Upper Jurassic
| Eon | Era | Period | Epoch | Start Million years ago |
|---|---|---|---|---|
| Phanerozoic | Cainozoic | Palaeogene | Palaeocene | 66 |
| Mesozoic | Cretaceous | Upper Cretaceous | 100.5 | |
| Lower Cretaceous | 145 | |||
| Jurassic | Upper Jurassic | 163.5 | ||
| Middle Jurassic | 174.1 | |||
| Lower Jurassic | 201.3 | |||
| Triassic | Upper Triassic | 237 | ||
| Middle Triassic | 247.2 | |||
| Lower Triassic | 252.17 | |||
| Palaeozoic | Permian | 298.9 | ||
The Upper Jurassic, or Late Jurassic, is the last epoch of the Jurassic Period. It lasted from 163.5 to ~145 million years ago.[1]
Contents |
Paleogeography [change]
During the Upper Jurassic epoch, Pangaea broke up into two supercontinents, Laurasia to the north, and Gondwana to the south. The result of this break-up was the spawning of the Atlantic Ocean. However, at this time, the Atlantic Ocean was relatively narrow.
Sea level was high, though not so high as during the Upper Cretaceous. The Laurasian landmass was broken up by the rising sea into large islands. The rocks were carbonate limestones and clays. The epoch included the famous Solnhofen limestone lagerstätte, where Archaeopteryx was found.
Stages [change]
The Upper Jurassic is divided into three stages (later stages above earlier):
| Stage | Time |
|---|---|
| Tithonian | 152–145 mya |
| Kimmeridgian | 157.3–152 mya |
| Oxfordian | 163.5–157.3 mya |
Organic productivity [change]
The Upper Jurassic of England and Europe bears a huge amount of the products of life. The Kimmeridge clay is the main source for the huge North Sea oil reserves, and the whole epoch is stuffed full of marine fossils. Many dinosaur remains have also been found. The epoch starts with the Oxford Clay deposited in a shallow seaway of 10 to 50 metres depth.[2]
The first fossils which show small dinosaurs with feathers are found: Anchiornis.
Related pages [change]
References [change]
| Precambrian (4.567 gya – 541 mya) | |
|---|---|
| In the left column are Eons, bold are Eras, not bold are Periods. gya = billion years ago, mya = million years ago | |
| Hadean (4.567 gya – 4 gya) | |
| Archaean (4 gya – 2.5 gya) | |
| Proterozoic (4 gya – 2.5 gya) | Palaeoproterozoic (2.5 gya – 1.6 gya)
Mesoproterozoic (1.6 gya – 1 gya) Neoproterozoic (1 gya - 541 mya) Tonian (1 gya – 850 mya) Cryogenian (850 mya – 635 mya) Ediacaran (635 mya – 541 mya) |
| Source | International Chronostratigraphic Chart 2013. International Commission on Stratigraphy, retrieved 8 April 2013. Divisions of geologic time – major chronostratigraphic and geochronologic units USGS, retrieved 8 April 2013. |
