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Ying Xiong - One of the best experts on this subject based on the ideXlab platform.
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middle ordovician multi stage penecontemporaneous Karstification in north china implications for reservoir genesis and sea level fluctuations
Journal of Asian Earth Sciences, 2019Co-Authors: Ying Xiong, Di Xiao, Jie ZhangAbstract:Abstract Palaeokarsts contain important information about subaerial exposures due to sea-level regression, which has been considered as a dominant genesis of reservoirs. Herein we describe a typical sedimentary core section of the Middle Ordovician Majiagou Formation that records multi-stage penecontemporaneous Karstification in North China. Petrographic observations and stable isotopic data reveal high-frequency penecontemporaneous subaerial exposure and resulting Karstification. Evidence for this includes erosional surfaces, gypsum breccias, facies-controlled dissolution vugs and vadose infillings, fabric-selective dissolution, and negative carbon and oxygen isotopic excursions. Karstification generally occurred in the middle and upper parts of an upward-shallowing sequence within a single depositional cycle, leading to meteoric water dissolution of shoals and mounds. This significantly enlarged the primary pores and generated new reservoir space. As such, high-quality hydrocarbon reservoirs became well developed, which are regularly and cyclically stacked at locations a few meters below the multiple exposure surfaces. Reservoir porosity also varies systematically with the high-frequency sedimentary cycles, and is generally at a maximum in the middle and upper parts of a cycle. The multi-stage penecontemporaneous subaerial exposure and resulting Karstification reflect high-frequency changes in relative sea level in North China at this time, thereby providing a framework for identifying thin carbonate reservoirs in and around the Ordos Basin.
Laurent Bruxelles - One of the best experts on this subject based on the ideXlab platform.
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the process of ghost rock Karstification and its role in the formation of cave systems
Earth-Science Reviews, 2014Co-Authors: Caroline Dubois, Yves Quinif, Jeanmarc Baele, L Barriquand, A Bini, Laurent Bruxelles, Gregory Dandurand, Cecile Havron, Olivier KaufmannAbstract:Abstract This paper presents an extensive review of the process of ghost-rock Karstification and highlights its role in the formation of cave systems. The process integrates chemical weathering and mechanical erosion and extends a number of existing theories pertaining to continental landscape development. It is a two stage process that differs in many respects from the traditional single-stage process of Karstification by total removal. The first stage is characterised by chemical dissolution and removal of the soluble species. It requires low hydrodynamic energy and creates a ghost-rock feature filled with residual alterite. The second stage is characterised by mechanical erosion of the undissolved particles. It requires high hydrodynamic energy and it is only then that open galleries are created. The transition from the first stage to the second is driven by the amount of energy within the thermodynamic system. The process is illustrated by detailed field observations and the results of the laboratory analyses of samples taken from the karstotype area around Soignies in southern Belgium. Thereafter, a series of case studies provide a synthesis of field observations and laboratory analyses from across western Europe. These studies come from geologically distinct parts of Belgium, France, Italy, and the United Kingdom. The process of ghost-rock Karstification challenges a number of axioms associated with the process of Karstification by total removal. On the basis of the evidence presented it is argued that it is no longer acceptable to use karst morphologies as a basis with which to infer specific karstogenetic processes and it is no longer necessary for a karst system to relate to base level as ghost-rock Karstification proceeds along transmissive pathways in the rock. There is also some evidence to suggest that ghost-rock Karstification may be superseded by Karstification by total removal, and vice versa, according to the amount of energy within the thermodynamic system. The proposed chemical weathering and subsequent mechanical erosion of limestone suggest that the development of karst terrain is related far more closely to the geomorphological development of aluminosilicate and siliceous terrains than is generally supposed. It is now necessary to reconsider the origin of many karst systems in light of the outlined process of ghost-rock Karstification.
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l alteration de type fantome de roche processus evolution et implications pour la Karstification
Geomorphologie-relief Processus Environnement, 2011Co-Authors: Yves Quinif, Laurent BruxellesAbstract:Depuis plusieurs annees, de nombreux exemples de fantomes de roche ont ete reconnus dans les karsts en Belgique, en France et en Italie. Ils correspondent a des poches ou a des couloirs de decalcification emplis d’alterite in situ. Leur genese releve d’un cas special de Karstification ou, a l’inverse des phenomenes de Karstification par enlevement total, le residu insoluble ou moins soluble reste en place et forme un squelette qui mime la structure initiale de la roche (fossiles, joints, lits de chailles, etc.). Cette alterite, qui peut egalement se developper sous une voute calcaire, forme un vaste reseau interconnecte et cale sur la fracturation. De fait, elle constitue une discontinuite importante au sein des massifs karstiques. Lorsque le niveau de base s’abaisse, l’alterite s’effondre sur elle-meme puis elle est erodee par des circulations souterraines qui se mettent en place a son toit. Des reseaux de galeries mais aussi des formes de surface se forment alors rapidement, essentiellement par evidement de l’alterite. Ce phenomene est maintenant reconnu dans le monde entier, affectant tous les types de roches, carbonatees ou non.
Yves Quinif - One of the best experts on this subject based on the ideXlab platform.
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the process of ghost rock Karstification and its role in the formation of cave systems
Earth-Science Reviews, 2014Co-Authors: Caroline Dubois, Yves Quinif, Jeanmarc Baele, L Barriquand, A Bini, Laurent Bruxelles, Gregory Dandurand, Cecile Havron, Olivier KaufmannAbstract:Abstract This paper presents an extensive review of the process of ghost-rock Karstification and highlights its role in the formation of cave systems. The process integrates chemical weathering and mechanical erosion and extends a number of existing theories pertaining to continental landscape development. It is a two stage process that differs in many respects from the traditional single-stage process of Karstification by total removal. The first stage is characterised by chemical dissolution and removal of the soluble species. It requires low hydrodynamic energy and creates a ghost-rock feature filled with residual alterite. The second stage is characterised by mechanical erosion of the undissolved particles. It requires high hydrodynamic energy and it is only then that open galleries are created. The transition from the first stage to the second is driven by the amount of energy within the thermodynamic system. The process is illustrated by detailed field observations and the results of the laboratory analyses of samples taken from the karstotype area around Soignies in southern Belgium. Thereafter, a series of case studies provide a synthesis of field observations and laboratory analyses from across western Europe. These studies come from geologically distinct parts of Belgium, France, Italy, and the United Kingdom. The process of ghost-rock Karstification challenges a number of axioms associated with the process of Karstification by total removal. On the basis of the evidence presented it is argued that it is no longer acceptable to use karst morphologies as a basis with which to infer specific karstogenetic processes and it is no longer necessary for a karst system to relate to base level as ghost-rock Karstification proceeds along transmissive pathways in the rock. There is also some evidence to suggest that ghost-rock Karstification may be superseded by Karstification by total removal, and vice versa, according to the amount of energy within the thermodynamic system. The proposed chemical weathering and subsequent mechanical erosion of limestone suggest that the development of karst terrain is related far more closely to the geomorphological development of aluminosilicate and siliceous terrains than is generally supposed. It is now necessary to reconsider the origin of many karst systems in light of the outlined process of ghost-rock Karstification.
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Karstification in dolomitized waulsortian mudmounds belgium
Geologica Belgica, 2013Co-Authors: Lorraine Dewaide, Yves Quinif, Jeanmarc Baele, Sara Vandycke, Pauline Collondrouaillet, Gaetan Rochez, Vincent HalletAbstract:The Waulsortian mudmounds consist of massive limestones that developed from late Tournaisian to early Visean. Secondary dolomitization has locally affected these mudmounds conducting to the coexistence of dolostone and limestone patches. Numerous karst cavities are preferentially developed in dolomitic intervals and are geometrically related to one or several fracture directions. These cavities, called the ``dolostone cavity type'' can be partially filled with coarse calcite and are usually bounded to the host dolostone by a calcitic transition zone which has roughly a lenticular shape. Petrographic observations, especially under cathodoluminescence, show the following sequence starting from the micro-cavities/micro-fractures network in the transition zone: 1) calcite cement in cavities, 2) dedolomite fabric, 3) host dolomite. The observed microscopic features, as well as morphological data, lead to the development of a conceptual genetic model of karst formation at macro- and microscale. In this model, first a strong dissolution of the host dolostone occurred from the fracture network thereby creating karst cavities (at macroscale) and important pervasive porosity (at microscale). Dissolution was then followed by dedolomitization in one or two-steps of the already corroded dolospar. Afterwards cementation of the residual porosity and precipitation of coarse calcite in the karst cavities occur. Even if the geological conditions under which these processes took place are not fully unraveled yet, a model that could fit with the data is presented. A discussion about the paleo-environment and paleo-hydrological conditions is settled and we also propose that the development of karst in the dolomitized mudmounds is favored by the coexistence of dolostone and limestone patches given their initial difference in porosity and competence.
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l alteration de type fantome de roche processus evolution et implications pour la Karstification
Geomorphologie-relief Processus Environnement, 2011Co-Authors: Yves Quinif, Laurent BruxellesAbstract:Depuis plusieurs annees, de nombreux exemples de fantomes de roche ont ete reconnus dans les karsts en Belgique, en France et en Italie. Ils correspondent a des poches ou a des couloirs de decalcification emplis d’alterite in situ. Leur genese releve d’un cas special de Karstification ou, a l’inverse des phenomenes de Karstification par enlevement total, le residu insoluble ou moins soluble reste en place et forme un squelette qui mime la structure initiale de la roche (fossiles, joints, lits de chailles, etc.). Cette alterite, qui peut egalement se developper sous une voute calcaire, forme un vaste reseau interconnecte et cale sur la fracturation. De fait, elle constitue une discontinuite importante au sein des massifs karstiques. Lorsque le niveau de base s’abaisse, l’alterite s’effondre sur elle-meme puis elle est erodee par des circulations souterraines qui se mettent en place a son toit. Des reseaux de galeries mais aussi des formes de surface se forment alors rapidement, essentiellement par evidement de l’alterite. Ce phenomene est maintenant reconnu dans le monde entier, affectant tous les types de roches, carbonatees ou non.
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tectonique et Karstification le cas de la region de han sur lesse belgique
Karstologia : revue de karstologie et de spéléologie physique, 2004Co-Authors: Cecile Havron, Yves Quinif, Sara VandyckeAbstract:Une analyse structurale a ete effectuee dans quatre massifs calcaires de la region de Han-sur-Lesse en Belgique en vue de cerner l'interaction entre type de karst et type de tectonique. Les massifs de Han et de Wellin possedent un systeme karstique perte-resurgence au contraire des massifs des Grignaux-Turmont et de Resteigne. L'analyse structurale etudie la geometrie des structures tectoniques comme les failles, les joints et les fentes de tension. Une histoire tectonique des massifs est ainsi etablie. Cette analyse a permis de preciser les relations entre l'evolution tectonique d'un massif et l'amorce de sa Karstification au sens de la presence d'un systeme endokarstique structure. Une etude des directions des joints karstifies a permis la mise en evidence de certains parametres regissant la geometrie des systemes karstiques. Une hypothese de karstogenese en deux temps est evoquee. En l'absence de potentiel hydrodynamique mais grâce a un champ de contraintes en extension, une Karstification de type «fantome » affecte certains massifs durant le Mesozoique suivant une direction generale N50°E -N65°E. Ensuite, une autre phase tectonique en extension au Cenozoique, alliee avec la naissance d'un potentiel hydrodynamique du a la surrection de l'Ardenne provoque la Karstification finale des massifs suivant une direction N140°E -N150°E, a l'origine des systemes de recoupement souterrain de meandre.
Jie Zhang - One of the best experts on this subject based on the ideXlab platform.
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middle ordovician multi stage penecontemporaneous Karstification in north china implications for reservoir genesis and sea level fluctuations
Journal of Asian Earth Sciences, 2019Co-Authors: Ying Xiong, Di Xiao, Jie ZhangAbstract:Abstract Palaeokarsts contain important information about subaerial exposures due to sea-level regression, which has been considered as a dominant genesis of reservoirs. Herein we describe a typical sedimentary core section of the Middle Ordovician Majiagou Formation that records multi-stage penecontemporaneous Karstification in North China. Petrographic observations and stable isotopic data reveal high-frequency penecontemporaneous subaerial exposure and resulting Karstification. Evidence for this includes erosional surfaces, gypsum breccias, facies-controlled dissolution vugs and vadose infillings, fabric-selective dissolution, and negative carbon and oxygen isotopic excursions. Karstification generally occurred in the middle and upper parts of an upward-shallowing sequence within a single depositional cycle, leading to meteoric water dissolution of shoals and mounds. This significantly enlarged the primary pores and generated new reservoir space. As such, high-quality hydrocarbon reservoirs became well developed, which are regularly and cyclically stacked at locations a few meters below the multiple exposure surfaces. Reservoir porosity also varies systematically with the high-frequency sedimentary cycles, and is generally at a maximum in the middle and upper parts of a cycle. The multi-stage penecontemporaneous subaerial exposure and resulting Karstification reflect high-frequency changes in relative sea level in North China at this time, thereby providing a framework for identifying thin carbonate reservoirs in and around the Ordos Basin.
Francisco Gutierrez - One of the best experts on this subject based on the ideXlab platform.
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evaluation of geochemical and hydrogeological processes by geochemical modeling in an area affected by evaporite Karstification
Journal of Hydrology, 2015Co-Authors: Patricia Acero, Francisco Gutierrez, J P Galve, L F Auque, Domingo Carbonel, M J Gimeno, Yoseph Yechieli, Maria P Asta, Javier B GomezAbstract:The Ebro Valley in the outskirts of Zaragoza (NE Spain) is severely affected by evaporite Karstification, leading to multiple problems related to subsidence and sinkhole formation. In this work, a combination of inverse (mixing + mass-balance) and forward (reaction-path) geochemical calculations is applied for the quantification of the main Karstification processes and seasonal variations in this area. The obtained results prove the suitability of the applied methodology for the characterization of similar problems in other areas with scarce geological and hydrogeological information. The hydrogeology and hydrochemistry of the system can be mainly attributed to the mixing of variable proportions of concentrated groundwater from the evaporitic aquifer and more dilute water from the overlying alluvial aquifer. The existence of a good connection between these aquifers is supported by: (1) the fast changes in the hydrochemistry of the karst aquifer related to recharge by irrigation, and (2) the deduced input of evaporitic groundwater in the alluvial materials. The evolution in some parts of the alluvial/evaporitic aquifer system is clearly dominated by the seasonal variations in the recharge by dilute irrigation waters (up to 95% of water volume in some sinkhole ponds), whereas other points seem to be clearly determined by the hydrochemistry of the concentrated evaporitic aquifer groundwater (up to 50% of the water volume in some springs). The following reactions, previous or superimposed to mixing processes, explain the observed hydrochemistry in the studied area: dissolution of halite (NaCI), gypsum (CaSO4.2H(2)O)/anhydrite (CaSO4) and dolomite (CaMg(CO3)(2)), CO2(B) input and degassing and calcite (CaCO3) dissolution/precipitation. The modeling results suggest the existence of a large spatial variability in the composition of the evaporitic groundwater, mainly caused by large differences in the availability of halite in contact with the groundwater. Active subsidence associated with halite dissolution is expected to continue in the study area, together with the episodic increase of gypsum dissolution associated with the input of dilute irrigation waters. (C) 2015 Elsevier B.V. All rights reserved.
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large depressions thickened terraces and gravitational deformation in the ebro river valley zaragoza area ne spain evidence of glauberite and halite interstratal Karstification
Geomorphology, 2013Co-Authors: Jesus Guerrero, Francisco Gutierrez, J P GalveAbstract:Abstract In the studied reach of the Ebro Valley, the terrace and pediment sediments deposited over glauberite- and halite-bearing evaporites show local thickenings (> 50 m) recording dissolution-induced synsedimentary subsidence. Recent data on the lithostratigraphy of the evaporite sequence allow relating the alluvium thickenings with either halite or glauberite dissolution. The alluvium-filled dissolution basin underlying the youngest terraces (T8–T11) is ascribed to halite Karstification; the top of a halite unit approximately 75 m thick is situated 40–15 m below the valley bottom. The thickenings of terrace (T1–T7) and pediment sediments are attributed to interstratal glauberite Karstification: (1) Coincidence between the elevation range of the terraces and that of the glauberite-rich unit. Glauberite beds reach 30 and 100 m in single-bed and cumulative thickness, respectively. (2) The exposed bedrock underlying thickened alluvium shows abundant subsidence features indicative of interstratal Karstification. The most common structure corresponds to hectometer-scale sag basins with superimposed collapses in the central sector of each basin. The subsided bedrock is frequently transformed into dissolution-collapse breccias showing a complete textural gradation, from crackle packbreccias to chaotic floatbreccias and karstic residues. (3) Paleokarst exposures show evidence of Karstification confined to specific beds made up of secondary gypsum after precursory glauberite, partly dissolved and partly replaced. Despite the magnitude of the subsidence recorded by the thickened alluvium and unlike nearby tributaries, the terraces show a continuous and parallel arrangement indicating that the fluvial system was able to counterbalance subsidence by aggradation. A number of kilometer-size flat-bottom depressions have been developed in the valley margin, typically next to and inset into thickened terrace and pediment deposits. The subsidence structures exposed in artificial excavations excavated in the bottom of some depressions and the correlation between the altitudinal distribution of these basins and that of the glauberite-rich unit reveal that subsidence related to interstratal glauberite Karstification is the main process involved in their genesis. This research ascribes for the first time the thickenings and deformation of specific terrace levels and pediment levels and the development of large karstic depressions to interstratal Karstification of exceptionally thick glauberite units.
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gypsum Karstification induced subsidence effects on alluvial systems and derived geohazards calatayud graben iberian range spain
Geomorphology, 1996Co-Authors: Francisco GutierrezAbstract:Abstract The Karstification of the tertiary gypsum formations in the Calatayud Graben has given rise to synsedimentary and postsedimentary subsidence phenomena in both the Neogene sediments of the endorheic graben fill and in the Quaternary alluvial sediments deposited under exorheic conditions. In the so-called Maluenda and Perejiles areas, covering 4.4 and 12 km2 respectively, the Neogene sedimentary units stratigraphically above the gypsum have subsided due to the Karstification of the underlying evaporites. The maximum subsidence in both areas has reached at least 200 m. The Jalon-Jiloca-Perejiles alluvial system has been affected by karstic subsidence during its Quaternary evolution. Ten stepped alluvial levels (pediment-terrace) have been identified. As a consequence of synsedimentary karstic subsidence the deposit of an alluvial level can be locally thickened, changing in a short distance from less than 10 m to more than 100 m in thickness. Thus, the deposit of an individual terrace can be locally superimposed on the deposits of older terraces. The palaeokarst recorded in the sediments of the different alluvial levels shows how the karstic subsidence has controlled the dynamics of the sedimentary system. The alluvial karstic subsidence is currently active in the flood plains affecting fluvial channels, buildings, communication ways, irrigation ditches and the Calatayud gypsum scarp.
