRELATION
PALEONTOLOGICAL EVIDENCES
Fossils contained within stratigraphic sequences which are now located on different continents can indicate that the two landmasses were once joined.
Mesosaurus fossils found in early Permian freshwater shales in both Brazil and southern Africa
Glossopteris, Cygnonathus, and Lystrosaurus are among others
PALEONTOLOGICAL EVIDENCES
PALEO-CLIMATIC EVIDENCE
PALEO-CLIMATIC EVIDENCE
OTHER EVIDENCES
PALEOMAGNETISM
PALEOMAGNETISM
PALEOMAGNETISM
PALEOMAGNETISM
1950’s: discovery of ancient rocks had magnetic directions and inclinations that did not correspond with the present magnetic pole position.