O objetivo deste trabalho foi descrever as principais características da matéria orgânica contida em rochas sedimentares do Jurássico da Unidade Tectono-Estratigráfico Placetas, compreendendo as Formações Constancia e Cifuentes da Bacia Marginal do Norte de Cuba. A combinação do estudo óptico e químico provê uma importante compreensão sobre o tipo de matéria orgânica (material amorfo derivado de algas marinhas versus material de plantas superiores), uma detalhada informação sobre as variações de diferentes fácies sedimentares e o potencial de geração de petróleo em ambas as formações. As análises da matéria orgânica indicaram uma composição diversa para o intervalo estudado. Predominando matéria orgânica amorfa com outros componentes, tais como liptinita foram identificados na Formação Cifuentes. Na Formação Constancia foi identificado material lenhoso (vitrinita e inertinita). A matéria orgânica lenhosa da Formação Constancia está composto por fitoclastos estruturados, a matéria orgânica amorfa é rara. Para a Formação Constancia os dados de pirólise Rock-Eval indicam um baixo teor de índice de hidrogênio, variando desde 36 a 128 mg hidrocarbonetos/g TOC. Os dados plotados no gráfico de índice de hidrogênio versus oxigênio correspondem a matéria orgânica Tipo III. Os valores de temperatura máxima (oC) geralmente corresponderam com outros parâmetros, e indicam algumas variações, causadas pelos precursores da matéria orgânica. O índice de hidrogênio versus índice de oxigênio e parâmetros óticos indicou na parte superior da Formação Constancia uma mistura de querogênio Tipo II e III. Os parâmetros obtidos desde a reflectância de vitrinita, índice de esporos e propriedades da fluorescência sugeriram um estagio imaturo. Os dados de índice de hidrogênio para a Formação Cifuentes mostraram valores médios a altos, variando desde 411 a 929 mg hidrocarbonetos/g TOC. O Índice de hidrogênio versus índice de oxigênio e parâmetros óticos indicou nesta formação uma mistura de querogênio Tipo I e II. Os extratos na Cromatografia líquida mostraram uma predominância dos compostos NSO sobre os hidrocarbonetos saturados e aromáticos para a Formação Cifuentes. Os parâmetros obtidos desde as análises de CG-EM sugerem um estágio imaturo para a Formação. Os biomarcadores refletiram a composição do material gerador e a possibilidade de geração de hidrocarbonetos desde matéria orgânica Tipo I e II em estágios imaturos. A caracterização geoquímica dos extratos orgânicos das rochas geradoras da Bacia Marginal de Cuba permitiu identificar dois grupos de Petróleo, geradas em fácies diferentes do intervalo Kimmeridgiano- Titoniano. Fácies geradoras de afinidade marinha produziram petróleo em cozinhas de geração localizadas na Província gaso-petrolíferas Norte durante o Eoceno. Embora o processo de geração seja responsável por diferenças na composição e nas características na composição do petróleo expulso pelas rochas, observou-se que as maiores modificações nas propiedades dos fluidos foram causadas por processos pósgenéticos. / The purpose of this thesis was to describe the principal characteristic of organic matter contained in sedimentary rocks of the Jurassic Placetas Tectono-Stratigrafic Unit (TSU), comprising of Constancia Formation and Cifuentes Formation (northern Marginal Basin of Cuba). The combined optical/chemical studies have provided important insight on the types of organic matter (amorphous material derived from marine algae versus vascular plant material), detailed information on its variations in different sedimentary facies, petroleum generation potential in both formations. In order to evaluate organic matter content and the type 115 samples were crushed and homogenized to be submitted to total organic carbon determination (TOC %), Rock-Eval pyrolysis, liquid and gas-chromatography, mass spectrometry and determination of optical parameters (vitrinite reflectance, spore color index and fluorescence properties), and semi-quantitative maceral identification. The organic matter analyses indicated a diverse composition for the studied intervals. Predominant amorphous organic matter with other liptinitic component was identified in the Cifuentes Formation and woody material (vitrinitie and inertinitie for the Constancia Formation). The woody organic matter of Constancia Formation is composed primarily of structured phytoclasts, amorphous organic matter is rare. For Constancia Formation Rock-Eval/TOC data indicate that an overall low Hydrogen index, ranging from 36 to 128 mg hydrocarbons/g TOC. Hence they plot in the Type III kerogen area of the oxygen index versus hydrogen index graph. The Tmax (oC) values of the organic matter generally correlate with other maturity parameters, and indicate some variations that appeared to be caused by differences in the precursor organic matter. Hydrogen and Oxygen indices and optical parameters indicate in the upper part of Constancia Formation a mixture of kerogen Type II and III. Parameter obtained from vitrinite reflectance, spore index and fluorescence properties suggest an immature stage. TOC and Rock-Eval data for the Cifuentes Formation show that all have medium to relatively high Hydrogen indices, ranging from 411 to 929 mg hydrocarbons/g TOC. Hydrogen versus Oxygen indices and optical parameters indicate in this formation a mixture of kerogen Type I and II. In the liquid chromatography extracts NSO hydrocarbons are more abundant then saturated and aromatic hydrocarbons for Cifuentes Formation. Parameters obtained from GC-MS analysis suggest an immature stage for Cifuentes Formation strata. Biomarker parameters reflect the composition of the original source material and the possibility of hydrocarbon generation from the organic matter Type I and II in the immature stage. The geochemestry caracterists of petroleum into Bacia Marginal of Cuban was generated by two different fácies os Kimmeridgian-Tithonian source rocks. Oils Kitchens of marine source rocks were developed in the Província gaso-petrolíferas Norte during Eocene. The type of organic matter and the level of thermal evolution of the source rocks produced the compositional differences in the expelled petroleum. However postgenetic processes are the main controls on the current fluid properties in the study área.

O objetivo deste trabalho foi descrever as principais características da matéria orgânica contida em rochas sedimentares do Jurássico da Unidade Tectono-Estratigráfico Placetas, compreendendo as Formações Constancia e Cifuentes da Bacia Marginal do Norte de Cuba. A combinação do estudo óptico e químico provê uma importante compreensão sobre o tipo de matéria orgânica (material amorfo derivado de algas marinhas versus material de plantas superiores), uma detalhada informação sobre as variações de diferentes fácies sedimentares e o potencial de geração de petróleo em ambas as formações. As análises da matéria orgânica indicaram uma composição diversa para o intervalo estudado. Predominando matéria orgânica amorfa com outros componentes, tais como liptinita foram identificados na Formação Cifuentes. Na Formação Constancia foi identificado material lenhoso (vitrinita e inertinita). A matéria orgânica lenhosa da Formação Constancia está composto por fitoclastos estruturados, a matéria orgânica amorfa é rara. Para a Formação Constancia os dados de pirólise Rock-Eval indicam um baixo teor de índice de hidrogênio, variando desde 36 a 128 mg hidrocarbonetos/g TOC. Os dados plotados no gráfico de índice de hidrogênio versus oxigênio correspondem a matéria orgânica Tipo III. Os valores de temperatura máxima (oC) geralmente corresponderam com outros parâmetros, e indicam algumas variações, causadas pelos precursores da matéria orgânica. O índice de hidrogênio versus índice de oxigênio e parâmetros óticos indicou na parte superior da Formação Constancia uma mistura de querogênio Tipo II e III. Os parâmetros obtidos desde a reflectância de vitrinita, índice de esporos e propriedades da fluorescência sugeriram um estagio imaturo. Os dados de índice de hidrogênio para a Formação Cifuentes mostraram valores médios a altos, variando desde 411 a 929 mg hidrocarbonetos/g TOC. O Índice de hidrogênio versus índice de oxigênio e parâmetros óticos indicou nesta formação uma mistura de querogênio Tipo I e II. Os extratos na Cromatografia líquida mostraram uma predominância dos compostos NSO sobre os hidrocarbonetos saturados e aromáticos para a Formação Cifuentes. Os parâmetros obtidos desde as análises de CG-EM sugerem um estágio imaturo para a Formação. Os biomarcadores refletiram a composição do material gerador e a possibilidade de geração de hidrocarbonetos desde matéria orgânica Tipo I e II em estágios imaturos. A caracterização geoquímica dos extratos orgânicos das rochas geradoras da Bacia Marginal de Cuba permitiu identificar dois grupos de Petróleo, geradas em fácies diferentes do intervalo Kimmeridgiano- Titoniano. Fácies geradoras de afinidade marinha produziram petróleo em cozinhas de geração localizadas na Província gaso-petrolíferas Norte durante o Eoceno. Embora o processo de geração seja responsável por diferenças na composição e nas características na composição do petróleo expulso pelas rochas, observou-se que as maiores modificações nas propiedades dos fluidos foram causadas por processos pósgenéticos. / The purpose of this thesis was to describe the principal characteristic of organic matter contained in sedimentary rocks of the Jurassic Placetas Tectono-Stratigrafic Unit (TSU), comprising of Constancia Formation and Cifuentes Formation (northern Marginal Basin of Cuba). The combined optical/chemical studies have provided important insight on the types of organic matter (amorphous material derived from marine algae versus vascular plant material), detailed information on its variations in different sedimentary facies, petroleum generation potential in both formations. In order to evaluate organic matter content and the type 115 samples were crushed and homogenized to be submitted to total organic carbon determination (TOC %), Rock-Eval pyrolysis, liquid and gas-chromatography, mass spectrometry and determination of optical parameters (vitrinite reflectance, spore color index and fluorescence properties), and semi-quantitative maceral identification. The organic matter analyses indicated a diverse composition for the studied intervals. Predominant amorphous organic matter with other liptinitic component was identified in the Cifuentes Formation and woody material (vitrinitie and inertinitie for the Constancia Formation). The woody organic matter of Constancia Formation is composed primarily of structured phytoclasts, amorphous organic matter is rare. For Constancia Formation Rock-Eval/TOC data indicate that an overall low Hydrogen index, ranging from 36 to 128 mg hydrocarbons/g TOC. Hence they plot in the Type III kerogen area of the oxygen index versus hydrogen index graph. The Tmax (oC) values of the organic matter generally correlate with other maturity parameters, and indicate some variations that appeared to be caused by differences in the precursor organic matter. Hydrogen and Oxygen indices and optical parameters indicate in the upper part of Constancia Formation a mixture of kerogen Type II and III. Parameter obtained from vitrinite reflectance, spore index and fluorescence properties suggest an immature stage. TOC and Rock-Eval data for the Cifuentes Formation show that all have medium to relatively high Hydrogen indices, ranging from 411 to 929 mg hydrocarbons/g TOC. Hydrogen versus Oxygen indices and optical parameters indicate in this formation a mixture of kerogen Type I and II. In the liquid chromatography extracts NSO hydrocarbons are more abundant then saturated and aromatic hydrocarbons for Cifuentes Formation. Parameters obtained from GC-MS analysis suggest an immature stage for Cifuentes Formation strata. Biomarker parameters reflect the composition of the original source material and the possibility of hydrocarbon generation from the organic matter Type I and II in the immature stage. The geochemestry caracterists of petroleum into Bacia Marginal of Cuban was generated by two different fácies os Kimmeridgian-Tithonian source rocks. Oils Kitchens of marine source rocks were developed in the Província gaso-petrolíferas Norte during Eocene. The type of organic matter and the level of thermal evolution of the source rocks produced the compositional differences in the expelled petroleum. However postgenetic processes are the main controls on the current fluid properties in the study área.

No description available.

The idea of studying the colour of organisms in the fossil record has for a long timeseemed nothing more than the far flung dreams of a few idealistic palaeontologists.The last 5 years however have brought sweeping advances in this area, such that theidea is no longer hypothetical but an actual possibilty. Recent studies on the preserva-tion of fossilised pigment containing organelles, melanosomes, have hailed a new eraof palaeontological study and reconstruction. In this work geochemical techniques areapplied to study such structures in fossil feathers and an amphibian, to determine thenecessary level of confidence that these structures are not bacterial, discuss the relativeadvantages and disadvantages of the techniques used in the study of fossil melanin, andextend the study of fossil colour to other pigments in fossil algae. Fourier transforminfrared spectroscopy (FTIR) data is shown to provide some of the most consistentevidence of the presence of melanin, however it does not enable us to adequately dis-tinguish between the two major types, eu- and pheomelanin. Determining the presenceof bacteria in fossil stromatolites is shown to be most effective by using tetra-methylammonium hydroxide assisted pyrolysis gas chromatography mass spectrometry (Py-GCMS) to look for the distribution pattern of fatty acid methyl esters. Such analysisshows that samples identified as bacterial have identical patterns that differ signifi-cantly from those of fossil plants and animals. Such a biomarker is shown to be morereliable than hopanes, further commonly used bacterial biomarkers. The combination of FTIR and Py-GCMS suggest the presence of the red algal pigment phycoerythrin inthe Jurassic fossil Solenopora jurassica, strengthening its identification as a calcareousalga.

The evolution of the sulphur content of humic substances extracted from a near-shore sediment core was investigated. Special attention was taken to avoid S contamination of the humic materials during sample handling and extraction. The S/C ratios increased continuously with depth to values which strongly suggest S addition to the humic matrix during early diagenesis by reactions between organic matter and H₂S or its oxidation products. The light isotopic composition of this organic sulphur supports this view; however, subsequent isotopic exchange has obscured the mechanism initially involved. Since a large fraction of the enrichment occurred above the sulphidic zone, redox boundaries, such as the interface of anoxic microniches within the more oxidized zones, or the sulphidic/suboxic boundary of the sediment column, must have been important sites for S addition. The influence of sulphur enrichment on the complexing capacity of humic materials was also investigated, and it was shown that S-addition increases significantly the number of sites on which Cu is irreversibly bound. Iodine is characteristically enriched at the surface of hemipelagic and nearshore sediments deposited under oxygenated conditions. In such sediments, bulk I/Corg ratios usually decrease with depth to values which are characteristic of anoxic sediments, reflecting a preferential release of iodine during early diagenesis. There is some debate as to whether sedimentary iodine is associated with the iron oxyhydroxide phase or with the organic fraction, and whether the decrease in I/Corg with depth is due to the dissolution of the iron oxyhydroxides or the decomposition of labile organic matter. In this study, it is shown that in a surficial hemipelagic sediment sample and in a nearshore sediment core iodine is mainly associated with the organic fraction and, moreover, that humic substances are involved in the surficial iodine enrichment. Laboratory experiments on the uptake and release of iodine by and from sedimentary humic substances also suggest a mechanism whereby humic materials reduce iodate at the sediment/water interface to an electrophilic iodine species which further reacts with the organic matter to produce iodinated organic molecules. During burial, this excess iodine could be displaced from the organic matrix by nucleophiles such as sulphide ions or thiosulphate, thus providing a possible explanation for the decrease in I/corg ratio with depth observed in many nearshore and hemipelagic sediments. Bulk metal concentrations were measured in the sediments of Saanich Inlet in an attempt to establish the occurrence of trace metal enrichments in the anoxic central basin. Ba, Ni, V, Cr, Zn, Pb, Cu, and Mo were found to be enriched in the anoxic ooze over the possible contributions from lithogenous sources. Spatial and seasonal variations in the chemical composition of the settling particulates collected with interceptor traps gave further indications of the mode of incorporation of these metals. Biogenic Ba and Cr appeared to be associated with opaline silica, although alternative explanations are also possible, particularly for Ba. Zinc seemed to be added to the sediment essentially in association with planktonic materials, while Cu required an additional source directly linked to the anoxic environment. Similarly, Ni, V, and Mo were added to the anoxic sediments by reactions occurring at the sediment-water interface. In the nearshore environment studied here, these metals were not associated to any significant extent with planktonic materials, particularly Ni and Mo. Of all the elements analyzed, Mo showed the largest enrichment in the anoxic sediments of Saanich Inlet. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The present study of the Abu Roash and Bahariya formations in well GPTSW-7 refines our understanding of the subsurface Cretaceous of the north Western Desert of Egypt. Our investigations are based on the palynological analyses of 71 cuttings samples, of which 24 have also been analyzed for geochemistry, in addition to 3 sidewall cores analyzed for vitrinite reflectance (Ro). Four palynological zones and three subzones in addition to a poorly fossiliferous interval ranging in age from Coniacian-Santonian to early Cenomanian are proposed. These include a poorly fossiliferous interval (Coniacian-Santonian), Dinogymnium vozzhennikovae Interval Zone (late to middle Turonian), Ephedripites ambiguus-Ephedripites multicostatus-Foveotricolpites giganteus-Foveotricolpites gigantoreticultus Assemblage Zone (early Turonian), Classopollis brasiliensis Interval Zone (late to middle Cenomanian), and Afropollis jardinus Interval Zone (early Cenomanian). The succeeding subzones are; Afropollis kahramanensis Interval Subzone, Elaterosporites klaszii Interval Subzone and Cretacaeiporites densimurus Interval Subzone, all of early Cenomanian age. Total organic carbon (TOC) and Rock-Eval pyrolysis and palynofacies analyses indicate that the Bahariya Formation and the Abu Roash G Member are primarily of kerogen III type and hence gas prone, suggesting a strong influence of hydrogen-enriched organic matter. The Abu Roash A, C-E Members may also be gas prone (type III kerogen) and appear to contain highly oxidized terrestrial organic matter. In contrast, the Abu Roash F Member has very high TOC and HI values and contains a very high proportion of amorphous organic matter (AOM) indicating a highly oil-prone facies. While this finding is not unexpected for anoxic black shale, it contrasts with earlier studies that suggest a gas prone nature. Ro measurements show that the Bahariya Formation represents an immature-early genesis dry gas phase. This is also true for all investigated samples from the Abu Roash and Bahariya formations, based on their low thermal alteration index (TAI). Quantitative and qualitative analyses of both the palynoflora and palynofacies show that the Abu Roash A and C Members (B is missing), both of Coniacian-Santonian age, represent oxic proximal and distal shelf environment. The Abu Roash D and E Members, dated as Turonian, represent oxic (proximal) shelf, whereas the Cenomanian Abu Roash F Member was deposited in a distal suboxic-anoxic basin. The Cenomanian Abu Roash G Member and the Bahariya Formation were deposited in a shallow marine and shallow marine to fluvio-deltaic setting, respectively. The Senonian Palmae Province is recognized in the palynoflora by the presence of Proteacidites, Auriculiidites reticulatus, Ariadnaesporites, Gabonisporis vigourouxii. On the other hand the Albian-Cenomanian Elaterates Province is characterized by the presence of Steevesipollenites, Gnetaceaepollenites, Elaterocolpites, Elaterosporites, Elateroplicites, Senegalosporites, Sofrepites, Afropollis and Cretacaeiporites.

Recent successful drilling operations at Lake El'gygytgyn, NE Russia have recovered sediment cores back to 3.6Ma, representing the longest time-continuous sediment record of past climate change in the terrestrial Arctic. Analysis of the hydrogen isotopic ratio (δD) of specific organic biomarkers allows reconstruction of past hydrological conditions, thereby providing a powerful tool for reconstructing past Arctic climate changes. Compound specific isotopic analysis of sedimentary lipids from this remote basin provides new insights into the climate evolution of the Arctic, capturing the mechanisms and dynamics of the last two glacial-interglacial transitions, potentially enhancing the accuracy of modeled future climate change projections and presenting an opportunity to estimate past polar amplification of climate change. The results of this research document the first continuous, high fidelity continental record of reconstructed δD in precipitation from terrestrial plant leaf waxes in the High Arctic spanning the last 120 ka. The hydrogen isotopic composition of lipid biomarkers were determined from previously obtained Lake El'gygytgyn sediment cores and compared with other multi-proxy evidence of past climate change within the lake basin. The modern isotope hydrology and controls on the δD lipid signal were first established within the El'gygytgyn Basin from modern precipitation, stream and lake waters, ice cover as well as modern vegetation, water column and lake bottom surface sediments in order to provide a modern context to properly constrain and interpret paleoclimatic proxy data. Reconstructed δD records of paleoprecipitation and temperature at Lake El'gygytgyn lead other northern hemisphere climate records (e.g. North Greenland Ice Core Project, NGRIP δ18O records) and are in phase with other continental and Antarctic climate records, suggesting early high northern latitude continental warming prior to established glacial-interglacial transitions. The data set generated here leads to multiple avenues of future work and provides critical insights into Arctic paleoclimate and paleohydrology, contributing to our understanding of high latitude environmental change over geological timescales. Collectively, the results of this dissertation research will provide a context for paleoclimate reconstructions and future organic geochemical and stable isotope analysis. Future application of compound-specific H isotope analyses to long drill cores (recovered in 2009; ~315m of sediment) will potentially provide a quantitative high-resolution record of paleoclimatic and paleoenvironmental changes spanning the last 3.6 Ma.

Africa's climate became progressively drier and more variable in the last few million years (e.g., deMenocal, 2004). Of particular interest, is a shift to drier and more variable conditions in the Olorgesailie Formation (Kenya) between 500 and 300 thousand years ago (ka) in which Potts et al. (2018) observed a turnover of ~85% of large-body mammalian fauna to smaller-body related taxa, suggesting that the shift was an evolutionary response to better adapt to the changing climate. However, a hiatus in the Olorgesailie record means that the cause of this faunal shift is still an outstanding question. Here, we analyze Lake Malawi drill core MAL 05–1 (~11ºS, 34ºE) to investigate if a specific climatic event stands out as a possible driver of the dramatic change observed in the East African mammal community. We use organic geochemical proxies including branched glycerol diaklyl glycerol tetraethers (GDGTs), leaf wax carbon and deuterium isotopic records to develop high-resolution temperature, vegetation, and precipitation records, respectively, between 600 and 200 ka. Results show a dramatic and abrupt temperature increase of ~6°C occurring in less than 3000 years during Glacial Termination V, which is the Marine Isotope Stage (MIS) 12 to MIS 11 transition at ~430 ka. Notably, this deglacial warming coincides with enriched leaf wax deuterium isotopic values suggesting a shift to more arid conditions in interglacial MIS 11 than in glacial MIS 12. Results also show another abrupt warming period in which temperature increased ~9°C around MIS 7 (~240 ka). We propose that the major warming and drying during Termination V in East Africa represents a significant abrupt change in the climate of eastern Africa and was a likely driver of the major faunal turnover noted in the Olorgesailie Basin.

Mono Lake (CA) is a hydrologically closed lacustrine basin well-known for its paleo-shorelines, which record fluctuations in water level for the last deglacial and late Holocene. Mono Lake is a sentinel of California’s water supply, situated in the rain shadow of the Sierra Nevada, a mountain range whose snowpack is a vital source of freshwater for urban and agricultural districts to the west and south. Recent droughts, floods, and wildfires show that California is threatened by climate change, but how these changes impact and get recorded by Mono Lake sediments remains poorly known. Here, we use a new radiocarbon-dated deepwater sediment core from Mono Lake to test the hypothesis that organic facies development is controlled by climate and limnological change. An integrated stratigraphic analysis of the core reveals seven lithostratigraphic units that track environmental changes from ~16-4 ka. When compared to available paleo-shoreline and shallow water core data, our results show that high amplitude lakelevel fluctuations of the late Pleistocene produce different patterns of sedimentation and organic enrichment than lower-amplitude water level changes of the early and middle Holocene. The results have implications for understanding patterns of paleo-production and hydroclimate change at Mono Lake.

No description available.