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The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous epoch or a stage in the Lower Cretaceous series. It spans the time between 132.9 ± 2 Ma and 129.4 ± 1.5 Ma (million years ago). The Hauterivian is preceded by the Valanginian and succeeded by the Barremian.〔See Gradstein ''et al.'' (2004) for a detailed geologic timescale〕 ==Stratigraphic definitions== The Hauterivian was introduced in scientific literature by Swiss geologist Eugène Renevier in 1873. It is named after the Swiss town of Hauterive at the shore of Lake Neuchâtel. The base of the Hauterivian is defined as the place in the stratigraphic column where the ammonite genus ''Acanthodiscus'' first appears. A reference profile for the base (a GSSP) had in 2009 not yet been established. The top of the Hauterivian (the base of the Barremian) is at the first appearance of ammonite species ''Spitidiscus hugii''. In the ammonite biostratigraphy of the Tethys domain, the Hauterivian contains seven ammonite biozones: * zone of ''Pseudothurmannia ohmi'' * zone of ''Balearites balearis'' * zone of ''Plesiospitidiscus ligatus'' * zone of ''Subsaynella sayni'' * zone of ''Lyticoceras nodosoplicatus'' * zone of ''Crioceratites loryi'' * zone of ''Acanthodiscus radiatus'' 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hauterivian」の詳細全文を読む スポンサード リンク
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