The Chattian is, in the geologic timescale , the younger of two ages or upper of two stages of the Oligocene Epoch / Series . It spans the time between 27.82 and 23.03 Ma . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (the lowest stage of the Miocene ).
5-541: The Morawan Formation is a Chattian age siliceous marine geological formation of the Oligo - Miocene Japanese Kawakami Group of eastern Hokkaido prefecture . The formation is fossil rich and contains source units where toothed baleen whales ( Aetiocetidae ) and Desmostylians have been discovered. The Morawan Formation is a very siliceous unit containing hard platy shales interbedded with tuffaceous mudstones and sandstones , and some pumice . The unnamed lower member
10-682: Is a hard platy shale alternating with beds of tuffaceous mudstones and sandstones, the Kamirawan member is a tuffaceous sandstone with pumice, the Lower Hard Shale is a very siliceous hard shale with tuffaceous sandstones and mudstones, and the Middle Hard Shales and the Upper tuffaceous siltstone are similar. Fossil species from the Morawan Formation include: Chattian The Chattian
15-532: The Chattian Stage (which is the base of the Aquitanian Stage, Miocene Series and Neogene System ) is at the first appearance of foram species Paragloborotalia kugleri , the extinction of calcareous nanoplankton species Reticulofenestra bisecta (which forms the base of nanoplankton biozone NN1), and the base of magnetic C6Cn.2n. The Chattian is coeval with regionally used stages or zones such as
20-514: The upper Avernian European mammal zone (it spans the Mammal Paleogene zones 30 through 26 and part of 25 ); the upper Geringian and lower Arikareean mammal zones of North America; most of the Deseadan mammal zone of South America; the upper Hsandgolian and whole Tabenbulakian mammal zone of Asia; the upper Kiscellian and lower Egerian Paratethys stages of Central and eastern Europe;
25-630: Was introduced by Austrian palaeontologist Theodor Fuchs in 1894. Fuchs named the stage after the Chatti , a Germanic tribe. The original type locality was near the German city of Kassel . The base of the Chattian is at the extinction of the foram genus Chiloguembelina (which is also the base of foram biozone P21b). An official GSSP for the Chattian Stage was ratified in October of 2016. The top of
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