What is subdivision of an era called?

Answer 1

No a Geological Period is a subdivision of a Geological Era

For example the Mesozoic Era (251 - 65.5 Ma) is subdivided into :-

• Triassic Period (251 - 199.6 Ma)
• Jurassic Period (199.6 - 145.5 Ma)
• Cretaceous Period (145.5 - 65.5 Ma)

In order from largest to smallest :-

1. SuperEon (not officially used by ICS)
2. Eon
3. Era
4. Period
5. Epoch
6. Age
7. Chrono (not officially used by ICS)

Answer 2

The history of the earth is broken up into a hierarchical set of divisions for describing geologic time. As increasingly smaller units of time, the generally accepted divisions are eon, era, period, epoch, age. In the time scale shown at left, only the two highest levels of this hierarchy are represented.

The Phanerozoic Eon represents the time during which the majority of macroscopic organisms, algal, fungal, plant and animal, lived. When first proposed as a division of geologic time, the beginning of the Phanerozoic (approximately 543 million years ago) was thought to coincide with the beginning of life. In reality, this eon coincides with the appearance of animals that evolved external skeletons, like shells, and the somewhat later animals that formed internal skeletons, such as the bony elements of vertebrates. The time before the Phanerozoic is usually referred to as the Precambrian, and exactly what qualifies as an "eon" or "era" varies somewhat depending on whom you talk to. In any case, the Precambrian is usually divided into the three "eras" shown.

The Phanerozoic also consists of three major divisions...the Cenozoic, the Mesozoic, and the Paleozoic Eras. The "zoic" part of the word comes from the root "zoo", which means animal. This is the same root as in the words zoology and Zoological Park (or Zoo). "Cen" means recent, "Meso" means middle, and "Paleo" means ancient. These divisions reflect major changes in the composition of ancient faunas, each era being recognized by its domination by a particular group of animals. The Cenozoic has sometimes been called the "Age of Mammals", the Mesozoic the "Age of Dinosaurs" and the Paleozoic the "Age of Fishes". This is an overly simplified view, which has some value for the newcomer but can be a bit misleading. For instance, other groups of animals lived during the Mesozoic. In addition to the dinosaurs, animals such as mammals, turtles, crocodiles, frogs, and countless varieties of insects also lived on land. Additionally, there were many kinds of plants living in the past that no longer live today. Ancient floras went through great changes too, and not always at the same times that the animal groups changed.

Answer 3

im asking this question there should already be an answer

Answer 4

epochs

Answer 5

Epochs