To increase the understanding of the Wolfcampian unconventional plays within the Permian Basin, we present an integrated subsurface study shedding light on multiple target stratigraphic units (Wolfcamp A, B, C). We analyzed a rich data set covering 1000 km2 (386 mi2) in the deep-water sector (basinward of the shelf margin) of the Delaware Basin to generate a robust sequence stratigraphic framework that allows for the prediction of rock types and reservoir quality within specific sequences and improves the mapping of common-risk segments, the development options, and the landing zones in the most productive area of this super basin. These analyses consist of generating maps from seismic data and wells at basin scale (9300 km2 [35,900 mi2]), describing 29 cores, integrating 11 lithofacies and 15 petrofacies with core analyses (gamma ray, x-ray diffraction, total organic carbon, water saturation, porosity, permeability, Young’s modulus, Poisson’s ratio, compressional wave/shear wave), calibrating well log signatures to cores (gamma ray, density, neutron, resistivity), and assigning geological significance to log signatures (electrofacies). Results demonstrate how to create a simplified electrofacies model to identify the four main rock types of the basin. Interpretation includes determining time lines, correlating wells based on core analyses and calibrated log signatures, and propagating correlations to wells without cores.The stratigraphic framework, which evolved from the integration and reconciliation of multiple subsurface data sets (1) serves as a common starting point for new subsurface projects, (2) identifies the black siliceous mudstones as the best reservoir quality lithofacies and the lean dolomitic mudstone as the worst, and (3) classifies the stratigraphic beta unit as the most appropriate candidate for the development of unconventional resources.
{"title":"Application of a deep-water stratigraphic framework to the production of the Wolfcampian units in the Permian Basin","authors":"Daniel Minisini, Patricio Desjardins","doi":"10.1306/08252322163","DOIUrl":"https://doi.org/10.1306/08252322163","url":null,"abstract":"To increase the understanding of the Wolfcampian unconventional plays within the Permian Basin, we present an integrated subsurface study shedding light on multiple target stratigraphic units (Wolfcamp A, B, C). We analyzed a rich data set covering 1000 km2 (386 mi2) in the deep-water sector (basinward of the shelf margin) of the Delaware Basin to generate a robust sequence stratigraphic framework that allows for the prediction of rock types and reservoir quality within specific sequences and improves the mapping of common-risk segments, the development options, and the landing zones in the most productive area of this super basin. These analyses consist of generating maps from seismic data and wells at basin scale (9300 km2 [35,900 mi2]), describing 29 cores, integrating 11 lithofacies and 15 petrofacies with core analyses (gamma ray, x-ray diffraction, total organic carbon, water saturation, porosity, permeability, Young’s modulus, Poisson’s ratio, compressional wave/shear wave), calibrating well log signatures to cores (gamma ray, density, neutron, resistivity), and assigning geological significance to log signatures (electrofacies). Results demonstrate how to create a simplified electrofacies model to identify the four main rock types of the basin. Interpretation includes determining time lines, correlating wells based on core analyses and calibrated log signatures, and propagating correlations to wells without cores.The stratigraphic framework, which evolved from the integration and reconciliation of multiple subsurface data sets (1) serves as a common starting point for new subsurface projects, (2) identifies the black siliceous mudstones as the best reservoir quality lithofacies and the lean dolomitic mudstone as the worst, and (3) classifies the stratigraphic beta unit as the most appropriate candidate for the development of unconventional resources.","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139051619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Post-Permian salt tectonic processes and their relationship with varied paleodepositional systems were a major controlling factor of the Mesozoic–Cenozoic basin evolution of the Southern North Sea. Detailed mapping and analysis of Zechstein salt structure morphologies is vital to conduct regional kinematic analysis and evolution of salt structures as well as understanding the relationship between thick- and thin-skinned tectonics across the basin.This study uses the supraregional Petroleum Geo-Services Southern North Sea three-dimensional seismic MegaSurvey for the systematic identification and classification of salt structure morphologies using seismic attributes and validation with regional seismic sections. The smoothed dip of maximum similarity attribute is used to highlight abrupt changes in the values of the attribute, which correspond to sudden changes in dip angle indicating faults or the edges of diapiric structures, whereas gradual changes in the attribute value coupled with the longer wavelength of structures correspond to salt anticlines. Of the 224 salt structures developed across the Southern North Sea, 119 were classified as concordant and 79 as discordant, with 26 having concordant and discordant flanks.Validation of these maps with regional seismic sections allows salt structures to be classified into salt anticlines, salt anticlines with a crestal graben, reactive diapirs, salt diapirs (walls and stocks), and salt overthrusts.This study provides guidelines for identifying different salt structure morphologies based on their seismic attribute signature, which could be applied to other salt basins around the world.
{"title":"Three-dimensional seismic classification of salt structure morphologies across the Southern North Sea","authors":"Christopher Brennan, Anna Preiss, Jürgen Adam","doi":"10.1306/08072221136","DOIUrl":"https://doi.org/10.1306/08072221136","url":null,"abstract":"Post-Permian salt tectonic processes and their relationship with varied paleodepositional systems were a major controlling factor of the Mesozoic–Cenozoic basin evolution of the Southern North Sea. Detailed mapping and analysis of Zechstein salt structure morphologies is vital to conduct regional kinematic analysis and evolution of salt structures as well as understanding the relationship between thick- and thin-skinned tectonics across the basin.This study uses the supraregional Petroleum Geo-Services Southern North Sea three-dimensional seismic MegaSurvey for the systematic identification and classification of salt structure morphologies using seismic attributes and validation with regional seismic sections. The smoothed dip of maximum similarity attribute is used to highlight abrupt changes in the values of the attribute, which correspond to sudden changes in dip angle indicating faults or the edges of diapiric structures, whereas gradual changes in the attribute value coupled with the longer wavelength of structures correspond to salt anticlines. Of the 224 salt structures developed across the Southern North Sea, 119 were classified as concordant and 79 as discordant, with 26 having concordant and discordant flanks.Validation of these maps with regional seismic sections allows salt structures to be classified into salt anticlines, salt anticlines with a crestal graben, reactive diapirs, salt diapirs (walls and stocks), and salt overthrusts.This study provides guidelines for identifying different salt structure morphologies based on their seismic attribute signature, which could be applied to other salt basins around the world.","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138574778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.1306/bltnintro07182023
Rachelle Kernen, Tim Shin
As government policy, consumer markets, and global geopolitics rapidly shift, it will be imperative that energy companies, universities, and government organizations have access to research that addresses the subsurface development of energy. A key area of research for the energy transition is related to the precipitation, deposition, and diapirism in salt basins. Traditionally, evaporite stratigraphy and diapirism have been of great interest to the oil and gas industry because of the active petroleum systems and will continue to be valuable, especially from an energy security perspective. Energy security is important for several reasons, as it has significant implications for a...
{"title":"Introduction to Salt Basins Special Issue Volume 2: Evaporite precipitation, physical modeling, basin evolution in honor of Bruno Vendeville","authors":"Rachelle Kernen, Tim Shin","doi":"10.1306/bltnintro07182023","DOIUrl":"https://doi.org/10.1306/bltnintro07182023","url":null,"abstract":"As government policy, consumer markets, and global geopolitics rapidly shift, it will be imperative that energy companies, universities, and government organizations have access to research that addresses the subsurface development of energy. A key area of research for the energy transition is related to the precipitation, deposition, and diapirism in salt basins. Traditionally, evaporite stratigraphy and diapirism have been of great interest to the oil and gas industry because of the active petroleum systems and will continue to be valuable, especially from an energy security perspective. Energy security is important for several reasons, as it has significant implications for a...","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138629315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Turki K. Alshammasi, Sian L. Evans, Christopher A.-L. Jackson
Welds form due to tectonically induced thinning and/or dissolution of salt, with their composition and completeness thought to at least partly reflect their structural position within the salt-tectonic system. Despite their importance as seals or migration pathways for accumulations of hydrocarbons and CO2, we have relatively few published examples of drilled subsurface welds; such examples would allow us to improve our understanding of the processes and products of welding and to test analytical models of the underlying mechanics. In this study, we integrate three-dimensional seismic reflection and borehole data from the Green Canyon area of the northern Gulf of Mexico, United States, to characterize the geophysical and geological expression of a tertiary weld, as well as its broader salt-tectonic context. These data show that although appearing complete in seismic reflection data, the weld contains 124 ft (38 m) of relatively pure halite. This thickness is consistent with the predictions of analytical models and with observations from other natural examples of subsurface welds. Our observations also support a model whereby compositional fractionation of salt occurs as the salt-tectonic system evolves; in this model, less mobile and/or denser units, if originally present, are typically stranded within the deeper, autochthonous level trapped in primary welds or near the basal root of diapirs, whereas less viscous and/or less dense units form the cores of these diapirs and potentially, genetically related allochthonous sheets and canopies. We also show that shearing of the weld during downslope translation of the overlying minibasin did not lead to complete welding.
{"title":"Salt welding during canopy advance and shortening in the Green Canyon area, northern Gulf of Mexico","authors":"Turki K. Alshammasi, Sian L. Evans, Christopher A.-L. Jackson","doi":"10.1306/01192321170","DOIUrl":"https://doi.org/10.1306/01192321170","url":null,"abstract":"Welds form due to tectonically induced thinning and/or dissolution of salt, with their composition and completeness thought to at least partly reflect their structural position within the salt-tectonic system. Despite their importance as seals or migration pathways for accumulations of hydrocarbons and CO2, we have relatively few published examples of drilled subsurface welds; such examples would allow us to improve our understanding of the processes and products of welding and to test analytical models of the underlying mechanics. In this study, we integrate three-dimensional seismic reflection and borehole data from the Green Canyon area of the northern Gulf of Mexico, United States, to characterize the geophysical and geological expression of a tertiary weld, as well as its broader salt-tectonic context. These data show that although appearing complete in seismic reflection data, the weld contains 124 ft (38 m) of relatively pure halite. This thickness is consistent with the predictions of analytical models and with observations from other natural examples of subsurface welds. Our observations also support a model whereby compositional fractionation of salt occurs as the salt-tectonic system evolves; in this model, less mobile and/or denser units, if originally present, are typically stranded within the deeper, autochthonous level trapped in primary welds or near the basal root of diapirs, whereas less viscous and/or less dense units form the cores of these diapirs and potentially, genetically related allochthonous sheets and canopies. We also show that shearing of the weld during downslope translation of the overlying minibasin did not lead to complete welding.","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138629400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Early post-Permian salt mobilization of the Zechstein Supergroup was a major controlling factor of the post-Permian basin evolution and complex Mesozoic–Cenozoic architecture of different subbasins across the Southern North Sea. Supraregional merged seismic data sets enable the basin-scale systematic analysis of salt tectonic processes and their regional tectonic and local paleodepositional controls.This study uses the Southern North Sea MegaSurvey basin-scale three-dimensional seismic data set for the systematic identification and classification of salt structures, with a particular focus on the onset and cessation of individual salt structures across different subbasins. Regional analysis of high-resolution isochron maps demonstrates the basin-wide onset of salt mobilization occurred in the Triassic in most of the subbasins. The exceptions are the Silverpit Basin and the Cleaver Bank high, where the onset of salt mobilization was delayed until the Jurassic and the Cretaceous. Jurassic mobilization was restricted to major depocenters such as the Broad Fourteens Basin, Silverpit Basin, and Southern Central Graben. Basin-wide pulses of mobilization occurred throughout the Cretaceous and, apart from the Sole Pit and Silverpit Basins, continued during the Paleogene. The cessation of salt mobilization occurred mainly throughout the Paleogene, with only a few isolated structures active until the Neogene in areas such as the Central Graben and the Broad Fourteens Basin.Improved understanding of these early salt tectonic processes will provide new insights into fundamental salt basin–forming processes and mechanisms while developing new exploration strategies in the suprasalt overburden in the mature Southern North Sea Basin.
{"title":"Regional variability of onset and cessation of salt tectonics in the Mesozoic and Cenozoic Southern North Sea subbasins","authors":"Christopher Brennan, Jürgen Adam","doi":"10.1306/08072221105","DOIUrl":"https://doi.org/10.1306/08072221105","url":null,"abstract":"Early post-Permian salt mobilization of the Zechstein Supergroup was a major controlling factor of the post-Permian basin evolution and complex Mesozoic–Cenozoic architecture of different subbasins across the Southern North Sea. Supraregional merged seismic data sets enable the basin-scale systematic analysis of salt tectonic processes and their regional tectonic and local paleodepositional controls.This study uses the Southern North Sea MegaSurvey basin-scale three-dimensional seismic data set for the systematic identification and classification of salt structures, with a particular focus on the onset and cessation of individual salt structures across different subbasins. Regional analysis of high-resolution isochron maps demonstrates the basin-wide onset of salt mobilization occurred in the Triassic in most of the subbasins. The exceptions are the Silverpit Basin and the Cleaver Bank high, where the onset of salt mobilization was delayed until the Jurassic and the Cretaceous. Jurassic mobilization was restricted to major depocenters such as the Broad Fourteens Basin, Silverpit Basin, and Southern Central Graben. Basin-wide pulses of mobilization occurred throughout the Cretaceous and, apart from the Sole Pit and Silverpit Basins, continued during the Paleogene. The cessation of salt mobilization occurred mainly throughout the Paleogene, with only a few isolated structures active until the Neogene in areas such as the Central Graben and the Broad Fourteens Basin.Improved understanding of these early salt tectonic processes will provide new insights into fundamental salt basin–forming processes and mechanisms while developing new exploration strategies in the suprasalt overburden in the mature Southern North Sea Basin.","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.1306/04272110712index
The format of the 2023 Bulletin index consists of titles, authors, and keywords. Beginning at the left, column one references a regular Bulletin article (BU) or a Bulletin abstract (BA). Column two indicates the volume and issue numbers (00000 = volume 000, issue number 0). Column three gives the page number. Column four indicates whether the entry is by title (T), author (A), or keyword (K). The fifth column is the entry itself. Please note that this index does not show multiple authors in any one listing; each author is listed separately.BU 10711 1837 T A genetic algorithm-driven support...
2023 年公报索引的格式包括标题、作者和关键词。从左侧开始，第一栏引用常规公报文章 (BU) 或公报摘要 (BA)。第二栏注明卷号和期号（00000 = 第 000 卷，第 0 期）。第三栏给出页码。第四栏标明条目是按题名（T）、作者（A）还是关键词（K）。第五栏是条目本身。请注意，该索引不会在任何一个列表中显示多个作者；每个作者都单独列出。BU 10711 1837 T A genetic algorithm-driven support...
{"title":"INDEX OF VOLUME 107 (2023)","authors":"","doi":"10.1306/04272110712index","DOIUrl":"https://doi.org/10.1306/04272110712index","url":null,"abstract":"The format of the 2023 Bulletin index consists of titles, authors, and keywords. Beginning at the left, column one references a regular Bulletin article (BU) or a Bulletin abstract (BA). Column two indicates the volume and issue numbers (00000 = volume 000, issue number 0). Column three gives the page number. Column four indicates whether the entry is by title (T), author (A), or keyword (K). The fifth column is the entry itself. Please note that this index does not show multiple authors in any one listing; each author is listed separately.BU 10711 1837 T A genetic algorithm-driven support...","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138577387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tim P. Dooley, Martin P. A. Jackson, Michael R. Hudec
Salt canopies form the most spectacular and complex structures in the realm of salt tectonics. In this study, we use two physical models to examine salt-canopy growth and evolution on a salt-detached slope. A series of 14 feeders were seeded in our models and grew upward as passive diapirs. Eventually, these passive diapirs spread as salt sheets, with motion vectors skewed down the imposed regional dip slope. Sutures between individual sheets were bowed in the direction of override and became dismembered as the canopy system matured. Feeders in the interior of the array faced increasing competition for salt due to drawdown and primary welding. In contrast, feeders on the canopy peripheries faced less competition and rose more vigorously, generating local elevation-head gradients and imparting salt-flow directions that were highly oblique to the regional dip slope. Finally, our model canopies were loaded by prograding sediments. Canopy formation is strongly controlled by the salt budget, among other factors, and our less mature model formed a series of small canopies and isolated salt sheets. During sedimentary loading, this model displayed intrasheet and intracanopy inflation–deflation flow cells as salt was driven downdip. Sutures were further dispersed, and some were everted. Loading of our mature model deflated the originally continuous canopy, driving salt seaward up a series of base-salt ramps to form a shallow distal canopy. Suture fragments were carried all the way to the toe of this shallow canopy.Our more mature model was also shortened before loading, which resulted in canopy remobilization, thickening, and enhanced suture deformation. Salt flow during shortening was channeled by feeders, forming salt streams with orientations commonly oblique to regional dip. Canopy salt responded to shortening primarily by thickening, whereas the sediments below the canopy displayed a contrasting story. Here, a complex network of thrusts and tear faults linked the variably welded feeders.
{"title":"Growth and evolution of salt canopies on a salt-detached slope: Insights from physical models","authors":"Tim P. Dooley, Martin P. A. Jackson, Michael R. Hudec","doi":"10.1306/08072222013","DOIUrl":"https://doi.org/10.1306/08072222013","url":null,"abstract":"Salt canopies form the most spectacular and complex structures in the realm of salt tectonics. In this study, we use two physical models to examine salt-canopy growth and evolution on a salt-detached slope. A series of 14 feeders were seeded in our models and grew upward as passive diapirs. Eventually, these passive diapirs spread as salt sheets, with motion vectors skewed down the imposed regional dip slope. Sutures between individual sheets were bowed in the direction of override and became dismembered as the canopy system matured. Feeders in the interior of the array faced increasing competition for salt due to drawdown and primary welding. In contrast, feeders on the canopy peripheries faced less competition and rose more vigorously, generating local elevation-head gradients and imparting salt-flow directions that were highly oblique to the regional dip slope. Finally, our model canopies were loaded by prograding sediments. Canopy formation is strongly controlled by the salt budget, among other factors, and our less mature model formed a series of small canopies and isolated salt sheets. During sedimentary loading, this model displayed intrasheet and intracanopy inflation–deflation flow cells as salt was driven downdip. Sutures were further dispersed, and some were everted. Loading of our mature model deflated the originally continuous canopy, driving salt seaward up a series of base-salt ramps to form a shallow distal canopy. Suture fragments were carried all the way to the toe of this shallow canopy.Our more mature model was also shortened before loading, which resulted in canopy remobilization, thickening, and enhanced suture deformation. Salt flow during shortening was channeled by feeders, forming salt streams with orientations commonly oblique to regional dip. Canopy salt responded to shortening primarily by thickening, whereas the sediments below the canopy displayed a contrasting story. Here, a complex network of thrusts and tear faults linked the variably welded feeders.","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138629102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pablo Granado, Pablo Santolaria, Josep Anton Muñoz
Our analogue modeling program simulates a thermally subsiding rifted margin with a regional late synrift to early postrift salt basin. End member models include (1) pure downbuilding in a confined salt basin and (2) dominant gliding on a tilted opened toe margin. The spectrum between these was completed by modeling different amounts of downbuilding versus dominant gliding. Our results provide structural geometries and tectono-stratigraphic architectures for salt structures related to those end member processes, as well as when these occur simultaneously. Downbuilding is represented by vertical aggradation of synkinematic strata, the erosional truncation of megaflaps, and synkinematic debris sourced from salt and prekinematic strata. Dominant gliding is represented by salt-detached extension and related diapirism, resulting in the progressive increase in line lengths of younger stratigraphic units. The transition from downbuilding to dominant gliding is represented by diapir shoulders and the widening of sedimentary depocenters toward flanking salt structures undergoing collapse and salt-detached extension, as well as the truncation of stratigraphy by younger, laterally expanding depocenters. Our modeling results favor the interpretation of an early downbuilding component, followed by gliding for both the South Gabon rifted margin and the Cotiella Basin involved in the southcentral Pyrenees fold-thrust belt.
{"title":"Interplay of downbuilding and gliding in salt-bearing rifted margins: Insights from analogue modeling and natural case studies","authors":"Pablo Granado, Pablo Santolaria, Josep Anton Muñoz","doi":"10.1306/08072221203","DOIUrl":"https://doi.org/10.1306/08072221203","url":null,"abstract":"Our analogue modeling program simulates a thermally subsiding rifted margin with a regional late synrift to early postrift salt basin. End member models include (1) pure downbuilding in a confined salt basin and (2) dominant gliding on a tilted opened toe margin. The spectrum between these was completed by modeling different amounts of downbuilding versus dominant gliding. Our results provide structural geometries and tectono-stratigraphic architectures for salt structures related to those end member processes, as well as when these occur simultaneously. Downbuilding is represented by vertical aggradation of synkinematic strata, the erosional truncation of megaflaps, and synkinematic debris sourced from salt and prekinematic strata. Dominant gliding is represented by salt-detached extension and related diapirism, resulting in the progressive increase in line lengths of younger stratigraphic units. The transition from downbuilding to dominant gliding is represented by diapir shoulders and the widening of sedimentary depocenters toward flanking salt structures undergoing collapse and salt-detached extension, as well as the truncation of stratigraphy by younger, laterally expanding depocenters. Our modeling results favor the interpretation of an early downbuilding component, followed by gliding for both the South Gabon rifted margin and the Cotiella Basin involved in the southcentral Pyrenees fold-thrust belt.","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138629656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexandros Konstantinou, Garry D. Karner, Erik Kneller, David Gombosi
This study addresses the geological conundrum of giant salt basins by challenging the longstanding assumption that salt deposition necessarily occurs in brines in which the water depth is less than 300 m. We integrate regional observations, quantitative paleowater depth estimates, and numerical mass-balance modeling to illustrate that this assumption is inconsistent with observations from three giant salt deposits: the Mediterranean, northern South Atlantic, and northern Gulf of Mexico Basins. Our analysis indicates that these basins were very deep depressions before the onset of salt deposition, with a water-filled equivalent accommodation that exceeded 3500 m. Regional observations of pinch-out and downlap or onlap positions of these evaporites indicate a regional bathymetric relief of the top of salt with a slope of 0.5° to 0.7°. Our results demonstrate that these giant salt deposits can form by precipitation in ultradeep brine (>1000 m) settings and do not require complete desiccation to precipitate bittern salts. We propose an ultradeep basin, ultradeep brine class of salt basins, even if the salt was deposited during a major (∼1500 m) base-level drawdown like that in the Mediterranean. The mechanism of maintaining ultradeep brine conditions involves dynamic inflow of large fluxes of seawater into a restricted basin and simultaneous evaporation, which results in extremely rapid rates of salt deposition (∼4–>40 km/m.y.).
{"title":"Salt deposition in ultradeep brine settings by dynamic inflow and evaporation","authors":"Alexandros Konstantinou, Garry D. Karner, Erik Kneller, David Gombosi","doi":"10.1306/05302322105","DOIUrl":"https://doi.org/10.1306/05302322105","url":null,"abstract":"This study addresses the geological conundrum of giant salt basins by challenging the longstanding assumption that salt deposition necessarily occurs in brines in which the water depth is less than 300 m. We integrate regional observations, quantitative paleowater depth estimates, and numerical mass-balance modeling to illustrate that this assumption is inconsistent with observations from three giant salt deposits: the Mediterranean, northern South Atlantic, and northern Gulf of Mexico Basins. Our analysis indicates that these basins were very deep depressions before the onset of salt deposition, with a water-filled equivalent accommodation that exceeded 3500 m. Regional observations of pinch-out and downlap or onlap positions of these evaporites indicate a regional bathymetric relief of the top of salt with a slope of 0.5° to 0.7°. Our results demonstrate that these giant salt deposits can form by precipitation in ultradeep brine (>1000 m) settings and do not require complete desiccation to precipitate bittern salts. We propose an ultradeep basin, ultradeep brine class of salt basins, even if the salt was deposited during a major (∼1500 m) base-level drawdown like that in the Mediterranean. The mechanism of maintaining ultradeep brine conditions involves dynamic inflow of large fluxes of seawater into a restricted basin and simultaneous evaporation, which results in extremely rapid rates of salt deposition (∼4–>40 km/m.y.).","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138629101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jier Zhao, Xinmin Ge, Yiren Fan, Jianyu Liu, Yiguo Chen, Lei Xing
{"title":"A genetic algorithm–driven support vector machine to discriminate the kerogen type using conventional geophysical logging data","authors":"Jier Zhao, Xinmin Ge, Yiren Fan, Jianyu Liu, Yiguo Chen, Lei Xing","doi":"10.1306/08022320102","DOIUrl":"https://doi.org/10.1306/08022320102","url":null,"abstract":"","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135222153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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