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Science of Minecraft shale.mp4Collections Database Info
Collections Database Info
Trilobites are an extinct group of arthropods—joint-legged invertebrates (animals without a backbone). Trilobites had a sturdy, mineralized outer “shell” (exoskeleton) that covered the upper body. The exoskeleton featured a prominent middle lobe and two side lobes running down its length (hence the name tri-LOBE-ite). It was also divided cross-wise into three sections: a cephalon (head) usually with a pair of prominent, mineralized, compound eyes; a thorax (middle region) with between 2 and 40 narrow segments, hinged for flexibility; and a pygidium (tail). Individual bits of exoskeletons are often found as fossils, representing separate pieces shed during growth or parts of carcasses broken apart after death. Complete exoskeletons are much less common, and fossils preserving non-mineralized body-parts (legs, etc.) of trilobites are very rare. All trilobites were sea-dwellers—most crawled on or burrowed into the sea-floor, some swam or floated. The oldest trilobite fossils come from rocks about 540 million years old, and the last trilobites died out about 250 million years ago.
This distinctive trilobite was first described and named by John Jeremiah Bigsby, who carried out some of the first geological explorations of Canada in the early 1800s. It is named for its discoverer, Lieutenant Bolton of the Royal Engineers, in 1825.
Transcript:
Transcript:
Sarah: And then this is another new section. You haven't seen this one before. So we're going down further into the rocks, so we're almost traveling in time, because I know that our friends know the further down we go, the older our rocks are. And here we're at about the same level as Zuul, and we have this cool thing, we have an ammonite.
Kim: Nice. I love ammonites.
Sarah: We're gonna go even further down. Okay. So we're going to take another elevator, because it's a long way.
Kim: Oh good idea. Oh! It actually knows which age it is.
Sarah: And so now we have this rock called shale.
Kim: Right.
Sarah: And this is another ROM exclusive one, our friends aren't going to know this if they play Minecraft in other places, but we have some shale, and I want to talk about the shale, but before we do, I just want to demonstrate something real quick. So I'm gonna clear up my inventory a little bit so that we can see, and this is a ROM exclusive tool, this isn't one that you find in regular Minecraft either, we have our geology hammer.
Kim: Wow.
Sarah: And we're gonna come on over here, and we're going to get rid of that one, so now we have some shale, and this shale looks like it has a bit of a crack in it. So I just found a trilobite.
Kim: Oh, nice!
Sarah: So do we want to talk about shale?
Kim: Sure. So shale is a fine grained sedimentary rock. It forms almost in layers, so it's all these small little sediments that are forming together, like silt-sized and clay-sized, and they all land together and form materials that gets kind of squished together. It does like to form in layers so every time there's another layering of dust and clay together it forms these these parallel lines on the rock, and then sometimes when those sediments are being deposited, some of the organisms that are living in that same sort of sea area can be deposited as well. So that is a lot of the host rock for some of the fossils that are found in our world and also in the Minecraft world, it looks like.
Sarah: That is really cool. So we know that these ones are way older than Zuul, because we're much much farther down, and we've actually got, if we explore around, we have a recreation of what their habitat might have looked like.
Kim: Wow.
Sarah: And we have all kinds of different trilobites that our friends can discover, because trilobites, I know that not a lot of people know this, that trilobites are not just one little critter it's actually many many many different species of trilobites that went extinct about 200 or 225 million years ago... 250 million years ago.
Kim: Sounds about right.
Sarah: Dave would know. They can learn about it from Dave.
Kim: That's right. Perfect.
Sarah: So they can learn about all of these different things, and I love the sound when you walk on the shale, too, because it's another unique sound which is really kind of fun.
Kim: Oh wow.
Sarah: So I guess when we look at it, if we have pebbles that stick together we get conglomerate, if we have sand that sticks together we get sandstone, and if we have mud that sticks together we get shale.
Kim: That's right.
Sarah: So you can get all kinds of rocks by sticking various things together. That's really neat.
Kim: Right. Those are all our sedimentary rocks, yeah, they're all very interesting.
This magnificent slab is a sea-floor “death assemblage”. It records the mass mortality and burial of about 30 large trilobites, of three different species, probably as a result of storm turbulence that buried them in mud. The assemblage was excavated in many pieces, carefully prepared to reveal the fossils, and then reassembled. The trilobite near the centre of the slab was moved from an outlying area to its new position.
The Burgess Shale is one of the best fossil sites in Canada. Usually, soft tissues decompose before a fossil is formed. In the Burgess Shale, the fossils are so well preserved that soft tissues, and sometimes even stomach contents of the animals are still visible!
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