Triassic Period Part 1

 The Triassic Period spans 50.6 million years, from 251.9 million years ago to 201.4 million years ago. It is the first and shortest period of the Mesozoic Era. It both started and ended with a major extinction event.

The Permian–Triassic extinction devastated terrestrial life. Diverse communities with complex food-web structures took 30 million years to reestablish.

The Triassic period ended with a mass extinction which was particularly severe in the oceans. All the marine reptiles disappeared except for the ichthyosaurs and plesiosaurs. Invertebrates like molluscs were severely affected. In the oceans, 22% of marine families and possibly half of marine genera went missing.

The vast supercontinent of Pangaea continued until the mid-Triassic, after which it began to gradually split into two separate landmasses, Laurasia to the north and Gondwana to the south.

During this time period, almost all the Earth's land mass was concentrated into a single supercontinent centered more or less on the equator and spanning from pole to pole. The Tethys Sea penetrated the east side of this continent for a good distance along the equator. There was an older branch of the ocean (called the Paleo-Tethys Ocean) north of the Tethys Sea that was now closed off by a group of moving islands that became a strip of land.

During the mid-Triassic, a similar sea penetrated along the equator from the west coast. This sea was not named in the article I read. All the rest of Pangaea's shores were surrounded by the world-ocean known as Panthalassa. Although it was not stated, my guess is that these 2 long seas coming from the east and the west along the equator finally met, and Pangaea was no more.

The sea level was consistently low compared to the other geological periods. The beginning of the Triassic saw the sea level at around present sea level, rising to about 10-20 m (30-60 ft) above sea level during the Early and Middle Triassic. Then the sea level began to rise, with it reaching up to 50 metres (150 ft) above the present sea level. It then began to decline, reaching a low of 50 metres below the present sea level, which continued into the next time period.

The global climate during the Triassic was mostly hot and dry, with deserts spanning much of Pangaea's interior. There is no evidence of glaciation at or near either pole. In fact, the polar regions were apparently moist and temperate, providing a climate suitable for forests and vertebrates, including reptiles. Pangaea's large size limited the moderating effect of the global ocean; it's continental climate was highly seasonal, with very hot summers and cold winters. The strong contrast between Pangea and the global ocean triggered intense monsoons.

The climate shifted and became more humid as Pangaea began to split apart. The Triassic may have mostly been a dry period, but evidence exists that it was punctuated by several episodes of increased rainfall in tropical and subtropical latitudes of the Tethys Sea and its surrounding land. It may be that volcanic activity helped trigger climate change during this period.

Next we'll take a look at the inhabitants of Earth during the Triassic Period.

https://en.wikipedia.org/wiki/Triassic

Mesozoic Era

 Okay, we're going to take a quick overview look at the Mesozoic Era, also known as the Age of Reptiles. It lasted from 252 to 66 million years ago. It has 3 Periods nestled within it; the Triassic, Jurassic and Cretaceous periods. It was characterized by dinosaurs, conifers and ferns, a hot greenhouse climate, and the tectonic break-up of Pangaea.

The Mesozoic began just after the largest well-documented mass extinction in Earth's history, and it ended with another extinction event.

During this era, the supercontinent Pangaea broke into separate landmasses that would eventually move into their current positions during the following era. There was not much mountain building during this era, but what little did occur took place around what is now known as the Arctic Ocean. In contrast, the supercontinent Pangaea gradually split into a northern continent, Laurasia, and a southern continent, Gondwana. (Seems like this name has been used before.) By the end of the era, the continents had split up and some had rejoined into their present forms, though not their present positions. Laurasia became North America and Eurasia, while Gondwana split into South America, Africa, Australia, Antarctica and the Indian subcontinent, which would eventually slam into Asia, giving rise to the Himalayas, but not during this Era.

The climate varied, alternating between warm and cool periods. Overall, the Earth was hotter than it is today. The Triassic (first) Period was generally dry and highly seasonal, especially in Pangaea's interior. Low sea levels would have exacerbated temperature extremes. Pangaea's interior probably included expansive deserts.

Sea levels began to rise during the Jurassic (second) Period, most likely caused by seafloor spreading. The sea levels could have risen as much as 656 ft (200 m) above today's sea level. This would have flooded coastal area. In addition, the breaking up of Gondwana into smaller continents created new shorelines. Temperatures continued to increase for a time, then began to stabilize. With the proximity of water, humidity also increased, and the deserts retreated.

The climate of the Cretaceous (third) Period is more widely disputed. Probably, higher levels of carbon dioxide in the atmosphere could have almost eliminated the north-south temperature gradient, meaning that temperatures were about the same across the planet, about 10 degrees Centigrade higher than today.

Dinosaurs first appeared mid-way through the first period, and became the dominant terrestrial vertebrates by early in the second period, then died out at the end of the third period. Archaic birds appeared during the 2nd period (Jurassic), evolving from a branch of dinosaurs. True birds appeared in the third period. Mammals also appeared during this era, but they remained small (less than 33 lb) until the third period. Flowering plants appeared early in the third period and rapidly diversified, replacing conifers and other gymnosperms as the dominant group of plants. But we'll take a closer look at flora and fauna as we get to those periods.

 

https://en.wikipedia.org/wiki/Mesozoic

The Sky is Falling

If you follow me on facebook, you may have noticed that I have shared many articles on climate change and that I have started using the comment, “The Sky is Falling.”

It seemed more appropriate than saying, “The Boy Cried Wolf.” In that story, the boy is lying, only looking to introduce some excitement into his own life, without regard for the consequences.

Chicken Little, on the other hand, was telling the truth, as best he knew it. Something (a raindrop) had come down from the sky and hit him. He had never experienced anything like that before, so the logical conclusion was that something terrible was happening, the sky was falling! Chicken Little ran around the farmyard squawking his terrible news, trying to warn all the other farm critters.

Even that doesn’t exactly fit the problem of climate change. Chicken Little was very young and inexperienced. But it’s scientists who have been trying to warn the world’s population that the climate was changing far quicker than it should. They have lots of experience at studying climate and how it has changed in the past, and they have a pretty darn good idea where it’s headed.

In the past week, I have read several articles concerning the number and severity of heatwaves that have been happening around the world. Not only has the world been having more of them, not only have they broken records for daytime high temperatures, they’ve broken records for the highest low temperatures as well. That means that after a sweltering day, you don’t get much relief during the night, because the heat that has accumulated all day doesn’t dissipate fast enough.

I think Europe has already broken several summer records during a heatwave in June of this year. There’s no guarantee they won’t have another later this summer. Or this fall, or... whenever. A heatwave can happen at any time on the calendar, because it is a comparison between the present and what has been ‘normal’ previously.

The scientists don’t ‘think’ any particular place will start having a heatwave every year. But it could happen. After all, they wanted us to keep the warming of the Earth to 2°C or less. What are they saying now, that it’s officially reached a warming of 1.8°C? But in Europe, the temperatures reached +4 to +8°C over ‘normal’.

I don’t know about you, but I don’t get much done when the temperature gets to 95°F. I sure don’t want it to consistently reach 123°F. Or higher.

Maybe Chicken Little isn’t the best story for me to quote to try to get my point across, but it’s the one I can remember as the summer heat settles in. So I’ll keep squawking my warning and hope somebody is listening, because...

The sky is falling.

A 500 Year Summer

My husband has been re-watching Game of Thrones. As I've said before, I don't like political intrigue, nor a cast of thousands, so this is not my cup of tea. But the characters mention they are ending a summer of 500 years, and the winter will soon be on them. That comment has me intrigued.

What kind of solar system would they be in that a season could last for hundreds of years?

I read a book many years ago - I don't remember the title or the author, sorry - where the planet's orbit was a lop-sided elliptical around its sun. When winter came, everything hibernated, even the people. The length of their year did not equal one of ours, but a year - one revolution around their sun - did involve seasons. So that wasn't the answer.

I then thought about the planet NASA has discovered that has 4 suns. That in itself is mind-boggling. The planet revolves around one star, which is in a mutual revolution with a second star, and that pair of stars is in a mutual revolution with another pair of stars.

I don't have enough math and physics to do any computations, so I just have to use some logic to try and get a feel for it. The first pair of stars have to be far enough away from each other that they don't tear each other apart, and also so they don't burn the planet to a crisp when it passes between them. But when that planet is between them, it would be extra warm. As the stars go around each other, that extra warmth would move around their calendar, until the 'extra warmth' was actually during their winter. It might not seem like they were having any winter.

How long would it take for this 'extra warmth' to move around the planet, from producing warm autumns through not-really winters and into warm springs? I don't know. It would depend on how long it takes for those 2 stars to revolve around each other. A thousand years might be too fast.

That might help explain a REALLY LONG summer, but it doesn't explain an equally long winter. When both stars were on the same side of the planet, they would have hot summers and cold winters. Bummer. I thought I might be on to something.

Do we have any physicists in the audience who would like to weigh in on this?