The Manuherikia Group is a

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

lacustrine A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

sedimentary fill in the

Central Otago Central Otago is located in the inland part of the Otago region in the South Island of New Zealand. The motto for the area is "A World of Difference". The area is dominated by mountain ranges and the upper reaches of the Clutha River and tributa ...

area of New Zealand, at the site of the prehistoric

Lake Manuherikia Lake Manuherikia was a prehistoric lake which once stretched over some in what is now inland Otago in New Zealand's South Island. It stretched from Bannockburn, New Zealand, Bannockburn and the Nevis River, Nevis valley in the west to Naseby, Ne ...

. The area consists of a valley and ridge

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sci ...

, with a series of

schist Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes o ...

greywacke Greywacke or graywacke (German ''grauwacke'', signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lit ...

mountains at roughly ninety degrees to each other. The Manuherika Group occurs in the current basins, and occasionally on the mountains themselves.

History

One of the earliest geologists to work in the area,

McKay McKay, MacKay or Mackay is a Scottish / Irish surname. The last phoneme in the name is traditionally pronounced to rhyme with 'eye', but in some parts of the world this has come to rhyme with 'hey'. In Scotland, it corresponds to Clan Mackay. Not ...

, understood that the Manuherikia Group was probably originally continuous. Although some workers came to believe the sediments were deposited in a series of small, interconnected basins between the mountain ranges, e.g. Park, later workers, like

Cotton Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus ''Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor perce ...

argued that the sediments had been isolated by later mountain growth. DouglasDouglas, B. J. 1986: Lignite resources of Central Otago. New Zealand Energy Research and Development Committee Publication P104: 367. placed the Manuherikia Group sediments into a coherent genetic context. He drew attention to Manuherikia Group sediments on the top of mountain ranges, and to the observation that sequences in distinct basins were similar. His conclusion was that the Manuherikia Group is the result of

sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...

in a single (except for the earliest stages) very large basin that was later intruded by the growth of the mountain ranges. This basin ultimately grew into a single huge lake –

– that extended over some 5600 km². Palynological work by Couper, Mildenhall, Mildenhall and Pocknall has indicated that the Manuherikia Group is basically

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

in age. The plant

macrofossil Macrofossils, also known as megafossils, are preserved organic remains large enough to be visible without a microscope. The term ''macrofossil'' stands in opposition to the term microfossil. Microfossils, by contrast, require substantial magnific ...

s, common in the lower Manuherikia Group, are mostly

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 Ma to 15.97 ± 0.05 Ma (million years ago). It was prece ...

, perhaps with some in the earliest

Middle Miocene The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0.05 Ma to 11.608 ± 0.005 Ma (million y ...

Stratigraphy

Following Douglas, the primary subdivision of the Manuherikia Group is into a lower, fluvial (commonly with coal) Dunstan Formation and an upper, lacustrine

Bannockburn Formation The Manuherikia Group is a fluvial-lacustrine sedimentary fill in the Central Otago area of New Zealand, at the site of the prehistoric Lake Manuherikia. The area consists of a valley and ridge topography, with a series of schist-greywacke mount ...

. The oldest unit of the Manuherikia Group is the Saint Bathans Member of the Dunstan Formation, consisting of the braided-river fill of valleys incised into the basement rocks. Traces of three St Bathans paleovalleys are known – one at Blue Lake, adjacent to St Bathans, is the best exposed. The St Bathans paleovalleys eventually filled, sedimentation spread out over a broader area, and the fluvial character became dominantly

meander A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex bank ...

ing. This material is grouped as the Fiddlers Member. Extensive coal swamps developed between the rivers and their flood basins. Individual flood basin lakes began to coalesce into a true lacustrine system –

. Its muddy and sandy sediments are grouped as the Bannockburn Formation. Around the lake margins, distinctive shoreline facies developed. The most widespread of these is the Kawarau Member which contains diverse plant fossils. Distinctive facies within the Kawarau Member have been termed the Cromwell Submember and the Ewing Submember. The Ewing is typically intercalated with the Lauder Member, an informal unit of the Bannockburn Formation. This contains a fossil fauna (the

Saint Bathans Fauna The St Bathans fauna is found in the lower Bannockburn Formation of the Manuherikia Group of Central Otago, in the South Island of New Zealand. It comprises a suite of fossilised prehistoric animals from the late Early Miocene (Altonian) period, ...

) of birds, fish, and a crocodilian, New Zealand's first known terrestrial mammal, as well as bats.

Stromatolite Stromatolites () or stromatoliths () are layered sedimentary formations (microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). The ...

s are also present. At two locations around the

depocenter A depocenter or depocentre in geology is the part of a sedimentary basin where a particular rock unit has its maximum thickness. Depending on the controls on subsidence and the sedimentary environment the location of basin depocenters may vary wit ...

river delta A river delta is a landform shaped like a triangle, created by deposition (geology), deposition of sediment that is carried by a river and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, res ...

s developed and large thicknesses of coal built up on upper delta plains. These are termed the Blackstone Delta and Teviot Delta. Fully lacustrine conditions ensued with the submergence of these deltas and for much of the mid Miocene,

was without known bounds. Rising mountains in the

Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Lake Manuherikia Lake Manuherikia was a prehistoric lake which once stretched over some in what is now inland Otago in New Zealand's South Island. It stretched from Bannockburn, New Zealand, Bannockburn and the Nevis River, Nevis valley in the west to Naseby, Ne ...

with gravel – the Maori Bottom, or Maniototo Conglomerate.

Fossil content

;Bannockburn Formation * '' Aegotheles zealandivetus'' * '' Deliaphaps'' * ''

Dunstanetta ''Dunstanetta johnstoneorum'' is a genus and species of extinct duck from the Miocene of New Zealand. It was described from fossil material (a distal left humerus) collected from a Saint Bathans Fauna site on Home Hills Station, in the lower ...

'' * '' Hakawai'' * ''

Heracles Heracles ( ; grc-gre, Ἡρακλῆς, , glory/fame of Hera), born Alcaeus (, ''Alkaios'') or Alcides (, ''Alkeidēs''), was a divine hero in Greek mythology, the son of Zeus and Alcmene, and the foster son of Amphitryon.By his adoptive ...

'' * '' Manuherikia douglasi'', ''M. lacustrina'', ''M. minuta'', ''M. primadividua''Croc Site L1, Mata Creek, H41/f84
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.org * ''

Matanas ''Matanas enrighti'' is an extinct duck from the Miocene of New Zealand. It was described from fossil material (a left humerus) collected from a Saint Bathans Fauna site near Mata Creek, in the lower Bannockburn Formation of the Manuherikia Gr ...

'' * '' Matuku'' * '' Miotadorna sanctibathansi'', ''M. catrionae'' * '' Neilus'' * '' Nelepsittacus donmertoni'', ''N. daphneleeae'', ''N. minimus'' * '' Notochen'' * '' Palaelodus aotearoa'' * ''

Pelecanoides miokuaka ''Pelecanoides miokuaka'' is an extinct species of diving petrel of New Zealand. Described in 2007, it is known only from a single humerus bone that was discovered from early Miocene sediments of the Manuherikia Group. Taxonomy The bone, a hum ...

'' * ''

Pikaihao ''Pikaihao bartlei'', also referred to as Bartle's bittern or the Saint Bathans bittern, is a genus and species of prehistoric small bittern from the Early Miocene of New Zealand. It was described in 2013 from fossil material (a left tarsometa ...

'' * ''

Proapteryx ''Proapteryx micromeros'' is an extinct kiwi known from the 16–19 million-year-old early Miocene sediments of the St Bathans Fauna of Otago, New Zealand. Features ''P. micromeros'' is considerably smaller than modern kiwis, weighing around 23 ...

'' * ''

Rupephaps ''Rupephaps taketake'', also referred to as the Saint Bathans pigeon, is an extinct species of pigeon from the Miocene of New Zealand. It is the first species of columbid to be described from pre- Pliocene fossil deposits in the Australasian re ...

* '' Zealandornis'' * Leiopelma indet. * '' Galaxias angustiventris'', '' G. brevicauda'', '' G. bobmcdowalli'', '' G. papilionis'', '' G. parvirostris'', '' G. tabidus'' * '' Mataichthys'' * '' Prototroctes modestus'', '' P. vertex'' ;St Bathans Member An extremely diverse macroflora flora, based on well-preserved cuticle. There are two cycad-like taxa: * '' Pterostoma douglasii'' * '' Greylackia'' The conifers total 16 species in 12 genera, including: * ''

Acmopyle ''Acmopyle'' is a genus of conifers belonging to the podocarp family, Podocarpaceae. The genus includes two species of evergreen small to tall well-branched trees and large trees. ''Acmopyle'' is limited to two species, '' A. pancheri'', endemic ...

'' * Araucariaceae (''

Araucaria ''Araucaria'' (; original pronunciation: .ɾawˈka. ɾja is a genus of evergreen Conifer, coniferous trees in the family Araucariaceae. There are 20 extant taxon, extant species in New Caledonia (where 14 species are endemism, ende ...

'' and ?''Agathis'') * ''

Dacrycarpus ''Dacrycarpus'' is a genus of conifers belonging to the family Podocarpaceae.Christopher N. Page. 1990. "Podocarpaceae" pages 332-346. In: Klaus Kubitzki (general editor); Karl U. Kramer and Peter S. Green (volume editors) ''The Families and Gene ...

'' * ''

Dacrydium ''Dacrydium'' is a genus of conifers belonging to the podocarp family Podocarpaceae. Sixteen species of evergreen dioecious trees and shrubs are presently recognized. The genus was first described by Solander in 1786, and formerly included many m ...

'' * '' Kakahuia'' * ''

Lepidothamnus ''Lepidothamnus'' is a genus of conifers belonging to the podocarp family Podocarpaceae. The genus includes three species of dioecious or monoecious evergreen trees and shrubs, and creepers. '' L. intermedius'' and '' L. laxifolius'' are nativ ...

'' * ''

Papuacedrus ''Papuacedrus papuana'' is a species in the conifer family Cupressaceae, the sole species in the genus ''Papuacedrus''. Some botanists do not consider this species as forming a distinct genus, but include it in the related genus '' Libocedrus''. ...

'' * ''

Podocarpus ''Podocarpus'' () is a genus of conifers, the most numerous and widely distributed of the podocarp family, the Podocarpaceae. The name comes from Greek πούς (poús, “foot”) + καρπός (karpós, “fruit”). ''Podocarpus'' species ...

'' * ''

Prumnopitys ''Prumnopitys'' is a genus of conifers belonging to the family Podocarpaceae. The nine recognized species of ''Prumnopitys'' are densely branched, dioecious evergreen trees up to 40 metres in height. Etymology The name ''Prumnopitys'' comes ...

'' * ''

Retrophyllum ''Retrophyllum'' is a genus of conifers in the family Podocarpaceae.Christopher N. Page. 1990. "Podocarpaceae" pages 332-346. In: Klaus Kubitzki (general editor); Karl U. Kramer and Peter S. Green (volume editors) ''The Families and Genera of Vas ...

'' * Taxaceae Other gymnosperms: * Gnetalaceae Monocots include: * ''

Astelia ''Astelia'' is a genus of flowering plants in the recently named family Asteliaceae. They are rhizomatous tufted perennials native to various islands in the Pacific, Indian, and South Atlantic Oceans, as well as to Australia and to the southern ...

'' * ''

Typha ''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrush or reedmace, in American English as reed, cattail, or punks, in A ...

'' The dicots include: * Winteraceae * Atherospermataceae * Monimiceae ('' Hedycarya'' sp.) * Proteaceae * Menispermaceae * Santalaceae (''

Amphorogyne ''Amphorogyne'' is a genus of hemiparasitic trees and shrubs in the family Santalaceae. The genus is endemic to New Caledonia in the Pacific and contains three species. Its closest relative is ''Daenikera'', also endemic to New Caledonia.Der, ...

'', ''

Notothixos ''Notothixos''Oliver D (1863) ''J. Proc. Linn. Soc., Bot.'' 7: 103 864 publ. 1863/ref> is a genus of mistletoe plant in the family Santalaceae. Species The Catalogue of Life The Catalogue of Life is an online database that provides an ind ...

'') * Casuarinaceae (''

Gymnostoma ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, in ...

'') * Paracryphiaceae (''

Paracryphia ''Paracryphia'' is a genus of a single species, ''Paracryphia alticola'', a small tree or shrub endemic to New Caledonia in the family Paracryphiaceae. Its closest relative is ''Sphenostemon ''Sphenostemon'' is the genus of small evergreen tre ...

'') * Elaeocarpaceae-Cunoniaceae * Meliaceae * Nothofagaceae (''

Nothofagus ''Nothofagus'', also known as the southern beeches, is a genus of 43 species of trees and shrubs native to the Southern Hemisphere in southern South America (Chile, Argentina) and Australasia (east and southeast Australia, New Zealand, New Gui ...

'') * Myrtaceae (''

Syzygium ''Syzygium'' () is a genus of flowering plants that belongs to the myrtle family, Myrtaceae. The genus comprises about 1200 species, and has a native range that extends from Africa and Madagascar through southern Asia east through the Pacific. I ...

'', ''

Metrosideros ''Metrosideros'' is a genus of approximately 60 trees, shrubs, and vines mostly found in the Pacific region in the family Myrtaceae. Most of the tree forms are small, but some are exceptionally large, the New Zealand species in particular. The n ...

'') * Phellinaceae ('' Phelline'') * Sapindaceae * Myrsinaceae * Grisselinaceae ('' Grisselinia'') * Argophyllaceae (''

Argophyllum ''Argophyllum'' is a genus in the Argophyllaceae family comprising eighteen species of shrubs and small trees. They feature alternate, simple leaves, often silvery white underneath. They appear in Australia and New Caledonia, where several specie ...

'') * Lauraceae, at least 22 species including''

Endiandra ''Endiandra'' is a genus of about 126 species of plants, mainly trees, in the laurel family Lauraceae. They are commonly called "walnut" despite not being related to the Northern Hemisphere walnuts (''Juglans'' spp.) which are in the family Jugl ...

'' and ''

Cryptocarya ''Cryptocarya'' is a genus of evergreen trees belonging to the laurel family, Lauraceae. The genus includes more than 350 species, distributed through the Neotropical, Afrotropical, Indomalayan, and Australasian realms. Overview The genus inc ...

''Pole, M., 2010. Was New Zealand a primary source for the New Caledonian flora? Alcheringa 34, 61–74.

History

Stratigraphy

Fossil content

See also

References

Further reading