UCL homepage JISC homepage
Calcareous Nannofossil Page Conodonts Page Diatoms Page Foraminifera Page Ostracods Page Palynology Page Radiolaria Page Home Page Links Page

 

Calcareous Nannofossils
Coccolithus pelagicus coccosphere




Introduction
Calcareous nannofossils include the coccoliths and coccospheres of haptophyte algae and the associated nannoliths which are of unknown provenance. The organism which creates the coccosphere is called a coccolithophore, they are phytoplankton (autotrophs that contain chloroplasts and photosynthesise). Their calcareous skeletons are found in marine deposits often in vast numbers, sometimes making up the major component of a particular rock, such as the chalk of England. One freshwater species has been reported. Formally coccolithophores are separated from other phytoplankton such as diatoms by the presence of a third flagella-like appendage called a haptonema, although the flagella bearing stage is often only one of a multi-stage life cycle.
A coccolith is a single disc-like plate which is secreted by the algal organism and held in combination with several other, sometimes varying shaped plates by an organic coating to form the coccosphere. On death the individual coccoliths invariably become separated and it is these that are most commonly preserved in the sedimentary record. Occasionally complete coccospheres are preserved and provide valuable information, particularly regarding coccospheres which possess two or more morphologicaly different coccoliths. There are two forms of coccoliths, the holococcoliths which are formed from calcite crystals which are essentially identical in shape and size and the heterococcoliths which are formed from larger calcite crystals which vary in size and shape. Most living forms are known to produce only heterococcoliths and then only during the non-motile stage of their life cycle. Those that do produce holococcoliths do so only during their motile stage.
History of Study
The first recorded use of the term "coccoliths" is from Ehrenberg's 1836 study of the chalk from the island of Rugen in the Baltic Sea. Ehrenberg and other early workers beleived coccoliths to have an inorganic origin. It was not untill the second half of the nineteenth century when Wallich found coccoliths joined to form coccospheres that an organic origin was suggested. Even after the publication of Sorby's 1861 paper, following which the organic origin of coccoliths was generally accepted, Ehrenberg remained unconvinced. The 1872 HMS Challenger expedition recovered coccospheres from the upper water layers and correctly concluded that they were the skeletons of calcareous algae. The term nannoplankton was coined by Lohmann in 1902. The study of coccolithophores has flourished since the 1960's, with much ground breaking work done on their biology as well as on the systematics of fossil and living forms. The Deep Sea Drilling Project (DSDP), now the Ocean Drilling Program (ODP), brought the stratigraphic value of calcareous nannofossils to the attention of industry as well as the scientific community. Today, due to the speed of preparation, calcareous nannofossils have bec ome the preferred tool for quick accurate stratigraphic age determination in post-Palaeozoic calcareous sequences.
Range
First recorded occurrences of calcareous nannofossils (nannoliths) are from the late Triassic (Carnian). The locations from which the earliest nannofossils are found include; the Northern and Southern Calcareous Alps, Timor, North-West Australia and Queen Charlotte Islands (Canada), all low latitude sites at the time. There are many claims for earlier occurrences but a lack of substantiated evidence means these must be excluded. One consequence of the first occurrence of calcareous nannofossils in the late Triassic lies in the fact that this was the first time open ocean planktonic organisms utilised calcareous skeletons and exported calcium carbonate into the deep oceans. This has important repercussions in terms of biogeochemical cycles. Today coccolithophores are one of the most important forms of phytoplankton found in the oceans, and may be described as the grass of the sea.
geologic time scale diagram click to view larger version
Classification
The classification of calcareous nannoplankton is carried out under the International Code of Botanical Nomenclature. They are formally classified in the Kingdom Protoctista, Phylum (or Division) Haptophyta, Class Prymnesiophyceae. Classification is complicated by the fact that some species are dimorphic, that is they possess more than one coccolith on a single coccosphere. This may lead to the belief that two species exist where in fact there is only one. Also, pleomorphism (where a holococcolith phase alternates with a heterococcolith phase) may also result in coccoliths being placed in different species or even genera when in fact they are simply different stages in the life cycle of the same species.
Applications
As the groups name suggests calcareous nannofossils are small, generally less than 30 microns across and usually between 5 and 10 microns (individual coccoliths). This has advantages and disadvantages. Advantages include:
  • Good preservation, their small size makes mechanical damage unlikely.
  • Widespread distribution, as part of the phytoplankton coccolithophores are distributed throughout the photic zone (predominantly the upper 50m of the water column) across almost all marine habitats.
  • A very large number of individual coccoliths may be preserved in a tiny amount of sediment hence only very small quantities of sample are needed to produce statistically valid results.
Disadvantages include:
  • Because of dissolution of calcium carbonate at depth in sea water (called the carbonate compensation depth (CCD)), preservation is compromised in deep water sediments.
  • Because of their small size and resistance to mechanical breakdown nannofossils can be reworked, great care is therefore needed especially when utilising nannofossils for biostratigraphic studies.
  • Again, because of the small size the opportunities for contamination are high, although careful and thorough preparation and collection techniques should significantly reduce this risk.
Biology
Culture techniques have resulted in great advances in the study of coccolithophore life cycles. The existence of a haploid and diploid phase has been proved by the extraction of DNA, with mitotic reproduction occurring in both stages. Syngamy (sexual reproduction) has not been observed but is assumed to occur, the recent discovery of combination coccospheres (where coccoliths of two distinct forms occur on the same coccosphere) has meant the traditional classification will have to be radically revised and updated.
The defining feature of the haptophytes is the flagella-like haptonema which is generally coiled. It differs from the flagella proper in its internal structure and its basal attachment. During the non-motile phase the flagella disappear but the haptonema often remains, the exact function of the haptonema is not fully understood. The algal cell contains a nucleus and two golden-brown chloroplasts which may be moved around the cell to optimise collection of available light. The cell also contains mitochondria which contain enzymes which produce the energy for cell function, vacuoles which deal with waste products and the Golgi body which is the site of coccolith secretion in many species. In many species overlapping oval organic scales coat the outer cell membrane. These have concentric ridges on their distal faces and radiating ridges on their proximal faces. It seems the organic scales act as bases for the precipitation of the calcite coccoliths. A variety of coccolith secretion strategies have been observed in different species, however it is probably true of all coccolithophores that the production of coccoliths is controlled by light. Emiliania huxleyi has been observed to start coccolith production within half an hour of being introduced to light, and produce an individual coccolith in one hour and a complete coccosphere in about thirty hours.
cross-section of coccosphere cell and cell wall coverings click to view larger version
Above diagram from Bown,P.(Ed.), 1998, Calcareous Nannofossil Biostratigraphy. Chapman and Hall.
The function of coccoliths is not known but may be one or more of four basic possibilities:
  • Protection; from bacteria, physical damage, predators such as copepods or to form a chemical buffer zone.
  • Flotation and buoyancy; aspherical forms may reduce sinking rates, the loss or addition of coccoliths may be a strategy employed to regulate position in the water column in order to optimise light or nutrient availability.
  • Light regulation; coccoliths may reflect sunlight protecting the cell from high light levels in the upper water column or refract sunlight into the cell allowing life in the lower photic zone.
  • Biochemistry; the cell may secrete calcite in order to expell a metabolic by-product enhancing the bichemical efficiency of the cell.
Life Cycle
Reproduction of coccolithophores is by single or double fission sometimes accompanied by a swarm-spore stage. The information we have on coccolithophore reproduction is based on only a few species so care must be taken when making generalisations, however, it is thought the coccolith-bearing phase is diploid and capable of asexual (mitotic) reproduction. This allows rapid population growth during periods of optimum conditions, producing what are known as "blooms". Motile naked haploid gametes may be produced by meiosis and non-motile benthic stages are also known to be produced. Sexual fusion has rarely been observed but is inferred by the variation of DNA found within coccolithophpores.
Preparation Techniques
Please remember all preparation techniques require the use of hazardous materials and equipment and should only be carried out in properly equiped laboratories, wearing the correct safety clothing and under the supervision of qualified staff.
Smear slides are produced by first cleaning a hand specimen by paring the outer surfaces off. A fine "dust" of material is then scraped off onto a cover slip. This is then moistened with distilled water and spread across the cover slip with a suitable utensile such as a wooden tooth pick. This takes a certain amount of experience to get right but when the corrrect coverage is obtained the cover slip is placed on a hot plate to dry. Once dry the cover slip is inverted and glued to a slide using Norland optical adhesive which is cured under U.V. light. Centrifuge slides are produced by first cleaning the sample as in the smear slide technique and then scraping a dust of material into a centrifuge tube. This is topped up with distilled water and spun at 350 rpm in a centrifuge for about two minutes. The pellet is then put to one side and the supernatant kept. The supernatant is then re-suspended and centrifuged at 1000rpm for four minutes this time keeping the pellet. This re-suspending and centrifuging at 1000rpm may need to be repeated several times depending on the lithology of the sample. After centrifuging the sample is dilluted to a slightly milky consistency with distilled water and strewn on to a cover slip placed on a hot plate and left to dry. The cover slip can then be mounted as in the smear slide technique. One of the major advantages calcareous nannofossils have over other microfossil groups, particularly in terms of industrial application is the speed at which samples can be prepared. Simple smear slides can be made in minutes and even centrifuge preparations are ready in less than half an hour. Another advantage is that no harmful or dangerous chemicals are needed nor even a fume cupboard. This makes calcareous nannofossils an extremely useful and widely used biostratigraphic tool especially on offshore drilling platforms and ships.
Observation Techniques
Since individualcoccoliths preserve fine structural crystallographic detail in calcite observation techniques depend on the use of petrological microscopes. The calcite crystals forming hetero- and holococcoliths often have differently oriented optic axes which produce distinctive extinction patterns under crossed nicols of a polarising microscope. Transmitted, cross polarised light is regularly used but phase contrast and bright field settings may also be advantageous. Scanning Electron Microscopy has become more widely available and greatly enhanced the study of nannofossils. Much of the work on the fine structure and formation of coccoliths has been made possible by scanning electron microscopes.
Images
The following images are of a representative selection of calcareous nannofossils aimed at giving a general overview of the different morphotypes. Each specimen is given a generic and if possible a species name followed by its age range, the site location from which the sample was obtained and the magnification at which the image was taken or its size in microns. PC (Phase Contrast), XPL (Crossed Polarised Light) SEM (Scanning Electron Microscope). Typical and selected marker species are illustrated from each main period of the geological column in which calcareous nannofossils occur. Click on an image to view a larger version.
Triassic and Jurassic
Anulasphaera helvetica Grun and Zweili, 1980
Callovian (Middle Jurassic)
Denver Borehole, UK
PC side view
Anulasphaera helvetica Grun and Zweili, 1980
Callovian (Middle Jurassic)
Denver Borehole, UK
XPL side view
Anulasphaera helvetica Grun and Zweili, 1980
Callovian (Middle Jurassic)
Denver Borehole, UK
(SEM) distal view
Anulasphaera helvetica Grun and Zweili, 1980
Callovian (Middle Jurassic)
Denver Borehole, UK
(SEM) proximal oblique view
Stephanolithion bigotii bigotii Deflandre, 1939
Lower Oxfordian (Upper Jurassic)
Cleveland Farm Pit, wiltshire, UK
XPL
Stephanolithion bigotii bigotii Deflandre, 1939
Upper Kimmeridgian (Upper Jurassic)
Gorodische, Russia
SEM
Stephanolithion speciosum octum Deflandre in Deflandre and Fert, 1954 ssp. Rood and Barnard, 1972
Lower Bathonian (Middle Jurassic)
Port en Bessin, N. France
XPL
Stephanolithion speciosum octum Deflandre in Deflandre and Fert, 1954 ssp. Rood and Barnard, 1972
Lower Bathonian (Middle Jurassic)
Port en Bessin, N. France
PC
Stephanolithion speciosum Deflandre in Deflandre and Fert, 1954 ssp. octum Rood and Barnard, 1972
Upper Bajocian-Lower Callovian (Middle Jurassic)
Escoville, France
distal view
Biscutum novum (Goy,1979) Bown, 1987
Aalenian/Bajocian
Brenha, Portugal
XPL
Biscutum novum (Goy,1979) Bown, 1987
Lower Toarcian
Trimeusel, Germany
distal view
Biscutum novum (Goy,1979) Bown, 1987
Upper Toarcian
Ballrechten, Germany
proximal view
Carinolithus superbus (Deflandre in Deflandre and Fert, 1954) Prins in Grun et al, 1974
Lower Toarcian-Lower Bajocian
Ilminster, UK
proximal oblique view SEM
Carinolithus superbus (Deflandre in Deflandre and Fert, 1954) Prins in Grun et al, 1974
Lower Toarcian-Lower Bajocian
Ilminster, UK
side view SEM
Crucirhabdus minutus Jafar, 1983
Norian-Rhaetian (Upper Triassic)
Fischerwiese, Austria
XPL distal view
Crucirhabdus minutus Jafar, 1983
Norian-Rhaetian (Upper Triassic)
Weissloferbach, S. Germany
distal view SEM
Lotharingius haufii Grun and Zweili in Grun et al, 1974
Lower Toarcian
Untersturmig, Germany
XPL
Lotharingius haufii Grun and Zweili in Grun et al, 1974
Upper Pliensbachian-Upper Bathonian
Untersturmig, Germany
PC
Lotharingius haufii Grun and Zweili in Grun et al, 1974
Upper Pliensbachian-Upper Bathonian
Untersturmig, Germany
SEM (collapsed coccosphere)
Parhabdolithus liasicus distinctus Deflandre in Grasse, 1952 ssp. Bown, 1987
Hettangian-Lower Toarcian
Timor
XPL plan view
Parhabdolithus liasicus distinctus Deflandre in Grasse, 1952 ssp. Bown, 1987
Hettangian-Lower Toarcian
Timor
XPL side view
Parhabdolithus liasicus distinctus Deflandre in Grasse, 1952 ssp. Bown, 1987
Hettangian-Lower Toarcian
Mochras Borehole, UK
side view (SEM)
Prinsiosphaera triassica Jafar, 1983
Norian-Rhaetian
Weissloferbach S. Germany
XPL
Prinsiosphaera triassica Jafar, 1983
Norian-Rhaetian
ODP Site 761, Wombat Plateau, NW Australian shelf
SEM
Lower Cretaceous
Axopodorhabdus albianus (Black, 1967) Wind and Wise in Wise and Wind, 1977
Middle Albian-Upper Cenomanian
Folkestone, UK
XPL
Axopodorhabdus albianus (Black, 1967) Wind and Wise in Wise and Wind, 1977
Middle Albian-Upper Cenomanian
English Channel Borehole R330, UK
distal view SEM
Calcicalathina oblongata (Worsley, 1971) Thierstein, 1971
Lower Valanginian-Lower Barremian
Bulgaria
XPL distal view
Calcicalathina oblongata (Worsley, 1971) Thierstein, 1971
Lower Valanginian-Lower Barremian
DSDP Site 547B, Atlantic Ocean
distal view SEM
Calcicalathina oblongata (Worsley, 1971) Thierstein, 1971
Lower Valanginian-Lower Barremian
DSDP Site 547B, Atlantic Ocean
side view SEM
Ceratolithina bicornuta Perch-Nielsen, 1988
Middle Albian-Upper Albian
Folkestone, UK
XPL
Corollithion kennedyi
Cenomanian
Lydden Spout, Folkestone, UK
XPL
Cruciellipsis cuvillieri (Manivit, 1966) Thierstein, 1971
Lower Berriasian-Upper Hauterivian
DSDP Site 397, E.Atlantic Ocean
XPL
Cruciellipsis cuvillieri (Manivit, 1966) Thierstein, 1971
Lower Berriasian-Upper Hauterivian
DSDP Site 547B, Atlantic Ocean
distal view SEM
Eiffellithus turriseiffelii (Deflandre in Deflandre and Fert, 1954) Reinhardt, 1965
Upper ALbian-Upper Maastrichtian
Folkestone, UK
XPL distal view
Eprolithus floralis (Stradner, 1962) Stover, 1966
Lower Aptian-?Lower Campanian
Folkestone, UK
XPL distal view
Gartnerago segmentatum
Cenomanian-Maastrichtian
Langdon Stairs, Dover, Kent, UK
XPL distal view
Micrantholithus obtusus Stradner, 1963
Berriasian-Upper Aptian
Speeton, UK
XPL
Micrantholithus obtusus Stradner, 1963
Berriasian-Upper Aptian
DSDP Site 398D, Atlantic Ocean
SEM
Nannoconus abundans Stradner and Grun, 1973
Barremian-?Lower Aptian
Speeton, UK
XPL
Nannoconus abundans Stradner and Grun, 1973
Barremian-?Lower Aptian
Speeton, UK
side view SEM
Prediscosphaera columnata (Stover, 1966) Perch-Nielsen, 1984
Lower Albian-Turonian
Folkestone, UK
XPL distal view
Prediscosphaera columnata (Stover, 1966) Perch-Nielsen, 1984
Lower Albian-Turonian
Folkestone, UK
XPL side view
Prediscosphaera columnata (Stover, 1966) Perch-Nielsen, 1984
Lower Albian-Turonian
Copt Point, UK
side view SEM
Watznaueria barnesae (Black in Black and Barnes, 1959) Perch-Nielsen, 1968
Lower Bajocian-Maastrichtian
Gorodische, Russia
XPL
Watznaueria barnesae (Black in Black and Barnes, 1959) Perch-Nielsen, 1968
Lower Bajocian-Maastrichtian
Speeton, UK
SEM (Coccosphere)
Watznaueria britannica (Stradner, 1963) Reinhardt, 1964
Lower Bajocian-Lower Cenomanian
Cleveland Farm Pit, Wiltshire, UK
XPL
Zeugrhabdotus erectus (Deflandre in Deflandre and Fert, 1954) Reinhardt, 1965
Lower Pliensbachian?-Upper Maastrichtian
Cleveland Farm Pit, Wiltshire, UK
XPL
Zeugrhabdotus erectus (Deflandre in Deflandre and Fert, 1954) Reinhardt, 1965
Lower Pliensbachian?-Upper Maastrichtian
Mochras Borehole, UK
distal view SEM
Zeugrhabdotus erectus (Deflandre in Deflandre and Fert, 1954) Reinhardt, 1965
Lower Pliensbachian?-Upper Maastrichtian
Dorset, UK
side view SEM
Upper Cretaceous
Arkhangelskiella cymbiformis Vekshina, 1959
Campanian-Maastrichtian
DSDP Site 249, Indian Ocean
XPL distal view
Arkhangelskiella cymbiformis Vekshina, 1959
Campanian-Maastrichtian
Keswick, Norfolk, UK
oblique distal view SEM
Eiffellithus eximius (Stover, 1966) Perch-Nielsen, 1968
Turonian-Campanian
Zoe C BH, South Africa
XPL
Eiffellithus eximius (Stover, 1966) Perch-Nielsen, 1968
Turonian-Campanian
Zoe C BH, South Africa
XPL rotated
Lithastrinus grillii Stradner, 1962
Coniacian-Campanian
near Plymouth Bluff, Lowndes County, Mississippi, USA
XPL
Lucianorhabdus cayeauxii Deflandre, 1959
Coniacian-Maastrichtian
near Portland, Dallas County, Alabama, USA
XPL
Marthasterites furcatus (Deflandre in Deflandre and Firt, 1954) Deflandre, 1959
Turonian-Campanian
DSDP Site 258, E.Indian Ocean
XPL
Marthasterites furcatus (Deflandre in Deflandre and Firt, 1954) Deflandre, 1959
Turonian-Campanian
DSDP Hole 550B, NE Atalntic Ocean
SEM
Microrhabdulus decoratus Deflandre, 1959
Cenomanian-Maastrichtian
DSDP Site 401, NE Atlantic Ocean
SEM
Microrhabdulus decoratus Deflandre, 1959
Cenomanian-Maastrichtian
DSDP Site 249, W. Indian Ocean
XPL
Micula staurophora (Gardet, 1955) Stradner, 1963
Coniacian-Maastrichtian
near Ripley, Tippah County, Mississippi, USA
XPL
Prediscosphaera arkhangelskyi (Reinhardt, 1965) Perch-Nielsen, 1984
Santonian-Maastrichtian
DSDP Site 249, W. Indian Ocean
XPL
Prediscosphaera cretacea (Arkhangelsky, 1912) Gartner, 1968
Cenomanian-Maastrichtian
DSDP Site 249, W. Indian Ocean
XPL
Prediscosphaera cretacea (Arkhangelsky, 1912) Gartner, 1968
Cenomanian-Maastrichtian
near Plymouth Bluff, Lowndes County, Alabama, USA
XPL
Quadrum gartneri Prins and Perch-Nielsen in Manivit et al, 1977
Turonian-?Maastrichtian
DSDP Site 217, N. Indian Ocean
XPL
Tranolithus orionatus (Reinhardt, 1966a) Reinhardt, 1966b
Albian-Maastrichtian
Folkestone, UK
XPL
Uniplanarius trifidus (Stradner in Stradner and Papp, 1961) Hattner and Wise, 1980
Campanian-Maastrichtian
DSDP Site 217 N. Indian Ocean
XPL
Uniplanarius trifidus (Stradner in Stradner and Papp, 1961) Hattner and Wise, 1980
Campanian-Maastrichtian
DSDP Site 241 W. Indian Ocean
XPL
Palaeogene
Chiasmolithus solitus (Bramlette and Sullivan, 1961) Locker, 1968
Lutetian-Bartonian (Middle Eocene)
Whitecliff Bay, UK
PC
Chiasmolithus solitus (Bramlette and Sullivan, 1961) Locker, 1968
Lutetian-Bartonian (Middle Eocene)
Fayum, Egypt
oblique distal view SEM
Discoaster tanii Bramlette and Riedel, 1954
Middle Eocene-Oligocene
Hampden Beach, New Zealand
distal view SEM
Discoaster saipanensis Bramlette and Riedel, 1954
Middle-Upper Eocene
Fayum, Egypt
distal view SEM
Discoaster saipanensis Bramlette and Riedel, 1954
Middle-Upper Eocene
Benidorm, Spain
distal view SEM
Discoaster saipanensis Bramlette and Riedel, 1954
Middle-Upper Eocene
Whitecliff Bay, UK
PC
Discoaster kuepperi Sradner, 1959
Lower-Middle Eocene
North Sea, UK
PC
Discoaster kuepperi Sradner, 1959
Lower-Middle Eocene
Benidorm, Spain
proximal view SEM
Discoaster kuepperi Sradner, 1959
Lower-Middle Eocene
Benidorm, Spain
distal view SEM
Discoaster kuepperi Sradner, 1959
Lower-Middle Eocene
Benidorm, Spain
side view SEM
Cruciplacolithus primus Perch-Nielsen, 1977
Upper Palaeocene
St. Paul Monastery, Egypt
oblique distal view SEM
Neococcolithus dubius (Deflandre in Deflandre and Fert, 1954) Black, 1967
Lower-Upper Eocene
Whitecliff Bay, UK
oblique distal view SEM
Neococcolithus dubius (Deflandre in Deflandre and Fert, 1954) Black, 1967
Lower-Upper Eocene
Whitecliff Bay, UK
distal view SEM
Fasciculithus tympaniformis Hay and Mohler in Hay et al, 1967
Upper Palaeocene-Lower Eocene
Pegwell Bay, Kent, UK
XPL
Fasciculithus tympaniformis Hay and Mohler in Hay et al, 1967
Upper Palaeocene-Lower Eocene
St. Paul Monastery, Egypt
oblique proximal view
Fasciculithus tympaniformis Hay and Mohler in Hay et al, 1967
Upper Palaeocene-Lower Eocene
St. Paul Monastery, Egypt
proximal view
Sphenolithus moriformis (Bronniman and Stradner, 1960) Brmlette and Wilcoxon, 1967
Palaeocene-Pliocene
DSDP Site 590B, S.W Pacific
SEM
Sphenolithus moriformis (Bronniman and Stradner, 1960) Brmlette and Wilcoxon, 1967
Palaeocene-Pliocene
DSDP Site 593, S.W Pacific
SEM
Discoaster lodoensis Bramlette and Riedel, 1954
Palaeocene-Pliocene
Benidorm, Spain
XPL
Discoaster lodoensis Bramlette and Riedel, 1954
Palaeocene-Pliocene
Benidorm, Spain
proximal view SEM
Discoaster lodoensis Bramlette and Riedel, 1954
Palaeocene-Pliocene
Benidorm, Spain
distal view SEM
Neogene
Amaurolithus amplificus (Bukry and Percival) Gartner and Bukry, 1975
Upper Miocene-Pliocene
Manavgat, S.Turkey
XPL
Amaurolithus amplificus (Bukry and Percival) Gartner and Bukry, 1975
Upper Miocene-Pliocene
Manavgat, S.Turkey
PC
Coccolithus pelagicus (Wallich, 1871) Schiller, 1930
Lower Palaeocene-Recent
N. Atlantic off S.W coast of Iceland
SEM entire coccosphere
Coccolithus pelagicus (Wallich, 1871) Schiller, 1930
Lower Palaeocene-Recent
ODP Site 1052b, Western N. Atlantic
SEM distal view 10 microns
Coccolithus pelagicus (Wallich, 1871) Schiller, 1930
Lower Palaeocene-Recent
ODP Site 1052b, Western N. Atlantic
SEM proximal view 10 microns
Discoaster challengeri Bramlette and Riedel, 1954
Miocene-Pliocene
Ghajn Tuffieha Bay, Malta
SEM proximal view
Discoaster challengeri Bramlette and Riedel, 1954
Miocene-Pliocene
G. Mihmandar Borehole, Malta
PC
Discoaster exilis Martini and Bramlette, 1963
Middle Miocene
Ghajn Tuffieha Bay, Malta
proximal view SEM
Discoaster exilis Martini and Bramlette, 1963
Middle Miocene
Ghajn Tuffieha Bay, Malta
PC
Discoaster variabilis Martini and Bramlette, 1963
Middle Miocene-Pliocene
Ghajn Tuffieha Bay, Malta
proximal view SEM
Discoaster variabilis Martini and Bramlette, 1963
Middle Miocene-Pliocene
Ghajn Tuffieha Bay, Malta
PC
Florisphaera profunda Okado and Honjo, 1973
Middle Miocene-Recent
Almerian Canyon, Western Mediterranian Sea
10 microns SEM
Gephyrocapsa oceanica Kamptner, 1943
Pleistocene-Recent
Almerian Canyon, Western Mediterranian Sea
10 microns SEM
Calcidiscus tropicus Kamptner, 1956
Lower Miocene-Recent
DSDP Site 593, S.W Pacific Ocean
SEM
Calcidiscus tropicus Kamptner, 1956
Lower Miocene-Recent
DSDP Site 593, S.W Pacific Ocean
SEM
Helicosphaera carteri (Wallich, 1877) Kamptner, 1954
Upper Oligocene-Recent
DSDP Site 590B, S.W Pacific Ocean
XPL
Helicosphaera carteri (Wallich, 1877) Kamptner, 1954
Upper Oligocene-Recent
DSDP Site 590B, S.W Pacific Ocean
proximal view SEM
Reticulofenestra pseudoumbilica (Gartner) Gartner, 1969
Miocene-Pliocene
Ghajn Tuffieha Bay, Malta
proximal view SEM
Reticulofenestra pseudoumbilica (Gartner) Gartner, 1969
Miocene-Pliocene
Ghajn Tuffieha Bay, Malta
coccosphere SEM
Sphenolithus heteromorphus Deflandre, 1953
Lower Miocene-Middle Miocene
DSDP Site 593, S.W Pacific Ocean
SEM
Sphenolithus heteromorphus Deflandre, 1953
Lower Miocene-Middle Miocene
DSDP Site 590B, S.W Pacific Ocean
SEM


Calcareous Nannofossil Page Conodonts Page Diatoms Page Foraminifera Page Ostracods Page Palynology Page Radiolaria Page Home Page Links Page

cookies