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Kokoamu Greensand facts for kids

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Kokoamu Greensand
Stratigraphic range: Chattian
~27.3–25.2Ma
Type Geological formation
Unit of Otiake Group
Underlies Otekaike Limestone
Overlies Earthquakes Marl
Thickness up to 7 metres (20 ft)
Lithology
Primary Greensand
Other Limestone
Location
Coordinates 44°42′S 170°30′E / 44.7°S 170.5°E / -44.7; 170.5
Approximate paleocoordinates 50°30′S 176°18′W / 50.5°S 176.3°W / -50.5; -176.3
Region Canterbury, Otago
Country  New Zealand
Extent Around Duntroon, South Island

The Kokoamu Greensand is a geological formation found in New Zealand. It is a fossil-bearing, late Oligocene, greensand rock unit of the eastern South Island, especially the Waitaki District of North Otago and the southern Canterbury region. The formation was named by geologist Maxwell Gage in the 1950s. In North Otago it underlies the thicker and harder Otekaike Limestone. The formation gets its green colour from the mineral glauconite which forms slowly on the ocean floor.

Fossil content

The formation was laid down in shallow seas some 26-30 million years ago. It contains abundant microfossils of foraminifera, ostracods and coccoliths, those of larger marine invertebrates such as the shells of brachiopods, gastropods and scallops, as well as corals, echinoderms, and crustaceans. Vertebrates found in the formation include fish, penguins and cetaceans. Many of the fossils discovered in the formation are held in the Geology Museum of the University of Otago.

Penguins
Cetaceans
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