What was Earth Like During the Eocene Epoch?

Eocene, about 53 million years ago ~ 36.5 million years ago, the second age of the Tertiary. The symbol is Ch Eocene, which is the second major stage of Paleogene in the geological age. It started about 57.8 million years ago and finally 36.6 million years ago. It is between the Paleocene and Oligocene. )between.

The names of Eocene (Eocene, Epoch), derived from the Greek (eo, dawn) and (caenos, neo), refer to the emergence of modern mammals. The Eocene is often divided into the early (57.8 million to 52 million years ago), the middle period (52 to 43.6 million years ago), and the late period (43.6 million to 36.6 million years ago). Most notably in the early Eocene, primitive modern mammals began to appear. The Eocene ended in a biological extinction event called the Grande Coupure (the "Great Break" in continuity).

Due to the occurrence of the fastest and most intense global warming event in the existing records of the geological history of the earth, known as the Paleocene-Eocene extreme heat event (PETM or IETM), the temperature of the earth increased rapidly. The New Age begins. This rapid and violent temperature increase (as much as 7 ° C in high latitudes) lasted less than 100,000 years, but led to the rapid extinction of a large number of species, resulting in the formation of

In the Eocene, the continents continued to drift to where they are today.

At the beginning of the Eocene, Australia and Antarctica were still connected, and at the same time, the warm equatorial ocean currents merged into the cold Antarctic waters, allowing the heat to be distributed globally, thereby maintaining high global temperatures. But 45 million years ago, when Australia split from the southern continent, the warm equatorial currents began to deviate from the Antarctic region, forming an isolated cold water channel between the two continents. The Antarctic region continues to become cold, and the Antarctic waters begin to freeze and transport cold water and sea ice to the north, further exacerbating the cold situation.

The northern supercontinent-

Paleontologists divide the history of the Earth into different levels of geological age. The highest level is called "

The Eocene is often divided into early and late periods, or is often divided into early, middle and late periods. The corresponding rocks are the Lower Eocene, the Middle Eocene, and the Upper Eocene. According to the activity of different animals, the Eocene can be subdivided into:

Priyan period (37.2 ± 0.1 33.9 ± 0.1 million years)

Baltonian period (40.4 ± 0.2 37.2 ± 0.1 million years)

Ludite period (48.6 ± 0.2 40.4 ± 0.2 million years)

In the early Eocene, a hot and humid environment was created due to the hot climate and warm ocean. Except for the arid desert, the surface is completely covered by forests.

The polar forests are vast. In the Arctic

Eocene shallow sea

The general characteristics of the London clay community in the Eocene are explained by the dorsal snail community. It exhibits a more differentiated and diverse benthic fauna than Lower London Clay, and has a very shallow water appearance. Gastropods have changed a lot in the surface animals, the most abundant of which is the Suweibo snail. This species has a thick and heavy shell with a wide lip and extends into finger-like protrusions. The species of modern day palm snails often bury themselves in parts of their bodies; their wide lips and their appendages separate the inflow and outflow breathing water. They eat about diatoms and algae debris. Grooved coneworm is also a common endogenous filter-feeder; organic grit particles are collected with gills, captured in mucus, and then pulled into the mouth. Tibialis snails and snails are also plant-based foods. Scorched conch and ribon snails may be hairy worms. Hairy double-hole tubes are also abundant.

The bivalves include sheep oysters and many endemic animals, most of which are filter-eating animals, like the silky-feathered clams. Although they are fixed, they can be inserted into the shell, but can quickly repair the exposed Any damage on the rear shell. Other common bivalves include slow arctic clams and more active miliform and egg clams with water pipes.

Bony fish and catfish are abundant, the latter mainly eating endogenous bivalves.

Faunas similar to this community can be found in the upper part of the mud and sand in shallow water shed environments under the mixed warm climate of modern subtropical regions, with a depth of about 10-50 meters.

The higher sequence of the Hampshire Basin's London Clay and the London Basin represent better conditions for the formation of relatively shallow water than the previous community. There are great changes in the combination of fossils between the various layers, which roughly represents the mosaicity of the bottom community, which develops in a shallow water shelf of 20-50m deep. This community is one of many diversity groups encountered in Hinfield.

Eocene Asia Coastal Sandy

The notable members here are the endogenous fauna, and the bivalve relatives clams that do not move are modern. They are the most abundant in the sheltered stable base, especially where the seaweed breeds. The sea shell goddesses Ha and Thrace of the long-water deep-dive burrow are also very rich. The shallow-dive burial are arctic clams and egg clams. A bivalve that eats no sediment in this community.

The superficial animals are oysters, large barnacle-top barnacle mite double-hole tubes, shrimp ancient sword shrimp, and upright stick-shaped radiant corals.

This is the third type of London clay community produced in Bognor near Hampshire Basin

Eocene sea chlorite sandy

This community lives in a shallow shack near the shore, with a water depth of 10-30m. As with other Cenozoic communities, a variety of shallow burrowed filter-feed bivalves predominate; the main members are large thick-shelled flat-folded clams, and the small pads and thicker have no water pipes; the burrows are slightly deeper and With water pipes, the light-shelled clams and giant salamanders. Other common endogenous animals are burrowing hornfish and ciliate gastropods. The snails and conical snails are chlorite sandy clay with marine fauna. The other is thin-layered clay sandstone and lignite of delta and swamp origin. Palaeogeographic restoration shows that during this period, Isle of Wight and Hampshire were located in shallow sea sheds, and rivers were injected into them. The rivers came from the west and northwest, and the delta facies were deposited. The Braxham period formed a bay on the coastline, which had shallow and warm sea water, possibly a seaweed layer. Later, silt in the bay rose, and swamps developed around the area. Evidence from foraminifera indicates that the seawater temperature is around 18 ° C and the salinity is normal or slightly reduced. ^[1]