November 21, 2019 • 6 mins
Just looking at a world map makes it clear that today's continents were once a single mass, but scientists are still researching how they came together and apart. Learn about the history of the Southern Hemisphere's continents in this episode of BrainStuff.
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Episode Transcript
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Speaker 1 (00:01):
Welcome to brain Stuff production of iHeartRadio. Hey brain Stuff,
Lauren Vogel bomb here. Sometimes good science can happen just
by looking at a map of the world and letting
your mind wander. For instance, observe how Africa and South
America seem to have been very recently cuddled together, even
though there are currently a couple of thousand miles of
(00:22):
ocean between them. Similarly, Madagascar fits perfectly into a little
nick in the eastern edge of Africa, and the Middle
East seems to be pulling away from the top of
Africa like a corner being pulled off of a hot cookie.
With a reasonably good representation of the shape and arrangement
of the world's continents in front of them, anyone could
easily assess that the Earth's land masses have definitely been
(00:44):
sneaking around. The name for the southern land mass that
once was is Gondwana Land, also known as Gondwana. But
it wasn't just the shape of the continents that cluded
researchers into its former existence. They've also looked at similarities
among plants and animals that live across the modern separate continents.
From those clues, Gondwana was an idea long before anybody
(01:07):
figured out how or why it worked, the secret, of
course being plate tectonics, an idea that didn't really start
gaining steam until the mid twentieth century. But a nineteenth
century Austrian geologist named Edward Seuss put a name to
the concept of the supercontinent in his book The Face
of the Earth, the first volume of which was published
in eighteen eighty three. SEUs didn't come up with many
(01:29):
completely novel ideas, but he did a great job of
synthesizing a bunch of the research of the day to
conclude that the southern continents and land masses we now
know as South America, Africa, Arabia, India, Sri Lanka, and
Madagascar had at one point in time been connected because one, well,
just look at them, and two they contained the same
(01:49):
rocks and the same fossils from an extinct feathery leaked
tree called Glosso Terraces. Austria and Antarctico would be added
to the theory thirty years later. Gondwana was named for
a densely forested region of central India where the first
fossil evidence of the supercontinent was found. In the nineteenth century.
Juana is a word for forest in Sanskrit, and the
(02:11):
Gonds are tribe that European explorers first found living in
the region. Even though we now know a lot about
the mechanism by which Gondwana was formed, it's extremely complicated
and still being investigated. There's at least one peer reviewed
scientific journal devoted entirely to the study of the supercontinent.
It's called appropriately Gondwana Research. However, there are a few
(02:35):
things that were pretty certain of. First. Gondwana wasn't built
in a day. The making of Gondwana was a long process,
most likely through three major mountain building events driven by
the movement of Earth's tectonic plates. We spoke via email
with Joseph Merritt, a professor in the Department of Geological
Sciences at the University of Florida. He explained, during the
(02:57):
interval from about six dred and fifty two five hundred
and fifty million years ago, various pieces of Africa and
South America collided along an ancient mountain chain called the
Braziliano Belt, slightly older but overlapping with the Braziliano seven
fifty to six hundred and fifty million years ago, is
the East African Oregon or Mozambique Belt that resulted from
the collision between East Africa and Madagascar, India, Sri Lanka,
(03:21):
and parts of East Antarctica. The final collision was along
the Quanga Oregon between all those assembled pieces and the
rest of Antarctica and Australia between five hundred eighty and
five hundred thirty million years ago. So it was a
couple hundred million years of extremely slow continental car wrex
that created this beta version of Gondwana. But it wasn't
(03:43):
done yet. Later, about three hundred million years ago, other
land masses would join forces with it to form the
giant ball of land we now know as Pangaea. But
one continent to rule them all couldn't last, and sometime
between two hundred and eighty and two hundred million years ago,
panned has started disintegrating as magma began pushing up from
(04:03):
beneath this mega supercontinent, creating riffs in the land that
would later become sea floor. As Pangia cracked, the top
part was pushed to the north, creating the continent laur
Asia and Gondwana headed south back when Gondwana was just
a baby Supercontinent between five hundred and fifty and four
eighty five million years ago. It hosted some of the
(04:24):
very first complex life forms, like child bites and brachiopods,
but since it continued to exist into the Jurassic Period,
lots of plant and animal evolution went down there. Merritt said,
Gondwana contains evidence for evolutionary changes in the very first
complex animals, the very first fish, amphibians, and reptiles. The
most famous fossils are the Gondwana flora, such as the
(04:47):
glasso terrace fern, a freshwater reptile called Mesosaurus, and a
land reptile called Lystrosaurus. Gondwana existed as a single land
mass for more than three hundred million years because of
its Hu Monga's size, but it covered an area of
a hundred billion square kilometers or about thirty nine billion
square miles, and because the continents moved a lot during
(05:08):
that time, Gondwana experienced many different climates. Merit said. During
the Cambrian, when Gondwana first formed, the Earth and Gondwana
were in a greenhouse state. In the late Ordovician four
fifty billion years ago, Gondwana was moving over the South
Pole and the climate was very cold. Gondwana continued to
move through a variety of latitudes, and depending on where
(05:29):
you were located, the climate might have been quite warm
or more temperate. The continent was so large that one
part of Gondwana might be located at the equator while
another might be located at the pole. It's true it
would have been cool to see Gondwana in its prime,
and although you won't personally get to see its victorious return,
that doesn't mean that it's not possible. The continents are
(05:52):
always moving and scientists have a lot of ideas. But
what our next supercontinent is going to look like? H
Today's episode was written by Jesslyn Shields and produced by
Tyler Clang. Brain Stuff is production of I Heart Radios,
How Stuff Works. For one and this and lots of
other mega super topics, visit our home planet how stuff
Works dot com and for more podcasts. For my Heart Radio,
(06:14):
visit my Heart Radio app, Apple Podcasts, or wherever you
listen to your favorite shows.
Welcome to brain Stuff production of iHeartRadio. Hey brain Stuff,
Lauren Vogel bomb here. Sometimes good science can happen just
by looking at a map of the world and letting
your mind wander. For instance, observe how Africa and South
America seem to have been very recently cuddled together, even
though there are currently a couple of thousand miles of
(00:22):
ocean between them. Similarly, Madagascar fits perfectly into a little
nick in the eastern edge of Africa, and the Middle
East seems to be pulling away from the top of
Africa like a corner being pulled off of a hot cookie.
With a reasonably good representation of the shape and arrangement
of the world's continents in front of them, anyone could
easily assess that the Earth's land masses have definitely been
(00:44):
sneaking around. The name for the southern land mass that
once was is Gondwana Land, also known as Gondwana. But
it wasn't just the shape of the continents that cluded
researchers into its former existence. They've also looked at similarities
among plants and animals that live across the modern separate continents.
From those clues, Gondwana was an idea long before anybody
(01:07):
figured out how or why it worked, the secret, of
course being plate tectonics, an idea that didn't really start
gaining steam until the mid twentieth century. But a nineteenth
century Austrian geologist named Edward Seuss put a name to
the concept of the supercontinent in his book The Face
of the Earth, the first volume of which was published
in eighteen eighty three. SEUs didn't come up with many
(01:29):
completely novel ideas, but he did a great job of
synthesizing a bunch of the research of the day to
conclude that the southern continents and land masses we now
know as South America, Africa, Arabia, India, Sri Lanka, and
Madagascar had at one point in time been connected because one, well,
just look at them, and two they contained the same
(01:49):
rocks and the same fossils from an extinct feathery leaked
tree called Glosso Terraces. Austria and Antarctico would be added
to the theory thirty years later. Gondwana was named for
a densely forested region of central India where the first
fossil evidence of the supercontinent was found. In the nineteenth century.
Juana is a word for forest in Sanskrit, and the
(02:11):
Gonds are tribe that European explorers first found living in
the region. Even though we now know a lot about
the mechanism by which Gondwana was formed, it's extremely complicated
and still being investigated. There's at least one peer reviewed
scientific journal devoted entirely to the study of the supercontinent.
It's called appropriately Gondwana Research. However, there are a few
(02:35):
things that were pretty certain of. First. Gondwana wasn't built
in a day. The making of Gondwana was a long process,
most likely through three major mountain building events driven by
the movement of Earth's tectonic plates. We spoke via email
with Joseph Merritt, a professor in the Department of Geological
Sciences at the University of Florida. He explained, during the
(02:57):
interval from about six dred and fifty two five hundred
and fifty million years ago, various pieces of Africa and
South America collided along an ancient mountain chain called the
Braziliano Belt, slightly older but overlapping with the Braziliano seven
fifty to six hundred and fifty million years ago, is
the East African Oregon or Mozambique Belt that resulted from
the collision between East Africa and Madagascar, India, Sri Lanka,
(03:21):
and parts of East Antarctica. The final collision was along
the Quanga Oregon between all those assembled pieces and the
rest of Antarctica and Australia between five hundred eighty and
five hundred thirty million years ago. So it was a
couple hundred million years of extremely slow continental car wrex
that created this beta version of Gondwana. But it wasn't
(03:43):
done yet. Later, about three hundred million years ago, other
land masses would join forces with it to form the
giant ball of land we now know as Pangaea. But
one continent to rule them all couldn't last, and sometime
between two hundred and eighty and two hundred million years ago,
panned has started disintegrating as magma began pushing up from
(04:03):
beneath this mega supercontinent, creating riffs in the land that
would later become sea floor. As Pangia cracked, the top
part was pushed to the north, creating the continent laur
Asia and Gondwana headed south back when Gondwana was just
a baby Supercontinent between five hundred and fifty and four
eighty five million years ago. It hosted some of the
(04:24):
very first complex life forms, like child bites and brachiopods,
but since it continued to exist into the Jurassic Period,
lots of plant and animal evolution went down there. Merritt said,
Gondwana contains evidence for evolutionary changes in the very first
complex animals, the very first fish, amphibians, and reptiles. The
most famous fossils are the Gondwana flora, such as the
(04:47):
glasso terrace fern, a freshwater reptile called Mesosaurus, and a
land reptile called Lystrosaurus. Gondwana existed as a single land
mass for more than three hundred million years because of
its Hu Monga's size, but it covered an area of
a hundred billion square kilometers or about thirty nine billion
square miles, and because the continents moved a lot during
(05:08):
that time, Gondwana experienced many different climates. Merit said. During
the Cambrian, when Gondwana first formed, the Earth and Gondwana
were in a greenhouse state. In the late Ordovician four
fifty billion years ago, Gondwana was moving over the South
Pole and the climate was very cold. Gondwana continued to
move through a variety of latitudes, and depending on where
(05:29):
you were located, the climate might have been quite warm
or more temperate. The continent was so large that one
part of Gondwana might be located at the equator while
another might be located at the pole. It's true it
would have been cool to see Gondwana in its prime,
and although you won't personally get to see its victorious return,
that doesn't mean that it's not possible. The continents are
(05:52):
always moving and scientists have a lot of ideas. But
what our next supercontinent is going to look like? H
Today's episode was written by Jesslyn Shields and produced by
Tyler Clang. Brain Stuff is production of I Heart Radios,
How Stuff Works. For one and this and lots of
other mega super topics, visit our home planet how stuff
Works dot com and for more podcasts. For my Heart Radio,
(06:14):
visit my Heart Radio app, Apple Podcasts, or wherever you
listen to your favorite shows.
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