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The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma (million years ago). The Albian is preceded by the Aptian and followed by the Cenomanian.〔For a detailed geologic timescale, see Gradstein ''et al.'' (2004)〕 ==Stratigraphic definitions== The Albian stage (French ''Albien'', from Alba = the River Aube in France) was first proposed in 1842 by Alcide d'Orbigny. The base of the Albian is defined as the place in the stratigraphic column where the coccolithophore species ''Praediscosphaera columnata'' first appears. A reference profile for the base of the Albian stage (its GSSP) had in 2009 not yet been established. The top of the Albian stage (the base of the Cenomanian stage and Upper Cretaceous series) is defined as the place where the foram species ''Rotalipora globotruncanoides'' first appears in the stratigraphic column.〔See Kennedy ''et al.'' (2004) for a description of the GSSP for the Cenomanian〕 The Albian is sometimes subdivided in Early/Lower, Middle and Late/Upper subages or substages. In western Europe, especially in the UK, a subdivision in two substages (Vraconian and Gaultian) is more often used. 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「Albian」の詳細全文を読む スポンサード リンク
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