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Jurassic Period Facts & Worksheets

Jurassic Period, the second period of the Mesozoic Era, which lasted from 201.3 to 145 million years ago

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The second of the Mesozoic Era’s three periods is the Jurassic Period, following the Triassic Period and was followed by the Cretaceous Period. The Jurassic was a time when significant global changes in continental configurations, oceanographic patterns, and biological systems took place. It lasted from 201.3 million to 145 million years ago.

See the fact file below for more information on the Jurassic Period, or you can download our 31-page Jurassic Period worksheet pack to utilize within the classroom or home environment.

Key Facts & Information

HISTORY AND ETYMOLOGY

  • Following their near extinction at the end of the Triassic, ammonites, and dinosaurs made a significant return in the Jurassic. The appearance of teleost fish, oysters, crabs, and lobsters. Along with ichthyosaurs, sharks, bony fish, cephalopods, and many other marine predators, plesiosaurs and marine crocodiles first appeared. 
  • Gastropods and the smaller populations of the decreasing Paleozoic fauna, such as brachiopods and sea lilies, found homes in the thriving reef ecosystems formed on the coral and sponge backbones.
  • Even after suffering catastrophic extinction losses at the end of the Triassic, reptiles continued to dominate the land. The largest saurischians started to appear in the Upper Jurassic as dinosaurs became bigger. The Jurassic marks the first appearance of the ornithischians, the other significant dinosaurs. 
  • The fossil record contains the first known birds, yet flying pterosaurs of all sizes still dominated the skies. Both groups of theropod dinosaurs, which gave origin to birds, were clothed in vibrant feathers, and both were still evolving. Insects evolved into a variety of contemporary forms, including wasps and beetles.
  • The first lizards likely consumed the new variety of insects. Conifers mostly grow in forests that produce coal. 
  • With conifers, ginkgo, and an understory of ferns, cycads, and horsetail rushes, the landscape was primarily covered in forests.
  • It was a different world from the one we live in today since flowering plants hadn’t yet evolved, and there were no grasses to create the vast plains of contemporary Earth.
  • With the formation of the Central Atlantic Ocean around the end of the Middle Jurassic, the supercontinent Pangaea began to fragment during the Jurassic. Sea levels started low and rose by the Middle Jurassic.
  • The chronostratigraphic term “Jurassic” relates to the Jura Mountains, a forested mountain range mostly bordering the France-Switzerland border. 
  • The word “Jura” derives from the Celtic root jor through the Gaulish iuris, “wooded mountain,” which was appropriated into Latin as a place name and developed into Juria and then Jura.
  • Alexander von Humboldt, a naturalist from Germany, visited the area in 1795 and correctly deduced that the carbonate deposits in the Jura Mountains were younger than the Triassic-aged Muschelkalk in Southern Germany. In 1799, he gave them the name Jura-Kalkstein (or “Jura limestone”).
  • The work “Description of the Terrains that Constitute the Crust of the Earth or Essay on the Structure of the Known Lands of the Earth,” was published in 1829 by the French naturalist Alexandre Brongniart.
  • When comparing the “Jura-Kalkstein” of Humboldt with similarly ancient oolitic limestones in Britain, Brongniart used the word terrains jurassiques, thus creating and publishing the name “Jurassic.”
  • The Black, Brown, and White Jurassic were initially designated from oldest to youngest by the German geologist Leopold von Buch, who developed the three-way divide of the Jurassic in 1839. 
  • William Conybeare and William Phillips first used the term “Lias” in 1822 to refer to strata in England that were the same age as the Black Jurassic.

GEOLOGY

  • Early, Middle, and Late are the three epochs that make up the Jurassic Period. The Jurassic is similarly separated into the Lower, Middle, and Upper series according to stratigraphy. 
  • The Jurassic rocks are divided by geologists into a stratigraphic series of units called stages, each formed over a comparable period termed an age.
  • Stages can be categorized either globally or locally. The International Commission on Stratigraphy (ICS) ratifies global locations based on a Global Border Stratotype Section and Point (GSSP) from a single formation (a stratotype), which identifies the lower boundary of the stage, for purposes of global stratigraphic correlation.

Early Jurassic

  • The oldest part of the Jurassic Period, roughly the same size as the Early Jurassic but also includes a section of the preceding Rhaetian, is known as the Lias or Liassic in historical literature.
  • The first discovery of the ammonite Psiloceras spelae tirolicum in the Kendlbach Formation revealed at Kuhjoch marks the start of the Hettangian and, consequently, the Jurassic as a whole. 
  • Albert Oppel’s 1856–1858 definition of the initial appearance of Psiloceras planorbis as the base of the Jurassic was later revised because it was thought too localized of an event to serve as an international boundary.

Middle Jurassic

  • The German city of Aalen is the source of the name for the Aalenian. Karl Mayer-Eymar, a Swiss geologist, first described the Aalenian in 1864. The Black Jurassic dark clays and the Brown Jurassic phases’ overlaying clayey sandstone and ferruginous oolite once formed southwest Germany’s bottom limit.
  • The GSSP for the Aalenian base was validated in 2000 and is situated at Fuentelsaz in the Iberian range close to Guadalajara, Spain. The earliest occurrence of the ammonite Leioceras opalinum identifies the base of the Aalenian.

Late Jurassic

  • Alcide d’Orbigny gave the Oxfordian its name in 1844 in honor of the English city of Oxford, about the Oxford Clay. There needs to be a clearly defined GSSP at the Oxfordian base. 
  • W. J. Arkell identified the lower border of the Oxfordian in research conducted between 1939 and 1946 as the location of the ammonite Quenstedtoceras mariae‘s initial appearance (then placed in the genus Vertumniceras). 
  • Cardioceras redcliffense is thought to have made its first appearance as the lower border in later suggestions.

PALEOGRAPHY AND PALEOCLIMATE

  • Although the dissolution of the Pangea supercontinent had already started in the Triassic Period, the continents were still relatively near to one another at the start of the Jurassic Period. 
  • The geographical masses were divided into two regions: Gondwana, which included South America, Africa, India, Antarctica, and Australia, and Laurasia, which included North America and Eurasia.
  • Tethys, a tropical east-west seaway, lay between these two areas. Throughout the Jurassic, spreading centers and oceanic rifts appeared between Eurasia and North America, between North America and Gondwana, and even within Gondwana.
  • Thick flood basalts were continuously forming and then being deposited in the ocean basins, gradually widening but still constrained. 
  • These deposits, such as the oil-bearing shales in the North Sea and the salt deposits in the Gulf of Mexico, are now economically significant.
  • Along with ocean basin spreading, continental rifting also started during the Jurassic, eventually dividing Antarctica, India, and Madagascar from Africa and South America. 
  • The complicated Caribbean region is made up of multiple microplates and blocks dating back to this period.
  • To enable the creation of new seafloor through the proto-Atlantic Ocean, significant subduction zones (where the seabed is destroyed) were active over nearly all of the continental edges surrounding Pangea, as well as in Southeastern Europe, Southern Tibet, and other locations.
  • The Farallon, Phoenix, and Izanagi tectonic plates, Panthalassa’s three main oceanic plates, triple intersected to form the Pacific Plate in the Early Jurassic about 190 million years ago.
  • Due to a bend in one of the plate borders, the formerly stable triple junction changed into an unstable configuration bordered on all sides by transform faults, leading to the development of the Pacific Plate at the center.
  • According to estimates, the eustatic sea level was roughly where it is today throughout the Hettangian and Sinemurian, rose many tens of meters during the late Sinemurian and early Pliensbachian, and then by the late Pliensbachian, began to decline to levels that are close to what they are today.
  • Jurassic climates can be reconstructed using geochemical studies, silt and fossil distribution analyses, and other techniques. Paleolatitudes of up to 60° N and 60° S are where warm-adapted plant fossils have been discovered, indicating an extended tropical zone.
  • Ferns and other frost-sensitive plants were discovered in higher paleolatitudes, suggesting that the equator-to-pole temperature difference was not as extreme as it is today.
  • Large Jurassic salt deposits indicate arid regions, whereas vast coal deposits point to highly precipitous areas. On the western side of Pangea, there may have been a dry belt, whereas the eastern side may have been more humid.
  • The oxygen isotope analysis of marine fossils indicates that the Jurassic period experienced relatively warm global temperatures.

JURASSIC LIFE

  • One of the five most significant mass extinctions on Earth occurred at the Triassic-Jurassic border. It is uncertain whether terrestrial animals or land plants also became extinct during this epoch, although around half of the genera of marine invertebrates were.
  • Additionally, at least two other Jurassic periods—one in the Early Jurassic time and another after the period—show increased faunal turnover that primarily affected marine invertebrates.
  • Rock strata from the Jurassic period preserve the earliest examples of numerous significant current biological groups. By the Middle Jurassic, the ocean’s’ bottom life had developed into a sophisticated, complex ecosystem with an abundance of mollusks and coral reef builders.
  • While ammonites and other squid-like animals, and enormous reptiles that are all extinct now coexisted with current fish in Jurassic seas, where they first started to become widespread.
  • Similar to how modern-looking amphibians and reptiles superseded the ancestral reptilian and mammal groups prevalent in the Late Triassic, dinosaurs, and mammals also did.

Marine Life

  • The massive mass extinction at the Triassic-Jurassic boundary has left traces in the early Jurassic marine environments. 
  • About half of the genera of marine invertebrate species were lost due to this extinction, and some groupings now have very few remaining species.
  • Around 183 million years ago, another extinction event among benthic (bottom-dwelling) invertebrates halted the general rebound and diversity at the Pliensbachian-Toarcian border.
  • Even though it has been studied best in Europe, biodiversity during this time appears to have declined globally. 
  • As evidenced by the current existence of layers of organic-rich shales, which must have formed in seas with so little oxygen that no burrowing organisms could survive and efficient breakdown of organic matter could not occur, the extinctions may be linked to the onset of low-oxygen conditions in epicontinental seas.

Dinosaurs

  • Following the end-Triassic extinction and the extinction of other reptile groups, dinosaurs, which underwent morphological diversification in the Late Triassic, significantly increased diversity and abundance during the Early Jurassic, emerging as the dominant vertebrate in terrestrial ecosystems.

Conodont

  • Conodonts are an extinct class of eel-like agnathan (jawless) animals. From the Cambrians until the start of the Jurassic, they were present in the planet’s waters for more than 300 million years.

Sarcopterygii

  • The Lower Devonian contains the earliest fossils of lobe-finned fish; by the end of this time, all critical lineages had emerged. Fast swimmers, these early lobe fins had heterocercal tails or tail fins that were asymmetrical and bigger on the dorsal side.

Actinopterygii

  • The Actinopterygii (ray-finned fish) are without internal nares, choanae, or a fleshy base to their paired fins and usually have well-ossified skeletons.

Jurassic Period Worksheets

This fantastic bundle includes everything you need to know about the Jurassic Period across 31 in-depth pages. These ready-to-use worksheets are perfect for teaching kids about the Jurassic Period, the second period of the Mesozoic Era, which lasted from 201.3 to 145 million years ago.

Jurassic Period worksheets
Jurassic Period worksheets
Jurassic Period worksheets

Download includes the following worksheets

  • Jurassic Period Facts
  • Unlock the Words
  • Just Jurassic
  • Match the Dinosaur
  • Pangaea
  • The Jurassic Period
  • What If?
  • How to be a Scientist
  • Storyboard
  • Jurassic Pop Culture
  • Memory of Jurassic

Frequently Asked Questions

What is the Jurassic Period best known for?

During the Jurassic Period, dinosaurs reigned supreme for an astounding 180 million years.

Why is it called Jurassic Period?

Step back to the Jurassic Period, from 199.6 to 145.5 million years ago – a 54-million-year stretch of the Mesozoic Era! Named after the Jura Mountains on France and Switzerland’s border, where scientists first explored these rocks, ‘Jurassic’ has since become a household name thanks to the immense success of the 1993 classic movie: Jurassic Park.

What plants lived in the Jurassic Period?

During the Jurassic, lush ferns, ginkgoes, Bennettitales, or “cycadeoids,” and true cycads flourished. Notably present were conifers resembling modern redwoods, cypresses, pines, and yews. To illustrate such success at an ancient time in history is seen above right with a living example of a cycad!

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Use With Any Curriculum

These worksheets have been specifically designed for use with any international curriculum. You can use these worksheets as-is, or edit them using Google Slides to make them more specific to your own student ability levels and curriculum standards.

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