Foulden Maar

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Foulden Maar
Foulden Marr Pit KC 2019.jpg
Foulden Maar pit as seen from Moonlight Road
LocationOtago, New Zealand
Coordinates45°31′36″S 170°13′06″E / 45.5268°S 170.2184°E / -45.5268; 170.2184Coordinates: 45°31′36″S 170°13′06″E / 45.5268°S 170.2184°E / -45.5268; 170.2184[1]
Volcanic fieldWaipiata

Foulden Maar, a fossil site near Middlemarch in Otago, New Zealand, formed in a volcanic eruption 23 million years ago. The resulting crater lake filled with diatomite, composed of layers of silica-shelled algae (diatoms) and exceptional fossils of plants, fishes, spiders and insects from the surrounding sub-tropical Miocene forest. As the only known maar of its kind in the Southern Hemisphere, it is one of New Zealand's pre-eminent fossil sites. A 2018 proposal to mine Foulden Maar for livestock-food additive has attracted significant public opposition.


Foulden Maar is named for the nearby farm of Foulden Hills, itself probably named after the town of Foulden in the Scottish Borders. Many other local locations—such as Kelso, Ettrick, Roxburgh, and the nearby Nenthorn—are similarly named.[2]


Foulden Maar is a maar-diatreme volcano in the Strath Taieri, southeast of Middlemarch in Otago, New Zealand.[3] Its crater was formed 23 million years ago and is filled with fossilised diatomite as well as sedimentary rock, debris flows, and pyroclastic rocks.[3][4] Foulden Maar is in the Waipiata Volcanic Field, which is an eroded phreatomagmatic eruption site.[4]


The Foulden Maar crater is approximately 1,000 metres (3,300 ft) in diameter; its diatomaceous layer is estimated to be 200 metres (660 ft) deep.[5] The Foulden Maar lake formed in a volcanic crater during the Waitakian (early Miocene), approximately 23 million years ago.[3][6] It was deep and anoxic at the bottom, which precluded decomposition of plant and animal remains. The lake was hydrologically isolated, meaning that no rivers or streams disturbed the sedimentation, which formed multiple laminated layers. These thin layers of silica are known as diatomite, as they are composed primarily of one diatom species, Encyonema jordaniforme Krammer, that grew on submerged rocks or aquatic plants in the lake.[7][8] As the lake gradually filled in and dried out, the diatomite layers capture a detailed fossil record of about 130,000 years.[1]


Foulden Maar is one of New Zealand's pre-eminent fossil sites, and is unique in the Southern Hemisphere for the time period it covers.[9][10] Fossils were first discovered at the site by gold prospectors in the early 1870s and were described as "polishing powder" by the geologists Frederick Hutton and George Ulrich in 1875.[11]

Although excavations have been limited to a small area the size of a tennis court, palaeontologists have discovered hundreds of undescribed species.[12] The sediments are rich in fossil flowers, fruits, seeds, pollen, and bark from plants, as well as fungi. Several new species of plants have been discovered, and the fossil plant genus Fouldenia is named in honour of its type locality Foulden Maar.[13]

Fossilised freshwater fish are common. The earliest galaxiid fish fossil and the earliest known fossilised eel both come from Foulden Maar.[14] Numerous arthropod fossils have been found at the site, among them Araneae (spiders), Plecoptera (stoneflies), Odonata (dragonflies), Isoptera (termites), Hemiptera (true bugs), Diptera (true flies), Coleoptera (beetles), Trichoptera (caddis flies), and Hymenoptera (wasps, ants and bees).[5] The four arachnids found at Foulden Maar are the first arachnid fossils identified in New Zealand; previous spider specimens had been found in amber but were not identifiable.[15] The first fossil hymenopteran in New Zealand is an ant found at Foulden Maar.[16]


This reconstruction of the lake at Foulden Maar 23 million years ago was commissioned by palaeontologist Dr. Daphne Lee and drawn by artist/ecologist Dr. Paula Peeters

The fossil evidence derived from pollen and spores suggests a warm temperate or sub-tropical rain forest with canopy trees, with an understorey of shrubs, ferns and on the margins pioneer species. Climatically, the area resembled modern-day south-eastern Queensland with species that no longer occur in the New Zealand flora.[7] The lake contained small and large galaxiid fishes and eels, ducks (inferred from coprolites), and likely crocodiles as well.[17][18]

Leaf fossils from the deposit have been used to link past spikes in carbon dioxide levels with melting of Antarctic ice,[19][20][21] and the variations in the laminations of the diatomite have been studied to reveal the New Zealand climate from that time.[1]


Diatomite was extracted in small quantities from the site during World War II when transport difficulties hindered access to foreign sources.[22][23] Diatomite has a range of applications, depending primarily on purity, diatom size, and the trace elements present.

1990s operation[edit]

Foulden Maar is on privately owned land. The area was initially developed for mining by Featherston Resources Ltd in 1997.[24] The deposit was estimated as 5 million tonnes (Mt) by NZ Petroleum and Minerals.[25] This proved uneconomic for the company, and its assets were sold to Plaman Resources Ltd in March 2015.[24]

2019 proposal[edit]

Plaman Resources claim the size of the deposit is 31 Mt.[26] The shareholders for Plaman Resources, are Iris Corporation, Kuala Lumpur, Malaysia (50.95 per cent) and Burleigh Nominees Ltd, Douglas, Isle of Man (49.05 per cent).[27] Plaman Resources' shareholders, the Iris Corporation and Burleigh Nominees, have allegedly been involved in corruption and humans-rights abuses and have unpaid debts.[28] It is unclear if Iris Corporation would remain a shareholder of Plaman if Overseas Investment Office (OIO) approval for the mine is received.[29]

Galaxias effusus from Foulden Maar is the oldest known species of Galaxias, the group to which whitebait belong.

Plaman hold the mining rights and plan to turn all of the fossil-containing diatomite into an additive for incorporating into the food of intensively farmed animals such as ducks and pigs.[30] Initial seed funding of about US$20 million (NZ$28 million) was raised through Goldman Sachs New Zealand Holdings, the Auckland branch of New York stock-exchange listed investment bank in August 2018.[31] The financial viability of these plans is reported to hinge on the purchase of an adjoining farm, which the OIO must rule on.[9][32] No timetable has been set for the decision.[33] The proposal would involve building a new $36.8m processing plant at Milton to crush the diatomite before shipping offshore from Port Chalmers or Bluff. It is estimated by the company that the trucking and processing would create 100 jobs over 27 years.[30] Plaman has discussed with local councils applying to New Zealand's Provincial Growth Fund for help with the costs of building the processing plant, although no application has been made.[34]

Previous mining at the site yielded low-quality diatomite only suitable for inclusion in concrete, rather than the high-quality product Plaman is marketing as "Black Pearl".[32] Plaman claims that livestock will benefit nutritionally from Black Pearl, because the diatomite is "rich in natural organic matter (which contains humics, such as humic and fulvic acid) and other valuable nutrients, which have been shown to be beneficial in animal nutrition."[35] Animal nutrition experts expressed doubt that the product produced by Plaman will have any animal-health benefits, as there is no published data to support their claims.[36] Concerns have also been expressed by the New Zealand Green Party that the diatomite would be sold as fertiliser to support the production of palm oil.[24]

Plaman Resources have offered to refrain from mining nearby Hindon Maar if opposition to the Foulden Maar proposal is dropped. They have also offered to set aside 5 hectares (12 acres) (12–20% of the deposit) of the eastern pit at Foulden Maar for scientific research,[37] but geologists say that if the deposit is drained for mining the fossils may be lost regardless.[38]

The company was placed in receivership and voluntary liquidation in June 2019, and the OIO approval process placed on hold.[39][40] The Save Foulden Maar group is considering crowdfunding to permanently protect the site.[41]


Some locals are opposed to the anticipated levels of dust, noise, and general disruption the proposed mine would create.[32] The Otago Regional Council has granted Plaman Resources resource consent to discharge air dust for the purpose of quarrying diatomite until 1 July 2020.[42] The original mining permit was for 20 years but has since been extended to November 2033.[43] A wider group of people concerned about the loss of the unique fossil record described as "Dunedin's Pompeii" and an "irreplaceable treasure box"[32][44] have launched a petition to preserve the site, garnering nearly 10,000 signatures in the first month.[28][45][46] A leaked report by Goldman Sachs details the engagement of former Labour MP Clayton Cosgrove as a lobbyist to "secure approval" for the mine.[32]

Some locals would like to see the area turned into a geo-park, along similar lines to other diatomite sites in Norway, Germany, and China.[44][47] Former Prime Minister Helen Clark suggested that the site could be protected as a scientific reserve under the Reserves Act 1977,[48] saying "It just doesn't stack up. It's a question of values. Do we value knowledge? Do we value natural heritage? Do we value science and research, or do we just want to a quick dollar from a low value pit? I mean, really, it's distressing."[28][49][50] MP Clare Curran voiced support for the mining proposal, saying that she had been given assurances by Plaman.[50] She argued that "misinformation" was abundant due to the slow overseas-investment-approval process and said that the resource-consent process would still need to be followed.[50] Dunedin Mayor Dave Cull, who wrote a letter of support for the mining proposal, has publicly called for clarification from Plaman after hearing details of the leaked Goldman Sachs report.[51] Clutha Mayor Bryce Cadogan, who also supports the proposal, expressed frustration that commercial sensitivity prevented the release of all the information in favour of the mine.[51] Dunedin City Council councillor Aaron Hawkins proposed that the council should "recognise the importance of Foulden Maar, and support its preservation, and protection as a scientific resource", and the council voted to do so, later formally opposing the mining proposal.[52][53] The University of Otago is also formally opposed to the mining proposal.[54] Sir Alan Mark, chair of the environmental group the Wise Response Society, called for the government to purchase the site and establish a geological reserve.[55]

Juliet Gerrard, the Prime Minister's Chief Science Adviser, has said that "the tale is far from simple and at least two weak spots at the interface of science and policy are exposed as we dig through the complexities: there is no obvious point in central government to consider the value of a fossil record; and the science community has perhaps not previously sufficiently communicated the national and international value of this geological site."[56] The Geoscience Society of New Zealand has called for the mining proposal to be stopped, with President Jennifer Eccles saying, "New Zealand’s national identity is strongly bound to its unique plants and animals. We cannot stand by and see this fountain of paleontological knowledge about where we have come from destroyed; particularly not for so little transient local and national gain."[10][57]

See also[edit]


  1. ^ a b c Lindqvist, Jon K.; Lee, Daphne E. (1 December 2009). "High-frequency paleoclimate signals from Foulden Maar, Waipiata Volcanic Field, southern New Zealand: An Early Miocene varved lacustrine diatomite deposit" (PDF). Sedimentary Geology. 222 (1–2): 98–110. Bibcode:2009SedG..222...98L. doi:10.1016/j.sedgeo.2009.07.009.
  2. ^ Reed, A. W. (2010). Peter Dowling (ed.). Place Names of New Zealand. Rosedale, North Shore: Raupo. pp. 201, 268, 354. ISBN 9780143204107.
  3. ^ a b c Kaulfuss, Uwe (2013). Geology and Paleontology of Foulden Maar, Otago, New Zealand (Doctor of Philosophy thesis). University of Otago.
  4. ^ a b Jones, Daniel Amir (2012). The Geophysical Characterisation of the Foulden Maar (Master of Science thesis). University of Otago.
  5. ^ a b Lee, Daphne E.; Kaulfuss, Uwe; Conran, John G.; Bannister, Jennifer M.; Lindqvist, Jon K. (1 October 2016). "Biodiversity and palaeoecology of Foulden Maar: an early Miocene Konservat-Lagerstätte deposit in southern New Zealand". Alcheringa: An Australasian Journal of Palaeontology. 40 (4): 525–541. doi:10.1080/03115518.2016.1206321. ISSN 0311-5518.
  6. ^ "Fossilworks: Gateway to the Paleobiology Database". Retrieved 20 May 2019.
  7. ^ a b Mildenhall, Dallas C.; Kennedy, Elizabeth M.; Lee, Daphne E.; Kaulfuss, Uwe; Bannister, Jennifer M.; Fox, Bethany; Conran, John G. (2014). "Palynology of the early Miocene Foulden Maar, Otago, New Zealand: Diversity following destruction". Review of Palaeobotany and Palynology. 204: 27–42. doi:10.1016/j.revpalbo.2014.02.003.(subscription required)
  8. ^ Harper, Margaret A.; Van De Vijver, Bart; Kaulfuss, Uwe; Lee, Daphne E. (2019). "Resolving the confusion between two fossil freshwater diatoms from Otago, New Zealand: Encyonema jordanii and Encyonema jordaniforme (Cymbellaceae, Bacillariophyta)". Phytotaxa. 394 (4): 231–243. doi:10.11646/phytotaxa.394.4.1. ISSN 1179-3163.
  9. ^ a b Hartley, Simon (20 April 2019). "Leaked report sheds light on mine project". Otago Daily Times. Retrieved 11 May 2019.
  10. ^ a b "GSNZ Release". Google Docs. Retrieved 17 May 2019.
  11. ^ Hutton, F.W.; Ulrich, G.H.F. (1875). Report on the geology and goldfields of Otago. Dunedin, NZ: Mills.
  12. ^ McPhee, Elena (30 May 2019). "Paleontologist breaks silence: 'horrified' over Foulden Maar". Otago Daily Times. Retrieved 30 May 2019.
  13. ^ Bannister, Jennifer M.; Lee, Daphne E.; Raine, J. Ian (January 2005). "Morphology and palaeoenvironmental context of Fouldenia staminosa, a fossil flower with associated pollen from the Early Miocene of Otago, New Zealand". New Zealand Journal of Botany. 43 (2): 515–525. doi:10.1080/0028825X.2005.9512972. ISSN 0028-825X.
  14. ^ Hartley, Simon (2 June 2018). "Miners, scientists unlikely allies". Otago Daily Times. Retrieved 10 May 2019.
  15. ^ Selden, Paul A.; Kaulfuss, Uwe (2 January 2019). "Fossil arachnids from the earliest Miocene Foulden Maar Fossil-Lagerstätte, New Zealand". Alcheringa: An Australasian Journal of Palaeontology. 43 (1): 165–169. doi:10.1080/03115518.2018.1450446. ISSN 0311-5518.
  16. ^ Kaulfuss, Uwe; Harris, Anthony C.; Conran, John G.; Lee, Daphne E. (2 October 2014). "An early Miocene ant (subfam. Amblyoponinae) from Foulden Maar: the first fossil Hymenoptera from New Zealand". Alcheringa: An Australasian Journal of Palaeontology. 38 (4): 568–574. doi:10.1080/03115518.2014.928181. ISSN 0311-5518.
  17. ^ "Fossil Hunt". RNZ. 17 March 2011. Retrieved 14 May 2019.
  18. ^ Peeters, Paula (18 August 2016). "Drawing on Queensland's present to recreate New Zealand's past". Paperbark Writer. Retrieved 11 May 2019.
  19. ^ "Otago leaf fossils help solve major climate mystery". RNZ. 20 October 2016. Retrieved 10 May 2019.
  20. ^ Backhouse, Matthew (20 October 2016). "Ancient crater lake in Central Otago offers clues for Antarctica". The New Zealand Herald. Retrieved 11 May 2019.
  21. ^ Morford, Stacey (13 October 2016). "Historic Shrinking of Antarctic Ice Sheet Linked to CO2 Spike". Popular Science. Retrieved 13 May 2019.
  22. ^ "Skin-Deep Secrets". Evening Star (Dunedin, New Zealand) (23970). 22 August 1941. Retrieved 20 May 2019 – via Papers Past.
  23. ^ "Otago Institute: Lecture by Dr. Watt". Otago Daily Times (22341). 15 August 1934. Retrieved 20 May 2019 – via Papers Past.
  24. ^ a b c Owens, Peter (8 February 2016). "Southland fertiliser popular with palm oil industries". Quarry & Mining Magazine. Retrieved 12 May 2019.
  25. ^ Christie T, Douch C, Winfield B, and Thompson B. "Industrial Minerals in New Zealand" . Undated. 19 May 2019
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  27. ^ "Plaman Resources Ltd, Auckland". NZ Companies Office. Retrieved 12 May 2019.
  28. ^ a b c Hancock, Farrah (14 May 2018). "Who is the fossil mining company?". Newsroom. Retrieved 14 May 2019.
  29. ^ Hartley, Simon (15 May 2019). "Diatomite company's ownership uncertain". Otago Daily Times. Retrieved 14 May 2019.
  30. ^ a b Hartley, Simon (28 May 2018). "Potential to create 100 jobs". Otago Daily Times. Retrieved 12 May 2019.
  31. ^ Ritchie, Neil (August 2018). "Mining Black Pearl". Quarrying & Mining Magazine.
  32. ^ a b c d e Hancock, Farah (10 May 2019). "Dunedin's 'Pompeii' to be mined to make pig food". Newsroom. Retrieved 10 May 2019.
  33. ^ "Sage holds key to sale of Otago fossil land to diatomite miner". Stuff. Retrieved 17 May 2019.
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  35. ^ "PLAMAN Global | Product". PLAMAN Global. Retrieved 19 May 2019.
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  38. ^ "Scientists reject fossil land swap". Newsroom. 5 June 2019. Retrieved 5 June 2019.
  39. ^ "Company seeking to mine Foulden Maar placed into receivership". Radio New Zealand. 19 June 2019.
  40. ^ "OIO puts Plaman application on hold". Retrieved 25 June 2019.
  41. ^ Miller, Tim (21 June 2019). "Group considering crowdfunding to secure Foulden Maar". Otago Daily Times. Retrieved 20 June 2019.
  42. ^ "Discharge to air permit". 26 June 2000. Retrieved 12 May 2019.
  43. ^ Hartley, Simon (13 November 2015). "Otago fertiliser to bolster oil palm plantations". Otago Daily Times. Retrieved 12 May 2019.
  44. ^ a b Morris, Chris (9 May 2019). "Mine threat to fossil record". Otago Daily Times. Retrieved 11 May 2019.
  45. ^ Miller, Tim (15 May 2019). "Foulden Maar petition attracts support". Otago Daily Times. Retrieved 14 May 2019.
  46. ^ "Save Foulden Maar". ActionStation. Retrieved 16 June 2019.
  47. ^ Hartley, Simon (13 May 2019). "Helen Clark joins opposition to Middlemarch mine proposal". Otago Daily Times. Retrieved 12 May 2019.
  48. ^ Clark, Helen (11 May 2019). "A low value but very destructive proposed mining operation in #Otago NZ threatens a geologically significant site rich in fossils & of considerable scientific interest. Wondering: has it been considered for scientific reserve status under Reserves Act?". @HelenClarkNZ. Retrieved 12 May 2019.
  49. ^ "Opposition grows to fossil mining". Newsroom. 13 May 2019. Retrieved 12 May 2019.
  50. ^ a b c Miller, Tim (14 May 2019). "Public lacks facts about mine: MP". Otago Daily Times. Retrieved 14 May 2019.
  51. ^ a b Miller, Tim (15 May 2019). "Mayor wants clarification on diatomite mine proposal". Otago Daily Times. Retrieved 14 May 2019.
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  53. ^ Rawlence, Nic. "Proposal to mine fossil-rich site in New Zealand sparks campaign to protect it". The Conversation. Retrieved 16 June 2019.
  54. ^ Miller, Tim (6 June 2019). "'Jaw-dropping inducements' over Foulden Marr". Otago Daily Times. Retrieved 5 June 2019.
  55. ^ Gibb, John (22 June 2019). "Plea to Govt to protect Foulden Maar". Otago Daily Times Online News. Retrieved 24 June 2019.
  56. ^ "Foulden Maar". Retrieved 17 May 2019.
  57. ^ Miller, Tim (16 May 2019). "Diatomite promoter hits back". Otago Daily Times. Retrieved 17 May 2019.

External links[edit]

Media related to Foulden Maar at Wikimedia Commons