Hettangian


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Hettangian

[he′tan·jē·ən]
(geology)
A stage of Lower Jurassic geologic time.
References in periodicals archive ?
TS IV conformably overlies TS III and consists of the late Rhaetian top member of the Blomidon Formation and (overlying the North Mountain Basalt) the McCoy Brook Formation, which is of latest Rhaetian to Hettangian (and possibly younger) age.
First, they contain the only currently known example of tightly temporally constrained latest Rhaetian and earliest Hettangian assemblages of continental tetrapods with associated radiometric ages anywhere.
The GSSP for the base of the Hettangian is now defined as the first appearance of the ammonite Psiloceras spelae tirolicum (Hillebrandt and Krystyn 2009) at the Kuhjoch section in the Karwendel Mountains of the Northern Calcareous Alps in Tyrol (Austria).
This is consistent with the projected correlation of the GSSP of the base of Hettangian stage to a level above the North Mountain Basalt (Whiteside et al.
The post-Scots Bay tetrapod assemblage with sauropodomorph dinosaurs at Wasson Bluff is plausibly earliest Hettangian in age, and the other McCoy Brook assemblages are of even younger, presumably Hettangian age.
The occurrence of sauropodomorph dinosaurs from the McCoy Brook Formation at Wasson Bluff is likely of earliest Hettangian age whereas the other bone-bearing localities in that formation are of older, latest Rhaetian age.
Precise U-Pb age constraints for end-Triassic mass extinction; its correlation to volcanism and Hettangian post-extinction recovery.
Precise U-Pb age constraints for end-Triassic mass extinction, its correlation to volcanism and Hettangian post-extinction recovery.