Scrutable

A bit of fun.

https://dinosaurpictures.org/ancient-earth#90

Ah, some of those configurations bring back happy memories. I said at the time it would be a mistake to move Antarctica down to the south pole. But did they listen?

lpm wrote: ↑

Tue Sep 01, 2020 12:45 pm

Ah, some of those configurations bring back happy memories. I said at the time it would be a mistake to move Antarctica down to the south pole. But did they listen?

What surprises (me at least) is that dinosaurs lived in Antarctica and somehow managed the X Months a year without sunlight. Were they migratory? Does anyone know if the Terrible Lizard podcast covers this?

Gfamily wrote: ↑

Tue Sep 01, 2020 2:21 pm

Were they migratory?

There was a bit of excitement over isotopic evidence from dinosaur teeth suggesting that some species migrated over hundreds of miles https://www.livescience.com/16737-dinos ... sonal.html

Amongst extant (avian) dinosaurs, the kinds of regular movements we call 'migration' are very common, and also occur on a spectrum, from pretty small scale movements (like the uphill/downhill migration in the teeth article, also seen in modern ungulate migrations for example) to the kind of intercontinental travel that's an awful lot easier once you can fly (or swim - I'd expect migrations to be pretty common amongst those marine not-dinosaurs-but creatures they used to have).

Pretty much any kind of environmental seasonality can give rise to migratory behaviour, for example tracking resources. It's also pretty common to migrate to breed, for instance nesting in a place with less food but also lower predation risk (or whatever), but then going back to the foody place afterwards.

So I'd bet anything migration was pretty widespread in dinosaurs, as it is amongst birds (dinosaurs' descendants) and large mammals (which occupy many similar niches) today. I'd love to hear more about the evidence for it, though.

Did they actually live on the land at the Antarctic while it was at the Antarctic?

Anyway, what surprised me is how much things change in just a few tens of millions of years. India positively rockets north from 120M years ago and smashes into Asia 20M years ago. I didn't have a grasp of just how fast plates can move.

Martin Y wrote: ↑

Tue Sep 01, 2020 2:41 pm

Did they actually live on the land at the Antarctic while it was at the Antarctic?

Yes - it would have been very far south and dark, but was still warm enough to have forests which makes year-round survival on land a bit easier. (I saw a couple of presentations on dinosaur metabolism and physiology, and whether or not they could hibernate, about a decade ago, and don't remember the answer or know how the field's moved on.)

There were also things like proto-penguins co-existing with yer typical big necky dinos and therapods and stuff, apparently, which is a fun mental image https://en.wikipedia.org/wiki/South_Pol ... #Dinosaurs

Martin Y wrote: ↑

Tue Sep 01, 2020 2:41 pm

Did they actually live on the land at the Antarctic while it was at the Antarctic?

Anyway, what surprised me is how much things change in just a few tens of millions of years. India positively rockets north from 120M years ago and smashes into Asia 20M years ago. I didn't have a grasp of just how fast plates can move.

I remember that from the BBC documentary "The Restless Earth" in the 1970s. The crumple zone of the impact being the Himalayas.

India goes so fast it looks like it has contrails.

Martin Y wrote: ↑

Tue Sep 01, 2020 2:41 pm

Did they actually live on the land at the Antarctic while it was at the Antarctic?

Anyway, what surprised me is how much things change in just a few tens of millions of years. India positively rockets north from 120M years ago and smashes into Asia 20M years ago. I didn't have a grasp of just how fast plates can move.

The figure in my head is 1 mm/y, or 1 km/My, which may be the speed of the mid-Atlantic spread. But India is something like two orders of magnitude faster.

Sciolus wrote: ↑

Wed Sep 02, 2020 10:32 am

The figure in my head is 1 mm/y, or 1 km/My, which may be the speed of the mid-Atlantic spread. But India is something like two orders of magnitude faster.

Mid Atlantic is said to be "at the same speed as fingernails grow" so a lot faster than 1mm/y

Yes I have in mind the fingernails thing (since the geology bits of my degree).

I was a bit awed when I read that parts of South Island of New Zealand are uplifting at about 5mm/y, which is 5km per million years. That's quite a lot of erosion!

Sciolus wrote: ↑

Wed Sep 02, 2020 10:32 am

Martin Y wrote: ↑

Tue Sep 01, 2020 2:41 pm

Did they actually live on the land at the Antarctic while it was at the Antarctic?

Anyway, what surprised me is how much things change in just a few tens of millions of years. India positively rockets north from 120M years ago and smashes into Asia 20M years ago. I didn't have a grasp of just how fast plates can move.

The figure in my head is 1 mm/y, or 1 km/My, which may be the speed of the mid-Atlantic spread. But India is something like two orders of magnitude faster.

The mid-Atlantic ridge is apparently spreading at about 25 mm per year by the way.

Hmm. I've been at the mid-Atlantic rift in Iceland and can't say I noticed anything.

lpm wrote: ↑

Wed Sep 02, 2020 12:44 pm

Hmm. I've been at the mid-Atlantic rift in Iceland and can't say I noticed anything.

I'm pretty sure the þing meets in Reykjavík now.

I should probably rely on Cunningham's Law less.

I wonder if Cunningham's Law applies to this post?