micropaleontology –science of microfossils · 7. bryozoa b. siliceous microfossils 8. radiolaria...
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Micropaleontology – Science of Microfossils
• Microfossils are the tiny remains of bacteria, protists, fungi, Microfossils are the tiny remains of bacteria, protists, fungi, Microfossils are the tiny remains of bacteria, protists, fungi, Microfossils are the tiny remains of bacteria, protists, fungi, animals, and plantsanimals, and plantsanimals, and plantsanimals, and plants
• A fossil group with at least two third of its population is visible A fossil group with at least two third of its population is visible A fossil group with at least two third of its population is visible A fossil group with at least two third of its population is visible under the microscope is a microfossilunder the microscope is a microfossilunder the microscope is a microfossilunder the microscope is a microfossil
• These are a heterogeneous group of fossil remains studiedThese are a heterogeneous group of fossil remains studiedThese are a heterogeneous group of fossil remains studiedThese are a heterogeneous group of fossil remains studiedas a single discipline. Includes taxonomically unrelated groups as a single discipline. Includes taxonomically unrelated groups as a single discipline. Includes taxonomically unrelated groups as a single discipline. Includes taxonomically unrelated groups united solely on the basis of their study under the microscopeunited solely on the basis of their study under the microscopeunited solely on the basis of their study under the microscopeunited solely on the basis of their study under the microscope
• As a discipline it lacks homogeneity, most are protists As a discipline it lacks homogeneity, most are protists As a discipline it lacks homogeneity, most are protists As a discipline it lacks homogeneity, most are protists ––––unicellular plants and animalsunicellular plants and animalsunicellular plants and animalsunicellular plants and animals
• Some are multicellular or microscopic parts of macroscopic Some are multicellular or microscopic parts of macroscopic Some are multicellular or microscopic parts of macroscopic Some are multicellular or microscopic parts of macroscopic • Some are multicellular or microscopic parts of macroscopic Some are multicellular or microscopic parts of macroscopic Some are multicellular or microscopic parts of macroscopic Some are multicellular or microscopic parts of macroscopic formsformsformsforms
• These are calcareous, siliceous, organicThese are calcareous, siliceous, organicThese are calcareous, siliceous, organicThese are calcareous, siliceous, organic----walled and phosphatic walled and phosphatic walled and phosphatic walled and phosphatic in test composition. Their morphology as well as genetic in test composition. Their morphology as well as genetic in test composition. Their morphology as well as genetic in test composition. Their morphology as well as genetic characters are differentcharacters are differentcharacters are differentcharacters are different
• Thus, microfossils, unlike other kinds of fossils, are not grouped Thus, microfossils, unlike other kinds of fossils, are not grouped Thus, microfossils, unlike other kinds of fossils, are not grouped Thus, microfossils, unlike other kinds of fossils, are not grouped according to their relationships to one another, but only according to their relationships to one another, but only according to their relationships to one another, but only according to their relationships to one another, but only because of their generally small size and methods of study. For because of their generally small size and methods of study. For because of their generally small size and methods of study. For because of their generally small size and methods of study. For example, fossils of bacteria, foraminifera, diatoms, very small example, fossils of bacteria, foraminifera, diatoms, very small example, fossils of bacteria, foraminifera, diatoms, very small example, fossils of bacteria, foraminifera, diatoms, very small invertebrate shells or skeletons, pollen, and tiny bones and invertebrate shells or skeletons, pollen, and tiny bones and invertebrate shells or skeletons, pollen, and tiny bones and invertebrate shells or skeletons, pollen, and tiny bones and teeth of large vertebrates, among others, can be teeth of large vertebrates, among others, can be teeth of large vertebrates, among others, can be teeth of large vertebrates, among others, can be called microfossils. But it is an unnatural groupingcalled microfossils. But it is an unnatural groupingcalled microfossils. But it is an unnatural groupingcalled microfossils. But it is an unnatural grouping
• They are found in all the ecosystems in water (marine, river, They are found in all the ecosystems in water (marine, river, They are found in all the ecosystems in water (marine, river, They are found in all the ecosystems in water (marine, river, estuarine) and on landestuarine) and on landestuarine) and on landestuarine) and on land
• They live in shallow marine, bathyal and abyssal depthsThey live in shallow marine, bathyal and abyssal depthsThey live in shallow marine, bathyal and abyssal depthsThey live in shallow marine, bathyal and abyssal depths• Their minute size, abundant occurrence and wide geographic Their minute size, abundant occurrence and wide geographic Their minute size, abundant occurrence and wide geographic Their minute size, abundant occurrence and wide geographic
distribution in sediments of all ages and in almost every marine distribution in sediments of all ages and in almost every marine distribution in sediments of all ages and in almost every marine distribution in sediments of all ages and in almost every marine environment make them usefulenvironment make them usefulenvironment make them usefulenvironment make them useful
• They range from the Precambrian to the RecentThey range from the Precambrian to the RecentThey range from the Precambrian to the RecentThey range from the Precambrian to the Recent• Some are planktic living in top 200 m making them useful in Some are planktic living in top 200 m making them useful in Some are planktic living in top 200 m making them useful in Some are planktic living in top 200 m making them useful in
monitoring sea surface temperature, e.g. foraminifera, diatoms, monitoring sea surface temperature, e.g. foraminifera, diatoms, monitoring sea surface temperature, e.g. foraminifera, diatoms, monitoring sea surface temperature, e.g. foraminifera, diatoms, radiolaria, coccolithsradiolaria, coccolithsradiolaria, coccolithsradiolaria, coccolithsradiolaria, coccolithsradiolaria, coccolithsradiolaria, coccolithsradiolaria, coccoliths
• Some are benthic (vagile/sessile) Some are benthic (vagile/sessile) Some are benthic (vagile/sessile) Some are benthic (vagile/sessile) –––– foraminifera, bryozoa, foraminifera, bryozoa, foraminifera, bryozoa, foraminifera, bryozoa, ostracoda, diatomsostracoda, diatomsostracoda, diatomsostracoda, diatoms
• Some have both benthic and planktic phases in their Some have both benthic and planktic phases in their Some have both benthic and planktic phases in their Some have both benthic and planktic phases in their reproductionreproductionreproductionreproduction
• Spores and pollens derived from land plants, are strongly Spores and pollens derived from land plants, are strongly Spores and pollens derived from land plants, are strongly Spores and pollens derived from land plants, are strongly climate dependentclimate dependentclimate dependentclimate dependent
• A small amount of sediment sample can give rise to thousands A small amount of sediment sample can give rise to thousands A small amount of sediment sample can give rise to thousands A small amount of sediment sample can give rise to thousands of specimens of foraminiferaof specimens of foraminiferaof specimens of foraminiferaof specimens of foraminifera
Importance:Importance:Importance:Importance:
• Microfossils are perhaps the most important group of all fossils Microfossils are perhaps the most important group of all fossils Microfossils are perhaps the most important group of all fossils Microfossils are perhaps the most important group of all fossils ———— they are extremely useful in agethey are extremely useful in agethey are extremely useful in agethey are extremely useful in age----dating, correlation and dating, correlation and dating, correlation and dating, correlation and paleoenvironmental reconstruction, all important in the oil, paleoenvironmental reconstruction, all important in the oil, paleoenvironmental reconstruction, all important in the oil, paleoenvironmental reconstruction, all important in the oil, mining, engineering, and environmental industries, as well as in mining, engineering, and environmental industries, as well as in mining, engineering, and environmental industries, as well as in mining, engineering, and environmental industries, as well as in general geologygeneral geologygeneral geologygeneral geology
• Billions of dollars have been made on the basis of microfossil Billions of dollars have been made on the basis of microfossil Billions of dollars have been made on the basis of microfossil Billions of dollars have been made on the basis of microfossil studiesstudiesstudiesstudies
• Because they usually occur in huge numbers in all kinds of Because they usually occur in huge numbers in all kinds of Because they usually occur in huge numbers in all kinds of Because they usually occur in huge numbers in all kinds of sedimentary rocks, they are the most abundant and most easily sedimentary rocks, they are the most abundant and most easily sedimentary rocks, they are the most abundant and most easily sedimentary rocks, they are the most abundant and most easily sedimentary rocks, they are the most abundant and most easily sedimentary rocks, they are the most abundant and most easily sedimentary rocks, they are the most abundant and most easily sedimentary rocks, they are the most abundant and most easily accessible fossilsaccessible fossilsaccessible fossilsaccessible fossils
• Indeed, some very thick rock layers are made entirely of Indeed, some very thick rock layers are made entirely of Indeed, some very thick rock layers are made entirely of Indeed, some very thick rock layers are made entirely of microfossils. The pyramids of Egypt are made of sedimentary microfossils. The pyramids of Egypt are made of sedimentary microfossils. The pyramids of Egypt are made of sedimentary microfossils. The pyramids of Egypt are made of sedimentary rocks, for example, that consist of the shells of foraminifera, a rocks, for example, that consist of the shells of foraminifera, a rocks, for example, that consist of the shells of foraminifera, a rocks, for example, that consist of the shells of foraminifera, a major microfossil groupmajor microfossil groupmajor microfossil groupmajor microfossil group
• Microfossils can also be very useful in teaching science at all levels. Microfossils can also be very useful in teaching science at all levels. Microfossils can also be very useful in teaching science at all levels. Microfossils can also be very useful in teaching science at all levels. Students are commonly fascinated by things they cannot see with their Students are commonly fascinated by things they cannot see with their Students are commonly fascinated by things they cannot see with their Students are commonly fascinated by things they cannot see with their naked eyes, especially when the objects are beautiful or interesting in naked eyes, especially when the objects are beautiful or interesting in naked eyes, especially when the objects are beautiful or interesting in naked eyes, especially when the objects are beautiful or interesting in their own right.their own right.their own right.their own right.
• Processing of micropaleontological samples is usually easy and safe Processing of micropaleontological samples is usually easy and safe Processing of micropaleontological samples is usually easy and safe Processing of micropaleontological samples is usually easy and safe enough for students to do themselves, or at least to watch.enough for students to do themselves, or at least to watch.enough for students to do themselves, or at least to watch.enough for students to do themselves, or at least to watch.
• Although plants and animals are the most obvious life around us today, Although plants and animals are the most obvious life around us today, Although plants and animals are the most obvious life around us today, Although plants and animals are the most obvious life around us today, they are not the most numerous nor the most important contributors of they are not the most numerous nor the most important contributors of they are not the most numerous nor the most important contributors of they are not the most numerous nor the most important contributors of microfossils.microfossils.microfossils.microfossils.
• Bacteria (prokaryotes) and protists far outnumber them, live in more Bacteria (prokaryotes) and protists far outnumber them, live in more Bacteria (prokaryotes) and protists far outnumber them, live in more Bacteria (prokaryotes) and protists far outnumber them, live in more diverse habitats, and leave a greater diversity of microfossils. diverse habitats, and leave a greater diversity of microfossils. diverse habitats, and leave a greater diversity of microfossils. diverse habitats, and leave a greater diversity of microfossils.
• Today these organisms live from Antarctic ice deserts to steaming Today these organisms live from Antarctic ice deserts to steaming Today these organisms live from Antarctic ice deserts to steaming Today these organisms live from Antarctic ice deserts to steaming volcanic hot springs, and from the highest mountains to the deepest volcanic hot springs, and from the highest mountains to the deepest volcanic hot springs, and from the highest mountains to the deepest volcanic hot springs, and from the highest mountains to the deepest
• Today these organisms live from Antarctic ice deserts to steaming Today these organisms live from Antarctic ice deserts to steaming Today these organisms live from Antarctic ice deserts to steaming Today these organisms live from Antarctic ice deserts to steaming volcanic hot springs, and from the highest mountains to the deepest volcanic hot springs, and from the highest mountains to the deepest volcanic hot springs, and from the highest mountains to the deepest volcanic hot springs, and from the highest mountains to the deepest sea. Some cause diseases, such as malaria which infects 350sea. Some cause diseases, such as malaria which infects 350sea. Some cause diseases, such as malaria which infects 350sea. Some cause diseases, such as malaria which infects 350----400 400 400 400 million people today; others are useful to humans. million people today; others are useful to humans. million people today; others are useful to humans. million people today; others are useful to humans.
• Most simply live their lives unknown to us but contributing enormously Most simply live their lives unknown to us but contributing enormously Most simply live their lives unknown to us but contributing enormously Most simply live their lives unknown to us but contributing enormously to our well being through the production of oxygen, the degradation of to our well being through the production of oxygen, the degradation of to our well being through the production of oxygen, the degradation of to our well being through the production of oxygen, the degradation of waste materials, recycling of nutrients, production of food, and a waste materials, recycling of nutrients, production of food, and a waste materials, recycling of nutrients, production of food, and a waste materials, recycling of nutrients, production of food, and a multitude of other functions, some of which take place in our own multitude of other functions, some of which take place in our own multitude of other functions, some of which take place in our own multitude of other functions, some of which take place in our own bodies. Fungi, another group in modern environments that both benefit bodies. Fungi, another group in modern environments that both benefit bodies. Fungi, another group in modern environments that both benefit bodies. Fungi, another group in modern environments that both benefit and plague humans, have a long, but mostly unstudied, microfossil and plague humans, have a long, but mostly unstudied, microfossil and plague humans, have a long, but mostly unstudied, microfossil and plague humans, have a long, but mostly unstudied, microfossil record.record.record.record.
• Prokaryotes and protists are very well represented in the fossil record. • Prokaryotes are the oldest known fossils, and they were the only life on Earth for
most of its history — from 3.7 to 1.5 billion years ago. • Protists joined them at least 1.5 bya, and animals and plants were latecomers at
less than .57 bya. • All these microfossils provide insights to Earth and life history, and so are important
to study in paleontology.
Table 1. Some primary differences between prokaryotes and eukaryotesTable 1. Some primary differences between prokaryotes and eukaryotesTable 1. Some primary differences between prokaryotes and eukaryotesTable 1. Some primary differences between prokaryotes and eukaryotes(from Lipps, 1992)(from Lipps, 1992)(from Lipps, 1992)(from Lipps, 1992)(from Lipps, 1992)(from Lipps, 1992)(from Lipps, 1992)(from Lipps, 1992)
PROKARYOTES EUKARYOTESNucleus absent Nucleus presentMeiosis absent Meiosis1 basic genome Chromosome number 2-600Mitochondria absent Mitochondria presentChloroplasts absent Chloroplasts may be presentEndoplasmic reticulum absent Endoplasmic reticulum presentVacuoles absent Vacuoles present
Processing of SamplesProcessing of SamplesProcessing of SamplesProcessing of Samples
• Soak soft samples in water and half a spoon of baking sodaSoak soft samples in water and half a spoon of baking sodaSoak soft samples in water and half a spoon of baking sodaSoak soft samples in water and half a spoon of baking soda• If samples are hard, add few drops of 5 ml of dil. H2O2 (15%)If samples are hard, add few drops of 5 ml of dil. H2O2 (15%)If samples are hard, add few drops of 5 ml of dil. H2O2 (15%)If samples are hard, add few drops of 5 ml of dil. H2O2 (15%)• Allow a sample soaked for 8Allow a sample soaked for 8Allow a sample soaked for 8Allow a sample soaked for 8----10 hours10 hours10 hours10 hours• Wash wet samples over an 8” dia 63 micron size sieve with a jet Wash wet samples over an 8” dia 63 micron size sieve with a jet Wash wet samples over an 8” dia 63 micron size sieve with a jet Wash wet samples over an 8” dia 63 micron size sieve with a jet
of water to allow finer particles washed awayof water to allow finer particles washed awayof water to allow finer particles washed awayof water to allow finer particles washed away• Transfer sample to the same beaker and dry it in an electric Transfer sample to the same beaker and dry it in an electric Transfer sample to the same beaker and dry it in an electric Transfer sample to the same beaker and dry it in an electric
oven at 50oven at 50oven at 50oven at 50----60 degree Celsius60 degree Celsius60 degree Celsius60 degree Celsius• Transfer dry samples to labeled glass vialsTransfer dry samples to labeled glass vialsTransfer dry samples to labeled glass vialsTransfer dry samples to labeled glass vials• Transfer dry samples to labeled glass vialsTransfer dry samples to labeled glass vialsTransfer dry samples to labeled glass vialsTransfer dry samples to labeled glass vials• Dry sieve sample over a 4 “ dia sieve of 125 micron size for Dry sieve sample over a 4 “ dia sieve of 125 micron size for Dry sieve sample over a 4 “ dia sieve of 125 micron size for Dry sieve sample over a 4 “ dia sieve of 125 micron size for
benthic foraminifera and 150 micron for planktic foraminiferabenthic foraminifera and 150 micron for planktic foraminiferabenthic foraminifera and 150 micron for planktic foraminiferabenthic foraminifera and 150 micron for planktic foraminifera• Radiolarian samples are washed over 53 micron size sieve Radiolarian samples are washed over 53 micron size sieve Radiolarian samples are washed over 53 micron size sieve Radiolarian samples are washed over 53 micron size sieve
because of small size of specimensbecause of small size of specimensbecause of small size of specimensbecause of small size of specimens• Examine the dry samples under stereozoom microscope, Examine the dry samples under stereozoom microscope, Examine the dry samples under stereozoom microscope, Examine the dry samples under stereozoom microscope,
identify the specimens and calculate their percentages for identify the specimens and calculate their percentages for identify the specimens and calculate their percentages for identify the specimens and calculate their percentages for population analysispopulation analysispopulation analysispopulation analysis
• Make plots of individual species for paleoenvironmental Make plots of individual species for paleoenvironmental Make plots of individual species for paleoenvironmental Make plots of individual species for paleoenvironmental interpretationsinterpretationsinterpretationsinterpretations
Microfossils
Marine Environments
Historical Review• Earliest mention is that of larger foraminifera Nummulites by Herodotus (5th
Century BC), Strabo (7th Century BC) and Pliny the Elder (1st Century AD)• Systemic study started with the discovery of microscope by Leeuwenhoek in
1660• Linne’s binommial system of nomenclature formed the basis of classification• d’Orbigny (1802-1875) published first comprehensive classification of
foraminifera in 1826, included foraminifera in cephalopoda. He is also known as father of micropaleontology
• French biologist Felix Dujardin (1835) described them as Rhizopoda since they possess a pseudopodia
• C.G. Ehernberg (1795-1876), a German biologist, made the first discovery and • C.G. Ehernberg (1795-1876), a German biologist, made the first discovery and description of silicoflagellates, ebridians, coccoliths, discoasters, dinoflagellates and numerous living protists. Also described radiolaria, diatoms and foraminifera. He suggested that foraminifera are Bryozoa – this view he maintained till 1858
• British school comprises of Reuss (1860s and 1870s), N.C. Williamson, W.K. Parker, T.R. Jones, W.B. Carpenter, H.B. Brady, and C.D. Sherborne
A largest impetus to descriptive micropaleontology• The voyage of H.M.S. Challenger (1873-1878) – collected dredge samples from
the world ocean• H.B. Brady published a monumental monograph in 1884• Revival of micropaleontological studies in the post-World War II period• Advent of JOIDES program in 1965 and its successor Deep Sea Drilling Project
(DSDP) in 1968 with the drilling ship D/V Glomar ChallengerCommercial
micropaleontology• The demand for oil during two world wars led to extensive use of micropaleotology.• Commercial micropaleontology is related to petroleum industry• Commercial micropaleontology is related to petroleum industry• During World War I, micropaleontology was introduced as a formal course in the
curriculum by Josia Bridge at the Missouri School of Mines and by H.N. Coryell at Columbia University and F.L. Whitney at the University of Texas
• J.J. Galloway began teaching micropaleontology at Columbia University in 1924• J.A. Cushman established Cushman Laboratory for Foraminiferal Research at
Shaorn, Massachusetts• H.G. Schenck introduced micropaleontology at Leland Stanford University in 1924• Before World War II, emphasis was on biostratigraphic correlation. After World War II,
the emphasis was on paleoecology and paleobathymetry
Main Microfossil GroupsClassified on the basis of test composition
A. Calcareous Microfossils1. Foraminifera (Cambrian to Recent)2. Calcareous Nannoplanktons (Jurassic to Recent) 3. Ostracodes (Cambrian to Recent)4. Pteropods (Late Cretaceous to Recent)5. Calpionellids (Late Jurassic to Early Cretaceous)6. Calcareous Algae (Precambrian to Recent)7. BryozoaB. Siliceous MicrofossilsB. Siliceous Microfossils8. Radiolaria (Cambrian to Recent)9. Marine Diatoms (Late Cretaceous to Recent)10. Silicoflagellates (Late Cretaceous to Recent) and Ebridians (Tertiary
to Recent)C. Phosphatic Microfossils11. Conodonts and other phosphatic microfossils (Cambrian to Triassic)D. Organic-Walled Microfossils12. Dinoflagellates (Silurian to Recent), Acritarchs (Precambrian to
Recent) and Tasmanitids (Cambrian to Tertiary)13. Spores and Pollens in the Marine realm14. Chitinozoa (Ordovician to Devonian)
Foraminifera
• Foraminifera are single-shelled belonging to Kingdom Protista, Phylum Protozoa, Class Sarcodina
• The word is from Latin foramen = hole, ferre = to bear• They possess pseudopodia• They have both benthic and planktic mode of life• Reproduction is through schizogony = asexual reproduction and gamogony=sexual
reproduction• Larger prolocus in individuals resulting from schizogony than resulting from
gamogony• Wall structure: Agglutinated, Microgranular, Calcareous hyaline, Calcareous
porcellaneousporcellaneous• Chamber shape and chamber arrangement: clavate, fistulose, globular, cuneate,
tubular, angular truncate, angular conical, lenticular biconvex, uniserial rectilinear, biserial, triserial, milioline, planispiral evolute, planispiral involute
• Pores – round, slit-like, or irregular openings• Ornamentations: ribs, ridges, furrows, spines, etc.• Ecology: study of the relationship between organisms and their environments• Physical Variables: water depth, temperature, hydrostatic pressure, light intensity• Chemical variables:
(i) salinity 35 psu to 45 psu. The genus Discorbinopsis can tolerate upto 57 psu(ii) Alkalinity(iii) Trace elements and nutrients
Distribution
Benthic foraminifera• Endobenthic – Bulimina aculeata Epibenthic – Epistominella exigua• Low oxygen, high organic carbon – Uvigerinids, Buliminids• Neritic species: Quinqulina seminulum, Ammonia beccarii
Benthic foraminifera: Marshes, Brackish environments, Carbonate platforms, reefs and back reefs, Continental shelf, open marinePlanktic foraminifera: Tropical to Polar
Microhabitat
• Bathyal species: Cibicides wuellerstorfi, Melonis barleeanum• Abyssal species: Nuttallides umbonifera, Epistominella exigua
Planktic foraminifera
• Tropical: Globorotalia menardii• Warm subtropical: Globigerinoides ruber• Cool subtropical: Globorotalia truncatulinoides• Subpolar: Globigerina bulloides• Polar: Neogloboquadrina pachyderma
Planktic Foraminifera(Jurassic to Recent)
Benthic Foraminifera(Cambrian to Recent)
Evolution of Foraminifera
• Late Precambrian witnessed a change in oxygen content leading to the evolution of organisms by adaptation
• Foraminifera evolved in Cambrian, prior to which forams existed as naked shells• Devonian is considered a period of extensive carbonate environments which were
invaded by foraminifera• Carboniferous was a period of radiation• In the late Carboniferous-Permian the first porcelaneous family ‘Agathamminidae’
appeared.• The Permian is termed the epoch of fusulinids• In the Triassic the diversification of foraminifera was slow. The Triassic is
considered an arid period marked by regressions of the sea• The Jurassic was the beginning of extensive transgressions, equable climates and
is known as the period of ‘milk and honey’• Cretaceous is considered to be the continuation of the period of “milk and honey”• The Cretaceous terminated with abrupt mass extinctions of majority planktons
and shallow dwelling benthic foraminifera• Cenozoic saw a revitalization of foraminiferal faunas• Early Tertiary had abundant calcareous foraminifera like Nummulites and
numerous smaller foraminifera
CALCAREOUS NANNOPLANKTONS
• The word is from Greek nano means dwarf• Unicellular, autotrophic marine algae/phytoplankton also
known as coccolithophores• Range from Jurassic to Recent• Cell secretes a skeleton of minute calcareous shields forming
coccosphere• Individual elliptical to circular shields or coccoliths range from ~1-15
microns• Discoasters also comprise this group• Discoasters also comprise this group
Historical review• First reference to the nannoplankton is by C.G. Ehrenberg in 1836, initially
called them as inorganic• In 1858, T.H. Huxley reported these in deep-sea oozes• G.C. Wallich and H.C. Sorby – another pioneers worked on this group• Wallich gave the name coccosphere & reported true nature of this group• In 1891, John Murray and A.F. Renard published work on sediments
collected during the voyage of HMS Challenger• Hans Lohmann worked on living nannoplanktons• M.N. Bramlette & W.R. Riedel worked on biostratigraphy of this group
Nutrition• Mostly photoautrophic• Some instances of ingestion of foreign organic material reported• Some are believed to be heterotrophic (utilizing both organic and
inorganic substances• Abundant in upwelling areas
Growth• Growth rates are relatively high, as some species multiply more than twice
in a day• Most species exist within narrow temperature range• Most species exist within narrow temperature range• Temperature range 7-27 degrees• Emiliania huxleyi has been observed at temperatures as low as 2 degrees• Made up of calcite and to a lesser degree aragonite
Function of coccoliths• Coccoliths shield the the enclosed cell from excessive sunlight• Equally popular is the opposing idea tha coccoliths concentrate light
toweards the cell interior• Also as floating devices, metabolic barriers, stabilizers, defensive shields
etc• Some think them as by-products of detoxification of carbonate
Ecology• Exclusively planktic marine• Euryhaline, occurring in lagoonal, littoral and estuarine environments• Can tolerate a salinity range of 16 to 45 psu• Photosynthetic living in upper 100-150 m or the photic zone• Rapidly decreases with depth
Biogeography• Greater concentration in zones of high organic productivity where
more nutrients are available due to upwellingmore nutrients are available due to upwelling• These zones are located north and south of 45 degrees
Paleoclimatic interpretations• Dissolution plays an important role• Reconstruction of Lysocline and water mass chemistry• Paleoproductivity
Geological distribution• First diversification occurred in Jurassic, at the end of Maastrischtian a
massive extinction of marine organisms, Taxa evolved from a small pool in the early Tertiary, the relative abundance and short stratigraphic range make them useful tool in biostratigraphy
OSTRACODES
•Range from Cambrian to Recent•Length between 0.15 and 2 mm•Bivalved (carapace), living in fresh, brackish, saline and hypersaline waters•Both benthic (abundant) and planktic (rare)•The oldest generic names given to ostracods are Cypris and Cythere by O.F. •The oldest generic names given to ostracods are Cypris and Cythere by O.F. Muller in the 1770's and 80's•H.B. Brady was the next pioneer worker. He published important monograph in 1880 describing material from H.M.S. Challenger•The first fossil ostracode was described in 1813•Interest in fossil ostracodes was stimulated in 1920s with increased demand for oil and became second to foraminifera•After World War II the study of ostracodes entered the stage of neontological and paleontological synthesis•Ostracodes are always divided into separate sexes. Not all of them, however, reproduce sexually
Ecology• Ostracodes probably originated in a marine environment• Largest number of species still inhabits the pelagic and benthic realms of the ocean from shoreline down to
several thousand meters• They are found from equator to the poles
Nutrition:• Both filter- and deposit-feeders• Numerous feed on marine plants and small living animals such as annelids or small crustaceans• Some eat detritus from decaying vegetal or animal tissues• Some are limnivorous eating bottom sediments without any selection• Some are commensals• Some are parasites living in the gills and nostrils of fishes
Distribution: physical, chemical and biological factorsDistribution: physical, chemical and biological factorsSalinity• Euryhaline (fresh to normal saline to hypersaline), StenohalineTemperature• Psychrospheric (deep-sea cold loving), Cryolophic (cold-loving shallow • species) and thermophilic (warm-loving)Substrate• Coarse grained sediments support a small population• Mud-mixed sands and pelitic sediments have a much larger populationDepth• In highl-energy shallow waters both diversity and density of ostracodes are lower than in deepser and more
stable offshore environments• Below photic zone, ostracode population becomes less diverseFood supply• High organic content of the sediment has been considered to be a factor controlling ostracode distribution
Geological Distribution
• Ordovician seas witnessed a great expansion of Ostracodes• In the Triassic ostracodes constitute one of the most important elements of the
microfauna• Many genera persist from Jurassic into early Cretaceous faunas• Cenozoic witnessed a different set of ostracode assemblage
PTEROPODS• Also known as sea butterflies, are marine gastropods
adapted to pelagic life• Range from late Cretaceous to Recent• Aragonitic shell and preserve between 700 and 3000 m water depth• Better preserved in basins having high bottom temperatures,
sluggish circulation and rapid rates of sedimentation such as the Red Sea and the Mediterranean Sea
• Known since the seventeenth century
Morphology• The animal is divisible into four regions(1) head, (2) foot, (3) visceral mass, and (4) mantle which secretes shell
ECOLOGY• Are exclusively marine and generally live in open ocean, swimming in
the uppermost 500 m• Salinity, temperature, food, oxygen and water depth control their
distributionTemperature• They are dominant in the tropics• Two polar seas are dominated by one pteropod speciesSalinity• Salinity is an important controlling factor• Salinity is an important controlling factor• Can tolerate salinity as high as 40 psuPaleoecology• The Pleistocene is marked by glacial-interglacial intervals• Population of pteropods vary on glacial-interglacial time scales• Avoid carbonate corrosive waters where surface production is high
like upwelling regions
CALCAREOUS ALGAE• Important in micropaleontology as records of ancient life• Calcium carbonate depositing benthic red and green algae• Significant producers of carbonate sediment• Algae represent a large and diversified assemblage of aquatic
photosynthetic plants, varying from a minute plankton to huge marine benthif plants
• Considered by petrographers as rock constituents and sedimentary structures
• Investigations of calcareous algae traditionally have included only the benthic forms and have excluded planktic calcareous algae –benthic forms and have excluded planktic calcareous algae –coccolithophores
General aspects• Algae are aquatic, autotrophic, nonvascular plants• The plant body of an alga is called thallus• Algae contain chlorophyll a, require oxygen for respiration and
produce oxygen during photosynthesis• Extreme variation in size, morphology, cellular organization,
biochemistry and reproduction
Classification of fossil algae
• Fossil algae can be distinguished into two major categories(1) Preserved skeletal remains representing direct or indirect evidence of algal
tissue : (a) Blue-green algae (Cyanophyta)(b) Red algae (Rhodophyta)(c) Green algae (Chlorophyta)(d) Charophyta(2) Non skeletal biosedimentary structures, generally called stromatolites
Blue-green algaeBlue-green algae• Are some of the most common marine and nonmarine algae since the
Precambrian• Build laminated sedimentary structures or stromatolites in a variety of
environments but most often in shallow marginal waters• Prefer muddy substrate• Tropical to polarRed Algae• Marine• Prefer reef and rocky substrate• Tropical to polar
Green Algae• Marine, preferring sandy and muddy substrates• Most abundant in relatively shallow, protected lagoonal environments• Tropical to subtropicalCharophytes• Fresh and brackish water• TropicsSTROMATOLOTES• Include a variety of external shapes ranging from flat-lying laminations
to domical and columnar structures, some with branching or digitate habitshabits
• Flat-lying laminae are called “algal-laminate sediments”• Most dominant in the Archaen• Decline in the Phanerozoic has been attributed to the expansion of
grazing and burrowing animals that destroyed algal laminae
SILICEOUS MICROFOSSILS
• Cambrian to Recent• First published description of Radiolaria by F.V.F. Meyen in 1834• C.G. Ehrenberg published extensively between 1838 and 1875• Johannes Mueller and Richard Hertwig studied living specimens from the
Mediterranean• Mueller coined the name ‘Radiolaria’• Hertwig (a noted biologist) was the first to firmly establish the unicellular
nature of radiolarians• The oceanographic expeditions of the late nineteenth and early twentieth
RADIOLARIA
• The oceanographic expeditions of the late nineteenth and early twentieth centuries initiated an explosion in the study of radiolarians
Reproduction• Simple cell division and sexual reproductionNutrition• Feed on various kinds of planktic organisms including microflagellates and
other protozoans, diatoms and possibly copepods• Symbiotic algae also contribute to radiolarian nutritionEcology• Exclusively marine, found in all the oceans• Planktic living at all depths• Characteristically open ocean organisms
Biogeography• Antarctic Convergences• Below CCD and upwelling zonesPaleoecology• Play an important role in the silica cycle in the oceans• Form radiolarian ooze• Help in understanding the role of igneous activity as volcanism
contribute indirectly to skeletal preservation• They accumulate in abundance in equatorial sediments where surface
productivity is high• Also rich under high-latitude productivity belts – around Antarctica • Also rich under high-latitude productivity belts – around Antarctica
and in the North Pacific• Radiolaria are generally very rare or absent in continental margin
sediments where they are diluted by large influxes of terrigenous material which also provide chemical sink for silica
Application
MARINE DIATOMS
• Range from Cretaceous to Recent• Abundant in high latitudes and in low latitude upwelling zones• Useful as biostratigraphic marker and paleoecologic proxy – indicators of
water chemistry, paleosalinity, paleodepth, paleotemperature, paleonutrient concentrations and paleocurrents
• Diatoms are photosynthetic, single-celled algae and inhabit many aquatic and subaquatic environments
• Diatoms may be free-floating (planktic) or attached to some foreign surface (sessile)
• They alongwith coccoliths make up bulk of marine phytoplankton mass• They alongwith coccoliths make up bulk of marine phytoplankton massSkeletal construction• Diatoms secret an external shell, the frustule – often compared to a pill box• Frustules are composed of opaline silica and larger of the two valves is called
the epitheca while the other is called the hypothecaValve Structure• Diatoms are of two types: Centric and pennate forms• Centric forms may be circular, triangular or oblong, but the main distinguishing
feature is that the surface markings radiate from a central area.• Pennate forms have one long axis and two short axes with the surface
markings at right angles to the long axis
Marine diatoms (contd….)Reproduction• Diatoms reproduce by simple cell division• Just before division, the epitheca and hypotheca move slightly away
from each other and separation of two valves takes place• New valves are formed on the exposed protoplasm from the central
area otwards• Thus original two valves both become epitheca in the new individuals• A steady decrease in valve diameter occurs with each succeeding
generationNutrition• Three nutrients are considered essential – phosphorus, nitrate, silica• When any of the three nutrients is missing, diatom growth and
reproduction ceases• Any are of upwelling in the ocean will bring a constant supply of these
nutrients to the surface and thus cause productivity blooms• Coastal regions receiving high concentration of nutrients from run-off
and rain will support diatom population• Some require vitamins like cobalamin (vitamin B12) and thiamin (B1).
Sulphur, iron and manganese are also considered essential
Habitats• Both fresh-water and marine waters• On land they are found in soils and occasionally on wetted rocks
and plants• In streams, lakes and ponds they are found attached to rocks and
plants as well as in bottom muds• Both planktic and benthic• Holoplanktic, Meroplantic and TychopelagicBiostratigraphic and paleoecologic importance
SILICOFLAGELLAGES
• Tiny creatures, phytoplanktons, small size population
PHOSPHATIC MICROFOSSILS
Includes the following groups:• Conoidal Shells: conical tubes 5-15 mm in length, Early Cambrian-Ordovician• Horny Brachiopods: Cambrian and early Ordovician• Horny ostracode-like arthropods: Cambrian• Remains of Vertebrates: Bone fragments, spines, scales and teeth of vertebrates,
sometimes used as index fossils around Silurian-Devonian boundary
• CONODONTS:• By far the most important and biostratigraphically important group of phosphatic
microfossils• Range in size from 200 microns to 6 mm• Cambrian to Triassic in age• First described by C.H. Pander in 1856 and coined the term ‘Conodont’• Consist of an organic matrix in which crystallites of apatite similar to the mineral francolite
are imbededMorphology:
Morphologically divided into:1. Simple cones2. Bar-type conodonts3. Blade-type conodonts4. Platform conodonts
Importance:Important as biostratigraphic markers, used in lower Himalayan biostratigraphy; can be used inthe exploration of phosphatic deposits
PHOSPHATIC MICROFOSSILS
PHOSPHATIC MICROFOSSILS
Microfossils in Petroleum Exploration
Applied Micropaleontology
Figure: Discrimination of marineenvironments by cross-plots of foraminiferal morphogroups, (fromMurray, 1973).
Figure: Variation in the ratio ofplanktonic to benthic foraminifera withdepth, (from Hayward, 1990).
The advantages of using microfossils for subsurface biostratigraphy
• Small Size• Abundance
Review of Techniques
• Correlation• Age determination• Unconformity Identification• Application to sequence stratigraphy analysis• Application to sequence stratigraphy analysis• Sequence stratigraphy models• Sequence analysis of well• Characterization of formations (“fingerprinting”)• Palaeoenvironmental interpretation
Role of Micropaleontology in hydrocarbon exploration and development programmes
Requirements for hydrocarbon accumulation: • Reservoir: biostratigraphy + sedimentology• Trap: biostratigraphy + seismic mapping• Seal: lithostratigraphy + biostratigraphy• Source: geochemistry + biostratigraphy
Appraisal of discoveries• Well correlation• Reservoir distribution and reserve estimation• Trap evaluation• Field development
Pitfalls in biostratigraphic correlation• Factors affecting data quality• Reworking and caving• Age Interpretations• Taxonomic nomenclature• Preparation techniques• Microfossil and zonal identification• Paleoenvironmental controls• Practical correlation and biostratigraphy
How can Micropaleontology help to find oil?
Marine Micropaleontology – An Introduction
• Includes taxonomically unrelated groups united solely on the basis of their study under the microscope
• As a discipline, it lacks homogeneity• Most microfossils are protists – unicellular plants and animals• Some are multicellular or microscopic parts of macroscopic forms• Their minute size, abundant occurrence and wide geographic distribution in
sediments of all ages and in almost every marine environment make them useful
• They range from the Precambrian to the Recent• Some are planktic living in top 200 m making them useful in monitoring sea
surface temperature – e.g. radiolaria, silicoflagellates, some foraminifera, diatoms, coccoliths, etc.
• Some are benthic (vagile/sessile) – some foraminifera, bryozoa, ostracoda, diatoms
• Some have both benthic and planktic phases in their reproduction –dinoflagellates
• Spores and pollens derived from land plants, are strongly climate dependent