Geography Reference
In-Depth Information
Where have you gone, Gondwanaland?
Various explanations were proposed. In the 1850s, Antonio Snider suggested that during Noah's time,
theEarthhadseveraldeepvolcano-relatedcracks.WaterpressureduringTheFloodexacerbatedthese
cracks, created the continents, and moved them apart. A few years later, Eduard Suess proposed that a
super-continent he dubbed
Gondwanaland
(after geological area in India) had fragmented and broken
apart for reasons that he did not identify or endorse.
Alfred Wegener, mover and shaker
But the greatest theorizer of all was Alfred Wegener, a German geographer and meteorologist.
In 1915, he proposed a theory that explained not only the shapes and locations of continents,
but also the geography of mountains. According to Wegener, Earth's surface once consisted
of a single super- continent called
Panagea
(“all the Earth”) and a single world ocean called
Panthalassa
(“all the seas”). Pangea subsequently broke into two pieces of roughly equal size:
a northern component called
Laurasia,
and a southern component called
Gondwanaland
(bor-
rowing from Suess). Both of these, in turn, later broke up. Pieces of Laurasia became North
America, Central America, Greenland, Europe, and Asia. Pieces of Gondwanaland became
South America, Africa, Australia, and Antarctica.
These pieces, Wegener suggested, subsequently “drifted” apart, hence the popular name for his the-
ory,
continental drift
. These continental “rafts” did not float on water, but instead bulldozed their way
over other firmament (ocean bottom, typically). Now, at some time in your life you have probably
watched a bulldozer do its thing. It scrapes the surface and produces a pile of debris as it moves for-
ward. As Wegener saw it, that is exactly what the continental rafts were doing: scraping the Earth
and producing mountains and mountain ranges along their leading edges. Thus, the “rafts” containing
North and South America were drifting westerly, bulldozing as they went, the result being the chain
of mountains that today extend along the west coast of the Americas from Alaska to the southern tip
of South America.
Wegener's theory was basically correct, but it remained unproven until after his death because the
matter of how Pangaea was broken up was unresolved. Obviously a mighty force was required to
break up Pangaea and cause its pieces to move. But what could that force be, and where did it come
from? Again, that was the puzzle within the puzzle.
