Correction| May 10, 2023 ERRATUM: New estimates of the magnitude of the sea-level jump during the 8.2 ka event Jonathan Obrist-Farner; Jonathan Obrist-Farner Search for other works by this author on: GSW Google Scholar Mark Brenner; Mark Brenner Search for other works by this author on: GSW Google Scholar Jeffery R. Stone; Jeffery R. Stone Search for other works by this author on: GSW Google Scholar Marta Wojewódka-Przybył; Marta Wojewódka-Przybył Search for other works by this author on: GSW Google Scholar Thorsten Bauersachs; Thorsten Bauersachs Search for other works by this author on: GSW Google Scholar Andreas Eckert; Andreas Eckert Search for other works by this author on: GSW Google Scholar Marek Locmelis; Marek Locmelis Search for other works by this author on: GSW Google Scholar Jason H. Curtis; Jason H. Curtis Search for other works by this author on: GSW Google Scholar Susan R.H. Zimmerman; Susan R.H. Zimmerman Search for other works by this author on: GSW Google Scholar Alex Correa-Metrio; Alex Correa-Metrio Search for other works by this author on: GSW Google Scholar Lorenz Schwark; Lorenz Schwark Search for other works by this author on: GSW Google Scholar Edward Duarte; Edward Duarte Search for other works by this author on: GSW Google Scholar Antje Schwalb; Antje Schwalb Search for other works by this author on: GSW Google Scholar Etienne Niewerth; Etienne Niewerth Search for other works by this author on: GSW Google Scholar Paula Gabriela Echeverría-Galindo; Paula Gabriela Echeverría-Galindo Search for other works by this author on: GSW Google Scholar Liseth Pérez Liseth Pérez Search for other works by this author on: GSW Google Scholar Author and Article Information Jonathan Obrist-Farner Mark Brenner Jeffery R. Stone Marta Wojewódka-Przybył Thorsten Bauersachs Andreas Eckert Marek Locmelis Jason H. Curtis Susan R.H. Zimmerman Alex Correa-Metrio Lorenz Schwark Edward Duarte Antje Schwalb Etienne Niewerth Paula Gabriela Echeverría-Galindo Liseth Pérez Publisher: Geological Society of America First Online: 10 May 2023 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2023 Geological Society of America Geology (2023) 51 (7): 703. https://doi.org/10.1130/G49296E.1 Article history First Online: 10 May 2023 Connected Content Errata: New estimates of the magnitude of the sea-level jump during the 8.2 ka event Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Jonathan Obrist-Farner, Mark Brenner, Jeffery R. Stone, Marta Wojewódka-Przybył, Thorsten Bauersachs, Andreas Eckert, Marek Locmelis, Jason H. Curtis, Susan R.H. Zimmerman, Alex Correa-Metrio, Lorenz Schwark, Edward Duarte, Antje Schwalb, Etienne Niewerth, Paula Gabriela Echeverría-Galindo, Liseth Pérez; ERRATUM: New estimates of the magnitude of the sea-level jump during the 8.2 ka event. Geology 2023;; 51 (7): 703. doi: https://doi.org/10.1130/G49296E.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search ORIGINAL ARTICLE: 2022, v. 50, no. 1, p. 86–90, https://doi.org/10.1130/G49296.1. First published 30 September 2021. ERRATUM PUBLICATION: 2023, v. 51, no. 7, p. 703–703, https://doi.org/10.1130/G49296E.1. First published 10 May 2023 Figure 2 of the original article contained an error in the location of some of the radiocarbon dates in Cores 1 and 2. This does not change the main findings of the paper. The corrected figure is below. View Original Article You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

As Earth's atmospheric temperatures and human populations increase, more people are becoming vulnerable to natural and human-induced disasters. This is particularly true in Central America, where the growing human population is experiencing climate extremes (droughts and floods), and the region is susceptible to geological hazards, such as earthquakes and volcanic eruptions, and environmental deterioration in many forms (soil erosion, lake eutrophication, heavy metal contamination, etc.). Instrumental and historical data from the region are insufficient to understand and document past hazards, a necessary first step for mitigating future risks. Long, continuous, well-resolved geological records can, however, provide a window into past climate and environmental changes that can be used to better predict future conditions in the region. The Lake Izabal Basin (LIB), in eastern Guatemala, contains the longest known continental records of tectonics, climate, and environmental change in the northern Neotropics. The basin is a pull-apart depression that developed along the North American and Caribbean plate boundary ∼ 12 Myr ago and contains > 4 km of sediment. The sedimentological archive in the LIB records the interplay among several Earth System processes. Consequently, exploration of sediments in the basin can provide key information concerning: (1) tectonic deformation and earthquake history along the plate boundary; (2) the timing and causes of volcanism from the Central American Volcanic Arc; and (3) hydroclimatic, ecologic, and geomicrobiological responses to different climate and environmental states. To evaluate the LIB as a potential site for scientific drilling, 65 scientists from 13 countries and 33 institutions met in Antigua, Guatemala, in August 2022 under the auspices of the International Continental Scientific Drilling Program (ICDP) and the US National Science Foundation (NSF). Several working groups developed scientific questions and overarching hypotheses that could be addressed by drilling the LIB and identified optimal coring sites and instrumentation needed to achieve the project goals. The group also discussed logistical challenges and outreach opportunities. The project is not only an outstanding opportunity to improve our scientific understanding of seismotectonic, volcanic, paleoclimatic, paleoecologic, and paleobiologic processes that operate in the tropics of Central America, but it is also an opportunity to improve understanding of multiple geological hazards and communicate that knowledge to help increase the resilience of at-risk Central American communities.

We analyzed sediment cores from coastal Lake Izabal, Guatemala, to infer Holocene biogeochemical changes in the lake. At ca. 8370 calibrated yr B.P. (cal. yr B.P.), marine waters entered the lake, which presently lies ~38 km from the Caribbean coast. Temporal correlation between Early Holocene drainage of high-latitude Lakes Agassiz and Ojibway (in North America) and marine flooding of Lake Izabal suggests a causal link between the two processes. Our data indicate a relative sea-level jump of 2.60 ± 0.88 m, which is larger than previous estimates of sea-level rise during the 8.2 ka event. The inferred sea-level jump, however, cannot be explained solely by the volume of water released during drainage of Lakes Agassiz and Ojibway. Instead, we propose that previous studies underestimated the magnitude of Lakes Agassiz and Ojibway discharge, or that additional meltwater sources contributed to global sea-level rise at that time.

ABSTRACT: Conducting safe and effective waste disposal and sequestration processes relies on an accurate determination of the reservoir extent and the prevailing boundary conditions. Due to the limitations surrounding the acquisition and analysis of the reservoir geometry, waste disposal, cuttings re-injection, and CO2 sequestration studies are based on simplifying assumptions regarding the lateral and vertical fluid flow boundary conditions. These assumptions can jeopardize the study’s outcomes, especially for green fields. Common boundary conditions considered are limited to either open (steady-state) or closed (semi-steady state) lateral boundaries, alongside a complete or partially sealing caprock. This study uses pressure transient analysis to provide a quantitative tool to assess a wider variety of fluid flow boundary conditions. We show that a short drawdown followed by a pro-longed buildup test can identify the fluid flow boundary condition, including closed, open, semi-open, and infinite systems. The significant difference in CO2 storage capacity and the different geomechanical risks associated with various fluid flow boundary conditions suggest that the presented methodology should be considered prior to fluid injection scenarios. 1 INTRODUCTION Geologic sequestration is an increasingly important strategy to dispose of drilling fluids, saltwater, and hazardous waste and to reduce the CO2 concentration in the atmosphere (Mortezaei et al., 2021). The most viable CO2 sequestration targets include deep saline aquifers and mature hydrocarbon fields (Garcia et al., 2010; Sarhosis et al., 2018; Bachu, 2003; Holloway, 2001; Holloway and Savage, 1993; Klara et al., 2003). The fluid flow boundary conditions of the target storage medium need to be known to predict the target formation’s storage capacity, the spreading of the injected plume, and the geomechanical risks associated with the pore pressure increase. The current practices commonly consider an assortment of simplified boundary conditions that include open and closed boundaries when it comes to sequestration.

ABSTRACT: Wellbore integrity to ensure efficient, economical, and environmentally friendly operations is a significant and fundamental challenge for CO2 sequestration wells. The carbonation reaction between Portland cement and CO2 can change the microstructure of the cement skeleton, change the cement mechanical properties, damage the annular seal, and finally induce CO2 leakage. This study utilizes an integrated approach including a CO2-cement degradation test, mechanical tests for strength and elastic properties, X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) for composition analysis, and finite element analysis for failure evaluation. The mechanical test results show that the carbonation reaction can improve the sealing effect of the cement during the early stage of degradation (~2 weeks). Mechanical and geochemistry test results show that the carbonation reaction would fundamentally change the composition and microstructure of the cement matrix after long-term CO2 degradation, thereby inducing significant decreases in strength, and enhanced porosity, and permeability. The numerical results indicate that during long-term CO2 injection, the sealing effect of the cement would decrease gradually, and the cement sheath is more likely to fail under external loads arising from wellbore pressure and temperature variations. The mechanical and geochemical test results also show that the temporal variations of cement strength and Ca2+ composition have a strong similarity, which should be further analyzed for possible correlation. In summary, this study provides an integrated approach to qualitatively and quantitatively evaluate the cement degradation and predict failure of CO2 sequestration wells. The allowable wellbore pressure and temperature ranges can be provided for different degrees of cement sheath degradation to assist the field operations and cement slurry design of CO2 sequestration wells. 1. INTRODUCTION The unwanted leakage from the CO2-injection wells impedes the stable and economic industrialization of the CO2 geological sequestration. Therefore, maintaining wellbore integrity becomes a priority task to ensure a successful CO2 sequestration project (Zhang et al. 2019, Xu et al. 2022). For CO2-injection wells, the carbonation reaction between Portland cement and CO2 is a complicated process controlled by CO2 concentration, presence of water, age of the cement, pressure, temperature, and the level of intactness of the cement matrix (Zhang et al. 2021, 2022a). Oilwell cement and CO2 reaction have been extensively investigated by various laboratory studies, including the influence of pressure and temperature (Barlet-Gouedard et al. 2006; Omosebi et al. 2017), reaction period (Barlet-Gouedard et al. 2006), and presence of various additives (Barlet-Gouedard et al. 2006). The major chemical reactions between CO2 and different compositions in the cement are presented in Figure 1 and Equation 1 to 5 (Kashef-Haghighi et al. 2015).

The Lake Izabal Basin in Guatemala is a major pull‐apart basin along the sinistral Polochic Fault, which is part of the North American and Caribbean plate boundary. The basin infill contains information about the tectonic and sedimentological processes that have imparted a significant control on its sedimentary section. The inception of the basin has been linked to the relative importance of the Polochic Fault in the tectonic history of the plate boundary; yet, its sedimentological record and its inception age have been poorly documented. This study integrates diverse datasets, including industry reports, well logs and reports, well cuttings, vintage seismic data, outcrop observations and geochronological data to constrain the initial infill and age of inception of the basin. The integrated data show that during the Oligocene–Miocene, a marine carbonate platform was established in the region which was later uplifted and eroded in the early Miocene. The fluvial–lacustrine deposits above this carbonate platform are part of the initial infill of the basin and are constrained with zircon weighted‐mean 206 Pb/ 238 U ages of 12.060 ± 0.008 from a volcanic tuff ~30 m above the unconformity. Sandstone, mudstone and coal dominate the interval from 12 to 4 Ma, with an increase in conglomerate correlating to the uplift of the Mico Mountains and San Gil Hill at 4 Ma. Fault switch activity between the Polochic and Motagua faults has been hypothesized to explain total offset along the Polochic Fault and the geologic and geodetic slip rates along the two faults. The 12 Ma age determined for the initial infill of the basin confirms this hypothesis. Consequently, our study confirms that at ~12 Ma the Polochic Fault served as the main fault of the plate boundary with inferred slip rates ranging from 13 to 21 mm/yr with a strong possibility that the Polochic Fault was, at some point between 15 Ma and 7 Ma, the only active fault of the plate boundary. The results of this study show that tectonic records preserved in sediments of strike‐slip basins improve the understanding of the relative significance of individual faults and the implications with respect to strain partitioning throughout its tectonic history.

Summary Artificial neural networks (ANNs) and multiple regression analysis (MRA) have been presented in this study to estimate formation permeability using petrophysical well log data. The correlation coefficient for the ANN model was found to be 0.95, whereas the R2 of MRA model was found to be equal 0.9. This demonstrates that ANN is more conservative than MRA in predicting permeability. The scattering between core porosity and permeability using the classical method is to be expected because of the heterogeneity of carbonate rocks. While the FZI method showed a good performance capacity in predicting permeability, it cannot be applied in uncored wells since it requires other parameters to be previously computed as core porosity and permeability. Furthermore, the presented models are not affected by the uncertainty introduced by the cementation factor and saturation exponent. It is important to note that the MRA technique has a few drawbacks, as it gave negative prediction in addition it deals with the average mean values. The developed models should be calibrated with actual permeability measurements if they will be used in another field study. This study presents predictive methods for better estimate permeability in uncored wells using conventional well logs.

Abstract It is known that pore pressure (Pp) is an integral part for the well planning process. Pore pressure can be directly measured from the wireline pressure and well tests, or indirectly measured from seismic velocities, well logs, and shale densities. While the direct measurements are limited due to the cost and time-saving purposes, the indirect methods are often used, especially the techniques that based on the mechanical compaction of fine-grained sediments. However, the loss of porosity in carbonate reservoirs is not only controlled by the effective stresses, but also affected by a variety of depositional environments and diagenetic processes. Most of the previous models were developed to detect the overpressure zones rather than the subnormal (i.e., depleted) zones. There are also some limitations in the traditional methods, as they are based on empirical relations and constants that can differ from basins to others. This study presents a regression analysis (RA) and artificial neural networks (ANNs) capable of predicting the Pp using measurable well logs. A field case, located in SE Iraq, has been investigated to determine the Pp from well log data. A database for five offset wells of Mishrif reservoir was subjected to the predictive methods. Two traditional methods, the Eaton and the Ratio methods, were also conducted to compare their performance with in-situ pore pressure data in carbonate reservoirs. The current results showed that the true vertical depth, bulk density, neutron porosity, gamma ray, compressional travel time, and unconfined compressive strength are the key parameters for the Pp prediction. An empirical model with a good performance using ANNs has been developed to estimate the Pp using petrophysical well logs. Although both RA and ANNs are conservative in predicting Pp, the higher value of determination coefficient (0.96) of ANNs demonstrated that the ANN can predict the subnormal pore pressures in carbonate reservoirs. While the Eaton and the Ratio methods which are based on the drilling derived dc values showed a closer alignment with the in-situ Pp direct measurements, they are not applicable in depleted carbonate reservoirs. Other indicators of the prediction Pp should be used in conjunction with penetration rate. The validity of the proposed models was successfully checked with the data from another field study in SE Iraq. This study presents efficient and cost-effective models to estimate the formation pore pressure in depleted carbonate environments utilizing petrophysical well logs.

The development of reliable geochemical indicators to guide the search for Ni-Cu-(PGE) sulfide ores associated with komatiites, komatiitic basalts and picrites has been a long-standing goal. Here we discuss the latest findings of a long-term study that tests the usefulness of laser ablation (LA) ICP-MS trace element analysis of minerals in the exploration for magmatic sulfide deposits. We show that the Ru contents of chromite and the Cu contents of olivine empirically correspond to the sulfur-saturation state of a mafic-ultramafic host rock during chromite and/or olivine crystallization. Sulfide mineralized systems are characterized by distinct Ru and Cu depletions relative to sulfur-undersaturated systems. The lower Ru and Cu contents of chromite and olivine, respectively, reflect the chalcophile behavior of these elements during sulfide segregation. Our compiled data indicate that LA-ICP-MS analysis of chromite and olivine allows to predict if a system has reached sulfur saturation, and therefore is prospective to host magmatic sulfide ore, with an accuracy of >90%. These findings highlight the importance of mineral chemistry for future exploration strategies, including (1) drill core studies to develop vectors towards ore zones, and (2) stream sediment and (3) laterite/soil sampling to develop chromite-Ru and olivine-Cu heat maps to guide greenfield exploration.