The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare,^[3] but geological formations containing land animal fossils include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland,^[4] the Calcaire de Caen of France,^[5] the Daohugou Beds in China, the Itat Formation in Russia, the Tiouraren Formation of Niger,^[6] and the Isalo III Formation of western Madagascar.

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Quick Facts Chronology, Etymology ...

Middle Jurassic
174.7 ± 0.8 – 161.5 ± 1.0 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Map of the world during the Middle Jurassic
Chronology
−200 — – −195 — – −190 — – −185 — – −180 — – −175 — – −170 — – −165 — – −160 — – −155 — – −150 — – −145 — – Mesozoic T Jurassic K Late T Early Middle Late Early K Hettangian Sinemurian Pliensbachian Toarcian Aalenian Bajocian Bathonian Callovian Oxfordian Kimmeridgian Tithonian       ← Triassic–Jurassic extinction event Subdivision of the Jurassic according to the ICS, as of 2022.[1] Vertical axis scale: millions of years ago.
Etymology
Name formality	Formal
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Epoch
Stratigraphic unit	Series
Time span formality	Formal
Lower boundary definition	FAD of the Ammonites Leioceras opalinum and Leioceras lineatum
Lower boundary GSSP	Fuentelsaz, Spain 41.1708°N 1.8333°W / 41.1708; -1.8333
Lower GSSP ratified	2000[2]
Upper boundary definition	Not formally defined
Upper boundary definition candidates	Horizon of Ammonite Cardioceras redcliffense.
Upper boundary GSSP candidate section(s)	Redcliff Point, Dorset, UK Savouron, Provence, France

Close

During the Middle Jurassic Epoch, Pangaea began to separate into Laurasia and Gondwana, and the Atlantic Ocean formed. Eastern Laurasia was tectonically active as the Cimmerian plate continued to collide with Laurasia's southern coast, completely closing the Paleo-Tethys Ocean. A subduction zone on the coast of western North America continued to create the Ancestral Rocky Mountains.Significant subduction zones were active along practically all of the continental edges surrounding Pangea, as well as in southern Tibet, southeastern Europe, and other locations, to allow the formation of fresh seabed in the proto-Atlantic Ocean. Plate tectonic activity in subduction zones caused the construction of north-south mountain ranges such as the Rocky Mountains and the Andes all along the west coast of North, Central, and South America.^{[citation needed]}

The Middle Jurassic is one of the key periods in the history of life on Earth. Many groups, including dinosaurs and mammals, diversified during this time.^[7][8]

Conifers were dominant in the Middle Jurassic. Other plants, such as ginkgoes, cycads, and ferns were also common.^{[citation needed]}