Дисертації з теми "Biostratigrapy"
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1
Shafique, Naseer Ahmed. "Spatial Biostratigraphy of NW Pakistan." Miami University / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=miami991186162.
2
Luo, Hui, and 羅煇. "Devonian radiolarian biostratigraphy of Southwest China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B3124211X.
3
Doherty, Stephen James. "Wenlock graptolite biostratigraphy of North Wales." Thesis, University of Portsmouth, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424217.
4
Robinson, Paul David. "Tertiary radiolarian biostratigraphy of coastal Ecuador." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261097.
5
Luo, Hui. "Devonian radiolarian biostratigraphy of Southwest China." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22718862.
6
Saunders, Kate Marie. "Silurian dendroid graptolites : taxonomy, palaeoecology and biostratigraphy." Thesis, University of Portsmouth, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343388.
7
Roelofs, Brett Peter Ashworth. "Utilisation of microvertebrates in biostratigraphy and chemostratigraphy." Thesis, Curtin University, 2016. http://hdl.handle.net/20.500.11937/48487.
Анотація:
The utility of marine microvertebrate fossils for bio- and chemostratigraphy and subsequent correlation were tested on the exceptionally preserved Devonian reef complexes of the Canning Basin, Western Australia. Microvertebrates provided refined age ranges for restricted depositional environments unable to be dated using conodonts or ammonoids. In addition, the O-isotope signatures recovered from hypermineralised tissues within microvertebrate fossils enabled the reconstruction of palaeoenvironmental conditions, in addition to providing the basis for chemical stratigraphy.
8
Leith, Thomas Leslie. "The role of coals and carbonaceous shale facies in the petroleum reservoir system : a case study from the Gullfaks Field, Norwegian North Sea." Thesis, Heriot-Watt University, 2000. http://hdl.handle.net/10399/545.
9
Smith, Giles A. "Palynology of the Jurassic/Cretaceous boundary interval in the Volga Basin, Russia." Thesis, University of Bristol, 1999. http://hdl.handle.net/1983/a981fc30-fa69-4cf5-aae5-7290d2a489df.
10
Hybertsen, Frida. "Distribution of Sabellidites (Annelida?) in the Basal Cambrian of the Digermulen Peninsula, Arctic Norway." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-325148.
Анотація:
The Digermulen Peninsula, Arctic Norway, offers a unique section of late Ediacaran to Cambrian sediments in an almost complete succession within the Vestertana Group. The proposed annelidan fossil Sabellidites cambriensis is found here, within the Lower Breidvika Member and is believed to exist also in the underlying Manndrapselva Member of the Stáhpogieddi Formation. Three cycles are recognized from the Manndrapselva Member, the uppermost being the third cycle, and the sediment interval of interest for this study ranges from the third cycle of the Manndrapselva Member to the Lower Breidvika Member where the Ediacaran–Cambrian boundary is situated. The distribution of Sabellidites has been investigated in three different localities on the Digermulen Peninsula, and from two of these stratigraphical logs were made and the sections were documented with photographs. The logs were created over sediments from Locality 1: Bárdeluovttjohka and Locality 3: Manndrapselva in the interval of the top of the Manndrapselva Member and Lower Breidvika Member. Previous studies have shown that the stratigraphical distribution of Sabellidites is within the Lower Breidvika Member. New results presented in this study extended the temporal distribution downwards in the third cycle of the Manndrapselva Member and closer to the Ediacaran–Cambrian boundary. The boundary is indicated by the trace fossil Treptichnus pedum. A few samples, collected from the logged sections, were found below the T. pedum level, indicating late Ediacaran origin. Three samples were collected even further down, close to the base of the Manndrapselva log, but these could only loosely be identified as Sabellidites and further analysis is required on these specimens. The Sabellidites distribution range from the Digermulen Peninsula was briefly compared to other locations and a global correlation is possible. The results here indicate that Sabellidites is an excellent reference taxon for the terminal Ediacaran and early Cambrian and that the succession on the Digermulen Peninsula may be one of the most important for global correlation across the Ediacaran-Cambrian boundary.På Digermulenhalvön i arktiska Norge finns en nästan helt oavbruten sektion av sediment från sen ediacara och tidig kambrium. Fossilet Sabellidites cambriensis, som tros tillhöra phylat Annelida, går att hitta här inuti sediment från det undre Breidvikaledet och det underliggande Manndrapselvaledet. De här två leden ingår i Vestertanagruppen. Tre cykler är identifierade från Manndrapselvaledet och den översta är den tredje cykeln. Distributionen av Sabellidites i de här sedimenten har undersökts i tre olika lokaler på Digermulenhalvön, och två biostratigrafiska loggar ritades och dokumenterades med foton. Tidigare har studier påvisat Sabellidites i det undre Breidvikaledet, men resultaten från den här studien visar att det går att hitta Sabellidites även i den tredje cykeln av Manndrapselvaledet vilket är längre ned i sedimentföljden, och således också äldre sediment som ligger nära gränsen mellan ediacara och kambrium, som är ett mycket intressant och omdiskuterat geologiskt tidsavsnitt. Gränsen indikeras av ett spårfossil vid namn Treptichnus pedum och resultat ifrån den här studien påvisar Sabellidites nedanför nivån för T. pedum. Det här förlänger spannet inom vilket man kan hitta Sabellidites och resultaten från Digermulenhalvön har jämförts med områden runt om i världen i ett försök att korrelera dem med varandra. Studien visar att en global korrelation är möjlig vilket gör Sabellidites till ett utmärkt referensfossil för undre kambrium och sektionen på Digermulenhalvön är exceptionellt bra för att undersöka förhållandena kring gränsen mellan ediacara och kambrium.
11
Racey, Andrew. "Nummulitid biostratigraphy and palaeogene palaeoenvironments : Sultanate of Oman." Thesis, Royal Holloway, University of London, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319983.
12
Van, Mourik Caroline A. "The greenhouse - icehouse transition : a dinoflagellate perspective /." Stockholm : Department of Geology and Geochemistry, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1073.
13
Longhim, Márcia Emília [UNESP]. "Palinologia do grupo Itararé em Salto, Estado de São Paulo (Bacia do Paraná, carbonífero superior)." Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/92941.
Анотація:
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longhim_me_me_rcla.pdf: 3997492 bytes, checksum: 0d698e3c432ce390fe5d3075c45a653d (MD5)Realizou-se um estudo palinológico detalhado de ritmitos do Grupo Itararé inferior a médio (Supergrupo Tubarão) no entroncamento das rodovias SP-75 e SP-308, em Salto, SP (coord. UTM 23K 262,095kmE/ 7.432,774kmN). Os ritmitos correspondem a turbiditos com seixos caídos (dropstones), depositados em ambiente glacial, provavelmente marinho. Ocorrem parcialmente invertidos devido a deslizamentos gravitacionais subaquáticos. Incluem também megásporos, atribuíveis a licófitas, e musgos fósseis pouco transportados, derivados de possíveis tundras. São registradas 58 espécies de palinomorfos (29 de esporos, 26 de grãos de pólen, duas de algas e uma de possível acritarca). Dois gêneros e cinco espécies são inéditos na Bacia do Paraná: Jayantisporites Butterworth et al., 1964; Meristocorpus Playford & Dino, 2000; Apiculiretusispora tuberculata Azcuy, 1975; Apiculiretusispora alonso Ottone, 1989; Cyclogranisporites cf. C. microgranulatus (Menéndez & Azcuy) Archangelsly & Gamerro, 1979, Tetraporina punctata (Tiwari & Navale) Kar & Bose, 1976 e Hamiapollenites cf. H. insolitus (Bharadwaj & Salujha) Balme, 1970; a última já foi registrada no Grupo Itararé, porém sob outra denominação. A assembléia palinológica corresponde à Palinozona Crucisaccites monoletus de Souza & Marques-Toigo (2001), aproximadamente equivalente aos intervalos informais G (exceto sua porção basal) + H1 + H2 de Daemon & Quadros (1970). Comparações com assembléias gondvânicas, principalmente argentinas, confirmaram a idade neocarbonífera (Westphaliano final-Stephaniano) sugerida por Souza (2000) para a palinozona.
A detailed palynological study was done of the lower to middle Itararé Group (Tubarão Supergroup) rhythmites at the meeting of the SP-75 e SP-308 roads, in Salto, SP (UTM coord. 23K 262,O95kmE/7.432,77kmN). The rhythmites are turbidites with dropstones, from a probable marine glacial environment. They were partially inverted by subaquatie gravitational sliding. They also include little transported megaspores of lycopod affinity and fossil mosses from a possible tundra. A total of 58 palynomorph species were found (29 spore, 26 poilen, two alga! and one possible acritarcha species). Two genera and five species were identified for the first time in the Pai-anã Basin: Jayantisporites Butterworth et ai., 1964; Merístocorpus Playford & Dino, 2000; Apiculiretusispora tuberculata Azcuy, 1975; Apiculiretusispora alonso Ottone, 1989; Cyciogranisporites cf. C. microgranulatus (Menéndez & Azcuy) Archangelsly & Gamerro, 1979, Tetraporina punctata (Tiwan & Navale) Kar & Bose, 1976 and Hamiapoilenites cf. H. insolitus (Bharadwaj & Salujha) Balme, 1970. The last species was already known iii the Itararé Group, but under another designation. The palynological assembiage corresponds to the Crucísaccites monoletus Palynozone proposed by Souza & Marques-Toigo (2001), which is approximately equivalent to the informal biostratigraphic intervais G (except its basal portion) + H1 + H2 of Daemon & Quadros (1970). Comparísons with gondwanic assemblages, specially from Argentina, confirm the Late Carboniferous (late Westphalian-Stephanian) age suggested by Souza (2000) for the palynozone. Keywords: Palynology, Biostratigraphy, Upper Carboniferous, Paraná Basin, ltararé Group.
14
Young, Timothy Peter. "The stratigraphy of the upper Ordovician of central Portugal." Thesis, University of Sheffield, 1985. http://etheses.whiterose.ac.uk/6043/.
Анотація:
The project has involved the revision of the stratigraphy of the upper part of the Ordovician succession in central Portugal. Using evidence derived principally from the study of measured sections, with some limited geological mapping, this thesis first considers a new lithostratigraphy of the upper Ordovician deposits. The scheme presented includes four groups, twelve formations and eleven members. Most of the elements of the scheme are described here for the first time. The sedimentology of the deposits has been studied to allow an interpretation of the depositional environment. The history of sedimentation in the upper Ordovician is divided into three broad phases. In the first of these (phase A) storm-dominated deposition of detrital clastics took place on a wide, flat, shallow shelf. During the second phase (B) a localised area of igneous activity developed in the area of highest subsidence seen in the preceding phase. This igneous activity was accompanied by the deposition of some carbonate sediments. The third phase of deposition (C) is linked to the effects of the upper Ordovician glaciation. A review of most of the macrofauna recovered 1s given. The faunas of Portugal form a highly distinct and homogeneous "province" with those of Armorica, Spain, Sardinia. The palaeoecology of the faunas Montagne Noire and collected during this study are discussed. Thirteen broad associations (sensu Lockley 1983) are identified. Factors other than latitude-related influences play an important role in controlling the diversity, abundance and taxonomic constitution of the palaeocommunities. Twelve biozones are erected to cover the range of fossiliferous Ordovician strata examined in this project. The correlation between the biostratigraphie scheme erected herein and the international standard is discussed. An overview attempts to place the study area within the context of the peri-Gondwana shelf, and within the Variscan fold-belt.
15
MacLennan, A. M. "Biostratigraphic and palynofacies analysis of selected Lower Cretaceous sections from Portugal." Thesis, University of Aberdeen, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379234.
16
Baggley, Kieron A. "The Late Tortonian - Early Messinian Foraminifera Record of the Abad Member (Turre Formation), Sorbas Basin, Almeria, southeast Spain." Thesis, University of Greenwich, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389509.
17
Ellis, Caroline Sarah. "Molluscan biostratigraphy of Flandrian slope deposits in East Sussex." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/7855.
18
Butcher, Anthony. "Chitinozoan biostratigraphy of the Rhuddanian of Illinois and Jordan." Thesis, University of Portsmouth, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424167.
19
Schreve, Danielle Caroline. "Mammalian biostratigraphy of the later Middle Pleistocene in Britain." Thesis, University College London (University of London), 1998. http://discovery.ucl.ac.uk/1317926/.
Анотація:
This study explores and develops the potential of fossil mammals to differentiate between the various climatic episodes of the post-Anglian Middle Pleistocene in Britain. Mammalian fossils are particularly valuable as biostratigraphic indicators on account of their morphological evolution and rapid turnover, through origination and extinction of species. Furthermore, the large-scale climatic fluctuations that affected north-west Europe during the Quaternary produced major shifts in the geographical distributions of many species, resulting in discernible patterns of presence and absence in the fossil record of a particular region. The development of a globally-applicable climatostratigraphic framework, based on the oxygen isotope record from deep-ocean sediments, has provided a new and challenging scheme for the interpretation of the British Quaternary record. Long fluvial sequences in Britain have been related to this record with considerable success, thereby providing a detailed archive of climatic change through the Pleistocene. The Thames valley was selected as a framework for the relative dating of the various climatic fluctuations, since it has been claimed to have the most reliably-dated long terrestrial sequence in the later Middle Pleistocene. The Thames model was therefore adopted as a testable hypothesis against which the mammalian evidence could be compared. The findings of this study confirm the presence of four complete climatic cycles between the Anglian and the Holocene, each with its own distinctive mammalian suite. In addition, it has been possible to identify subdivisions within these temperate stages, probably representing smaller-scale climatic fluctuations within an interglacial, and perhaps corresponding to isotopic substages. It has been possible to resolve a longstanding controversy concerning the age of the British type Hoxnian Interglacial. Amino acid geochronology had suggested that sediments at Hoxne belonged to a later interglacial than deposits from the first post-Anglian temperate episode in the Thames valley, such as Swanscombe. The results of the present study reveal close similarity between the mammalian fauna from Hoxne and that from Swanscombe, suggesting that there was indeed a single Hoxnian Interglacial, and that it directly post-dated the Anglian (i.e. Stage 11). Sediments of this age can be distinguished from those attributable to two other late Middle Pleistocene interglacials, all of them distinct from and older than, the Ipswichian. It has been suggested that distinctive mammalian assemblages can be identified from interglacials equivalent to oxygen isotope stages 9 and 7; moreover, it is apparent that the assemblages from warm Substages 7c and 7a differed from one another in species composition. Certain useful characters have also been determined, which can permit useful separation of some of the late Middle Pleistocene cold episodes, although in comparison with the interglacials, the evidence from these is scanty. The present study has provided a new biostratigraphic framework that may be both tested and refined as new sites become available in Britain, and also compared with the evidence from continental north-west Europe.
20
Askew, Alexander J. "The Middle Devonian palynology and biostratigraphy of northern Spain." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22442/.
Анотація:
The Naranco, Huergas and Gustalapiedra formations of the Asturias, León and Palencia provinces of northern Spain represent a nearshore marine clastic sequence deposited during the Mid Devonian. The formations are laterally equivalent, becoming more offshore in character through León and Palencia but representing the same stratigraphic interval. They have received limited palynological study, despite previous reports of their palynological assemblage and their important stratigraphic interval at the onset of early forests. A palynomorph assemblage from these formations is described here, comprising acritarchs, prasinophytes, chitinozoans and dispersed spores, with additional comment on the formations' lithology. The sampled rock was processed using standard palynological procedures and yielded a well-preserved assemblage, though thermal maturity was variable. A quantitative count of the palynomorph assemblage was undertaken using a Lycopodium spike. The assemblage is an early Givetian one, as evidenced by the presence of Geminospora lemurata, with some evidence of diachronism in the further offshore locations. The formations' biostratigraphy, in conjunction with lithological evidence, indicates that deposition was rapid. The assemblage presents various unexpected features, with some important taxa absent and others present at an unusual time. The palynomorph assemblage is significantly endemic to Iberia, and this is interpreted as indicating significant palaeogeographic isolation of northern Spain during the Middle Devonian. Terrestrial spores were prevented from dispersing here by a large geographic separation, while marine plankton may have been stopped by ocean currents running past these isolated islands, also indicating an open Rheic Ocean able to support such currents. This deposition also took place just after the Kačák Event, a major extinction event in the marine realm. The results presented here support an existing, monsoonal hypothesis for the origin of the Kačák Event, as this would also create the rapid nearshore deposition observed here, however this raises questions over how the event would be expected to manifest around the world. As an environmental event, the anoxia usually used to mark the event may have been sporadic or localised, not necessarily occurring in all areas, especially the nearshore location studied here. These results lend support to the existing idea of the Kačák Event as a longer, possibly polyphased event extending into the earliest Givetian.
21
Perez, Ramos Olivia 1946. "Permian biostratigraphy and correlation between southeast Arizona and Sonora." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/558194.
22
Falzoni, F. "SANTONIAN-CAMPANIAN PLANKTONIC FORAMINIFERAL BIOSTRATIGRAPHY, TAXONOMY AND ISOTOPE PALEOECOLOGY." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/169982.
Анотація:
Current biozonations based on Santonian-Campanian (Late Cretaceous) planktonic foraminiferal bioevents do not provide a high stratigraphic resolution, when compared to other time intervals. Moreover, some of the marker species of the Tethyan biozonation show a diachronous lowest occurrence across latitudes and a restricted geographic distribution. Thus, paleoclimatic and paleoceanographic inferences are poorly constrained by biostratigraphy and, in addition, are often based on diagenetically altered material.
This study is aimed to 1) improve the biostratigraphic resolution of Santonian-Campanian zonal schemes based on planktonic foraminiferal bioevents; 2) reconstruct the evolutionary history of key biostratigraphic species and revise the taxonomy of problematic groups (planispiral and globigeriniform taxa) often overlooked in the literature; 3) infer the paleoecological preferences of selected planktonic foraminiferal species based on stable isotope analyses, and 4) reconstruct the paleoclimatic context of the Santonian-Campanian time interval.
The Santonian-Campanian samples analyzed in this study were selected from four different localities: 1) Tanzania - western Indian Ocean (Tanzanian Drilling Project - TDP Sites 23, 28, 32 and 35); 2) Shatsky Rise - northwestern Pacific Ocean (Ocean Drilling Program - ODP Leg 198, Hole 1210B); 3) Exmouth Plateau - eastern Indian Ocean (ODP Leg 122, Hole 762C); 4) Bottaccione section outcropping in the Umbro-Marchigian Apennines near Gubbio (Italy). Samples were prepared following the standard methodologies and considering the different lithologies. A scanning electron microscope (SEM) was used to document the species, observe and describe the wall texture of the specimens at higher magnification. Cathodoluminescence analyses on selected specimens were applied to assess the degree of wall alteration. Well-preserved specimens were finally analyzed to obtain reliable δ18O and δ13C values and provide paleotemperature estimations.
Results allow description of the mid Campanian Contusotruncana plummerae Zone, defined as the stratigraphic interval between the appearance of the nominate species and of Radotruncana calcarata and suggest that Globotruncanita atlantica is a promising marker species useful to correlate early Campanian stratigraphic sections especially at low latitudes. In addition, several bioevents (i.e., the lowest occurrence of Contusotruncana morozovae, Rugoglobigerina hexacamerata, Radotruncana subspinosa and the extinction of Hendersonites carinatus) also appear reliable for detailed correlations across latitudes.
Stable isotope results suggest that Santonian Marginotruncanids behave as spring/autumn dwellers in the surface water column. During the Campanian, C. plummerae, Contusotruncana fornicata and Globotruncana bulloides inhabited the summer mixed layer, whereas Globotruncanita stuartiformis and Globotruncanita elevata proliferate in the cool winter sea surface. Globotruncana orientalis, Globotruncana mariei, Globotruncana arca and Gublerina rajagopalani were more adapted to stable and deeper environments close to the permanent thermocline. Interestingly, data show that Heterohelix sphenoides and C. plummerae were likely adapted to particularly 13C-enriched environments. High δ13C values have been interpreted as the isotopic signal indicating a symbiotic relationship between these species and photoautotrophic algae. However, results show that this kind of relationship is not supported by clear evidences and should be investigated by further and more detailed isotopic analyses.
Paleoclimatic reconstructions inferred from Tanzanian pristinely preserved planktonic foraminifera suggest that Santonian-Campanian subtropical sea-surface temperatures reached 30°C, hence, 4° to 5°C warmer than modern mean values. Oxygen isotopic values measured on planktonic foraminifera from Shatsky Rise and Exmouth Plateau indicate up to 10°C cooler and 20°C warmer temperatures, respectively, when compared to modern mean values. These results would support the “cool tropic paradox” hypothesis, that Late Cretaceous equatorial and tropical sea surface temperatures were several degrees lower than modern mean values. This hypothesis implies a different climatic scenario with respect to the traditional interpretation of the greenhouse world that would predict an Earth global warming. However, the observed secondary recrystallization of planktonic foraminiferal shells from Shatsky Rise and Exmouth Plateau led to an overprinting of the original isotopic signal and thus to erroneous paleotemperature estimations, whose extent is, however, still unknown.
Taxonomic analyses of well preserved and diversified planktonic foraminiferal assemblages allowed description of one new species (Globotruncana neotricarinata) and identification of three new morphotypes (Globigerinelloides n. sp. 1, Muricohedbergella n. sp. 1 and Costellagerina n. sp. 1) that are surely new species. The formal description of these taxa is in progress. Stratophenetic observations and isotopic analyses on Rugoglobigerina species indicate that the development of the meridional ornamentation represents an adaptation to different ecological parameters of the water masses. This study suggests that more reliable diagnostic criteria, other than the development of the ornamentation, should be applied to discriminate among Costellagerina, Rugoglobigerina, and Archaeoglobigerina.
23
Carlsson, Veronica. "Artificial intelligence in radiolarian fossil identification : taxonomic, biostratigraphic and evolutionary implications." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILR092.
Анотація:
La micropaléontologie ne consiste pas seulement à étudier les organismes eux-mêmes, mais plutôt à comprendre les environnements passés de la Terre, avec des applications allant de la biostratigraphie à la paléoocéanographie, en passant par la capacité d'étudier les changements évolutifs au sein des morphoespèces dans le temps et dans l'espace. Ce domaine est confronté à de nombreux défis, car l'analyse des microfossiles nécessite un effort humain important et une expertise taxonomique, conduisant souvent à des incohérences dans les interprétations. Ce travail de thèse se concentre sur l'application de l'utilisation de l'intelligence artificielle (IA), telle que les réseaux de neurones artificiels (ANN), pour la reconnaissance automatique d'images de radiolaires de l'Éocène moyen de l'Atlantique tropical. De grands ensembles de données ont été construits afin de former différents réseaux de neurones et nos résultats montrent que les réseaux de neurones peuvent automatiquement classer plusieurs classes différentes de radiolaires jusqu'au niveau de l'espèce, ainsi que dans de nombreux cas, être capables d'identifier des espèces étroitement apparentées et même des morphotypes qui font partie d'une transition évolutive. Le réseau de neurones a également pu identifier correctement les radiolaires moins brisés ou flous. Il a également été appliqué avec succès à la reconnaissance automatique d'images pour un travail biostratigraphique, qui pouvait en général détecter des âges plus généraux ou des événements biologiques très précis. Ce travail inclut l'utilisation des approches classiques de réseaux de neurones pour analyser le contexte visuel, telles que les réseaux de neurones convolutifs (CNN), mais comprend également l'utilisation de réseaux de neurones à pointes (SNN), qui ne sont pas aussi couramment utilisés pour la reconnaissance automatique d'images que les CNN. Les SNN ont permis d'obtenir une précision égale ou presqu'égale à celle des CNN, avec simplement leur utilisation étant plus efficace en termes de calcul et du fait qu'il prennent moins de mémoire. Il y a également eu quelques comparaisons utilisant des analyses morphométriques traditionnelles, telle que l'analyse de discrimination linéaire (LDA), donnant à peu près le même type de résultats. Nos recherches visent non seulement à simplifier et à accélérer le processus d'analyse, mais contribuent également à accroître la précision et la cohérence des interprétations micropaléontologiques, lesquelles, à terme, contribueront à des études de haute résolution afin de comprendre l'histoire passée de la TerreMicropaleontology is not only about studying the organisms themselves, rather understanding Earth's past environments, with applications ranging from biostratigraphy to paleoceanography as well as being able to study evolutionary changes within morphospecies in time and space. This field is facing numerous challenges, since the analysis of microfossils demands significant human effort and taxonomic expertise, often leading to inconsistencies in interpretations. This work focuses on the application of using Artificial Intelligence (AI), such as Artificial Neural Networks (ANNs), for automatic image recognition of tropical Atlantic middle Eocene radiolarians. Large datasets have been constructed, in order to train different neural networks and our results show that the neural networks can automatically classify several different classes of radiolarians down to a species level, as well as in many cases being able to identify closely related species and even evolutionary transition morphotypes. It has also been able to correctly identify less broken or blurry radiolarians. It was also successfully applied to automatic image recognition for a biostratigraphic work, which in general could detect more general ages or highly precise bio events. This work includes the use of the classical neural network approaches for analysing visual context such as Convolutional Neural Networks (CNNs) but also includes the use of Spiking Neural Networks (SNNs), which is not as commonly used for automatic image recognition, as CNNs. SNNs resulted in almost or equal amount of accuracy obtained as for CNNs, just that the use is more computational efficient and takes up less memory. There have also been some comparisons using traditional morphometric analyses, such as Linear Discrimination Analysis (LDA), giving approximately the same kind of results. Our research not only aims to simplify and speed up the analysis process but also helps in increasing the accuracy and consistency of micropaleontological interpretations, which eventually, will contribute to the high-resolution studies in order to understand Earth's past history
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Carter, Elizabeth Sibbald. "Early and middle Jurassic Radiolarian biostratigraphy, Queen Charlotte Islands, B.C." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24586.
Анотація:
Radiolarian biostratigraphy is used to construct an informal zonation for sediments of upper Pliensbachian to lower Bajocian age from the Maude and Yakoun Formations, Queen Charlotte Islands, B.C. Paleoenvironmental studies assess depositional environment and the effects of changing facies relationships on the fauna.
Seven distinctive assemblages are recognized comprising 167 species of spumellarian and nassellarian Radiolaria. The first well established middle Toarcian radiolarian assemblages are documented and both these and upper Toarcian assemblages are highly diverse and contain many new and unusual forms. Five genera and 89 new species are described many of which have restricted biostratigraphic ranges. A chlorophyte algal cyst appearing in all lowest Bajocian samples may, with further study, prove to be a significant marker for the lower Bajocian in the Queen Charlotte Islands.
Although Toarcian Radiolaria have been little studied, the assemblages compare with others from North America, the Mediterranean and Japan, and are distinctly Tethyan in aspect. This is consistent with the position of Wrangellia, which paleomagnetic and ammonite biogeographic evidence indicates was in the northern hemisphere within 30° of the equator during the Early to Middle Jurassic.
Studies of the abundance of spumellarians vs. nassellarians indicate thatnassellarians predominate, are abundant and diverse in deeper-water deposits (middle Toarcian and lower Bajocian shales) whereas spume Marians, particularly those with multi-layered or spongy tests, dominate in shallow-water deposits (upper middle Toarcian to Aalenian sandstones). Shallow-water nassellarians are much less diverse but a few species (all multicyrtids with thickened tests) are very abundant. Depth appears to be the major factor controlling radiolarian distribution patterns in this relatively shallow-water setting.
Studies of eustatic sea-level changes throughout the Jurassic have indicated that major phases of sea-level rise occurred in the early to mid Toarcian and in the early Bajocian with a major phase of sea-level lowering in the late Toarcian to Aalenian; detailed study of the radiolarian faunal succession in the Queen Charlotte Islands appears to confirm this major worldwide trend.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
25
Bohach, Lisa Lynn. "Systematics and biostratigraphy of Lower Cambrian trilobites of western Laurentia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ32705.pdf.
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Batten, Randy S. R. "Biostratigraphy of the Lower Ordovician chitinozoa of western Newfoundland, Canada." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/MQ55482.pdf.
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Hanslik, Daniela. "Late Quaternary Biostratigraphy and Paleoceanography of the central Arctic Ocean." Doctoral thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-57245.
Анотація:
The central Arctic Ocean is one of the least explored deep sea regions and long biostratigraphic sediment records are sparse. The main focus of this thesis is the Arctic Ocean foraminiferal record and its application to reconstruct paleoceanographic variations and summer sea ice cover changes between late Quaternary interglacial periods. One of the studied cores was retrieved from the central Lomonosov Ridge Intra Basin. This core contains a relatively high-resolution biostratigraphic record spanning Marine Isotope Stages (MIS) 1–3, although with a hiatus encompassing the Last Glacial Maximum. Radiocarbon age calibrations in this core show a decreasing trend of high marine reservoir ages of about 1400 years during the last deglaciation to 700 years in the late Holocene. The cores from the Lomonosov Ridge off Greenland and the Morris Jesup Rise contain preserved calcareous microfossils further back in time than most previously studied central Arctic Ocean cores. The calcium content estimated by X-ray fluorescence scanning of these cores shows a distinct pattern of calcium rich intervals coinciding with peaks in foraminiferal abundance in the sediment record of MIS 1–7. The calcium peaks originate from material accumulated during interglacials, primarily through detrital carbonate and dolomite input from the decaying North American ice sheet and secondarily from biogenic material. Intervals of calcareous benthic foraminifera are found in pre MIS 7 sediments on both the southern Lomonosov Ridge and Morris Jesup Rise. Their assemblage composition and stable carbon isotope data suggest increased primary production and decreased summer sea ice cover compared to the Holocene central Arctic Ocean. This is also suggested for an interval of high abundance of the subpolar planktic foraminifera Turborotalita quinqueloba on the southern Lomonosov Ridge with a proposed MIS 11 age.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Submitted.
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GILARDONI, SILVIA ELENA. "LATE ALBIAN-CENOMANIAN PLANKTONIC FORAMINIFERAL BIOSTRATIGRAPHY, TAXONOMY AND PALEOCEANOGRAPHIC INFERENCES." Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/479427.
Анотація:
The mid-Cretaceous period (about 120 Ma to 80 Ma) was characterized by unusually warm climate, low thermal gradient between latitudes and by a series of Oceanic Anoxic Events (OAEs) promoting deposition of black shales (e.g. Bréhéret, 1988; Gale et al., 1996; Coccioni, 2001; Bornemann et al., 2005; Gambacorta et al., 2014, among others). During the late Albian-Cenomanian (~105-93 Ma), a major radiation of planktonic foraminifera did occur for the first time in their evolutionary history and was marked by the appearance of novel morphologies (biserial taxa and single-keeled trochospiral taxa with supplementary apertures) and by the development of new and more complex wall textures (macroperforate, muricate and costellate) on planispiral and trochospiral taxa that lasted until the end of the Cretaceous (González-Donoso et al., 2008; Lipson-Benitah, 2008; Georgescu and Huber, 2006, 2009; Huber and Leckie, 2011). However, the often imprecise usage of the key taxonomic criteria for species identification (morphology vs. wall texture) and/or broad species concept used for the identification of some upper Albian-Cenomanian species have lead to uncertainties in the planktonic foraminiferal biozonation.
This study is aimed 1) to review the upper Albian-Cenomanian planktonic foraminiferal species in order to clarify the key taxonomic features of some often misidentified species (e.g., Th. reicheli, R. cushmani, R. montsalvensis); 2) to refine the planktonic foraminiferal biozonation according to the revised taxonomy; 3) to describe the planktonic foraminiferal preferred trophic regime in the upper Albian-Cenomanian interval through the observation and comparison of relative abundances and diversity of species with inferred similar depth ecology; and 4) to clarify the planktonic foraminiferal response to the upper Albian Oceanic Anoxic Event 1d (OAE1d) (Erbacher and Thurow, 1997) and to the Mid Cenomanian Event (MCE) (Ernst et al., 1983).
The upper Albian-Cenomanian samples analyzed were selected from different sedimentary basins:
1) the Umbria-Marche Basin (Monte Petrano and Le Brecce sections) and 2) the Mazagan Plateau (Deep Sea Drilling Program - DSDP Leg 79, Sites 547A and 545).
All the studied sections include the Albian/Cenomanian boundary and the OAE1d (Leckie, 1984; Nederbragt et al., 2001; Gambacorta et al., 2014, 2015, 2016).
In addition, the Monte Petrano section also records the MCE (Coccioni and Galeotti, 2003; Gambacorta et al., 2014, 2015, 2016).
Samples from the Umbria-Marche Basin were processed using a technique with acetic acid, while those from the Mazagan Plateau were prepared with the standard methodology. A scanning electron microscope (SEM) was used to document the species and to observe the wall texture at higher magnification. Finally, quantitative analysis were performed for the Monte Petrano and Site 547A to document variations in abundance of species and genera respect to the total planktonic foraminifera, and, consequently, to evaluate the evolutionary trends and the changes in the assemblages composition.
Five Biozones and one Subzone (Robaszynski and Caron, 1995) were identified, specifically from base to top: Pseudothalmanninella ticinensis Zone, Thalmanninella appenninica Zone, Planomalina buxtorfi Subzone, Thalmanninella globotruncanoides Zone, Thalmanninella reicheli Zone and Rotalipora cushmani Zone.
Moreover, the LO (lowest occurrence) of Th. appenninica, the LO of P. buxtorfi, the LO of P. libyca, the LO of Th. brotzeni, the LO of Th. globotruncanoides, the LO of Th. greenhornensis, and the LO of R. cushmani are identified to be potentially useful bioevents for regional and global correlations by comparing the results from this study with data reported from the literature (Mont Risou section, Vocontian Basin: Gale et al., 1996; Kennedy et al., 2004; Petrizzo et al., 2015; and Blake Nose ODP Site 1050C, northwestern Atlantic: Petrizzo and Huber, 2006a; Petrizzo et al., 2008; Ando et al., 2010; Petrizzo et al., 2015).
Thalmanninella reicheli that in the current planktonic foraminiferal biozonation (Robaszynski and Caron, 1995) defines the base of the nominal Zone, resulted to be a problematic marker, as it is a rare taxon and/or displays a scattered stratigraphic distribution. Therefore, the lowest occurrences of Th. greenhornensis and of Whiteinella sp. are proposed to be potentially useful bioevents to approximate the base of the Th. reicheli Zone in the absence of the zonal marker.
The lowest occurrence of Th. globotruncanoides, primary criterion for the definition of the Albian/Cenomanian boundary (Kennedy et al., 2004), falls close to the interval of maximum values of the δ13C in all the studied sections and at Site 1050C (Blake Nose, northern west Atlantic Ocean). On the contrary, in the Mont Risou section, (stratotype section for the Cenomanian GSSP), Th. globotruncanoides first appears below the interval of higher δ13C values (Gale et al., 1996). Although the observed discrepancies may rely on different causes (e.g., sampling resolution, diagenesis) new integrated stratigraphy studies of the stratotype section are certainly needed to verify the reproducibility of the primary and secondary criteria for the definition of the base of the Cenomanian Stage in localities from different paleogeographic areas.
According to the composition of the planktonic foraminiferal assemblages, both sedimentary sections record a late Albian time interval characterized by a dominant oligo-mesotrophic regime with a rather stable column water stratification, sometimes disrupted by perturbations possibly related to the late Albian OAE1d. In fact, as confirmed also at Blake Nose (Wilson and Norris, 2001; Petrizzo et al., 2008), in the stratigraphic interval inferred to be coincident with the OAE1d, the extinction of the warmest planktonic foraminiferal genera (Biticinella, Paracostellagerina and Ticinella) is documented, indicating a reduced thermal gradient of the water column. The low abundance and diversity of warmer taxa (Protoheterohelix) and the increase in abundance and diversity of colder taxa (Praeglobotruncana, rotaliporids, Muricohedbergella), suggest a mesotrophic to meso-eutrophic regime with a low temperature gradient in the stratigraphic interval comprised between the OAE1d and the MCE.
The variation in the composition of the planktonic foraminiferal assemblages across the MCE at Monte Petrano reveals a remarkable decrease in relative abundance of warm taxa (Whiteinella), which might be associated to a minimum of temperature in agreement with the data reported in the Anglo-Paris Basin (Voigt et al., 2004; Wilmsen et al., 2007), where the MCE is correlated to a cold event, the so-called primus Event (LO of the belemnite Praeactinocamax primus).
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Parsons, Derek Graham. "Foraminferid palaeoecology of late Cretaceous phosphogenic cycles, South West Atlas, Morocco." Thesis, University of Hull, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327836.
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Cole, David Charles. "Sequence palynology of the lower jurassic (Sinemurian - Toarcian) strata of N W Europe." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342883.
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Longhim, Márcia Emília. "Palinologia do grupo Itararé em Salto, Estado de São Paulo (Bacia do Paraná, carbonífero superior) /." Rio Claro : [s.n.], 2003. http://hdl.handle.net/11449/92941.
Анотація:
Orientador: Rosemarie Rohn DaviesBanca: Mary Elizabeth C. Bernardes de Oliveira
Banca: Joel Carneiro de Castro
Resumo: Realizou-se um estudo palinológico detalhado de ritmitos do Grupo Itararé inferior a médio (Supergrupo Tubarão) no entroncamento das rodovias SP-75 e SP-308, em Salto, SP (coord. UTM 23K 262,095kmE/ 7.432,774kmN). Os ritmitos correspondem a turbiditos com seixos "caídos" (dropstones), depositados em ambiente glacial, provavelmente marinho. Ocorrem parcialmente invertidos devido a deslizamentos gravitacionais subaquáticos. Incluem também megásporos, atribuíveis a licófitas, e musgos fósseis pouco transportados, derivados de possíveis tundras. São registradas 58 espécies de palinomorfos (29 de esporos, 26 de grãos de pólen, duas de algas e uma de possível acritarca). Dois gêneros e cinco espécies são inéditos na Bacia do Paraná: Jayantisporites Butterworth et al., 1964; Meristocorpus Playford & Dino, 2000; Apiculiretusispora tuberculata Azcuy, 1975; Apiculiretusispora alonso Ottone, 1989; Cyclogranisporites cf. C. microgranulatus (Menéndez & Azcuy) Archangelsly & Gamerro, 1979, Tetraporina punctata (Tiwari & Navale) Kar & Bose, 1976 e Hamiapollenites cf. H. insolitus (Bharadwaj & Salujha) Balme, 1970; a última já foi registrada no Grupo Itararé, porém sob outra denominação. A assembléia palinológica corresponde à Palinozona Crucisaccites monoletus de Souza & Marques-Toigo (2001), aproximadamente equivalente aos intervalos informais G (exceto sua porção basal) + H1 + H2 de Daemon & Quadros (1970). Comparações com assembléias gondvânicas, principalmente argentinas, confirmaram a idade neocarbonífera (Westphaliano final-Stephaniano) sugerida por Souza (2000) para a palinozona.
Abstract: A detailed palynological study was done of the lower to middle Itararé Group (Tubarão Supergroup) rhythmites at the meeting of the SP-75 e SP-308 roads, in Salto, SP (UTM coord. 23K 262,O95kmE/7.432,77kmN). The rhythmites are turbidites with dropstones, from a probable marine glacial environment. They were partially inverted by subaquatie gravitational sliding. They also include little transported megaspores of lycopod affinity and fossil mosses from a possible tundra. A total of 58 palynomorph species were found (29 spore, 26 poilen, two alga! and one possible acritarcha species). Two genera and five species were identified for the first time in the Pai-anã Basin: Jayantisporites Butterworth et ai., 1964; Merístocorpus Playford & Dino, 2000; Apiculiretusispora tuberculata Azcuy, 1975; Apiculiretusispora alonso Ottone, 1989; Cyciogranisporites cf. C. microgranulatus (Menéndez & Azcuy) Archangelsly & Gamerro, 1979, Tetraporina punctata (Tiwan & Navale) Kar & Bose, 1976 and Hamiapoilenites cf. H. insolitus (Bharadwaj & Salujha) Balme, 1970. The last species was already known iii the Itararé Group, but under another designation. The palynological assembiage corresponds to the Crucísaccites monoletus Palynozone proposed by Souza & Marques-Toigo (2001), which is approximately equivalent to the informal biostratigraphic intervais G (except its basal portion) + H1 + H2 of Daemon & Quadros (1970). Comparísons with gondwanic assemblages, specially from Argentina, confirm the Late Carboniferous (late Westphalian-Stephanian) age suggested by Souza (2000) for the palynozone. Keywords: Palynology, Biostratigraphy, Upper Carboniferous, Paraná Basin, ltararé Group.
Mestre
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Tang, Qing. "Paleobiology, Biostratigraphy, and Taphonomy of Neoproterozoic Eukaryotes and Cambrian Animals with Carbonaceous Preservation." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/98556.
Анотація:
Carbonaceous fossil preservation is an important taphonomic window that provides critical perspectives on the evolutionary history of life. However, phylogenetic interpretation of carbonaceous fossils is not straightforward. This is largely because critical biological information is usually lost during fossilization and three-dimensional morphologies are flattened into two-dimensional compressions. Hence, innovative techniques and methods are required in order to better understand the evolutionary significance of these fossils. To achieve this goal, this dissertation is focused on using an array of innovative research techniques to investigate the paleobiology, biostratigraphy, and taphonomy of carbonaceous fossils in critical times of early life evolution, including Neoproterozoic and Cambrian. Chapters 2 to 5 in this dissertation present original research that helps to decipher hidden biological structures of various carbonaceous fossils using a series of research methods. An improved understanding of these carbonaceous remains will ultimately advance our knowledge regarding the early evolutionary history of life on Earth.
Chapter two describes new cellular structures of the carbonaceous compression macrofossil Chuaria using backscattered electron scanning electron microscopy. The data show that Chuaria, which is one of the most common fossils in Neoproterozoic and whose phylogenetic interpretation has been uncertain, is likely a multicellular eukaryote. Chapter three is aimed to resolve a long debate on the depositional age of the Gouhou Formation in the Huaibei region of North China and to constrain the Precambrian-Cambrian (P-C) boundary in this area. Using a low manipulation maceration technique, this study reveals a diverse assemblage of organic-walled microfossils from the lower Gouhou Formation, suggesting that the lower Gouhou Formation is Tonian in age and the P-C boundary may be located within the Gouhou Formation. Chapter four reports a group of problematic carbonaceous compression macrofossils from the Hetang Formation in South China. Taphonomic analysis using optical and electron microscopy tentatively suggests that these carbonaceous macrofossils are probably carapaces of bivalved arthropods. The last chapter describes a group of sponge fossils with carbonaceous preservation from the early Cambrian Hetang Formation in South China. Using an array of electron microscopy techniques, this study reveals that siliceous spicules of the Hetang sponges have large axial filaments and large proportions of organic material, suggesting early sponge in the Precambrian and Cambrian may have had weakly mineralized or entirely organic skeletons. Results from this study helps to reconcile the apparently conflicting molecular clocks, biomarker fossils, and spicular fossils of early sponges.PHD
33
Hagström, Jonas. "Acritarch-based Biostratigraphy of the Lower Cambrian deposits in Västergötland, Sweden." Thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 1987. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-88939.
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White, Marigold Roberts. "Foraminiferal biostratigraphy of tertiary limestones in northern Oman and western Pakistan." Thesis, Royal Holloway, University of London, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283011.
35
Ross, Andrew J. "The Purbeck and Wealden cockroaches and their potential use in biostratigraphy." Thesis, University of Brighton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341285.
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Speller, George R. "Molluscan biostratigraphy, stable isotope analyses and dating of Irish Holocene tufas." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436656.
37
Meyrick, Richard Andrew. "The biostratigraphy and dating of Holocene tufa successions in NW Europe." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624275.
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Pérez, Cano Jordi. "Barremian charophytes from the Maestrat Basin: taxonomy, palaeoecology, palaeobiogeography and biostratigraphy." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673634.
Анотація:
This thesis is focused on the taxonomical, biogeographical, palaeoecological and biostratigraphical characterization of the Barremian charophytes of the Maestrat Basin (Eastern Iberian Chain, Spain). Thirty-four charophyte taxa, including fructifications and thalli, which belong to the three families that co-existed during the Early Cretaceous, i.e., the Porocharaceae, the Characeae and the Clavatoraceae, were identified in two Barremian sections (Fredes and Herbers-Mas de Petxí). Twenty-six of them correspond to clavatoracean utricles, including Clavator grovesii var. jiuquanensis, which is herein firstly reported in the Iberian Chain. Similar clavatoracean richness is not found elsewhere, showing the importance of the Maestrat Basin as a hotspot for the clavatoracean species-richness during Barremian.
New characters found in the clavatoracean utricles and thalli improved the knowledge on this important, mainly Cretaceous, family. The Echinochara lazarii utricle was reinterpreted as bilaterally symmetrical, rather than triradiated. This type of symmetry was previously unknown within genus Echinochara and in the whole subfamily Atopocharoidae, leading to a taxonomic emendation of this genus. This species was found attached to the thallus Charaxis spicatus allowing the reconstruction of the Echinochara whole-plant. The cortication of this thallus was reviewed and a new type of cortication, called double triplostichous cortication, was described. A second important result was the characterization of a gradualistic evolutionary lineage in Clavator calcitrapus. This lineage includes two anagenetic varieties, C. calcitrapus var. jiangluoensis and C. calcitrapus var. calcitrapus, linked by all possible intermediary morphotypes. This lineage has important biogeographic implications since the oldest variety had a subcosmopolitan range, while the second was endemic to Iberia. Finally, a previously unknown centripetal calcification pattern was found in the internodal cell of genus Munieria. This type of calcification is reminiscent of the one observed in the clavatoroid gyrogonites, providing further support to the hypothesis that this thallus belonged to the Clavatoraceae.
The expanded sedimentary record of the Herbers-Mas de Petxí section and the abundance and diversity of charophyte remains found, provided a unique context, at least at European scale, to study the palaeoecology of charophyte species and the evolution of charophyte floras through the Barremian. Three sedimentary units, named from base to top Cantaperdius, Artoles and Morella formations, were analysed. Within these lithostratigraphic units, five charophyte associations were distinguished. 1) A charophyte association developed in freshwater lakes with low clastic input was found in the lower part of the Cantaperdius Formation and was mainly composed of Atopochara trivolvis var. triquetra, Clavator harrisii, Ascidiella stellata, and A. triquetra. Besides, Hemiclavator-rich populations were locally dominant. 2) An association characteristic of freshwater lakes with high clastic input mainly composed of Echinochara lazarii, Globator maillardii var. trochiliscoides, A. trivolvis var. triquetra, C. harrisii, Hemiclavator neimongolensis var. neimongolensis, and occasionally also Clavator calcitrapus. This association is mostly found in the upper part of the Cantaperdius Formation. 3) Porochara maestratica populations mainly thrived in low-clastic-influenced brackish settings; while 4) E. lazarii preferably thrived in clastic-influenced brackish settings. Both these brackish settings where abundant in the Artoles Formation. 5) The charophyte association developed in lakes formed in coastal mudflat to floodplain settings was mainly constituted by E. lazarii, A. trivolvis var. triquetra and var. trivolvis, and C. harrisii var. harrisii and var. reyi. This association is found in the Morella Formation. The environmental distribution of the associations recognized depended on the salinity, the clastic influence, and the depth.
A new Barremian–early Aptian charophyte biostratigraphy is proposed. Two biozonations, European and Eurasian, were distinguished and correlated. Furthermore, these biozones were calibrated to the Geological Time Scale by means of strontium-isotope stratigraphy, enabling their correlation with the coeval marine realm. The European biostratigraphy is formed by two partial range biozones (characterized by the First Appearance Data, FAD), of index species that were endemic from the Western Tethyan Archipelago (extant Europe and North Africa): (1) Globator maillardii var. trochiliscoides (early Barremian) and (2) Ascidiella cruciata-Pseudoglobator paucibracteatus. The base of this latter biozone was calibrated with an oyster shell sample with an 87Sr/86Sr ratio of 0.707482, translating to a late early Barremian age, giving a total timespan of late early Barremian–early Aptian for this biozone. The Eurasian biozone is composed of three partial range biozones. (1) Atopochara trivolvis var. triquetra biozone is almost equivalent to the G. maillardii var. trochiliscoides biozone. (2) Hemiclavator neimongolensis var. neimongolensis biozone, which was calibrated with an oyster shell whose 87Sr/86Sr ratio is 0.707481 (late early Barremian). (3) The next biozone is defined by the FAD of Clavator grovesii var. jiuquanensis. Its base was dated with an oyster shell gathered 24.5 m below the FAD of the index species and its 87Sr/86Sr ratio is 0.707489 (late early Barremian). The FAD of C. grovesii var. corrugatus defines the next biozone. The biozonation described herein is intended to facilitate the correlation between different basins of the western Tethys, and between non-marine basins in whole Eurasia.Aquesta tesi es focalitza en la caracterització taxonòmica, biogeogràfica, paleoecològica i biostratigràfica dels caròfits barremians de la conca del Maestrat (Cadena Ibèrica). Dels 34 taxons identificats, pertanyents a tres famílies que coexistiren durant el Cretaci Inferior (Porocharaceae, Characeae i Clavatoraceae) 26 pertanyen a utricles de clavatoràcies. Aquesta diversitat és única a escala mundial i mostra que el Maestrat fou un punt calent de biodiversitat d’aquesta família. Des del punt de vista morfològic s’ha mostrat que l’utricle d’Echinochara lazarii tenia una simetria bilateral, en comptes de presentar la simetrial triradial descrita originalment pel gènere. A més s’ha pogut reconstruir de la planta sencera d’ i Echinochara gràcies a haver descobert la connexió anatòmica entre Echinochara lazarii i el tal·lus descrit prèviament com Charaxis spicatus. Aquesta planta presentava una corticació desconeguda fins ara, que s’ha anomenat triplòstica doble. S’ha descrit també un nou llinatge evolutiu dins les clavatoràcies, format per dues varietats anagenètiques dins l’espècie de Clavator calcitrapus, que és de gran interès en paleobiogeografia i biostratigrafia. Finalment, la descripció d’una calcificació centrípeta als entrenusos del tal·lus de Munieria (un fòssil que ha estat motiu de controvèrsia respecte a la seva afinitat taxonòmica), dóna suport a la hipòtesi de que pertanyia a una clavatoràcia. L’estudi paleoecològic ha permès distingir diferents associacions de caròfits: 1) L’associació característica de llacs d’aigua dolça amb poca influència clàstica on predominava Atopochara trivolvis var. triquetra, Clavator harrisii, Ascidiella stellata i A. triquetra. 2) Una associació de llacs d’aigua dolça amb molta influència clàstica, dominada per Echinochara lazarii, Globator maillardii var. trochiliscoides, A. trivolvis var. triquetra, C. harrisii, Hemiclavator neimongolensis var. neimongolensis. 3) Porochara maestratica dominava als ambients salabrosos amb poca influència clàstica, mentre que 4) E. lazarii dominava ambients salabrosos amb més influència clàstica. 5) L’associació característica de basses i aiguamolls de fangars i planes d’inundació incloïa E. lazarii, A. trivolvis var. triquetra i C. harrisii. Es revisa la biostratigrafia dels caròfits del Barremià–Aptià inferior amb dues biozonacions, una per l’àmbit de l’Arxipèlag Cretaci de la Tetis (Europa, nord d’Àfrica i Orient mitjà) i una segona d’àmbit eurasiàtic. La primera biozonació està composta per dues biozones, les espècies índex de les quals eren endèmiques de l'arxipèlag: (1) Globator maillardii var. trochiliscoides (Barremià inferior) i (2) Ascidiella cruciata-Pseudoglobator paucibracteatus. La base d’aquesta última s’ha calibrat amb l’escala del temps geològic mitjançant uns valor d’ 87Sr/86Sr de 0,707482 (Barremià inferior terminal) obtinguts en una valva d’ostreid. Aquesta biozona inclou l’interval Barremià inferior terminal–Aptià inferior. La biozonació euroasiàtica conté tres biozones, les espècies índex de les quals estan presents a tota Euràsia. (1) La biozona Atopochara trivolvis var. triquetra té una edat de Barremià inferior. (2) La base de la biozona H. neimongolensis var. neimongolensis fou calibrada amb l’escala del temps geològic mitjançant una mostra d’ostreid que va proporcionar un valor de l’ 87Sr/86Sr de 0,7074781 (Barremià inferior superior). (3) La biozona Clavator grovesii var. jiuquanensis s’ha calibrat calibrat amb l’escala del temps geològic mitjançant una mostra d’ostreid que va proporcionar uns valors d’ 87Sr/86Sr de 0,707489 (Barremià superior inferior). Aquesta nova proposta biostratigràfica es preveu que faciliti la correlació entre les conques del Tetis i entre les conques continentals d’Euràsia.
39
Dresbach, Russell Ivan. "Early ordovician conodonts and biostratigraphy of the Arbuckle group in Oklahoma /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9901233.
40
O'Brien, Jennifer Ann. "Jurassic biostratigraphy and evolution of the Methow Trough, southwestern British Columbia." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/558073.
41
Brame, Roderic Ian. "Revision of the Upper Devonian in the Central-Southern Appalachian Basin: Biostratigraphy and Lithostratigraphy." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/25981.
Анотація:
The Upper Devonian of the central-southern Appalachians Valley and Ridge province of Virginia lacks stratigraphic resolution, revised formal nomenclature, and detailed biostratigraphic data. Eight of the most complete sections available in a three thousand square mile area were used to build a framework for revising the stratigraphy of the Upper Devonian strata in southwestern Virginia. Detailed lithologic descriptions of about four thousand feet (1.3 km) of rock were made at each outcrop. John Dennison's (1970 and 1976) nomenclature for the Upper Devonian along the Alleghany Front was successfully tested for it usefulness in Southwestern Virginia and are hereby applied to these rocks. The stratigraphic interval ranges in age from the Middle Devonian to the Lower Carboniferous. The stratigraphic units include the Middle Devonian Millboro Shale, the Upper Devonian Brallier, Scherr, Foreknobs (formally the "Chemung"), Hampshire, and the Lower Carboniferous Price Formation. The Brallier contains two members (Back Creek Siltstone and Minnehaha Springs), the Foreknobs is divided into five members (Mallow, Briery Gap, Blizzard, Pound, and Red Lick), and the lower Price is divided into three members (the Cloyd Conglomerate, Sunbury Shale, and the Ceres). 23046 fossils were collected and 160 taxa were identified. The biostratigraphic range of each taxon was compiled, analyzed, and then divided into biostratigraphic zones. 19 local biozones are described. The Frasnian/Famennian boundary is accurately placed based on occurrences of internationally known index fossils. The Frasnian/Famennian extinction event is recognized and is determined to have two pulses. The local biostratigraphic zonations doubled the resolution of previous studies. Lithostratigraphic and biostratigraphic data were combined to look at the timing and rates of events. The lithostratigrapic divisions were tested to see if their boundaries are or are not time transgressive. The Brallier/Foreknobs, Blizzard/Pound, and Pound/Redlick boundaries are crossed by biozones. Conversely the Frasnian/Famennian boundary crosses the lithologic boundary between the Pound and Red Lick Members. This documents the prograding nature of the clastic wedge. Composite biostratigraphic ranges correlate with ranges in New York and western Maryland. This detailed lithostraigraphic and biostratigraphic study documents a comprehensive and higher resolution understanding of the Upper Devonian in the Central-Southern Appalachian Basin.Ph. D.
42
Tobenski, Tony Lee. "PTEROTOCRINUS OF THE MENARD LIMESTONE AND KINKAID FORMATION (ELVIRAN STAGE) CHESTERIAN SERIES IN THE ILLINOIS BASIN." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/822.
Анотація:
Pterotocrinus is an echinoderm of the class Crinoidea that is restricted to the Chesterian Series (Chestnut and Ettensohn, 1988; Sutton, 1934). The most identifiable and best preserved remains of Pterotocrinus are the wing plates (Welsh, 1978). These wing plates are specialized tegmen plates that give Pterotocrinus its name (from pteron, Greek for "wing") (Welsh, 1978). This study questions whether or not wing plates can be used for biostratigraphy throughout the Chesterian Series, as well as what the functions of the wing plates were. New morphologies of Pterotocrinus found within the Menard Limestone during this study bring into question the biostratigraphical usefulness of many of the morphologies of Pterotocrinus wing plates. Certain species of Pterotocrinus appear to remain valuable index fossils within the Menard Limestone and the Kinkaid Formation. Four new morphologies were collected within the Menard Limestone during this study. These new finds draw questions about our knowledge of this genus. This study also attempted to explain the function of the wing plate, and how it may have changed over time. Pterotocrinus wing plates evolved rapidly during the Chesterian Series developing vastly different morphologies from the time the Menard Limestone was deposited to the time when the Kinkaid Formation was deposited. This study suggests a functional shift over time, with the wing plates of the Menard Limestone acting as rudders to orient the calyx to either assist in feeding or reduce stress on the calyx, and the wing plates of the Kinkaid Formation acting as an antipredatory defense mechanism. This study presents new conclusions and new questions regarding the wing plates of Pterotocrinus.
43
Dojen, Claudia. "Early Devonian ostracods from Celtiberia (NE Spain) taxonomy, palaeoecology, biostratigraphy, and biogeography /." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=97774082X.
44
Cuevas, Elba Dayton. "The radiolarian biostratigraphy of the oceanic formation, Conset Bay, Barbados, West Indies." FIU Digital Commons, 1994. http://digitalcommons.fiu.edu/etd/2681.
Анотація:
A hemipelagic/pelagic sequence from Conset Bay, Barbados, West Indies, was prepared and reviewed to establish the radiolarian biostratigraphy and zonation of the area. This study shows that the sequence extends from the Middle Eocene, Dictyoprora mongolfieri zone, to the Late Eocene, Thyrsocyrtis bromia zone. Two zones, the Podocyrtis ampla zone and the Podocyrtis mitra zone have not been identified although the sequence appears to be stratigraphically continuous. Their absence is related to a sampling gap where an interval of the outcrop is covered with slope wash. The Conset Bay sediments are characterized by extensive reworking of older taxa from several stratigraphic level throughout the time span covered in the present study.
45
Rutledge, David Charles. "Calcareous nannofossils of the Boreal Lower Cretaceous : applications in biostratigraphy and palaeoceanography." Thesis, University College London (University of London), 1994. http://discovery.ucl.ac.uk/1360347/.
Анотація:
The marine Lower Cretaceous sediments of northern, Boreal latitudes yield diverse and well-preserved calcareous nannofossil assemblages. The calcareous nannofloras of nine core and outcrop sections (of Ryazanian-Albian age) in England, Germany, the North Sea, and Barents Sea, are examined in detail (utilising 773 samples). Dense sampling of key outcrop sections (in particular, Speeton) enables calibration of the observed nannofossil events against ammonite zones. The Barents Sea sections, which are shown to be highly condensed, yield the northernmost Lower Cretaceous nannofossils to be described. The previously chaotic taxonomy of Lower Cretaceous nannofossils is revised, and a major rationalisation of genera proposed - this involves several generic emendations, and twenty five new combinations. Two new genera, Apertasphaera and Neoparhabdolithus, and nine new species are described - Apertasphaera jakubowskii, Calculites bumettiae, Clepsilithus maculosus, Cyclagelosphaera papilla, Nannoconus inomatus, Nannoconus pseudoseptentrionalis, Rucinolithus windleyae, Tegumentum bergeni and Tubodiscus parvus. In addition, one new subspecies - Rhagodiscus angustus parvus - is described, and a number of species are split into informal varieties, to avoid biostratigraphical ambiguity. Following these revisions, the suprageneric classification is reappraised, and a new family - Family Tubodiscaceae - is proposed. An updated nannofossil zonation scheme for the Ryazanian to Aptian of the Boreal area is presented; this comprises twenty two zones (labelled BC1 to BC22, in ascending order), and a number of additional subzones. Biostratigraphical resolution in the HauterivianBarremian is comparable with current ammonite zonations, and enables detailed sequence stratigraphical interpretation. Following the publication of new data from Tethyan sections (Bergen, 1994), the potential for direct inter-regional correlation is investigated; the nannofossil datums utilised generally support traditional, ammonite-based correlations but suggest that, in Boreal areas, the Hauterivian-Barremian boundary should be placed at the top of the variabilis ammonite Zone, slightly higher than its current position. Finally, the palaeoceanographical applications of Lower Cretaceous nannofossils are considered, in the light of new data on modem nannoplankton. Surface water temperature is believed to have been the principal factor controlling species distribution, throughout the history of nannoplankton; the importance of surface water fertility has probably been exaggerated in previous palaeoceanographical studies, which have been hampered by broad taxonomic concepts. There remains much to be done, in deducing the environmental preferences of Cretaceous nannofossils, but the potential for their application to palaeoenvironmental studies is good.
46
Khan, Suleman. "Biostratigraphy and microfacies of the cretaceous sediments in the Indus Basin, Pakistan." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8240.
Анотація:
In this thesis I document the biostratigraphy of two Cretaceous sections in Pakistan, the Chichali Nala Section and the Moghal Kot Section. Furthermore, I document the stratigraphy of the so-called Oceanic Anoxic Events (OAEs) in the Moghal Kot Section. In addition, I establish potential links between the planktonic foraminiferal evolution and these OAEs in the Moghal Kot Section. Sea Surface Temperatures (SSTs) are established for the Valanginian time by using the TEX86 and δ18O proxies in the Chichali Nala Section. The new biostratigraphy of the Chichali Nala Section shows that the ages of the sediments are mainly Valanginian. The biostratigraphy of the Moghal Kot Section show ranges in age from the Early Aptian to Early Maastrichtian. Seven OAEs were recorded in the Moghal Kot Section based on the combined study of biostratigraphy, microfacies, and δ13C analysis. These OAEs correlate well with previously documented OAEs elsewhere, therefore the new record of the OAEs in the Moghal Kot Section confirms the widespread occurrence of these events, possibly all global in nature. A quantitative review of the planktonic foraminiferal evolution in the Moghal Kot Section indicates that the environmental changes along the OAE2 have strongly forced the evolution of the planktonic foraminifera. Conversely, no clear relationship is observed between other OAEs and planktonic foraminiferal evolution in the same section. The SST results based on the TEX86 in the Chichali Nala Section show that the surface ocean was consistently much warmer (10-12 oC) than today at the paleolatitude of ~-35o during the Valanginian time. Such warm conditions are also supported by the spore and pollen assemblages of the Chichali Nala Section. Collectively the two datasets indicate strongly that the Valanginian world was overall extremely warm. Such warming during the Valanginian is incompatible with previously suggested cooler conditions during this time period.
47
Golding, Martyn Lee. "Biostratigraphy and sedimentology of Triassic hydrocarbon-bearing rocks in northeastern British Columbia." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46325.
Анотація:
The Triassic Montney and Doig formations in the subsurface of northeastern British Columbia are important hydrocarbon reserves for the province. However the age and tectonic setting of these formations, and their outcrop equivalents (Grayling, Toad and Liard formations), are poorly constrained. The collection of conodont and detrital zircon samples from outcrop sections, and from core taken from subsurface hydrocarbon wells, has allowed the biostratigraphy of these formations to be improved, and the tectonic setting to be inferred. The study of new conodont samples, together with re-examination of existing collections, has led to the recognition of more than thirty new species and morphotypes within the Anisian (Middle Triassic) of British Columbia. These new taxa have in turn allowed the recognition of 11 new faunal assemblages that further refine the conodont biostratigraphic scale for the Anisian of British Columbia. Conodont biostratigraphy of the Montney and Doig formations in the subsurface has allowed correlation of these formations with those of surface sections, and also for the first time provided an age for the boundary between them. The boundary is recognised to be diachronous, and it is oldest in the centre of the study area. The basal Doig Formation is condensed, and shows most condensation at the edges of the study area. Both observations imply the presence of palaeo-highs to the west as well as to the east during the Triassic. This conclusion is supported by detrital zircon geochronology, which demonstrates the presence of sediment derived from the Arctic and from the pericratonic Yukon-Tanana terrane in the Triassic rocks of northeastern British Columbia. Previous hypotheses of Permo-Triassic accretion of this terrane onto the North American margin (the Klondike Orogeny) are supported by this study, and the Triassic sediments of northeastern British Columbia are interpreted to have been deposited in the foreland basin of this orogeny.???
48
Willing, M. J. "The biostratigraphy of Flandrian tufa deposits in the Cotswold and Mendip districts." Thesis, University of Sussex, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371206.
49
Burnett, Jacqueline Anne. "North-west European late cretaceous calcareous nannofossils : biostratigraphy and selected evolutionary lineages." Thesis, University College London (University of London), 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295154.
50
Poole, C. R. "The late Neogene planktonic foraminifera genus Globigerinoidesella : taxonomy, biostratigraphy, evolution and palaeoecology." Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1557291/.
Анотація:
Planktonic foraminifera have one of the most complete fossil records of any group, and have proved invaluable in the fields of biostratigraphy, palaeoceanography and evolutionary studies. Gradual morphological change characterises their evolution, meaning that species delimitation for biostratigraphic purposes is typically artificial and arbitrary. Delimited taxa in the fossil record are ‘morphospecies’ rather than biological species. The late Neogene morphospecies Globigerinoidesella fistulosa is of considerable biostratigraphic utility because of its short stratigraphic range (mid-Pliocene to early Pleistocene) and unique morphology. It evolved distinctive protuberances on the final chamber(s), but morphospecies delimitation is problematic because of intergradation with its ancestor Trilobatus sacculifer. The fossil record of Globigerinoidesella fistulosa was investigated from multiple ocean basins, with research focused on four main areas: (1) Systematic taxonomy of G. fistulosa and the Trilobatus sacculifer plexus; (2) Biostratigraphy and biochronology of the extinction of G. fistulosa; (3) The role of heterochrony (i.e. changes in the timing and/or rate of development) in the morphological evolution of G. fistulosa; (4) Determination of the palaeoecology of G. fistulosa in relation to its ancestor T. sacculifer, to understand the mode of speciation and the potential palaeoceanographic applications of G. fistulosa. The taxonomic concepts of Globigerinoidesella fistulosa and the Trilobatus sacculifer plexus were revised, resolving numerous taxonomic issues in the group. Protuberance development was found to not only occur in Pliocene-Pleistocene T. sacculifer, but was also observed in Trilobatus immaturus, Trilobatus quadrilobatus and modern T. sacculifer specimens. New ages for the extinction of G. fistulosa and comparison with updated literature ages revealed that the currently used age of 1.88 Ma is only suitable locally and not applicable at other sites worldwide, where the extinction occurred between 1.716 and 1.74 Ma (~150,000 years later). The morphological evolution of G. fistulosa is demonstrated to be an example of the heterochronic process hypermorphosis. Stable isotope analyses (δ13C and δ18O) and palaeobiogeographic data reveal that G. fistulosa was a photosymbiotic, shallow-dwelling morphospecies with a distribution that tracked warm water oceanographic features. Geochemical depth profiles through test walls of G. fistulosa and T. sacculifer generated through laser ablation inductively coupled plasma mass spectrometry show heterogeneous Mg/Ca distribution, including cyclic high and low Mg/Ca banding and low Mg/Ca outer crusts.