12 geologic time periods Precambrian
Precambrian
The Precambrian or Pre-Cambrian, sometimes abbreviated pЄ, is the largest span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale.
Ordovician
The Ordovician /ɔːrdəˈvɪʃən/ is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 485.4 and 443.8 million years ago. It follows the Cambrian Period and is followed by the Silurian Period.
Triassic
The Triassic /traɪˈæsɪk/ is a geologic period and system that extends from roughly 250 to 200 Mya (252.17 to 201.3 million years ago), an interval of 51.04 million years. It is the first period of the Mesozoic Era, and lies between the Permian and Jurassic periods. Both the start and end of the period are marked by major extinction events.
Cretaceous
The Cretaceous, derived from the Latin "creta" (chalk), usually abbreviated K for its German translation Kreide (chalk), is a geologic period and system from 145 ± 4 to 66 million years (Ma) ago. In the geologic timescale, the Cretaceous follows the Jurassic Period and is followed by the Paleogene Period of the Cenozoic Era.
| Era | Period | Plant and Animal Development |
|---|---|---|
| Mesozoic | Cretaceous (144) | First flowering plants First birds Dinosaurs dominant. |
| Jurassic (206) | ||
| Triassic (248) | ||
| Paleozoic | Permian (290) | Extinction of trilobites and many other marine animals First reptiles Large coal swamps Large Amphibians abundant. |
What are the four eras of geologic time?
The four eras that make up the geologic time scale are:
- Precambrian Era: This is the first era of the earth’s history and it is also the longest. ...
- Paleozoic Era: The 400 million years following the Precambrian Era make up the Paleozoic Era. ...
- Mesozoic Era: This era was dominated by the dinosaurs. ...
- Cenozoic Era: Since the end of the Mesozoic Era, the earth has existed within the Cenozoic Era. ...
What are the names of the geologic periods?
The 11 Periods of Geologic Time
- Cambrian (540 – 489 Million Years Ago)
- Ordovician (489 – 444 Million Years Ago)
- Silurian (444 – 416 Million Years Ago)
- Devonian (416 – 360 Million Years Ago)
- Carboniferous (360 – 300 Million Years Ago)
- Permian (300 – 250 Million Years Ago)
- Triassic (250 – 201.6 Million Years Ago)
- Jurassic (201.6 – 145.5 Million Years Ago)
What are geologic eras?
era. era, a very long span of geologic time; in formal usage, the second longest portions of geological time ( eons are the longest). Ten eras are recognized by the International Union of Geological Sciences: the Eoarchean Era (4.0 billion to 3.6 billion years ago), the Paleoarchean Era (3.6 billion to 3.2 billion years ago), the Mesoarchean Era (3.2 billion to 2.8 billion years ago), the Neoarchean Era (2.8 billion to 2.5 billion years ago), the Paleoproterozoic Era (2.5 billion to 1.6 ...
What is the geologic timeline?
What is the Geologic Timeline? The Geologic Timeline was developed by geologists (scientists who study the materials and processes that make up the Earth) as a way of showing the Earth’s geologic history, from the time the planet formed to the present day. It does this by illustrating geologic time by breaking it up into sections.
What are the geologic time periods in order?
The Precambrian, Paleozoic, Mesozoic, and Cenozoic Eras The Geologic Time Scale is the history of the Earth broken down into four spans of time marked by various events, such as the emergence of certain species, their evolution, and their extinction, that help distinguish one era from another.
How many geological periods are there?
A period is a major rank below an era and above an epoch. It is the geochronologic equivalent of a chronostratigraphic system. As of April 2022 there are currently 22 defined periods/systems.
What are the 11 periods on the geologic time scale in order from oldest to present?
The 11 Periods of Geologic TimeCambrian (540 – 489 Million Years Ago) ... Ordovician (489 – 444 Million Years Ago) ... Silurian (444 – 416 Million Years Ago) ... Devonian (416 – 360 Million Years Ago) ... Carboniferous (360 – 300 Million Years Ago) ... Permian (300 – 250 Million Years Ago) ... Triassic (250 – 201.6 Million Years Ago)More items...•
What is meant by geological time scale 12?
Solution : Geological Time Scale is the table showing the sequence and duration of eras, and their periods and epochs with their dominant forms of life since the beginning of life on the earth. It proves gradual complexity of life and even extinction of a number of species. Loading Books. Answer.
What is a geologic time period?
GEOLOGIC TIME PERIODS. The Geologic Time Scale is a chronological model that uses the stratigraphy of the earth, or the layers of rock, in relation to time. It is a model studied by earth scientists, such as geologists and paleontologists to study the events that occurred in our earth's history.
What are the 6 eras?
Geological ErasCenozoic Era: Topic. Last major division of geologic time lasting from 65 million years ago to the present. ... Mesozoic Era: Topic. [Gr.,=middle life], major division of geologic time (see Geologic Timescale, table) from 65 to 225 million years ago. ... Paleozoic Era. ... Precambrian: Topic. ... Archean Eon. ... Proterozoic Eon.
What is the order of the geologic time scale from oldest to youngest?
Earth's history is characterized by four eons; in order from oldest to youngest, these are the Hadeon, Archean, Proterozoic, and Phanerozoic.
What is the oldest period in the geologic time scale?
The oldest is the Paleozoic Era, which means “ancient life.” Fossils from the Paleozoic Era include animals and plants that are entirely extinct (e.g., trilobites) or are rare (e.g., brachiopods) in the modern world.
What was the first period on Earth?
PrecambrianPrecambrian. The Precambrian includes approximately 90% of geologic time. It extends from 4.6 billion years ago to the beginning of the Cambrian Period (about 539 Ma). It includes three eons, the Hadean, Archean, and Proterozoic.
What are the four major eras and in geological time scale?
The four main ERAS are, from oldest to youngest: PreCambrian, Palaeozoic, Mesozoic and Cenozoic. Periods are a finer subdivision in the geological time scale.
How do you remember the geologic time scale?
Ø Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, Holocene (or Recent): * Pretty Eager Old Men Play Poker Hard. * Pigeon Egg Omelets Make People Puke Heartily.
Why is it necessary to determine the age of fossils 12?
The age of the fossil must be determined so it can be compared to other fossil species from the same time period. Understanding the ages of related fossil species helps scientists piece together the evolutionary history of a group of organisms.
How are geologic periods named?
In the early 1800's a system for naming geologic time periods was devised using four periods of geologic time. They were named using Latin root words, Primary, Secondary, Tertiary and Quaternary. That worked for the time but we know so much more now than was known in the 1800's.
What was the first period on Earth?
PrecambrianPrecambrian. The Precambrian includes approximately 90% of geologic time. It extends from 4.6 billion years ago to the beginning of the Cambrian Period (about 539 Ma). It includes three eons, the Hadean, Archean, and Proterozoic.
What is the oldest period in the geologic time scale?
the PrecambrianThe oldest subdivision of the time scale is the Precambrian (symbolized by PC, X, Y, or Z in the GRI GIS data). The Precambrian is split into three eons: Hadean (4600-4000 MYA), Archean (4000-2500 MYA), and Proterozoic (2500-541 MYA).
What is geologic time?
Geologic time, the extensive interval of time occupied by the geologic history of Earth. Formal geologic time begins at the start of the Archean Eon (4.0 billion to 2.5 billion years ago) and continues to the present day. Modern geologic time scales additionally often include the Hadean Eon, which is an informal interval ...
How is the geologic time scale developed from the fossil record numerically quantified?
The relative geologic time scale developed from the fossil record has been numerically quantified by means of absolute dates obtained with radiometric dating methods.
What is the ability to quantify the geologic time scale?
The ability to quantify the geologic time scale—i.e., to date the events of the geologic past in terms of numbers of years—is largely a result of coupling radiometric dating techniques with older, classical methods of establishing relative geologic ages. As explained earlier, radiometric dating methods are based on the general…
Why are living things important to geologic time?
Living things play critical roles in the development of geologic time scales, because they have undergone evolutionary changes over geologic time. Moreover, particular kinds of organisms are characteristic of particular parts of the geologic record.
Which period was the most catastrophic extinction?
The most catastrophic extinction took place at the end of the Permian Period. Encyclopædia Britannica, Inc. The Editors of Encyclopaedia Britannica This article was most recently revised and updated by John P. Rafferty, Editor. History at your fingertips.
What are the significant moments in Earth's history?
Encyclopædia Britannica, Inc./Christine McCabe. Grand Canyon rock layering. The steep walls of the Grand Canyon contain a number of layers of sedimentary rock laid down over millions of years.
How many timelines show the geologic time scale?
The following five timelines show the geologic time scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. Therefore, the second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in the third timeline, the most recent period is expanded in the fourth timeline, and the most recent epoch is expanded in the fifth timeline.
Who first proposed the geologic time scale?
Avicenna also first proposed one of the principles underlying geologic time scales, the law of superposition of strata, while discussing the origins of mountains in The Book of Healing (1027). The Chinese naturalist Shen Kuo (1031–1095) also recognized the concept of " deep time ".
What is the Hadean eon?
The Hadean eon represents the time before the fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga ( billion years ago). Other subdivisions reflect the evolution of life; the Archean and Proterozoic are both eons, the Palaeozoic, Mesozoic and Cenozoic are eras of the Phanerozoic eon.
How long is the Phanerozoic eon?
This is not to scale, and even though the Phanerozoic eon looks longer than the rest, it merely spans 500 million years, whilst the previous three eons (or the Precambrian supereon) collectively span over 3.5 billion years. This bias toward the most recent eon is due to the relative lack of information about events that occurred during the first three eons (or supereon) compared to the current eon (the Phanerozoic).
What is the largest division of time?
The primary and largest catalogued divisions of time are periods called eons . The first eon was the Hadean, starting with the formation of the Earth and lasting over 600 million years until the Archean eon, which is when the Earth had cooled enough for continents and the earliest known life to emerge.
How old is the Earth?
Evidence from radiometric dating indicates that Earth is about 4.54 billion years old. The geology or deep time of Earth's past has been organized into various units according to events that are thought to have taken place. Different spans of time on the GTS are usually marked by corresponding changes in the composition of strata which indicate major geological or paleontological events, such as mass extinctions. For example, the boundary between the Cretaceous period and the Paleogene period is defined by the Cretaceous–Paleogene extinction event, which marked the demise of the non-avian dinosaurs as well as many other groups of life. Older time spans, which predate the reliable fossil record (before the Proterozoic eon ), are defined by their absolute age.
What is the significance of the Cambrian Explosion?
This is about the significance of the Cambrian Explosion, a massive diversification of multi-cellular life forms that took place in the Cambrian period at the start of the Phanerozoic. The following five timelines show the geologic time scale.
What is geologic time?
Effective communication in the geosciences requires consistent uses of stratigraphic nomenclature, especially divisions of geologic time. A geologic time scale is composed of standard stratigraphic divisions based on rock sequences and is calibrated in years (Harland and others, 1982). Over the years, the development of new dating methods and the refinement of previous methods have stimulated revisions to geologic time scales.
What are the two color schemes used in geologic maps?
Two principal color schemes are used, one by the Commission for the Geologic Map of the World (CGMW) and another by the USGS.
What is the term for the division of time older than the Phanerozoic?
Precambrian. For many years, the term "Precambrian" was used for the division of time older than the Phanerozoic. For consistency with the time scale in Hansen (1991), the term "Precambrian" is considered to be informal and without specific stratigraphic rank (although it is here capitalized).
What is the uppermost part of the Cambrian called?
In the ICS time scale, the uppermost part of the Cambrian has been named "Furongian" and the lowermost part the "Terreneuvian.". The GNC, however, will not include these names in the Divisions of Geologic Time until all series/epochs of the Cambrian are named.
Is the tertiary period a time scale?
Although the Tertiary is not recognized by many international time scales, the GNC agrees that it is important that it be recognized as a system/period; the map symbols "T" (Tertiary) and "Q" (Quaternary) have been used on geologic maps for more than a century and are widely used today.
What Is Geologic dating?
Hadean
- The oldest of the geologic eons is the Hadean, which began about 4.6 billion years ago with the formation of Earth and ended about 4 billion years ago with the appearance of the first single-celled organisms. This eon is named after Hades, the Greek god of the underworld, and during this period the Earth was extremely hot. Artist renderings of the Hadean Earthdepict a hellish, molte…
Archean
- The next geologic eon, the Archean, began about 4 billion years ago. During this period, the cooling of the Earth's crust allowed for the formation of the first oceans and continents. Scientists are not exactly sure what these continents looked like since there is so little evidence from the period. However, some believe the first landmass on Earth was a supercontinent known as Ur. O…
Proterozoic
- The Proterozoic eon began about 2.5 billion years ago and ended about 500 million years ago when the first complex lifeforms appeared. During this period, the Great Oxygenation Event transformed the Earth's atmosphere, allowing for the evolution of aerobic organisms. The Proterozoic was also the period in which the Earth's first glaciers formed. Some scientists even …
Phanerozoic
- The most recent geologic eon is the Phanerozoic, which began about 540 million years ago. This eon is very distinct from the previous three—the Hadean, Archean, and Proterozoic—which are sometimes known as the Precambrian era. During the Cambrian period—the earliest part of the Phanerozoic—the first complex organisms appeared. Most of them were aqu...