The Clarendonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 13,600,000 to 9,000,000 years BP , a period of 3.3 million years .
5-761: It is usually considered to overlap the Serravallian age of the Middle Miocene and the Tortonian age of the Late Miocene . The Clarendonian is preceded by the Barstovian and followed by the Hemphillian NALMA stages. The Clarendonian can be further divided into the substages of: This geochronology article is a stub . You can help Misplaced Pages by expanding it . Serravallian The Serravallian is, in
10-458: Is at the first occurrence of fossils of the nanoplankton species Sphenolithus heteromorphus and is located in the chronozone C5ABr. The official Global Boundary Stratotype Section and Point (GSSP) for the Serravallian is in the 'Ras il-Pellegrin' section, located at the 'Ras il-Pellegrin' headland in the vicinity of 'Fomm ir-Rih' Bay, SW Malta.The base of the Serravallian is represented in
15-611: The Laventan and lower Mayoan South American Land Mammal Ages . It is also coeval with the Sarmatian and upper Badenian Stages of the Paratethys time scale of Central and eastern Europe. The Serravallian Stage was introduced in stratigraphy by the Italian geologist Lorenzo Pareto in 1865. It was named after the town of Serravalle Scrivia in northern Italy. The base of the Serravallian
20-543: The geologic timescale , an age or a stage in the middle Miocene Epoch / Series , which spans the time between 13.82 Ma and 11.63 Ma (million years ago). The Serravallian follows the Langhian and is followed by the Tortonian . It overlaps with the middle of the Astaracian European Land Mammal Mega Zone , the upper Barstovian and lower Clarendonian North American Land Mammal Ages and
25-734: The field as the formation boundary between the Globigerina Limestone formation and the Blue Clay formation. The base of the Serravallian is related to the Mi3b oxygen isotope excursion marking the onset of the Middle Miocene Cooling step. The top of the Serravallian (the base of the Tortonian Stage) is at the last common appearance of calcareous nanoplanktons Discoaster kugleri and planktonic foram Globigerinoides subquadratus . It
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