Waipara Greensand

Waipara Greensand
Stratigraphic range: Palaeocene, ~62–58 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Selandian-Thanetian
Type	Geological formation
Sub-units	Mount Ellen Member, Stormmont Member
Underlies	Ashley Mudstone
Overlies	Loburn Formation
Lithology
Primary	Sandstone
Location
Coordinates	43.076°S 172.807°E / -43.076; 172.807
Region	Canterbury
Country	New Zealand
Type section
Named for	Waipara River

The Waipara Greensand is a geological rock unit found in Canterbury, New Zealand. It dates from just after the Cretaceous–Paleogene extinction event, the Selandian and Thanetian, around 62–58 million years ago in the Palaeocene. It is well known for its fossils, particularly for containing the oldest penguins (Sphenisciformes) and also containing shark and fish fossils.

Geology

The Waipara Greensand is a fine to medium-grained, richly glauconitic quartzose sandstone. It crops out throughout North Canterbury. It has been interpreted as having been deposited in a shallow marine setting under conditions of very slow sedimentation. It is deepest in the Waipara River area, where it reaches a thickness of about 80 metres (260 ft), thinning to the south and north.^[1]

The Waipara Greensand are Thanetian and Selandian in age (62 to 58 Mya). The top of the Waipara Greensand marks the Teurian–Waipawan New Zealand stage boundary, which is correlated internationally with the Paleocene-Eocene boundary.

Fossils

The Waipara Greensand is only sparsely fossiliferous, but there are some significant discoveries made from this rock unit. There have been at least at least 16 neoselachian sharks found, including Chlamydoselachus keyesi and Centroselachus goord,^[2] as well as the enigmatic Waiparaconus, which is either a barnacle or a coelenterate,^[3] the remains of two species of proto‐penguin Waimanu and Muriwaimanu,^[4] Clymenoptilon, an early tropicbird,^[5] rarely also fish bones and poorly preserved molluscs. Nanofossils include two key age‐diagnostic taxa, Chiasmolithus bidens and Hornbrookina teuriensis.^[2]

The majority of shark specimens were recovered from loose weathered material that accumulates at the foot of steep banks along the Waipara River. Gypsum often encrusts the teeth, making identification difficult.

References

1. Browne, G.H. and Field, B.D. 1985. Lithostratigraphy of Late Cretaceous to Early Pleistocene rocks of northern Canterbury, New Zealand. New Zealand Geological Survey Record, 6, 1–63.
2. Mannering, A. A., and N. Hiller. 2008. An early Cenozoic neoselachianshark fauna from the southwest Pacific. Palaeontology 51:1341–1365.
3. Buckeridge, J. S. 1993. A re‐evaluation of the Gondwanan invertebrate Waiparaconus as a coelenterate. Records of the Western Australian Museum, 16, 221– 233.
4. Fordyce, R.E. and Jones, C.M. 1990. The history of penguins and new fossil penguin material from New Zealand. 419–446. In Davis, L.S. and Darby, J.T. (eds). Penguin biology III. Academic Press, San Diego, 467 pp.
5. Daly, Michael (3 September 2023). "Zealandia fossil find may turn historical record on its head". Stuff. Retrieved 3 September 2023.