Question 1

How do you say Paleogene?

Accepted Answer

Paleogene is pronounced PAY-lee-oh-jeen. Break it into four parts: PAY, then lee, then oh, then jeen, and put the strongest stress on the first syllable PAY. It rhymes roughly with 'pay me oh mean' said quickly. Once you say it a few times it feels totally natural, and it is one of the cooler-sounding geologic period names out there.

Question 2

What does Paleogene mean?

Accepted Answer

Paleogene comes from two Greek words: 'palaios' meaning ancient or old, and 'genos' meaning birth or origin. So the name basically means 'ancient origin' or 'old beginning.' It was named this way because it represents the earliest part of the Cenozoic Era, the age of mammals, making it the ancient beginning of the world we recognize today. The following period, the Neogene, means 'new origin,' forming a neat old-and-new pair.

Question 3

When did the Paleogene Period start and end?

Accepted Answer

The Paleogene Period started 66 million years ago, right at the moment the asteroid impact wiped out the non-avian dinosaurs at the end of the Cretaceous. It ended 23.03 million years ago when Earth transitioned into the Neogene Period. That means the Paleogene lasted about 43 million years in total. To put that in perspective, the entire existence of our human genus Homo spans only about 2 to 3 million years.

Question 4

What animals lived during the Paleogene?

Accepted Answer

The Paleogene was the great age of early mammals, and almost every major mammal group we know today got its start here. Early horses the size of dogs, ancestral whales that still had legs, giant flightless predatory birds, and the first primates all lived during this period. In the oceans, early sharks, enormous sea turtles, and serpentine whales like Basilosaurus ruled the waves. It was also the time when bats first took to the air, with the oldest known bat fossils dating to around 52 million years ago in the Eocene.

Question 5

Did any dinosaurs live in the Paleogene?

Accepted Answer

Non-avian dinosaurs, the giant ones like T. rex and Triceratops, went completely extinct at the very start of the Paleogene 66 million years ago. However, birds are technically avian dinosaurs, and they absolutely survived and thrived during the Paleogene. Some Paleogene birds were genuinely terrifying, including giant flightless terror birds like Gastornis that could be as tall as a grown adult human and hunted mammals on the ground.

Question 6

How warm was the Earth during the Paleogene?

Accepted Answer

During the warmest part of the Paleogene, the Eocene Epoch around 50 million years ago, Earth was significantly warmer than it is today. Global average temperatures were roughly 10 to 15 degrees Celsius higher than modern levels. There was no permanent ice at the North or South Pole, and tropical forests stretched almost to the Arctic Circle. The most extreme warming event was the Paleocene-Eocene Thermal Maximum around 56 million years ago, when temperatures spiked by an additional 5 to 8 degrees Celsius in just 20,000 years.

Question 7

What caused the Paleogene to start?

Accepted Answer

The Paleogene began because of the Chicxulub asteroid impact 66 million years ago. The asteroid, about 12 kilometers wide, struck the shallow sea near what is now the Yucatan Peninsula in Mexico and released energy billions of times more powerful than any nuclear bomb. The impact caused massive wildfires, blocked sunlight for months with a global ash cloud, triggered acid rain, and wiped out about 75 percent of all species. This catastrophic boundary, called the K-Pg boundary, marks the exact start of the Paleogene.

Question 8

What is the difference between Paleogene and Neogene?

Accepted Answer

The Paleogene and Neogene are the two periods that make up the Cenozoic Era. The Paleogene covers the older stretch from 66 to 23 million years ago, when mammals were just getting started and the world was generally much warmer. The Neogene covers 23 million years ago to about 2.6 million years ago, when grasslands spread, mammals grew larger and more modern-looking, and Antarctica became permanently glaciated. Their names reflect this divide: Paleogene means ancient origin, and Neogene means new origin.

Question 9

Was the Paleogene part of the Tertiary Period?

Accepted Answer

Yes. For a long time, geologists used an older system that grouped the Paleogene and Neogene together under a single informal name called the Tertiary Period. The word Tertiary dates back to the 1700s and was used for centuries in textbooks and on maps. In 2004 the International Commission on Stratigraphy officially retired Tertiary as a formal term and replaced it with the separate Paleogene and Neogene Periods. You will still see Tertiary used informally in older books and some scientific papers.

Question 10

What is the Paleocene-Eocene Thermal Maximum?

Accepted Answer

The Paleocene-Eocene Thermal Maximum, usually shortened to PETM, was an extreme global warming event that happened around 56 million years ago during the Paleogene. In roughly 20,000 years, which is very fast in geologic terms, global temperatures jumped by 5 to 8 degrees Celsius. Scientists think massive releases of carbon dioxide and methane caused the spike, possibly from volcanic eruptions or thawing seafloor methane deposits. The PETM caused widespread ocean acidification, deep-sea extinctions, and dramatic changes in mammal body sizes, and scientists study it closely as a natural parallel to modern climate change.

Question 11

What three epochs make up the Paleogene?

Accepted Answer

The Paleogene is divided into three epochs in order from oldest to youngest: the Paleocene, the Eocene, and the Oligocene. The Paleocene lasted from 66 to about 56 million years ago and was the recovery phase after the asteroid impact. The Eocene ran from 56 to about 33.9 million years ago and was the warmest, most tropical part of the Paleogene. The Oligocene spanned 33.9 to 23 million years ago and was a cooler, drier time when grasslands began to replace many forests.

Question 12

How long did the Paleogene last?

Accepted Answer

The Paleogene lasted approximately 43 million years, from 66 million years ago to 23.03 million years ago. To put that in perspective, the entire time since the asteroid killed the dinosaurs to the appearance of the first walking human ancestors is roughly covered by this single period. Modern humans, Homo sapiens, have only existed for about 300,000 years, so the Paleogene is more than 140 times longer than the entire history of our species.

Question 13

Why did Antarctica freeze over during the Paleogene?

Accepted Answer

Antarctica froze over near the end of the Paleogene, around 33 to 34 million years ago, because of the way the continents were moving. As Antarctica drifted south and separated from South America, a powerful circular ocean current called the Antarctic Circumpolar Current formed and cut off warm tropical water from reaching the continent. Without that warm water, Antarctica rapidly cooled and developed a permanent ice sheet for the first time in hundreds of millions of years. This freezing locked up enormous amounts of water and lowered global sea levels significantly.

Question 14

What came before and after the Paleogene?

Accepted Answer

The Paleogene was preceded by the Cretaceous Period, the last period of the Mesozoic Era and the age of the famous giant dinosaurs. The Cretaceous ended 66 million years ago with the asteroid impact that kicked off the Paleogene. After the Paleogene came the Neogene Period, starting 23 million years ago, which continued the story of mammal evolution and eventually led to the Ice Ages and the appearance of early human ancestors. Together the Paleogene and Neogene make up the majority of the Cenozoic Era.

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