Despite my confusion over the
location of ‘the Baltic States’, they are right where normal people would
expect them; along the Baltic Sea. Somehow, over the years, my mind had decided
that the otherwise-un-named Baltic states were located immediately north and
northwest of Greece. However, I looked them up (for the sake of this blog), and
boy, was I wrong. I had put these states in Eastern Europe, but way too far
south.
The Baltic States (Estonia, Latvia,
and Lithuania) are in Eastern Europe, snuggled up east of the Baltic Sea and
west of the Ural Mountains of Asia. And that places them right on the
protocontinent of Baltica!
So, yes, this is kind of related to
the Supercontinents blogs, but I’m only going to explore this one little piece
of crust. Sometimes it roamed around on its own. At other times, it gathered
together with other pieces of crust. Right now, it is smooshed between NorthEastern
Europe and NorthWestern Asia. Will it succumb and eventually be pushed under
these larger plates, or will it somehow break free again? I don’t know. But let’s
see what is known about it.
The thick core of Baltica is also
known as the East European Craton and is more than 3 billion years old.
About 2 billion years ago, small
pieces of crust started colliding. These included Sarmatia (which was the
Ukrainian Shield and Voronezh Massif*) and Volgo-Uralia. That seemed to work
pretty well, so about 1.8 billion years ago, they added Fennoscandia, which
included the Baltic Shield.
Now, if I’m reading the articles
right, about 750 million years ago, Baltica and Laurentia (most of North
America) both rotated clockwise, bumped each other lightly and headed for the
south pole. At some point (possibly 650 million years ago), it is postulated
that Earth became completely covered in snow and ice. (Yes, Snowball Earth.)
It turns out that Siberia was
located fairly close to the South Pole, too, and it apparently didn’t take long
for Siberia to completely lose its cool. According to one theory, Siberia
started having some severe volcanic eruptions, and the build-up of green house
gases in the atmosphere from that source resulted in a complete melt-down of
all that snow and ice in as little as 2,000 years.
Anyway, Laurentia beat feet and
headed north, but Baltica remained in the south at least long enough to hang
around Gondwanaland. After that, Baltica drifted north and approached Laurentia
again. However, around 425 million years ago, Scotland-Greenland and Norway all
collided together, forcing Baltica to look elsewhere for new continental buddies.
Just when you thought you’d found a
friend. Poor Baltica.
* Now
a piece of Central Russia
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