ForamViT-GAN: Exploring New Paradigms in Deep Learning for Micropaleontological Image Analysis

Micropaleontology in geosciences focuses on studying the evolution of microfossils (e.g., foraminifera) through geological records to reconstruct past environmental and climatic conditions. This field heavily relies on visual recognition of microfossil features, making it suitable for computer vision technology, specifically deep convolutional neural networks (CNNs), to automate and optimize microfossil identification and classification. However, the application of deep learning in micropaleontology is hindered by limited availability of high-quality, high-resolution labeled fossil images and the significant manual labeling effort required by experts. To address these challenges, we propose a novel deep learning workflow combining hierarchical vision transformers with style-based generative adversarial network algorithms to efficiently acquire and synthetically generate realistic high-resolution labeled datasets of micropaleontology in large volumes. Our study shows that this workflow can generate high-resolution images with a high signal-to-noise ratio (39.1 dB) and realistic synthetic images with a Frechet inception distance similarity score of 14.88. Additionally, our workflow provides a large volume of self-labeled datasets for model benchmarking and various downstream visual tasks, including fossil classification and segmentation. For the first time, we performed few-shot semantic segmentation of different foraminifera chambers on both generated and synthetic images with high accuracy. This novel meta-learning approach is only possible with the availability of high-resolution, high-volume labeled datasets. Our deep learning-based workflow shows promise in advancing and optimizing micropaleontological research and other visual-dependent geological analyses

Origin and evolution of fault-controlled hydrothermal dolomitization fronts: a new insight

Dolomitization is one of the most significant diagenetic reactions in carbonate systems, occurring where limestone (CaCO3) is replaced by dolomite (CaMg (CO3)2) under a wide range of crystallization temperatures and fluids. The processes governing its formation have been well studied, but the controls on the position of dolomitization fronts in ancient natural settings, particularly in a fault-controlled hydrothermal system (HTD), have received remarkably little attention. Hence, the origin and evolution of HTD dolomitization fronts in the stratigraphic record remain enigmatic. Here, a new set of mineralogical and geochemical data collected from different transects in a partially dolomitized Cambrian carbonate platform in western Canada are presented to address this issue. Systematic patterns of sudden decrease in the magnesium content (mol% MgCO3) and increase in porosity were observed towards the margin of the body. Furthermore, fluid temperatures are cooler and δ18 Owater values are less positive at the dolomitization front than within the core of the body. These changes coincide with a change from poorly ordered, planar-e dolomite with multiple crystal zonations at the margin, to an unzoned, well-ordered, interlocking mosaic of planar-s to nonplanar dolomite in the core of the body. These phenomena are hypothesized to reflect dynamic, self-limiting processes in the formation and evolution of HTD dolomitization fronts through (i) plummet of dolomitization potential at the head of dolomitizing fluids due to progressive consumption of magnesium and fluid cooling; and (ii) retreat of dolomitization fronts towards the fluid source during subsequent recrystallization of the dolomite body, inboard of the termination, once overdolomitization took place. This new insight illustrates how dolomitization fronts can record the oldest phase of dolomitization, instead of the youngest as is often assumed. Formation of porosity is interpreted to occur as the result of acidification-induced grain leaching during the development of dolomitization fronts. This mechanism, coupled with retrogradation of dolomitization fronts, may help to explain the apparent enhancement of porosity in proximity to dolomitization fronts

Dolomitization of early-post rift Lower Jurassic carbonate platforms along the Moroccan Atlantic Margin: Origin and significance

Dolomitization is the most significant diagenetic process to affect Jurassic carbonate reservoirs along the Central Atlantic Margin (CAM). Despite several studies on dolomitization from different parts of CAM, the origin of these dolomites and their influence on the subsequent diagenetic evolution of Jurassic carbonate systems remains enigmatic. In addition, while dolomitization is evident at the surface and in the subsurface of the Moroccan Atlantic Margin, virtually no detailed studies have been conducted to determine the origin, mechanism, and significance of dolomitization in this basin. Therefore, the principal objective of this study is to assess the origin and occurrence of dolomite in the of Upper Sinemurian-Lower Pliensbachian carbonates of the Arich Ouzla Formation in the Essaouira-Agadir Basin by using petrography and geochemistry.The shallow marine carbonates of the Arich Ouzla Formation have been partially dolomitized and are exposed on the salt-cored Amsittene Anticline. The dolomite is stratabound, and predominantly fabric-retentive, although in some parts it is partially replaced by non-stratabound, fabric-destructive dolomites. From petrographic ob- servations and geochemical proxies, the fabric-preserving dolomites show dolomitization by reflux of mesohaline seawater (δ18Odolomite average = − 3.5 ‰ VPDB, and δ13Cdolomite average = 2.0 ‰ VPDB). In contrast, petro- graphic and geochemical characteristics of the fabric destructive dolomites suggest precipitation from modified seawater/formational brines convected along faults and fractures evidenced by depleted δ18O isotopic values (average = − 4.1 ‰ VPDB) with high fluid temperatures (average = 78 ◦C; range = 66–90 ◦C) where fluids interacted with the basal Triassic evaporites and siliciclastic sediments.Fabric preserving dolomite has higher porosity (average = 6.0 %) than the precursor limestones (average = 0.4 %), whereas permeability in both rock types (average = 0.48 mD, and average = 0.02 mD, respectively) is low. Fabric destructive dolomite has low porosity in proximity to fracture corridors (average = 1.9 %) due to dolomite recrystallization (overdolomitization), whereas porosity increases to an average of 7.4%, away from fracture corridors. The dolomites are post-dated by calcite cement which occludes vugs, intercrystalline pores and fractures. The calcite is interpreted to be meteoric in origin, because of its non-cathodoluminescence and depleted δ18O (average = − 4.7 ‰ VPDB) and δ13C (average = − 9.3 ‰ VPDB) isotopic values with respect to Jurassic marine carbonates. The meteoric calcites co-exist with bitumen suggesting that hydrocarbon migration in the basin likely occurred at the same time, most likely during basin inversion and exposure. This work con- siders dolomitization to be a localised process due to salt diapirism and demonstrates that the coincidence of hydrocarbon emplacement with basin inversion results in degradation and probably leakage of hydrocarbons. This emphasises the importance of local and regional tectonics, including salt diapirism, on patterns of diagenetic overprint in sedimentary basins

Variations in architecture and cyclicity in fault-bounded carbonate platforms: Early Miocene Red Sea Rift, NW Saudi Arabia

The Early Miocene was a period of active rifting and carbonate platform development in the Midyan Peninsula, NW Saudi Arabia. However, there is no published literatures available dealing with detail characterization of the different carbonate platforms in this study area. Therefore, this study aims at presenting new stratigraphic architectural models that illustrate the formation of different carbonate platforms in the region and its forcing mechanisms that likely drove their formation. This study identified the following features formed during active rifting: a) a Late Aquitanian (N4) fault-block hangingwall dipslope carbonate ramp b) a Late Burdigalian (N7-N8) isolated normal fault-controlled carbonate platform with associated slope deposits, and c) a Late Burdigalian (N7-N8) attached fault-bounded, rimmed shelf developed on a footwall fault-tip within a basin margin structural relay zone formed coinciding with the second stage of rifting. Variations in cyclicity have been observed within the internal stratigraphic architecture of each platform and also between platforms. High-resolution sequence stratigraphic analysis show parasequences observed as the smallest depositional packages (meter-scale cycles) within the platforms. The hangingwall dipslope carbonate ramp and the attached platform demonstrate aggradational-progradational parasequence stacking patterns. These locations appear to have been more sensitive to eustatic cyclicities, despite the active tectonic setting. The isolated, fault-controlled carbonate platform reveals disorganized stratal geometries in both platform-top and slope facies, suggesting a more complex interplay of rates of tectonic uplift and subsidence, variation in carbonate productivity, and resedimentation of carbonates, such that any sea-level cyclicity is obscure. This study explores the interplay between different forcing mechanisms in the evolution of carbonate platforms in active extensional tectonic regions. Characterization of detailed parasequence-scale internal architecture allows the spatial variation in syn-depositional relative base-level changes to be inferred and is critical for understanding the development of rift basin carbonate platforms. Such concepts may be useful for the prediction of subsurface facies relationships beyond interwell areas in hydrocarbon exploration and reservoir modeling activities

Hierarchical automated machine learning (AutoML) for advanced unconventional reservoir characterization

Abstract Recent advances in machine learning (ML) have transformed the landscape of energy exploration, including hydrocarbon, CO2 storage, and hydrogen. However, building competent ML models for reservoir characterization necessitates specific in-depth knowledge in order to fine-tune the models and achieve the best predictions, limiting the accessibility of machine learning in geosciences. To mitigate this issue, we implemented the recently emerged automated machine learning (AutoML) approach to perform an algorithm search for conducting an unconventional reservoir characterization with a more optimized and accessible workflow than traditional ML approaches. In this study, over 1000 wells from Alberta’s Athabasca Oil Sands were analyzed to predict various key reservoir properties such as lithofacies, porosity, volume of shale, and bitumen mass percentage. Our proposed workflow consists of two stages of AutoML predictions, including (1) the first stage focuses on predicting the volume of shale and porosity by using conventional well log data, and (2) the second stage combines the predicted outputs with well log data to predict the lithofacies and bitumen percentage. The findings show that out of the ten different models tested for predicting the porosity (78% in accuracy), the volume of shale (80.5%), bitumen percentage (67.3%), and lithofacies classification (98%), distributed random forest, and gradient boosting machine emerged as the best models. When compared to the manually fine-tuned conventional machine learning algorithms, the AutoML-based algorithms provide a notable improvement on reservoir property predictions, with higher weighted average f1-scores of up to 15–20% in the classification problem and 5–10% in the adjusted-R2 score for the regression problems in the blind test dataset, and it is achieved only after ~ 400 s of training and testing processes. In addition, from the feature ranking extraction technique, there is a good agreement with domain experts regarding the most significant input parameters in each prediction. Therefore, it is evidence that the AutoML workflow has proven powerful in performing advanced petrophysical analysis and reservoir characterization with minimal time and human intervention, allowing more accessibility to domain experts while maintaining the model’s explainability. Integration of AutoML and subject matter experts could advance artificial intelligence technology implementation in optimizing data-driven energy geosciences

Appendix B: Clumped Isotopes

Clumped Isotopes data from (i) Western Canada Basin; (ii) Essaouira-Agadir Basin, Morocco; (iii) Southern Pennine Basin, U

Clumped isotope acid fractionation factors for dolomite and calcite revisited: Should we care?

During the analysis of the Δ47 values of CO2 derived from carbonates, the acid fractionation factor not only allows Δ47 values produced from carbonates and reacted at different temperatures (usually 25 and 90 °C) to be compared to one another, but also provides an effective tool to better understand the mechanism and rate of isotopic exchange of oxygen with water during the phosphoric acid digestion of carbonate minerals. In this study, experiments have been conducted in which calcite (1 sample) and dolomite (4 samples), with varying Δ47 values, have been digested in phosphoric acid (H3PO4) at five different temperatures between 25 and 90 °C using both the common acid bath and sealed vessel methods. From these experiments, we show that calcite has an acid fractionation factor which is independent of the reaction method. In contrast, all four dolomites show significant differences between the two methods with the sealed vessel reactions showing much smaller acid fractionation factors than the common acid bath. The magnitude of the acid fractionation factor in the dolomites is also dependent upon the absolute Δ47 value of the sample, with samples possessing lower Δ47 values producing lower acid fractionation factors than those with higher Δ47 values. The explanation for the difference in the behavior of acid fractionation factors between calcite and dolomite, in regard to the technique used, is believed to be related to the rate of reaction of the two minerals and thus the time in which the CO2 is in contact with the acid and allowed to exchange with the H2O in the acid and produced during the reaction.•Four dolomite and one calcite were digested using common acid bath and sealed vessel methods.•Five reaction temperatures in these two experimental methods were conducted from 25 to 90 °C.•Insignificant differences in Δ47 values between CDES and I-CDES correcting frameworks.•All dolomites show a significant difference between two reaction methods.•The magnitude of acid fractionation factors in dolomite and calcite depends on absolute Δ47 values