A single eon covers a period of several hundred million years. Gy 111 lecture notes geological time university of south alabama. Discusses how major events in the evolution of life are divided into units and used by scientists to divide up the geologic time scale to refer to times in earth history. An explanation of the relative scale highlights events in the growth of geologic science itself. The geologic time scale the timescale used by geologists as a framework for earths history, its sequence of rocks and fossils and the events they record, was largely established during the 1800s using stenos principles of relative geologic age, smiths principle of faunal succession, and the theory of unconformities by hutton and others. Milankovitch durations have been achieved for portions of older periods. A geologic time scale article pdf available in newsletters on stratigraphy 452. They have created a tool for measuring geologic time, breaking it into useable, understandable segments. All of earth history is represented in this time scale. The evolution of life on earth is also a part of the earths very long history. Eons are the largest intervals of geologic time and are hundreds of millions of years in duration. It is used by geologists, paleontologists, and other earth scientists to describe the timing and relationships of events that have occurred during earths history. We also have a printable version of the geologic time scale as a.
The geologic time scale gts is a system of chronological dating that relates geological. This page uses frames, but your browser doesnt support them. Geologic time scale and brief history of life on earth university at. Scientists developed the time scale by studying rock layers and fossils world wide. The geological society of america geologic time scale j. The numbers included below refer to the beginnings of the division in which the title appears. Explain the relationships among eons, eras, epochs and periods of the geologic time scale.
The marks the formation and movement of a supercontinent geologists call pangaea. Measuring time the geological time scale is a record of the life forms and geological events in earths history. Eras of the geologic time scale mesozoic era paleozoic era dominated by fish, amphibians, early reptiles, land plants emergeearly birds appear, first flowing plants, dinosaurs dominantmammals, primates, and humans. An eon is the longest division of geologic time, so long in fact that. The geologic time scale is divided into four major units.
You are to design an enticing brochure, or pamphlet that advertises the geologic time period assigned to you. Geologic time scale missouri geological survey fact sheet number 12 112016 missouri geological survey director. The vast expanse of geological time has been separated into eras, periods, and epochs. Ngss msess14 geologic time scale worksheet worksheet. Geological time scale digital atlas of ancient life. With large dinosaurs now extinct, smaller mammals that had survived were able to grow and become dominant. The geologic time scale is an essential tool for understanding the history of earth and the evolution of life. A symposium on the classification and nomenclature of geologic timedivisions. Geologists use the names of the geologic time scale because it is a type of shorthand easier to remember than dates in years. Explain the relationship between the fossil record and the eras in the geological timescale.
A geologic era is a subdivision of geologic time that divides an eon into smaller units of time. Joe gillman the age of the earth on the geological clock, the age of the earth is represented by the 12 hours on the face of the clock. Gsa geologic time scale geological society of america. Simple flashcards for learning placement of eons, eras, periods, and epochs on the geologic time scale. In this lesson, explore the principal eons, eras, periods, and epochs that help us. Geologic time scale time units of the geologic time. For the purposes of geology, the calendar is the geologic time scale. Scientists used major changes in life forms in the fossil record to form the geologic time. Geologic time spans are divided into units and subunits, the largest of which are eons. Geologic time scale time units of the geologic time scale development of eon era period epoch plants and animals phanerozoic proterozoic archean.
Lesson3 its a matter of time objectives comprehend geologic time. Thousands and millions of years are used on a geological time scale. Each era is divided into periods and each period is divided into epochs. Geologic time is the chronology of the earths formation, changes, development, and existence. 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. Keyed to the relative time scale are examples of index fossils, the forms of life which existed during limited periods of geologic time and thus are used as guides.
How the geologic time scale was developed by scientists. The geologic time scale gts is a system of chronological dating that relates geological strata. Now that you have learned about the hierarchical components of the geological time scaleeons, eras, periods, and epochsconsider again how all of these parts fit together. The geological time scale gts is a system of chronological measurement that relates stratigraphy to time, and is used by geologists, paleontologists, and other earth scientists to describe the timing and relationships between events that have occurred throughout earths history. During that time, life evolved into the familiar forms we see today.
You should illustrate the cover and the inside with handdrawn or magazine pictures. In this activity, students in groups of three will construct a vertical representation of a geologic time scale and research facts, events, and organisms that differentiate between time scale eras, periods, and epochs. Seventh grade lesson geologic time mini project betterlesson. The entire interval of the existence of visible life is called the phanerozoic eon. These materials are provided to assist in understanding time relationships and how life on earth changed through time. Geologic time scale gsastyle scio logo caps period. The climate changed drastically over a relatively short period of time, becoming much cooler and drier than during the mesozoic era. Exploring geologic time poster illustrated teachers guide. In the time scale above you can see that the phanerozoic is divided into three eras. Discuss the difference between relative and absolute rock ages. Illustrate and label two possible causes of mass extinction.
The history of earth has been divided into three eons. It is used by geologists study earths matter, paleontologists study earths. This was done by making a linear time line on the left side of the time columns. Geologic time scale time units of the geologic time scale. Concise geologic timescale international commission on. Explain why the fossil record is inevitably incomplete, especially for organisms that lived more than 600 million years ago. Identify each of the following fossils and explain its significance within the geological timescale.
Earths history is divided into 4 eras which are subdivided into smaller periods. These eras are separated by catastrophic extinction boundaries, the pt boundary. Thicker units such as the proterozoic were longer in duration than thinner units such as the cenozoic. A geologic time scale is composed of standard stratigraphic divisions based on rock sequences and calibrated in years harland and others, 1982. Silurian ordovician cambrian collectively called precambrian comprises about 87% of the geological time scale holocene pleistocene pliocene miocene palaeocene oligocene eocene age of. Onscreen display and production of usertailored timescale charts is provided by the timescale creator, a public java package available from the ics website. Paleogene neogene 540 510 439 408 360 323 290 245 208 146 57 35 23 5 1. A geologic time scale 2004 why, how and where next. The table of geologic time spans, presented here, agree with the nomenclature, dates and standard color codes set. The geologic time scale is a system used by scientists to describe earths history in terms of major geological or paleontological events such as the formation of a new rock layer or the appearance or demise of certain lifeforms. In a similar way, the most recent era is expanded in the third timeline, and the most recent period is expanded in the fourth timeline.
The geological time scale is divided into five main eras. The dates shown were compiled from several available sources. Coenozoic, mesozoic, paleozoic, proterozoic and archezoic. The development of the earth has taken place over a period of billions of years. The geologic time of the earth is divided into five major eras as.
Humans subdivide time into useable units such as our calendar year, months, weeks, and days. The geologic time scale gts is a system of chronological dating that relates geological strata stratigraphy to time. Media in category geologic time scale the following 61 files are in this category, out of 61 total. The scale of geologic time is vast, currently estimated at nearly 4. Eras modern geologic time scale paleozoic ordovician cambrian silurian devonian mississippian pennsylvanian permian mesozoic triassic jurassic cretaceous paleocene eocene oligocene miocene pliocene pleistocene cenozoic ertiary holocene quat.
The final time period on the geologic time scale is the cenozoic period. These time scales are drawn to scale so you can compare the relative lengths of geologic time divisions. Understanding geologic time eras eons are made up of eras. The phanerozoic eon is divided into three such time frames.
Babcock4 1department of geology, university of kansas, lawrence, kansas 66045, usa 2department of geosciences, roc 21, university of texas at dallas, richardson, texas 75080, usa, and department of earth and planetary sciences, msc 03 2040, 1 university of new mexico, albuquerque. The table of geologic time spans presented here agrees with the nomenclature, dates and standard color codes set. Geologic time scale a brief history of earth since 4. Note that some boundaries those that follow horizontal lines on the time scale are equivalent in age. Two additional eras have been added to the geological time scale. Construct a scientific explanation based on evidence from rock strata for how the geologic time scale is used to organize earths 4.
The geologic time scale geology modification for lehman. Over the years, the development of new dating methods and refinement of previous ones have stimulated revisions to geologic time scales. Presentation of the earths history through the various geologic eras keywords. Very significant events in earths history are used to determine the boundaries of the eras. Divisions of geologic time major chronostratigraphic and.
These key events frame the chapters in the story of life on earth and the system we use to bind all these chapters together is the geologic time scale. Geologic time is the chronological time related to the events that have occurred during earths history. Eons are the largest spans of time in the geologic time scale. There is another kind of time division used the eon. The geological society of america geologic time scale 1888. Geologic time travel brochure cabarrus county schools. Often, the students have a hard time visualizing how. Geologic time travel brochure pretend you are a travel agency. Chart of geological time infographic by karl tate 22 april 2016. You must include all of the following facts about the time period such as. Students will define the geologic time scale and describe how fossils were used to organize the geologic time scale. The study of the geological time scale is necessary to every student of earth and other sciences.
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