词条 | Albian Stage |
释义 | Albian Stage geology uppermost of six main divisions of the Lower Cretaceous Series, representing rocks deposited worldwide during the Albian Age, which occurred between 112 million and 99.6 million years ago during the Cretaceous Period. Albian rocks overlie rocks of the Aptian Stage and underlie rocks of the Cenomanian Stage. The name for this stage is derived from the Alba, the Roman name for Aube, France, for which the surrounding area serves as the classic type district for rocks of this age. In Britain the Albian is represented by the Upper Greensand–Gault Clay sequence of rocks; elsewhere in northern Europe it consists of the upper portions of the thick Hils clay. Sandstones and shaley limestones dominate the Albian of the Middle East and North Africa, and sandstones, shales, and basaltic lavas occur in East Asia. The Albian is divided into several biozones (biozone) representing shorter spans of time that are characterized by various distinctive ammonite (ammonoid) genera. |
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