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  • 00:00

    What you are looking at is a satellite view of not one, but two adjacent impact craters

  • 00:04

    in the tundra of northeast Canada.

  • 00:07

    Known as the Clearwater Craters, these two impact craters were once thought to have originated

  • 00:11

    from a single impact event where a large asteroid fragmented in two before before entering the

  • 00:16

    atmosphere.

  • 00:17

    After all, we witnessed this exact scenario occur in 1994 where a large comet called shoemaker

  • 00:23

    levy broke into a dozen pieces before impacting Jupiter.

  • 00:27

    However, recent evidence has shown that despite the odds, the proximity of these two craters

  • 00:32

    within Canada truly is just a coincidence.

  • 00:35

    They formed from separate impact events 180 million years apart.

  • 00:39

    This video will discuss when exactly these craters formed, what the landscape was like

  • 00:43

    at the time, and the consequences the asteroid strikes had on the planet.

  • 00:48

    The Clearwater Craters can be found a remote northern section of Quebec.

  • 00:51

    Specifically, it is 130 kilometers east of the edge of Hudson Bay.

  • 00:56

    The two Clearwater Craters are divided by their relative location and are thus named

  • 01:00

    Clearwater West and Clearwater East.

  • 01:03

    The larger of the two is Clearwater West which measures 36 kilometers or 22 miles wide.

  • 01:09

    Meanwhile, the smaller Clearwater East crater measures 26 kilometers or 16 miles wide.

  • 01:14

    So, how do we know that these massive craters were not formed from the same impact?

  • 01:19

    The answer is radioactive argon dating.

  • 01:22

    By heating rock and releasing two isotopes of argon, you can determine the approximate

  • 01:27

    age of a rock.

  • 01:28

    In this case, the relative abundances of these isotopes showed that Clearwater West is 286

  • 01:33

    million years old, while Clearwater East is much older at 460 million years old.

  • 01:39

    Approximately 460 million years ago, a large asteroid was on a collision course with earth.

  • 01:44

    This asteroid measured 2300 meters wide.

  • 01:47

    Known as a type CL carbonaceous chondrite, this asteroid was a member of the first group

  • 01:52

    of asteroids to form during the beginning of the solar system 4.57 billion years ago.

  • 01:57

    As it approached Earth, this mass of rock was traveling at 18 kilometers per second

  • 02:01

    or 40,000 miles per hour.

  • 02:04

    Entering the atmosphere, a bright streak of light would have been visible across a wide

  • 02:08

    swath of the planet.

  • 02:09

    Only a few seconds later, this asteroid struck off the coast of a continent in a shallow

  • 02:14

    sea during the middle Ordovician period, when numerous trilobites roamed the ocean.

  • 02:19

    This created a massive explosion equivalent in energy to the detonation of 542 billion

  • 02:24

    tons of tnt.

  • 02:26

    In mere moments, anything within a 450 kilometer radius ignited due to the immense thermal

  • 02:32

    radiation.

  • 02:33

    Further away, at a distance of 700 kilometers, any plants would have been knocked over as

  • 02:37

    they faced a 155 kilometer per hour wind from the shockwave.

  • 02:40

    Due to the size of this impact, large fragments of ejected rock fell across the planet starting

  • 02:41

    numerous wildfires.

  • 02:42

    As the dust cleared, a large impact crater measuring 26 kilometers across became visible.

  • 02:46

    Despite the energy released by this impact, and the subsequent impact winter, it did not

  • 02:50

    cause any mass extinctions.

  • 02:53

    Many millions of years later, approximately 286 million years ago, a slightly larger asteroid

  • 02:58

    was on a collision course with earth.

  • 03:00

    This asteroid measured 2800 meters wide, and was far more dense than its prior counterpart.

  • 03:06

    Traveling at a similar speed of 18 kilometers per second, it impacted the ground a mere

  • 03:10

    30 kilometers to the northwest of the adjacent Clearwater East Crater.

  • 03:15

    At this period of Earth's history, the impact site was a humid Permian rainforest in the

  • 03:19

    center of the supercontinent Pangaea.

  • 03:22

    Impacting with the equivalent energy of 1.4 trillion tons of tnt, it devastated the landscape

  • 03:28

    in a several hundred kilometer radius.

  • 03:30

    Owing to its larger size, a 36 kilometer wide impact crater formed.

  • 03:35

    In the thousands of years following this impact, the underlying crust at the deepest part of

  • 03:39

    the impact crater began pushing upwards.

  • 03:42

    A good analogy is removing the top third of a sponge in water.

  • 03:46

    It will still float, and the removal of this section will cause it to rebound upwards.

  • 03:50

    Thus, the center of the impact crater was uplifted by more than 1000 meters, forming

  • 03:54

    a domed center.

  • 03:56

    In the many millions of years since, the top of the dome eroded away, leaving behind a

  • 04:00

    ring structure of islands.

  • 04:02

    I hope that you enjoyed this video!

  • 04:04

    If you would like to request a specific topic, please leave a comment below.

  • 04:08

    Additionally, if you wish to support this channel consider becoming a patron on patreon!

All

The example sentences of CARBONACEOUS in videos (2 in total of 2)

known verb, past participle as preposition or subordinating conjunction a determiner type noun, singular or mass cl proper noun, singular carbonaceous adjective chondrite noun, singular or mass , this determiner asteroid noun, singular or mass was verb, past tense a determiner member noun, singular or mass of preposition or subordinating conjunction the determiner first adjective group noun, singular or mass
but coordinating conjunction only adverb the determiner carbonaceous adjective chondrites noun, plural contain verb, non-3rd person singular present water noun, singular or mass - as adverb well adverb as preposition or subordinating conjunction lots noun, plural of preposition or subordinating conjunction carbon noun, singular or mass , if preposition or subordinating conjunction you personal pronoun

Definition and meaning of CARBONACEOUS

What does "carbonaceous mean?"

/ˌkärbəˈnāSHəs/

adjective
(chiefly of rocks or sediments) consisting of or containing carbon or its compounds.