Hettangian

System/
Period
Series/
Epoch
Stage/
Age
Age (Ma)
CretaceousLower/
Early
Berriasianyounger
JurassicUpper/
Late
Tithonian~145.0152.1
Kimmeridgian152.1157.3
Oxfordian157.3163.5
MiddleCallovian163.5166.1
Bathonian166.1168.3
Bajocian168.3170.3
Aalenian170.3174.1
Lower/
Early
Toarcian174.1182.7
Pliensbachian182.7190.8
Sinemurian190.8199.3
Hettangian199.3201.3
TriassicUpper/
Late
Rhaetianolder
Subdivision of the Jurassic system
according to the ICS, as of 2017.[1]

The Hettangian is the earliest age or lowest stage of the Jurassic period of the geologic timescale. It spans the time between 201.3 ± 0.2 Ma and 199.3 ± 0.3 Ma (million years ago).[2] The Hettangian follows the Rhaetian (part of the Triassic period) and is followed by the Sinemurian.[3]

In European stratigraphy the Hettangian is a part of the time span in which the Lias was deposited. An example is the British Blue Lias, which has an upper Rhaetian to Sinemurian age. Another example is the lower Lias from the Northern Limestone Alps where well-preserved but very rare ammonites, including Alsatites, have been found.

Stratigraphic definitions

The Hettangian was introduced in the literature by Swiss palaeontologist, Eugène Renevier, in 1864. The stage takes its name from Hettange-Grande, a town in north-eastern France, just south of the border with Luxembourg on the main road from Luxembourg City to Metz.

The base of the Hettangian stage (which is also the base of the Lower Jurassic series and the entire Jurassic system) is defined as the place in the stratigraphic column where fossils of the ammonite genus Psiloceras first appear. A global reference profile (a GSSP) for the base was defined 2010 at the Kuhjoch in the Karwendel in western Austria.[4] The top of the Hettangian stage (the base of the Sinemurian) is at the first appearances of ammonite genera Vermiceras and Metophioceras.

Biostratigraphy

The Hettangian contains three ammonite biozones in the Tethys domain:

Other Languages
Afrikaans: Hettangium
العربية: الهتانجي
asturianu: Hettanxanu
català: Hettangià
Deutsch: Hettangium
español: Hettangiense
euskara: Hettangiar
فارسی: هتانجین
français: Hettangien
italiano: Hettangiano
Latina: Hettangium
magyar: Hettangi
Nederlands: Hettangien
norsk nynorsk: Hettangium
polski: Hettang
português: Hettangiano
srpskohrvatski / српскохрватски: Hetangij
українська: Геттангський ярус