Regional maturity and source-rock potential of palaeozoic and mesozoic strata, Melville Island, Arctic Canada

PhD ThesisThe thermal maturity and source-rock potential of the Palaeozoic and Mesozoic sediments in Melville Island, Arctic Canada were studied using organic petrology and Rock-Eval pyrolysis. A total of 2,000 polished whole-rock samples were examined and their phytoclast reflectances (% Ro random) measured. In addition, selected samples Were analyzed qualitatively and quantitatively using ultraviolet excitation. Hydrogen-rich organic matter was dominated by alginite (Botryococcus and Iasmanites), dinoflagellate cysts and amorphous fluorescing matrix. Sporinite, cutinite, resinite and liptodetrinite formed the lesser hydrogen-rich organic matter. Vitrinite reflectance in Cretaceous sediments ranged from Ro = 0.36 to 0.65%; in Jurassic sediments it ranged from Ro = 0.40 to 1.0% and in Triassic sediments from Ro = 0.45 to 1.30%. Vitrinite showed an overall increase in %Ro with increasing depth of burial but Variations do occur, possibly due to the effects of mineral matrix (lithology) and liptinite Content. It was observed that when total liptinite percentage was high (20-30%), reflectance was lowered by a magnitude of 0.1 to 0.15%. In addition, the lowering of the reflectance, which was genuine and not experimental, was due to: 1) the effect of bitumen impregnation (staining); and 2) differences in the type of organic matter (hydrogen-rich Vitrinite of marine origin). A large number of shale samples exceeded the worldwide average total organic carbon (TOC) content of 1.05 wt% with the Jurassic-Cretaceous shales and siltstones having higher values than those of Triassic age. The Triassic Schei Point Group shales and siltstones contained organic matter of marine origin, whereas the predominantly Plant-derived organic matter present in the Jameson Bay, Ringnes and Deer Bay formations had a higher TOC. Among the Schei Point Group sediments, the Cape Richards and Eden Bay Members of the Hoyle Bay Formation were richer in TOC (>2.0 wt%) than the Murray Harbour Formation (Cape Caledonia Member), which may reflect differences in the level Of maturity or in the depositional environment (more anoxic conditions for the former). Higher average TOC contents (> 3.0 wt%) were reported in the Cape Richards Member in drill hole Hecla C-32, as well as in the Eden Bay Member in drill holes Hecla C-32, Roche Paint J-43 and North Sabine H-49, all located in Sabine Peninsula. The Schei Point Group sediments contained mainly liptinitic organic matter of marine origin, were Occasionally bitumen stained and have high potential for the generation of liquid hYdrocarbons. Organic matter in the Palaeozoic strata of the Franklinian miogeosyncline was represented mainly by bitumen in the Silurian and Devonian. Different bitumen types Were identified depending on their morphology, reflectance range and association with the enclosing mineral matrix. Thermal maturity of the Palaeozoic strata, based on vitrinite reflectance calculated from bitumen reflectance was high, an indication that the strata Were in the overmature stage of hydrocarbon generation and that only dry gas should be expected. There is petrological evidence that hydrocarbons were generated and Illigrated through the sediments. Regional variations in the level of thermal maturity of Mesozoic sediments in the Sverdrup Basin are a function of burial depth. The Mesozoic formations thicken towards the basin centre (N-NE direction), reflecting the general pattern of increasing thermal maturity north of the Sabine Peninsula. In addition, periods of high heat flow Illost likely existed during rifting episodes from Carboniferous to Early Tertiary. The contour pattern of the regional variation of maturity at the base ofnumerous Triassic formations is similar to that of the structural contours of the Sverdrup Basin, indicating that present-day maturation levels are largely controlled by basin subsidence.Institute of Sedimentary and Petroleum Geology, Geological Survey of Canada

Coalbed methane producibility from the Mannville coals in Alberta, Canada: A comparison of two areas

International audienceThe Mannville coals in the Fenn area, Alberta Plains, have desorbed gas content averaging 8.57 cm3/g (275 scf/t), which is similar to the same coals in the Corbett Creek area, almost 400 km away. Vitrinite reflectance values are also similar, although the coals at Corbett Creek are situated about 300 m shallower, which points to a rank excursion from Hilt's burial law curves at Corbett Creek. Coals from both areas are within the “oil window”. The Medicine River Seam in the Fenn area has higher total inertinite content and greater proportions of inertodetrinite and detrovitrinite, suggesting that peat deposition occurred in swamps and marshes and were prone to periodic flooding. At Corbett Creek, the Mannville coal seams are characterized by greater concentrations of telo-inertinite, which contributes to coal meso-porosity and the potential for free gas storage in the open cell lumens, and to an increased gas flow along lithotype boundaries (horizontal permeability). Non-fluorescing vitrinite was present mostly in the upper Medicine River Seam, which was deposited in a regressive environment. The lower Medicine River Seam, which formed during a marine transgressive phase, contained greater amounts of fluorescing vitrinite. The Mannville coals in the Fenn area are moderately under-pressured in relation to those at Corbett Creek, which may have an impact on gas retention capacity. The difference in absolute coal permeability (1-3.5 mD at Fenn versus 3-4 mD at Corbett Creek), which is likely the result of higher in-situ stresses in the deeper Mannville coals at Fenn, has had an effect on both gas and water production rates from these coals. However, the largest impact on gas production volumes has been made by the application of horizontal drilling technology, initially at Fenn, and more recently by multiple horizontal wells drilled at Corbett Creek

The Effect of Social Skills on Middle School Belonging and Academic Motivation in Low-Income, Minority Students

The present research investigated associations between the basic need satisfaction of belongingness and intrinsic academic motivation in low-income, minority middle school students. Current literature suggests that students in middle school suffer a drop in basic need satisfaction and school engagement. Students reporting supportive relationships are better adjusted and more academically engaged. One method used to encourage these relationships is the emphasis of social skills. Therefore, the present research explored whether adding social skills lessons to a middle school curriculum increased intrinsic academic motivation by increasing belonging among students, particularly among a low-income, minority student sample. This was tested in a three-week long study where participants enrolled in summer school (n = 95) completed baseline, weekly, and follow-up measures of need satisfaction and intrinsic academic motivation while receiving weekly social skills lessons. Results indicated that there were no significant differences between baseline and follow-up belongingness satisfaction or intrinsic academic motivation. Study limitations include a small sample size and fidelity challenges, and future research should aim for a larger sample size and a lengthier, more structured longitudinal design.Psychology, Department ofHonors Colleg

Belongingness Program Evaluation with Local Middle-School Students

The present research investigates correlations between the basic need satisfaction of belongingness and intrinsic academic motivation in middle school students. Current literature describes that students in middle school suffer a drop in basic need satisfaction and school engagement. Students reporting supportive relationships are more academically engaged, and one method used to encourage these relationships is the emphasis of social skills. Therefore, the present researchers test whether adding social skills to a middle school curriculum increases intrinsic academic motivation by increasing belongingness among students. The study population consists of 32 5th grade students from a low-income charter school in a large southwestern city. The study is a 4-week long program evaluation where students participating in summer school reviewed a new social skill each week and practiced it throughout the week, later reporting if/how they utilized the skill. Intrinsic academic motivation was measured at baseline and follow-up, and belongingness was measured at baseline, weekly, and at follow-up. Academic engagement was measured by self-reported skill use and optional homework completion.Psychology, Department ofHonors Colleg

Nanopore structures of isolated kerogen and bulk shale in Bakken Formation

Pores that exist within the organic matter can affect the total pore system of bulk shale samples and, as a result, need to be studied and analyzed carefully. In this study, samples from the Bakken Formation, in conjunction with the kerogen that was isolated from them, were studied and compared through a set of analytical techniques: X-ray diffraction (XRD), Rock-Eval pyrolysis, Fourier Transform infrared spectroscopy (FTIR), and gas adsorption (CO 2 and N 2 ). The results can be summarized as follows: 1) quartz and clays are two major minerals in the Bakken samples; 2) the samples have rich organic matter content with TOC greater than 10 wt%; 3) kerogen is marine type II; 4) gas adsorption showed that isolated kerogen compared to the bulk sample has larger micropore volume and surface area, meso- and macropore volume, and Brunauer–Emmett–Teller (BET) surface area; 5) deconvolution of pore size distribution (PSD) curves demonstrated that pores in the isolated kerogen could be separated into five distinct clusters, whereas bulk shale samples exhibited one additional pore cluster with an average pore size of 4 nm hosted in the minerals. The comparison of PSD curves obtained from isolated kerogen and bulk shale samples proved that most of the micropores in the shale are hosted within the organic matter while the mesopores with a size ranging between 2 and 10 nm are mainly hosted by minerals. The overall results demonstrated that organic matter-hosted pores make a significant contribution to the total porosity of the Bakken shale samples

Thermal history of the Northwestern Argentina, Central Andean Basin, based on first-ever reported graptolite reflectance data

The thermal maturity from the Early Paleozoic strata in Northwestern Argentina was studied using reflected light microscopy and Rock-Eval analyses. The graptolites were collected from the Acoite and Lipeón formations, at the Los Colorados section, Cordillera Oriental, and the Huaytiquina, and Muñayoc sections, Puna highland, corresponding to the “Coquena” Formation and the Cochinoca-Escaya Magmatic-Sedimentary Complex. Rock-Eval parameters were unreliable due to the low TOC, S1, and S2 values. The Cordillera Oriental region sediments have low maturity based on low reflectance (%GRo= 0.63%–1.11%) and anisotropy of graptolites. In contrast, the higher graptolite reflectance of samples from the Muñayoc and Huaytiquina sections (%GRo= 5.57%–6.62%), in the Puna region, indicates considerably higher maturity. This could result from the combination of hydrothermal fluids with a temperature range from 336 °C to 358 °C, associated volcanism, and deformation related to tectonics events, which produced a higher geothermal gradient in the Puna. The Los Colorados section's thermal maturity modeling shows a better fit considering erosion episodes at the Late Paleozoic and Early Cenozoic. However, more studies about geothermal parameters and stratigraphy are necessary to corroborate these preliminary models and propose new approaches for the Puna region.Fil: Herrera Sánchez, Nexxys Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Toro, Blanca Azucena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Ruiz Monroy, Ricardo. German Research Centre For Geosciences; AlemaniaFil: Gentzis, Thomas. Core Laboratories; Estados UnidosFil: Ocubalidet, Seare. Core Laboratories; Estados UnidosFil: Carvajal Ortiz, Humberto. Core Laboratories; Estados Unido

Organic Matter Assessment And Paleoenvironmental Changes Of The Middle Jurassic Main Source Rocks (Khatatba Formation) In The North Western Desert, Egypt: Palynofacies And Palynomorph Perspectives

The Middle Jurassic in the north Western Desert, Egypt, was a time of complex tectonics and increased environmental perturbations attributed to the predominant sedimentation of organic carbon-rich fine siliciclastic and carbonate deposits of the Khatatba Formation. Although some studies have addressed the hydrocarbon potential and source rock characteristics of the Khatatba Formation, a regional-scale investigation of the prevalent paleoenvironmental conditions and organic matter characteristics is still necessary. In this study, the Khatatba Formation is investigated for detailed palynofacies analysis and palynomorph composition to assess organic matter kerogen types and reconstruct the depositional paleoenvironmental patterns on a regional scale. For this purpose, 116 drill cuttings were collected from five wells in the Matruh, Shushan, and Dahab-Mireir Basins. Moderately diverse assemblages of spores, pollen, and dinoflagellate cysts are reported. Age-diagnostic dinoflagellate cysts, including Adnatosphaeridium caulleryi, Dichadogonyaulax sellwoodii, Korystocysta gochtii, Wanaea acollaris, and Pareodinia ceratophora, along with occasional records of Systematophora areolate and Systematophora penicillate, defined a Bajocian–Callovian age. Based on particulate organic matter (POM) composition, four palynofacies assemblages (PFAs) are identified. PFA-1 is the most common within the Khatatba Formation in the five studied wells. It contains high proportions of phytoclast fragments versus low contents of amorphous organic matter (AOM) and palynomorphs and is defined by a gas-prone kerogen Type III. PFA-2 is comprised of moderate abundances of AOM and phytoclast characteristics of oil-prone kerogen Type II. PFA-3 is dominated by phytoclasts and moderate to low proportions of AOM and palynomorphs of kerogen Type III, whereas PFA-4 consists of AOM and palynomorphs defining kerogen Type II. PFA-1 indicates predominant deposition in proximal active fluvio-deltaic sources to marginal marine conditions with enhanced contributions of terrestrial/riverine influx. PFA-2 and PFA-3 reveal deposition under an enhanced dysoxic to anoxic proximal inner neritic shelf due to the abundant occurrences of spores and coastal to shallow marine dinoflagellate cysts. PFA-4 suggests deposition under enhanced suboxic to anoxic distal inner neritic conditions because of enhanced AOM and abundant proximate and some chorate dinoflagellate cysts. Thus, the Middle Jurassic experienced a predominantly marginal to shallow water column in this part of the southern margin of the Tethyan Ocean where the Matruh, Shushan, and Dahab-Mireir Basins were located

Application of multiple sorption model to estimation of CO 2

The aim of the study is to estimate the theoretical capacity of coal deposits in terms of carbon dioxide storage and methane recovery estimate during the injection of carbon dioxide. The Multiple Sorption Model was used for this purpose. The range of sorption measurement data on which the simulations were based does not exceed the critical point for both methane and carbon dioxide. The model allows to calculate absorption, adsorption, expansion and total theoretical sorption. For further consideration absorption was used as the process of the percolation of the gas in the bulk of the coal matter as well as the total theoretical sorption, the occurrence of which is possible due to the presence of fractures in the coal seam. Calculated levels of absorption and the total theoretical adsorption were applied to estimate the possible storage capacity of carbon dioxide based on the data associated with the content of coal in the mining fields of individual Polish coal mines. Moreover, MSM development for the gas mixture sorption can be used to roughly assess the recovery of methane naturally occurring in coal deposits during such a process

Earliest land plants created modern levels of atmospheric oxygen

The progressive oxygenation of the Earth’s atmosphere was pivotal to the evolution of life, but the puzzle of when and how atmospheric oxygen (O2) first approached modern levels (~21%) remains unresolved. Redox proxy data indicate the deep oceans were oxygenated during 435-392 Ma, and the appearance of fossil charcoal indicates O2>15-17% by 420-400 Ma. However, existing models have failed to predict oxygenation at this time. Here we show that the earliest plants, which colonized the land surface from ~470 Ma onwards, were responsible for this mid- Paleozoic oxygenation event, through greatly increasing global organic carbon burial – the net long-term source of O2. We use a trait-based ecophysiological model to predict that cryptogamic vegetation cover could have achieved ~30% of today’s global terrestrial net primary productivity by~445 Ma. Data from modern bryophytes suggests this plentiful early plant material had a much higher molar C:P ratio (~2000) than marine biomass (~100), such that a given weathering flux of phosphorus could support more organic carbon burial. Furthermore, recent experiments suggest that early plants selectively increased the flux of phosphorus (relative to alkalinity) weathered from rocks. Combining these effects in a model of long-term biogeochemical cycling, we reproduce a sustained +2‰ increase in the carbonate carbon isotope (δ13C) record by ~445 Ma, and predict a corresponding rise in O2 to present levels by 420-400 Ma, consistent with geochemical data. This oxygen rise represents a permanent shift in regulatory regime to one where fire-mediated negative feedbacks on organic carbon burial stabilise high O2 levels