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Ichnology,classification & significance of trace fossil
Ichnology, classification & significance of trace fossil
Most trace fossils are largely facies dependant.
No secondary displacement or transport.
Trace fossils are common in rocks that otherwise are unfossiliferous. (siliciclastics, shorelines)
Non-preservation of the causative organism.
Multiple architects may produce a single structure.
The same individual can produce different structures corresponding to different behavior.
The same individual may produce different structures corresponding with identical behavior but in different substrates.
Identical structures may be produced by the activity of systematically different organisms where behavior is similar.
Abundance - one animal, especially if mobile, can make many traces during its lifetime, whereas it may or may not have its body preserved in the fossil record.
Sedimentary structures smallas
Sedimentary structures provide important information about depositional environments and allow the orientation of sedimentary beds to be determined. Key structures discussed include beds and bedding planes, laminations, graded bedding indicating changes in grain size over time, cross-bedding showing current direction, sole structures like flute casts formed by erosion on sediment surfaces, and trace fossils providing evidence of organism behavior and helping determine the correct vertical orientation of strata. Together, an understanding of these sedimentary structures is essential for interpreting the depositional history preserved in sedimentary rocks.
Classification of micro fossil theory
Microscopic animal
Microscopic Algae
Bacteria
Microfossil of uncertain effinities
Microfossil elements of smaller animal
Microfossil fragments of larger organism
chapt. 9 nannofossil coccolithophores (1).pptx
This document provides information about nannofossils, specifically coccolithophores. It defines nannofossils as the smallest members of plankton, usually 5-60 micrometers in size. Coccolithophores are one-celled plant-like organisms that surround themselves with calcite plates called coccoliths. They are classified taxonomically and ecologically dominate warm surface waters, where their calcareous remains can form deposits like chalk. The geological record of calcareous nannofossils dates back to the late Triassic. Their small size, widespread distribution, and good preservation make them useful for biostratigraphy.
Igneous rock textures
All Igneous rock textures with examples in easy and simple way to understand and increase microscopic studies skills and the way to easily identify igneous rocks under polarized microscope.
Paleoceanography
Paleoceanography is the study of ancient ocean systems based on sedimentary material including microfossils. Key points:
- Sediment cores provide paleo-information but are expensive to collect through programs like DSDP, ODP, and IODP.
- Study focuses on microfossils like foraminifera and isotopes of oxygen and carbon to understand past ocean conditions like climate.
- Isotopic composition from carbonates allows estimation of past temperatures using equations like Epstein's, revealing long-term global cooling over the Cenozoic.
Basalt
This document discusses basalts, which are volcanic rocks formed from the solidification of magma. It describes two main types of basalts based on their tectonic environment: mid-ocean ridge basalts (MORB) and ocean-island basalts (OIB). MORB comes from the depleted upper mantle, while E-MORB comes from the deeper, more fertile mantle. The document also discusses how basalts are categorized based on their chemical composition and the partial melting of mantle rock that leads to the formation of basaltic magma. Finally, it outlines some industrial uses of basalt, including in fibers that are superior to other fibers for properties like thermal stability and durability.
SIGNIFICANCE OF CONODONTS IN MICROFOSSIL HISTORY
Conodonts are an extinct group of microscopic fossils that are significant in microfossil history. They are composed of calcium phosphate and resemble eel-like creatures. Conodonts first appeared in the Late Cambrian period and became extinct in the Late Triassic. They are useful for correlating strata and determining environmental factors like climate and water depth due to their abundance and wide geographic range during the Paleozoic era. Their tooth-like elements are prepared and studied using acid treatment and microscopy. Conodonts have been important for biostratigraphy and tracing evolutionary relationships.
Recommended
Ichnology,classification & significance of trace fossil
Ichnology, classification & significance of trace fossil
Most trace fossils are largely facies dependant.
No secondary displacement or transport.
Trace fossils are common in rocks that otherwise are unfossiliferous. (siliciclastics, shorelines)
Non-preservation of the causative organism.
Multiple architects may produce a single structure.
The same individual can produce different structures corresponding to different behavior.
The same individual may produce different structures corresponding with identical behavior but in different substrates.
Identical structures may be produced by the activity of systematically different organisms where behavior is similar.
Abundance - one animal, especially if mobile, can make many traces during its lifetime, whereas it may or may not have its body preserved in the fossil record.
Sedimentary structures smallas
Sedimentary structures provide important information about depositional environments and allow the orientation of sedimentary beds to be determined. Key structures discussed include beds and bedding planes, laminations, graded bedding indicating changes in grain size over time, cross-bedding showing current direction, sole structures like flute casts formed by erosion on sediment surfaces, and trace fossils providing evidence of organism behavior and helping determine the correct vertical orientation of strata. Together, an understanding of these sedimentary structures is essential for interpreting the depositional history preserved in sedimentary rocks.
Classification of micro fossil theory
Microscopic animal
Microscopic Algae
Bacteria
Microfossil of uncertain effinities
Microfossil elements of smaller animal
Microfossil fragments of larger organism
chapt. 9 nannofossil coccolithophores (1).pptx
This document provides information about nannofossils, specifically coccolithophores. It defines nannofossils as the smallest members of plankton, usually 5-60 micrometers in size. Coccolithophores are one-celled plant-like organisms that surround themselves with calcite plates called coccoliths. They are classified taxonomically and ecologically dominate warm surface waters, where their calcareous remains can form deposits like chalk. The geological record of calcareous nannofossils dates back to the late Triassic. Their small size, widespread distribution, and good preservation make them useful for biostratigraphy.
Igneous rock textures
All Igneous rock textures with examples in easy and simple way to understand and increase microscopic studies skills and the way to easily identify igneous rocks under polarized microscope.
Paleoceanography
Paleoceanography is the study of ancient ocean systems based on sedimentary material including microfossils. Key points:
- Sediment cores provide paleo-information but are expensive to collect through programs like DSDP, ODP, and IODP.
- Study focuses on microfossils like foraminifera and isotopes of oxygen and carbon to understand past ocean conditions like climate.
- Isotopic composition from carbonates allows estimation of past temperatures using equations like Epstein's, revealing long-term global cooling over the Cenozoic.
Basalt
This document discusses basalts, which are volcanic rocks formed from the solidification of magma. It describes two main types of basalts based on their tectonic environment: mid-ocean ridge basalts (MORB) and ocean-island basalts (OIB). MORB comes from the depleted upper mantle, while E-MORB comes from the deeper, more fertile mantle. The document also discusses how basalts are categorized based on their chemical composition and the partial melting of mantle rock that leads to the formation of basaltic magma. Finally, it outlines some industrial uses of basalt, including in fibers that are superior to other fibers for properties like thermal stability and durability.
SIGNIFICANCE OF CONODONTS IN MICROFOSSIL HISTORY
Conodonts are an extinct group of microscopic fossils that are significant in microfossil history. They are composed of calcium phosphate and resemble eel-like creatures. Conodonts first appeared in the Late Cambrian period and became extinct in the Late Triassic. They are useful for correlating strata and determining environmental factors like climate and water depth due to their abundance and wide geographic range during the Paleozoic era. Their tooth-like elements are prepared and studied using acid treatment and microscopy. Conodonts have been important for biostratigraphy and tracing evolutionary relationships.
Introduction of foraminifera in oil exploration
This document discusses the application of foraminifera in oil exploration. It begins with an introduction to foraminifera and their importance in oil exploration due to their sensitivity to environmental changes. It then covers the conditions required for oil formation, concepts in using foraminifera for oil exploration like biostratigraphy and paleoenvironment interpretation, and micropaleontological techniques. Foraminifera are useful for biostratigraphic correlation, interpreting depositional environments, and reconstructing the geologic history of sedimentary basins to aid in oil exploration.
Principle of correlation and fossils
The document discusses principles of correlation using fossils. It describes how fossils are formed from the remains of ancient organisms and preserved in sedimentary rocks. Index fossils, which have short time ranges and wide distributions, are particularly useful for correlating rock formations between different areas. The document outlines different types of fossils including molds, casts, carbonization and imprints. Fossils are important for determining the relative ages of strata and providing information about past environments and climate.
Foraminifera and its Applications
Foraminifera are single-celled organisms that produce shells or tests made of calcium carbonate, agglutinated particles, or organic materials. They are abundant microfossils commonly used for biostratigraphy, paleoecology, and paleobiogeography reconstructions. Foraminifera have a wide environmental range and different species are found in different environments and time periods, making them useful for correlating and dating rock units. Their tests also provide information about past ocean conditions like temperature, salinity, and circulation patterns. Foraminifera analysis is applied to oil exploration by helping determine the age and environment of rock samples from drill cores.
Coral Reefs: Biodiversity and Beauty at Risk
Coral reefs are the largest structures built by living organisms and are home to 25% of ocean species, yet they are at severe risk. Coral reefs provide many benefits like fisheries, shoreline protection, tourism, and medicines, valued at $233 billion to $1.3 trillion annually. However, threats from overfishing, pollution, disease, bleaching due to warming oceans, and ocean acidification have already damaged many reefs and are projected to severely damage most reefs by 2050 if issues are not addressed.
Lecture notes 2
This document provides an overview of sedimentary rock formation processes including weathering, erosion, transportation, deposition, and diagenesis. It discusses various types of weathering mechanisms and factors that influence weathering. Various sedimentary environments are also described such as fluvial, lacustrine, paludal, glacial, and desert. Specific sedimentary structures and deposits associated with different environments are outlined.
Microfossils and their Applications in petroleum Industry
It's a class presentation at Dept. Of Earth Sciences IIT bombay. I have included main type of the Microfossils and their index feature and applications.
Ore texture and paragenesis krishanu
1. The document discusses ore textures and paragenetic sequences, beginning with definitions and requirements for studying ore textures.
2. It describes various ore textures including single grain textures, magmatic ore textures, open space filling textures, and replacement textures.
3. The document concludes with a discussion on developing paragenetic sequences by analyzing features like cross-cutting relationships and exsolution textures.
Minerals Used In Refractory Industries by Jatin Pant.pptx
1. Refractory minerals are minerals that can withstand high temperatures, sudden temperature changes, abrasion, and shock. They are used to line furnaces, incinerators, spark plugs, kilns, and other industrial equipment operating under extreme conditions.
2. Refractory minerals are divided into acid, neutral, and basic categories based on their reaction with slags. Common acid refractories include silica, fire clay, and ball clay. Common neutral refractories include chromite, graphite, and asbestos. Common basic refractories include magnesite and dolomite.
3. Major deposits of refractory minerals are found in India in states like Jharkhand, Karnataka
Micro fossils
Micro fossils and micro palaeontology with the special focus on the foraminifers systematic description and morphology of test.
Calcareous microfossils by Rathinavel
This document provides an overview of calcareous microfossils, specifically focusing on foraminifera. It defines foraminifera as single-celled organisms with shells composed of calcite or aragonite. Their shells are made of one or multiple chambers. Foraminifera morphology and mineralogy form the basis for identification and classification. They first appeared in the Cambrian period and have been important for paleoclimate reconstruction, paleoceanography studies, archaeology, biostratigraphy, and oil exploration.
Evaporites
Evaporites are mineral sediments that form through the evaporation of aqueous solutions, leaving behind dissolved ions like calcium, sodium, and chlorine. They tend to form in arid climates where evaporation greatly exceeds rainfall. For large evaporite deposits to form, a bay needs fresh water input limited, a restricted connection to the open sea, and a parched, dry climate where seawater evaporates constantly but is replenished at a steady rate, remaining supersaturated. Major evaporite minerals include halite, gypsum, and dolomite. The Dead Sea is a hypersaline lake bordered by Israel, Palestine, and Jordan that forms large evaporite deposits due to its extremely dry climate and high salinity
Presentation On Ophiolites
Ophiolites are fragments of oceanic crust and upper mantle that have been uplifted and emplaced on continental margins. They consist of five main layers: sediment, pillow basalt, sheeted dikes, gabbro, and peridotite. Ophiolites provide evidence for seafloor spreading and plate tectonics. While similar in composition, ophiolites differ from oceanic crust in thickness, age, density, and composition due to uplift and emplacement processes. Ophiolites in Pakistan are found in collision zones from the Indian plate colliding with the Eurasian and Afghan plates.
Radiolarian micropalaeontology: morphology and taxonomy
This document provides an introduction to radiolarian micropalaeontology, including:
1) An overview of radiolarians, focusing on polycystine radiolarians and their morphology.
2) Descriptions of the general morphology of spumellarian and nassellarian radiolarians.
3) An introduction to some common radiolarian taxonomic forms found in Quaternary studies.
Morphology of ostracods
Ostracods are bivalved crustaceans that are commonly used in micropaleontology and paleoecology research. They have a complex morphology and are found in both marine and freshwater environments around the world. Key aspects of ostracod anatomy include their carapace, hinge patterns, and ornamentation, which are important for classifying and interpreting species. Ostracods first appeared in the late Cambrian and have adapted to occupy nearly all aquatic habitats, with over 2000 known living species today. Their fossil record allows them to be used for biostratigraphy and paleoenvironmental reconstruction.
Karst Topography.pptx
Karst topography develops under ideal conditions where limestone deposits are thick, well-jointed and fractured, located above the water table, and exposed to rain in a warm climate. Groundwater dissolves the limestone over time, creating sinkholes, caves, swallow holes, and dolines. Caves form below the water table as mineral-rich groundwater dissolves the rock, eventually creating large underground voids. Within caves, stalactites hang down and stalagmites build up from mineral deposition, sometimes joining to form pillars.
Fisheries and the Environmental Challenges of the Gorai-Madhumati River System
Fisheries and the Environmental Challenges of the Gorai-Madhumati River SystemInternational Water Management Institute (IWMI)
By M. Niamul Naser, University of Dhaka
Revitalizing the Ganges Coastal Zone Conference
21-23 October 2014, Dhaka, Bangladesh
http://waterandfood.org/ganges-conference/Gondwana stratigraphy
The document summarizes the Gondwana system of sedimentary rocks found in India. It describes the lithology, topography, sedimentation processes, flora and fauna of the different formations within the Gondwana group. These include the Talchir formation containing glacial deposits, the marine-influenced Bap and Badhaura formations, and the coal-bearing Damuda group. The climate changed from cold glacial conditions to warmer and wetter periods favorable for coal formation over the depositional period.
Basalts
Basalt is a common volcanic rock formed from rapidly cooled lava. It most often occurs in lava flows due to its low volatile content. Basalt is composed mainly of plagioclase feldspar and pyroxene. There are three main types - tholeiitic, alkaline, and transitional - which differ in their mineral composition and origin. The massive Deccan Traps basalt deposits in India were formed from volcanic eruptions associated with the Réunion hotspot around 65 million years ago.
Application of fluid inclusion
1. Fluid inclusion studies were conducted on samples from 10 wells in the Irish Porcupine Basin to determine the chronology of aqueous and oil-bearing fluids during basin evolution.
2. Three types of fluid inclusions were identified: low-salinity aqueous inclusions; monophase aqueous inclusions; and two-phase oil-bearing inclusions.
3. Oil-bearing inclusions observed in Jurassic sandstone cements and grains indicate trapping of heavier, less mature oil early during cementation and later ingress of lighter, more mature oil.
Nanno planktons
Nannoplanktons are very small unicellular planktonic algae that live in the ocean. They produce calcium carbonate plates called coccoliths. Nannoplanktons have a life cycle that alternates between motile and non-motile phases, and they reproduce through both sexual fusion and cell division. They are classified into major morphological groups based on the structure of their coccoliths. Nannoplanktons play an important role in the marine ecosystem and fossilized coccoliths are useful for paleoecological analysis.
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Introduction of foraminifera in oil exploration
This document discusses the application of foraminifera in oil exploration. It begins with an introduction to foraminifera and their importance in oil exploration due to their sensitivity to environmental changes. It then covers the conditions required for oil formation, concepts in using foraminifera for oil exploration like biostratigraphy and paleoenvironment interpretation, and micropaleontological techniques. Foraminifera are useful for biostratigraphic correlation, interpreting depositional environments, and reconstructing the geologic history of sedimentary basins to aid in oil exploration.
Principle of correlation and fossils
The document discusses principles of correlation using fossils. It describes how fossils are formed from the remains of ancient organisms and preserved in sedimentary rocks. Index fossils, which have short time ranges and wide distributions, are particularly useful for correlating rock formations between different areas. The document outlines different types of fossils including molds, casts, carbonization and imprints. Fossils are important for determining the relative ages of strata and providing information about past environments and climate.
Foraminifera and its Applications
Foraminifera are single-celled organisms that produce shells or tests made of calcium carbonate, agglutinated particles, or organic materials. They are abundant microfossils commonly used for biostratigraphy, paleoecology, and paleobiogeography reconstructions. Foraminifera have a wide environmental range and different species are found in different environments and time periods, making them useful for correlating and dating rock units. Their tests also provide information about past ocean conditions like temperature, salinity, and circulation patterns. Foraminifera analysis is applied to oil exploration by helping determine the age and environment of rock samples from drill cores.
Coral Reefs: Biodiversity and Beauty at Risk
Coral reefs are the largest structures built by living organisms and are home to 25% of ocean species, yet they are at severe risk. Coral reefs provide many benefits like fisheries, shoreline protection, tourism, and medicines, valued at $233 billion to $1.3 trillion annually. However, threats from overfishing, pollution, disease, bleaching due to warming oceans, and ocean acidification have already damaged many reefs and are projected to severely damage most reefs by 2050 if issues are not addressed.
Lecture notes 2
This document provides an overview of sedimentary rock formation processes including weathering, erosion, transportation, deposition, and diagenesis. It discusses various types of weathering mechanisms and factors that influence weathering. Various sedimentary environments are also described such as fluvial, lacustrine, paludal, glacial, and desert. Specific sedimentary structures and deposits associated with different environments are outlined.
Microfossils and their Applications in petroleum Industry
It's a class presentation at Dept. Of Earth Sciences IIT bombay. I have included main type of the Microfossils and their index feature and applications.
Ore texture and paragenesis krishanu
1. The document discusses ore textures and paragenetic sequences, beginning with definitions and requirements for studying ore textures.
2. It describes various ore textures including single grain textures, magmatic ore textures, open space filling textures, and replacement textures.
3. The document concludes with a discussion on developing paragenetic sequences by analyzing features like cross-cutting relationships and exsolution textures.
Minerals Used In Refractory Industries by Jatin Pant.pptx
1. Refractory minerals are minerals that can withstand high temperatures, sudden temperature changes, abrasion, and shock. They are used to line furnaces, incinerators, spark plugs, kilns, and other industrial equipment operating under extreme conditions.
2. Refractory minerals are divided into acid, neutral, and basic categories based on their reaction with slags. Common acid refractories include silica, fire clay, and ball clay. Common neutral refractories include chromite, graphite, and asbestos. Common basic refractories include magnesite and dolomite.
3. Major deposits of refractory minerals are found in India in states like Jharkhand, Karnataka
Micro fossils
Micro fossils and micro palaeontology with the special focus on the foraminifers systematic description and morphology of test.
Calcareous microfossils by Rathinavel
This document provides an overview of calcareous microfossils, specifically focusing on foraminifera. It defines foraminifera as single-celled organisms with shells composed of calcite or aragonite. Their shells are made of one or multiple chambers. Foraminifera morphology and mineralogy form the basis for identification and classification. They first appeared in the Cambrian period and have been important for paleoclimate reconstruction, paleoceanography studies, archaeology, biostratigraphy, and oil exploration.
Evaporites
Evaporites are mineral sediments that form through the evaporation of aqueous solutions, leaving behind dissolved ions like calcium, sodium, and chlorine. They tend to form in arid climates where evaporation greatly exceeds rainfall. For large evaporite deposits to form, a bay needs fresh water input limited, a restricted connection to the open sea, and a parched, dry climate where seawater evaporates constantly but is replenished at a steady rate, remaining supersaturated. Major evaporite minerals include halite, gypsum, and dolomite. The Dead Sea is a hypersaline lake bordered by Israel, Palestine, and Jordan that forms large evaporite deposits due to its extremely dry climate and high salinity
Presentation On Ophiolites
Ophiolites are fragments of oceanic crust and upper mantle that have been uplifted and emplaced on continental margins. They consist of five main layers: sediment, pillow basalt, sheeted dikes, gabbro, and peridotite. Ophiolites provide evidence for seafloor spreading and plate tectonics. While similar in composition, ophiolites differ from oceanic crust in thickness, age, density, and composition due to uplift and emplacement processes. Ophiolites in Pakistan are found in collision zones from the Indian plate colliding with the Eurasian and Afghan plates.
Radiolarian micropalaeontology: morphology and taxonomy
This document provides an introduction to radiolarian micropalaeontology, including:
1) An overview of radiolarians, focusing on polycystine radiolarians and their morphology.
2) Descriptions of the general morphology of spumellarian and nassellarian radiolarians.
3) An introduction to some common radiolarian taxonomic forms found in Quaternary studies.
Morphology of ostracods
Ostracods are bivalved crustaceans that are commonly used in micropaleontology and paleoecology research. They have a complex morphology and are found in both marine and freshwater environments around the world. Key aspects of ostracod anatomy include their carapace, hinge patterns, and ornamentation, which are important for classifying and interpreting species. Ostracods first appeared in the late Cambrian and have adapted to occupy nearly all aquatic habitats, with over 2000 known living species today. Their fossil record allows them to be used for biostratigraphy and paleoenvironmental reconstruction.
Karst Topography.pptx
Karst topography develops under ideal conditions where limestone deposits are thick, well-jointed and fractured, located above the water table, and exposed to rain in a warm climate. Groundwater dissolves the limestone over time, creating sinkholes, caves, swallow holes, and dolines. Caves form below the water table as mineral-rich groundwater dissolves the rock, eventually creating large underground voids. Within caves, stalactites hang down and stalagmites build up from mineral deposition, sometimes joining to form pillars.
Fisheries and the Environmental Challenges of the Gorai-Madhumati River System
Fisheries and the Environmental Challenges of the Gorai-Madhumati River SystemInternational Water Management Institute (IWMI)
By M. Niamul Naser, University of Dhaka
Revitalizing the Ganges Coastal Zone Conference
21-23 October 2014, Dhaka, Bangladesh
http://waterandfood.org/ganges-conference/Gondwana stratigraphy
The document summarizes the Gondwana system of sedimentary rocks found in India. It describes the lithology, topography, sedimentation processes, flora and fauna of the different formations within the Gondwana group. These include the Talchir formation containing glacial deposits, the marine-influenced Bap and Badhaura formations, and the coal-bearing Damuda group. The climate changed from cold glacial conditions to warmer and wetter periods favorable for coal formation over the depositional period.
Basalts
Basalt is a common volcanic rock formed from rapidly cooled lava. It most often occurs in lava flows due to its low volatile content. Basalt is composed mainly of plagioclase feldspar and pyroxene. There are three main types - tholeiitic, alkaline, and transitional - which differ in their mineral composition and origin. The massive Deccan Traps basalt deposits in India were formed from volcanic eruptions associated with the Réunion hotspot around 65 million years ago.
Application of fluid inclusion
1. Fluid inclusion studies were conducted on samples from 10 wells in the Irish Porcupine Basin to determine the chronology of aqueous and oil-bearing fluids during basin evolution.
2. Three types of fluid inclusions were identified: low-salinity aqueous inclusions; monophase aqueous inclusions; and two-phase oil-bearing inclusions.
3. Oil-bearing inclusions observed in Jurassic sandstone cements and grains indicate trapping of heavier, less mature oil early during cementation and later ingress of lighter, more mature oil.
Nanno planktons
Nannoplanktons are very small unicellular planktonic algae that live in the ocean. They produce calcium carbonate plates called coccoliths. Nannoplanktons have a life cycle that alternates between motile and non-motile phases, and they reproduce through both sexual fusion and cell division. They are classified into major morphological groups based on the structure of their coccoliths. Nannoplanktons play an important role in the marine ecosystem and fossilized coccoliths are useful for paleoecological analysis.
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Microfossils and their Applications in petroleum Industry
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Alveolina
- 1. Alveolina
- 2. • ALVEOLINE (PALEOCENE SUP –EOCENE) Foraminifero a guscio calcareo imperforato dalle grandi dimensioni 1cm-10cm il guscio puo variare da planospirale globoso a fusispirale del tutto involuto e si è formato dall ‘avvolgimento planispirale involuto attorno ad un asse piu o meno allungato di una lamina spirale calcarea. Si unflette all’interno ad intervalli regolari per formare i SETTI PRIMARI, questi dividono lo spazio formando tutte camere allungate parallele all’asse di avvolgimento le camere sono a loro volta suddivise in camerette SETTI SECONDARI perpendicolari ai setti primari, in alcune forme nei setti primari si forma un canale pre-settale e uno post-settale che mettono in comunicazione le varie camerette di una camera principale.le camere son disposte nel piano quindi le alveoline sono PLANOSPIRALI. Hanno la forma di un pallone da rugby.
- 4. Essendo calcareo imperforato il guscio a LUCE TRASMESSA ci appare NERO, mentre a LUCE RIFLESSA ci appare bianco porcellanaceo. Al centro dell’organismo vediamo la camera principale il proloculus. I setti primari si estendono da un polo all’altro dell’organismo. Negli organismi che si sono formati nel cretacico avro solo canale presettale invece in quelli che vanno dal post cretacico all’attuale avro canale pre e post settale. Gli spazi vuoti li vedrò sempre bianchi mentre le strutture sempre nere.
- 5. La struttura dell’alveoline viene studiata con quattrosezioni diverse: SEZIONE EQUATORIALE Attraverso il proloculus perpendicolare all’asse di avvolgimento equidistante rispetto ai poli questa sezione ha un cntrono quasi circolare NON VEDIAMO I SETTI SECONDARI in quanto andiamo a tagliare il guscio sul setto vedremo infatti una camera grigiastra. In questa sezione distinguiamo i giri delle spire
- 6. SEZIONE ASSIALE il controno di questa sezione è solitamente ellittico qui distinguiamo srtti primari secondari anche se questi ultimi sono difficili da individuarein quanto sono neri come il guscio Attraverso il proloculus comprende l’asse di avvolgimento e i poli, quindi parallela all’asse di avvolgimento.
- 7. SEZIONE TANGENZIALE Quasi parallela all’asse di avvolgimento sfiora l’organismo senza passare per il proloculus. Questo tipo di sezione ci fa guardare dentro la camera in quanto taglia solo una piccola fetta dell’esemplare, però è la migliore sezion che CI FA VEDERE SETTI SECONDARI e i canali pre e post settali che vediamo come strice bianche poste immediatamente prima e dopo i setti.questa sezione interseca una o piu spire dell’animale, i setti primari stanno sopra e sotto, mentre i secondari si trovano dentro le camere e sono verticali
- 8. SEZIONE OBLIQUA il taglio puo avere diverse angolazioni. Il contorno è quasi ellittico, ovviamente dipende dall’angolazione e dall’inclinazione del piano. I setti secondari li vediamo tagliati come se guardassimo dall’alto. La sezione obliqua è intermedia la distinguiamo in OBLIQUA CENTRATA passante per il proloculus e contorno piu assiale e OBLIQUA NON CENTRATA non passante per il proloculus e con contorno piu allittico. Vediamo quindi le strutture a metà e alcune camere si presentano allungate. DISTRIBUZIONE GEOGRAFICA le alveoline attuali come quelle fossili prediligono acque di bassa piattaforma e quelle di scogliera sono in genere epifite. Gli alveolinidi attuali presentano nelle loro camerette ricche associazioni in alghe simbiotiche. Le alveoline sono state per lungo tempo abitanti della teide soprattutto dal cretacico all’eocene