128 results found
Garfi G, John CM, Rucker M, et al., 2022, Determination of the spatial distribution of wetting in the pore networks of rocks, JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 613, Pages: 786-795, ISSN: 0021-9797
Sun X, Gomez-Rivas E, Alcalde J, et al., 2022, Origin and distribution of calcite cements in a folded fluvial succession: The Puig-reig anticline (south-eastern Pyrenees), SEDIMENTOLOGY, Vol: 69, Pages: 2319-2347, ISSN: 0037-0746
Marchegiano M, John CM, 2022, Disentangling the Impact of Global and Regional Climate Changes During the Middle Eocene in the Hampshire Basin: New Insights From Carbonate Clumped Isotopes and Ostracod Assemblages, PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY, Vol: 37, ISSN: 2572-4517
Fiordalisi E, Marchegiano M, John CM, et al., 2021, Late Cretaceous volcanism and fluid circulation in the South Atlantic: Insights from continental carbonates in the onshore Namibe Basin (Angola), MARINE AND PETROLEUM GEOLOGY, Vol: 134, ISSN: 0264-8172
Cruset D, Verges J, Benedicto A, et al., 2021, Multiple fluid flow events from salt-related rifting to basin inversion (Upper Pedraforca thrust sheet, SE Pyrenees), BASIN RESEARCH, Vol: 33, Pages: 3102-3136, ISSN: 0950-091X
Cai C, Li K, Liu D, et al., 2021, Anaerobic oxidation of methane by Mn oxides in sulfate-poor environments, GEOLOGY, Vol: 49, Pages: 761-766, ISSN: 0091-7613
Davies AJ, Davis S, John CM, 2021, Evidence of taxonomic non-equilibrium effects in the clumped isotope composition of modern cephalopod carbonate, CHEMICAL GEOLOGY, Vol: 578, ISSN: 0009-2541
Bernasconi SM, Daeron M, Bergmann KD, et al., 2021, InterCarb: A Community Effort to Improve Interlaboratory Standardization of the Carbonate Clumped Isotope Thermometer Using Carbonate Standards, GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, Vol: 22
Anderson NT, Kelson JR, Kele S, et al., 2021, A Unified Clumped Isotope Thermometer Calibration (0.5-1,100 degrees C) Using Carbonate-Based Standardization, GEOPHYSICAL RESEARCH LETTERS, Vol: 48, ISSN: 0094-8276
John CM, Kussanov I, Hawie N, 2021, Constraining stratal architecture and pressure barriers in the subsalt Karachaganak Carboniferous carbonate platforms using forward stratigraphic modelling, MARINE AND PETROLEUM GEOLOGY, Vol: 124, ISSN: 0264-8172
Herlambang A, John CM, 2021, Combining clumped isotope and trace element analysis to constrain potential kinetic effects in calcite, GEOCHIMICA ET COSMOCHIMICA ACTA, Vol: 296, Pages: 117-130, ISSN: 0016-7037
Elyamani M, John CM, Bell RE, 2021, SENSITIVITY ANALYSIS OF THE AMPLITUDE OF EARLY CRETACEOUS EUSTATIC CHANGES USING FORWARD STRATIGRAPHIC MODELLING (RESOLUTION GUYOT), Pages: 2332-2336
Multiple studies focused on eustatic changes during the Cretaceous as an example of greenhouse world. Most of these studies were performed in local areas. These sea level estimates might be derived from localised effects and therefore reflect relative sea level changes rather than eustasy. Based on that, sensitivity analysis to test the applicability of using the Cretaceous ESL curves of Rohl & ogg (1996), Sahagian et al. (1996), Hardenbol et al. (1998), and Haq (2014) is crucial to validate or refute them. To do that, forward stratigraphic modelling of one of the Mid-Pacific mountain guyots, Resolution Guyot, is performed. The study area is unique as it represents deposition of Cretaceous carbonates (growing at sea-level) on an isolated volcanic island away from the influence of continents and tectonic activity. The initial results show that Haq (2014) ESL curve wasn’t perfectly fitting some of our constraints, and some of the cycles need finer subdivision. The outcomes of this study will constrain the fluctuations of ESL in the Cretaceous and serve as a test to whether the amplitude and timing of regionally-derived eustatic curves are valid for other locations, or whether these curves are too influenced by specific local conditions in the areas.
Tagliavento M, John CM, Anderskouv K, et al., 2020, Towards a new understanding of the genesis of chalk: Diagenetic origin of micarbs confirmed by clumped isotope analysis, SEDIMENTOLOGY, Vol: 68, Pages: 513-530, ISSN: 0037-0746
Munoz-Lopez D, Alias G, Cruset D, et al., 2020, Influence of basement rocks on fluid evolution during multiphase deformation: the example of the Estamariu thrust in the Pyrenean Axial Zone, SOLID EARTH, Vol: 11, Pages: 2257-2281, ISSN: 1869-9510
Cruset D, Cantarero I, Benedicto A, et al., 2020, From hydroplastic to brittle deformation: Controls on fluid flow in fold and thrust belts. Insights from the Lower Pedraforca thrust sheet (SE Pyrenees), MARINE AND PETROLEUM GEOLOGY, Vol: 120, ISSN: 0264-8172
Munoz-Lopez D, Cruset D, Cantarero I, et al., 2020, Fluid Dynamics in a Thrust Fault Inferred from Petrology and Geochemistry of Calcite Veins: An Example from the Southern Pyrenees, GEOFLUIDS, Vol: 2020, ISSN: 1468-8115
Beaudoin NE, Labeur A, Lacombe O, et al., 2020, Regional-scale paleofluid system across the Tuscan Nappe-Umbria-Marche Apennine Ridge (northern Apennines) as revealed by mesostructural and isotopic analyses of stylolite-vein networks, SOLID EARTH, Vol: 11, Pages: 1617-1641, ISSN: 1869-9510
Cruset D, Cantarero I, Benedicto A, et al., 2020, Geochronological and geochemical data from fracture-filling calcites from the Lower Pedraforca thrust sheet (SE Pyrenees), Data in Brief, Vol: 31, Pages: 1-7, ISSN: 2352-3409
U-Pb dating using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), δ13C, δ18O, clumped isotopes and 87Sr/86Sr analysis, and electron microprobe have been applied to fracture-filling calcites and host carbonates from the Lower Pedraforca thrust sheet, in the SE Pyrenees. These data are used to determine the type and origin of migrating fluids, the evolution of the palaeohydrological system and timing of fracturing during the emplacement of this thrust sheet, as described in the article “From hydroplastic to brittle deformation: controls on fluid flow in fold and thrust belts. Insights from the Lower Pedraforca thrust sheet (SE Pyrenees)” – Marine and Petroleum Geology (2020). The integration of these data is also used to compare the fluid flow evolution of the Southern Pyrenees with that of other orogens worldwide and to generate a fluid flow model in fold and thrust belts. At a more local scale, the U-Pb dataset provides new absolute ages recording the deformation in the Lower Pedraforca thrust sheet, which was previously dated by means of indirect methods such as biostratigraphy of marine sediments and magnetostratigraphy of continental deposits.
Cruset D, Ibanez-Insa J, Cantarero I, et al., 2020, Significance of Fracture-Filling Rose-Like Calcite Crystal Clusters in the SE Pyrenees, MINERALS, Vol: 10
Adlan Q, Davies AJ, John CM, 2020, Effects of oxygen plasma ashing treatment on carbonate clumped isotopes, Rapid Communications in Mass Spectrometry, Vol: 34, ISSN: 0951-4198
Rationale:For clumped isotope analysis (Δ47), hydrocarbon and organic moleculespresent an important contaminant that cannot always be removed by CO2purification through a Porapak-Q trap. Low-temperature oxygen plasma ashing (OPA)is a quick and easy approach for treatment; however, the impact of this treatment onthe original carbonate clumped isotope values has never been fully studied.Methods:We tested the isotopic impact of OPA using three natural samples with alarge range of initialΔ47values. Crushed and sieved (125μm mesh) samples wereplaced into a Henniker Plasma HPT-100 plasma system and treated at a flow rate of46 mL/min and a power of 100 W at a vacuum of 0.2 mbar for 10, 20, 30 and60 min before clumped isotope analysis using two MAT 253 isotope ratio massspectrometers modified to measure masses 44–49.Results:OPA treatment for 30 min or more on calcite powder samples has thepotential to alter the clumped isotopic composition of the samples beyond analyticalerror. A systematic positive offset is observed in all samples. The magnitude of thisalteration translates to a temperature offset from known values ranging from 4 Cto13 C. We postulate that the observed positive offset inΔ47occurs because thebonds within lighter isotopologues are preferentially broken by plasma treatment,leading to an artificial increase in the‘clumping’value of the sample.Conclusions:We recommend that any laboratory performing OPA treatments shouldreduce the runs to 10–20 min or carry out successive runs of 10 min followed bysample stirring, as this procedure showed no alteration in the initialΔ47values. Ourresults validate the use of OPA for clumped isotope applications and will allow futureresearch to use clumped isotopes for challenging samples such as oil-stainedcarbonates, bituminous shales or host rocks with very high organic carbon content.
Garfi G, John CM, Lin Q, et al., 2020, Fluid Surface Coverage Showing the Controls of Rock Mineralogy on the Wetting State, GEOPHYSICAL RESEARCH LETTERS, Vol: 47, ISSN: 0094-8276
Lukoczki G, Haas J, Gregg JM, et al., 2020, Early dolomitization and partial burial recrystallization: a case study of Middle Triassic peritidal dolomites in the Villany Hills (SW Hungary) using petrography, carbon, oxygen, strontium and clumped isotope data, INTERNATIONAL JOURNAL OF EARTH SCIENCES, Vol: 109, Pages: 1051-1070, ISSN: 1437-3254
Le Blevec T, Dubrule O, John C, et al., 2020, Geostatistical Earth modeling of cyclic depositional facies and diagenesis, AAPG Bulletin, Vol: 104, Pages: 711-734, ISSN: 0149-1423
In siliciclastic and carbonate reservoirs, depositional facies are often described as being organized in cyclic successions that are overprinted by diagenesis. Most reservoir modeling workflows are not able to reproduce stochastically such patterns. Herein, a novel geostatistical method is developed to model depositional facies architectures that are rhythmic and cyclic, together with superimposed diagenetic facies. The method uses truncated Pluri-Gaussian random functions constrained by transiograms. Cyclicity is defined as an asymmetric ordering between facies, and its direction is given by a three-dimensional vector, called shift. This method is illustrated on two case studies. Outcrop data of the Triassic Latemar carbonate platform, northern Italy, are used to model shallowing-upward facies cycles in the vertical direction. A satellite image of the modern Bermuda platform interior is used to model facies cycles in the windward-to-leeward lateral direction. As depositional facies architectures are modeled using two Gaussian random functions, a third Gaussian random function is added to model diagenesis. Thereby, depositional and diagenetic facies can exhibit spatial asymmetric relationships. The method is applied in the Latemar carbonate platform that experiences syn-depositional dolomite formation. The method can also incorporate proportion curves to model non-stationary facies proportions. This is illustrated in Cretaceous shallow-marine sandstones and mudstones, Book Cliffs, Utah, for which cyclic facies and diagenetic patterns are constrained by embedded transition probabilities.
Garfi G, John CM, Berg S, et al., 2019, The sensitivity of estimates of multiphase fluid and solid properties of porous rocks to image processing, Transport in Porous Media, Vol: 131, Pages: 985-1005, ISSN: 0169-3913
X-ray microcomputed tomography (X-ray μ-CT) is a rapidly advancing technology that has been successfully employed to study flow phenomena in porous media. It offers an alternative approach to core scale experiments for the estimation of traditional petrophysical properties such as porosity and single-phase flow permeability. It can also be used to investigate properties that control multiphase flow such as rock wettability or mineral topology. In most applications, analyses are performed on segmented images obtained employing a specific processing pipeline on the greyscale images. The workflow leading to a segmented image is not straightforward or unique and, for most of the properties of interest, a ground truth is not available. For this reason, it is crucial to understand how image processing choices control properties estimation. In this work, we assess the sensitivity of porosity, permeability, specific surface area, in situ contact angle measurements, fluid–fluid interfacial curvature measurements and mineral composition to processing choices. We compare the results obtained upon the employment of two processing pipelines: non-local means filtering followed by watershed segmentation; segmentation by a manually trained random forest classifier. Single-phase flow permeability, in situ contact angle measurements and mineral-to-pore total surface area are the most sensitive properties, as a result of the sensitivity to processing of the phase boundary identification task. Porosity, interfacial fluid–fluid curvature and specific mineral descriptors are robust to processing. The sensitivity of the property estimates increases with the complexity of its definition and its relationship to boundary shape.
Tagliavento M, John CM, Stemmerik L, 2019, Tropical temperature in the Maastrichtian Danish Basin: Data from coccolith Delta(47) and delta O-18, GEOLOGY, Vol: 47, Pages: 1074-1078, ISSN: 0091-7613
Petersen SV, Defliese WF, Saenger C, et al., 2019, Effects of Improved O-17 Correction on Interlaboratory Agreement in Clumped Isotope Calibrations, Estimates of Mineral-Specific Offsets, and Temperature Dependence of Acid Digestion Fractionation, GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, Vol: 20, Pages: 3495-3519
MacDonald JM, Faithfull JW, Roberts NMW, et al., 2019, Clumped-isotope palaeothermometry and LA-ICP-MS U-Pb dating of lava-pile hydrothermal calcite veins, Contributions to Mineralogy and Petrology, Vol: 174, ISSN: 0010-7999
Calcite veins are a common product of hydrothermal fluid circulation. Clumped-isotope palaeothermometry is a promising technique for fingerprinting the temperature of hydrothermal fluids, but clumped-isotope systematics can be reset at temperatures of > ca. 100 °C. To model whether the reconstructed temperatures represent calcite precipitation or closed-system resetting, the precipitation age must be known. LA-ICP-MS U–Pb dating of calcite is a recently developed approach to direct dating of calcite and can provide precipitation ages for modelling clumped-isotope systematics in calcite veins. In this study, clumped-isotope and LA-ICP-MS U–Pb calcite analyses were combined in basalt-hosted calcite veins from three settings in Scotland. Samples from all three localities yielded precipitation temperatures of ca. 75–115 °C from clumped-isotope analysis, but veins from only two of the sites were dateable, yielding precipitation ages of 224 ± 8 Ma and 291 ± 33 Ma (2σ). Modelling from the dated samples enabled confident interpretation that no closed-system resetting had occurred in these samples. However, the lack of a precipitation age from the third location meant that a range of possible thermal histories had to be modelled meaning that confidence that resetting had not occurred was lower. This highlights the importance of coupling clumped-isotope thermometry and LA-ICP-MS U–Pb calcite dating in determining the temperature of hydrothermal fluids recorded in calcite veins. This paired approach is shown to be robust in constraining the timing and precipitation temperature of calcite formation, and thus for tracking hydrothermal processes.
McDougall K, John CM, 2019, Benthic foraminiferal biotic events related to the Paleocene-Eocene Thermal Maximum along the California margin, MARINE MICROPALEONTOLOGY, Vol: 150, ISSN: 0377-8398
Veillard C, John C, Krevor S, et al., 2019, Rock-buffered recrystallization of Marion Plateau dolomites at low temperature evidenced by clumped isotope thermometry and X-Ray diffraction analysis, Geochimica et Cosmochimica Acta, Vol: 252, Pages: 190-212, ISSN: 0016-7037
Much debate exists on the extent to which early dolomites recrystallize and preserve the signature of their primary diagenetic setting. Here, we combine clumped isotopes thermometry with X-ray diffraction and thin section petrography to study dolomite recrystallization under shallow burial (<1 km) conditions. We analysed 26 dolomite samples from two Miocene carbonate platforms on the Marion Plateau, NE Australia. Marion Plateau dolomites provide an ideal case study to examine the effects of recrystallization because of the relative simplicity of the geological setting, with simple subsidence, and several episodes of early dolomitization by normal Miocene sea water. Results show that Marion Plateau dolomites are very rich in calcium and their formation temperature inferred from clumped isotopes T(Δ47dol) ranges between 12 and 35°C. The apparent fluid composition (δ18Ow (app)) falls in the range of sea water composition, but a correlation between T(Δ47dol), δ18Odol, and δ18Ow (app) exists: the higher the crystallization temperature, the more negative the fluid composition is. T(Δ47dol) and δ18Ow (app) increase with depth, whereas δ18Odol and δ13Cdol tend to both decrease with depth. We interpret the negative correlation between T(Δ47dol) and δ18Ow (app) as evidence of shallow burial recrystallization via dissolution/re-precipitation. Modelling of the T(Δ47dol), δ18Odol, and δ18Ow (app) indicates that the recrystallization happened at very low water to rock ratio. Carbon isotopes are inherited from the dolomitization process, and not reset during recrystallization. This study shows that dolomite recrystallization has the potential to affect T(Δ47dol) at depths shallower than previously demonstrated. It emphasizes the fact that high calcium dolomites (and possibly aragonite and high Mg-calcite) can have a range of T(Δ47dol) before entering the solid-state reordering re
Lukoczki G, Haas J, Gregg J, et al., 2019, Multi-phase dolomitization and recrystallization of Middle Triassic shallow marine–peritidal carbonates from the Mecsek Mts. (SW Hungary), as inferred from petrography, carbon, oxygen, strontium and clumped isotope data, Marine and Petroleum Geology, Vol: 101, Pages: 440-458, ISSN: 1873-4073
Shallow marine to peritidal carbonates of the Triassic Csukma Formation in the Mecsek Mts. of SW Hungary are made up of dolomites, limestones and dolomitic limestones that show evidence of a complex diagenetic history. Integration of petrographic, conventional stable oxygen and carbon isotope, clumped isotope, and strontium isotope data with the paleogeography, paleoclimate, and burial history of the region revealed four major diagenetic stages. Stage 1: The peritidal carbonates were dolomitized penecontemporaneously during the Middle Triassic by refluxing evaporatively concentrated brines. Stage 2: Increasing burial during the Late Triassic–Jurassic resulted in recrystallization of the Kán Dolomite Member in an intermediate burial setting. Stage 3: During the Early Cretaceous seawater was drawn down and circulated through rift-related faults, causing renewed recrystallization of the Kán Dolomite Member as well as dolomitization of the Kozár Limestone Member and the underlying limestones in a deep burial setting, but only in the vicinity of the faults. Stage 4: During the Late Cretaceous and Cenozoic thrusting resulted in tectonic expulsion of basinal fluids and precipitation of multiple saddle dolomite cement phases near the faults.The results of this study imply that the clumped isotope method integrated with other geochemical data can successfully be applied to identify the nature and potential sources of extra-formational diagenetic fluids responsible for dolomitization and recrystallization. This study provides conclusive evidence for multi-phase dolomitization and dolomite recrystallization over several millions of years (Middle Triassic through Early Cretaceous) and several thousands of meters of burial in the Csukma Formation in SW Hungary. Furthermore, this study is the first to identify fault-controlled dolomitization by circulating Cretaceous seawater within Triassic carbonates of central Europe, further supporting the viability
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