Lower Jurassic facts for kids
The Lower Jurassic was the first part of the Jurassic period. It started about 201.3 million years ago and ended around 174.1 million years ago.
The Jurassic period is split into three main parts: Lower, Middle, and Upper. The Lower Jurassic began right after a huge event called the end-Triassic extinction event. This was when many types of plants and animals died out.
During the Lower Jurassic, many rocks formed in Europe. These rocks are called the Lias group. They are mostly limestone, but also include some clay and siltstone. These rocks formed in the sea. Famous fossil hunter Mary Anning found many amazing fossils in these rocks along the Dorset Jurassic Coast in England.
The Jurassic period was a time when dinosaurs roamed the Earth. By the start of the Jurassic, many groups of animals from the earlier Triassic period had disappeared.
Contents
Life on Earth
The Lower Jurassic was a time of new beginnings for life. After the big extinction event, new types of animals and plants started to appear and spread.
- Dinosaurs: Many different kinds of dinosaurs lived during this time. They were becoming the main large land animals.
- Marine Life: The oceans were full of life. There were many ammonites (shelled creatures like squids), ichthyosaurs (fish-like reptiles), and plesiosaurs (long-necked marine reptiles).
- Plants: Forests of conifers, cycads, and ferns covered the land. These plants were food for many plant-eating dinosaurs.
Ancient Britain
At the start of the Jurassic period, Britain was much warmer than it is today. It was like a warm temperate or subtropical area. The temperature would have been between 12 and 29 degrees Celsius.
Shallow seas covered much of southern England. Higher areas, like the Mendip Hills, were like a string of islands. These islands stretched west towards South Wales.
North America's Landscape
The Lower Jurassic in western North America was quite different from Europe. Here, the rocks formed on land, not in the sea. They are mostly sandstones. These sandstones were laid down by shifting streams and rivers over a very long time. This process started in the later Permian period and continued into the Lower Jurassic.
Related pages
Images for kids
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Massive cliffs in Zion Canyon consist of Lower Jurassic formations, including (from bottom to top): the Kayenta Formation and the massive Navajo Sandstone
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Terrestrial environment of the Pliensbachian-Toarcian boundary Fennoscandinavia, with flora based on the Sorthat Formation. Dinosaurs are based on material found on various locations of the German realm of the Ciechocinek Formation and on lesser extent, footprints of the Drzewica Formation
See also
In Spanish: Jurásico Inferior para niños
