Paleocene

A long time ago, the Earth changed.

Large dinosaurs were gone. Small animals began to live and grow. The world was very warm.

Green forests grew everywhere. These woods even grew at the top and bottom of the world. Many small animals lived in the trees. Some animals grew to be very big.

Plants from this time turned into coal. This was a very special time for life.

The Paleocene was a time long ago. It lasted from 66 to 56 million years ago.

This era began after a big event. An asteroid hit the Earth. This event killed 75% of all species. Most famous were the dinosaurs. After they were gone, new life grew.

Small animals began to change quickly. They took over the empty world. Many mammals grew during this time. Some were very large. In the oceans, ray-finned fish became leaders.

The Earth was very warm then. There was no ice at the poles. Thick forests grew everywhere. These forests even grew at the poles.

Parts of the Earth were still moving. South America and Antarctica were close. The Rocky Mountains were rising up. Later, a big change happened. A lot of carbon went into the air. This made the world even hotter.

Some plants from this time turned into coal. We still mine this coal today. The Paleocene was a big step for life.

The Paleocene was a very important time for our planet. It was a geological epoch that lasted from 66 to 56 million years ago.

This era was the very first part of the Paleogene Period. The name comes from Greek words meaning "old" and "new." It basically means the "old part of the Eocene." This period was a time of big changes for life.

Everything changed because of a huge event at the start. An asteroid hit the Earth near the Yucatán Peninsula. This is called the Chicxulub impact. Some scientists think volcanoes also played a part.

This event killed 75% of all species on Earth. The most famous ones to disappear were the non-avian dinosaurs. Because so many species died, the world became empty. This allowed new types of life to begin growing.

Life began to fill the empty spaces in many ways. Many small creatures started to change and grow very quickly.

Mammals became very common during this time. We see the very first placental and marsupial mammals here. In the deep oceans, ray-finned fish became the leaders of the reefs. The Earth was also very warm and had no ice at the poles.

Thick forests grew all over the world, even in the cold polar areas.

Scientists have studied how to name this time for a long time. A man named Wilhelm Philipp Schimper first used the name in 1874.

He was a geologist who studied plants. Later, the International Commission on Stratigraphy helped set the rules. They divided the Paleocene into three stages. These are called the Danian, the Selandian, and the Thanetian.

Geologists find clues about these stages in rocks in places like Tunisia and Spain.

We can still see the effects of the Paleocene today. Many important coal deposits formed during this time.

For example, the Cerrejón mine in Colombia is a huge open-pit mine. Some coal from this era is even found in Svalbard, Norway. In the North Sea, people found natural gas and oil from this period. The moving continents also left marks. The Indian Plate began hitting Asia, and the Rocky Mountains were rising up.

The Paleocene helped shape the world we live in now.

The Paleocene was a major geological epoch in Earth's history. It lasted from approximately 66 to 56 million years ago (Ma). This epoch marks the very beginning of the Paleogene Period. It also sits at the start of the modern Cenozoic Era. The name comes from Ancient Greek words. "Palaios" means old, and "kainos" means new. Together, it translates to "the old part of the Eocene."

This era was a bridge between the age of dinosaurs and the modern world.

The epoch began with a massive catastrophe known as the K–Pg extinction event. This event was likely caused by the Chicxulub impact, where a large asteroid hit the Yucatán Peninsula. Volcanism from the Deccan Traps may have also contributed. This disaster killed about 75% of all species on Earth. Most famously, it ended the reign of the non-avian dinosaurs.

This sudden loss of life caused a massive turnover in species. Many previously common animals vanished. They were replaced by species that were previously uncommon or rare.

During the Paleocene, the Earth's physical environment was very different. The climate was a greenhouse climate. This means the global average temperature was much higher than it is today. There were no permanent ice sheets at the North or South Poles. Because of this warmth, thick forests grew all over the planet. Even the polar regions were covered in lush plant life.

However, these forests had low species richness compared to later times. Most animals were quite small. They were rapidly evolving to fill the empty spaces left by extinct species. While some animals grew large, most remained small and moved through dense forests.

Geography was also in a state of constant change. The continents were not in their current positions. In the Northern Hemisphere, land bridges still connected some continents. South America, Antarctica, and Australia had not yet completely separated.

In the mountains, the Rocky Mountains were undergoing uplift. The Indian Plate had also begun its slow collision with Asia. In the oceans, the circulation of water was different. Instead of the North Atlantic, downwellings likely occurred in the North Pacific. Water density was controlled mostly by salinity rather than temperature.

Geologists divide the Paleocene into three distinct stages. These stages are the Danian, the Selandian, and the Thanetian. The Danian is the first stage, spanning from 66 to 61.6 Ma. It was first defined by Pierre Jean Édouard Desor using Danish chalks. The Selandian follows from 61.6 to 59.2 Ma. It is often studied at the sea cliffs of Zumaia, Spain.

Finally, the Thanetian lasts from 59.2 to 56 Ma. Scientists use specific fossils and magnetic shifts to tell these stages apart. For example, the appearance of the algae *Discoaster* helps mark the Thanetian.

The Paleocene ended with a massive climatic event. This is called the Paleocene–Eocene Thermal Maximum, or PETM. During this time, about 2,500 to 4,500 gigatons of carbon were released. This carbon entered the atmosphere and the ocean systems. The result was a sudden spike in global temperatures. It also caused ocean acidification. This event led to the extinction of 30% to 50% of certain marine species.

These species, called benthic foraminifera, are vital indicators of ocean health.

We can still find the physical remains of the Paleocene today. Many important energy resources formed during this epoch. Large coal deposits were created, such as the Cerrejón mine in Colombia. This is one of the largest open-pit mines in the country.

Other coal is found in Svalbard, Norway, and the Canadian Arctic. In the North Sea, the Paleocene left behind massive reserves of natural gas and oil. These resources total billions of barrels of oil and trillions of cubic meters of gas. The Paleocene was a time of recovery, change, and immense geological power.