Dedolomitization: review and case study of uncommon mesogenetic formation conditions

Schoenherr, Johannes; Reuning, Lars; Hallenberger, Maximilian; Lüders, Volker; Lemmens, Laurent; Biehl, Bianca Coline; Lewin, Anna; Leupold, Maike; Wimmers, K.; Strohmenger, Christian J.

doi:10.1016/j.earscirev.2018.07.005

Cited by 41 publications

(33 citation statements)

References 70 publications

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“…7). The presence of stylolites acting as barriers to calcitization fluids has also been reported from studies of mudstones of the Zechstein Ca2 Stassfurt carbonate of the Southern Permian Basin (NW Germany) (Koehn et al, 2016;Schoenherr et al, 2018;Humphrey et al, 2019). Although the extent and distribution of dolomite recrystallization and calcitization products are difficult to quantify, the Benicàssim case study demonstrates that stylolites can constrain these diagenetic reactions acting as barriers for the fluids that caused them.…”

Section: Stylolites As Dolomite Recrystallization and Calcitization Reaction Bafflesmentioning

confidence: 63%

Stylolites and stylolite networks as primary controls on the geometry and distribution of carbonate diagenetic alterations

Gomez‐Rivas¹,

Martín‐Martín²,

Bons³

et al. 2022

Preprint

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There is an ongoing debate on whether stylolites act as barriers or conduits for fluids, or even play no role in terms of fluid transport. This problem can be tackled by examining the spatial and temporal relationships between stylolites and other diagenetic products at multiple scales. Using the well-known Lower Cretaceous Benicàssim case study (Maestrat Basin, E Spain), we provide new field and petrographic observations of how bedding-parallel stylolites can influence different diagenetic processes during the geological evolution of a basin. The results reveal that stylolites can serve as baffles or inhibitors for different carbonate diagenetic reactions, and act as fronts for dolomitization, dolomite recrystallization and calcitization processes. Anastomosing stylolites, which pre-date burial dolomitization, likely acted as a collective baffle for dolomitization fluids in the study area, resulting in stratabound replacement geometries at the metre-to-kilometre scale. The dolomitization front weaves up and down following consecutive anastomosing stylolites, which are typical of mud-dominated facies that characterize limestone-dolostone transition zones. Contrarily, dolostone bodies tend to correspond to grain-dominated facies characterized by parallel (non-anastomosing) stylolites. The same stylolites subsequently acted as fluid flow conduits and barriers again when the burial and stress conditions changed. Stylolites within dolostones close to faults are found corroded and filled with saddle dolomite riming the stylolite pore, and high-temperature blocky calcite cements filling the remaining porosity. The fluids responsible for these reactions were likely released from below at high pressure, causing hydraulic brecciation, and were channelised through stylolites, which acted as fluid conduits. Stylolites are also found acting as baffles for subsequent calcitization reactions and occasionally appear filled with iron oxides released by calcitization. This example demonstrates how the same type of stylolites can act as barriers/inhibitors and/or conduits for different types of diagenetic reactions through time, and how important it is to consider their collective role when they form networks.

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Section: Stylolites As Dolomite Recrystallization and Calcitization Reaction Bafflesmentioning

confidence: 63%

Stylolites and stylolite networks as primary controls on the geometry and distribution of carbonate diagenetic alterations

Gomez‐Rivas¹,

Martín‐Martín²,

Bons³

et al. 2022

Preprint

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“…undersaturated with respect to dolomite and oversaturated with respect to calcite) and be able to remove the liberated Mg 2+ to maintain dolomite undersaturation (Ayora et al, 1998). Importantly, dedolomitisation is known to occur under a wide variety of conditions, from karst and shallow subsurface settings due to interaction with meteoric waters at relatively low temperatures (<50 °C) and CO 2 partial pressures (Flügel, 2010;Nader et al, 2008;Rameil, 2008;Vandeginste and John, 2012) to deep burial environments (Budai et al, 1984;Land and Prezbindowski, 1981;Schoenherr et al, 2018;Woo and Moore, 1996) and hydrothermal systems (e.g., Faust, 1949;Matsumoto et al, 1988;Stoessell et al, 1987), such as those envisaged for the Zaonega Formation. One of the most convincing features to identify dedolomitisation microscopically is the replacement of dolomite rhombohedrons by equicrystalline anhedral calcite (Schoenherr et al, 2018).…”

Section: Secondary Alteration In the Zaonega Carbonate Rocksmentioning

confidence: 99%

“…vicinity of the veins. The intensification of dedolomitisation at bed margins acted to reduce permeability (as documented, for example, in Permian Zechstein carbonate rocks;Schoenherr et al, 2018) thereby shielding the middle part of carbonate beds from pervasive alteration.Dedolomitisation was additionally hindered inside the carbonates beds due to the closedsystem behaviour with smaller supply of Ca 2+ and/or slower removal of liberated Mg.Decreasing fluid temperatures inward are also evident from petrographical features of dolomite-calcite aggregates in the carbonate beds of the Zaonega Formation: these change from calcite occurring as patchy dolomite replacement in bed interiors to pseudomorphic replacement along the bed margins. Such textures have been generated in hydrothermal dedolomitisation experiments(Stoessell et al, 1988) via calcite replacement of dolomite in the interior of dolomite crystals associated with crystal imperfections.…”

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confidence: 98%

Hydrothermal dedolomitisation of carbonate rocks of the Paleoproterozoic Zaonega Formation, NW Russia — Implications for the preservation of primary C isotope signals

et al. 2019

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The Paleoproterozoic Zaonega Formation in Karelia, NW Russia, has played a key role in understanding the environmental conditions postdating the Great Oxidation and Lomagundi-Jatuli Events. Its carbonate-and organic-rich rocks (shungite) define the postulated Shunga Event representing an accumulation of very organic-rich sediments at c. 2 Ga and are central in ideas about changing ocean-atmosphere composition in the wake of those worldwide biogeochemical phenomena. Our work focussed on a key interval of carbonate rocks in the upper part of the Formation to: (i) obtain new high-resolution carbon, oxygen and strontium isotope data complemented by detailed petrography and mineralogical characterisation and (ii) expand upon previous studies by using our data to constrain geochemical modelling and show in greater detail how magmatic hydrothermal fluids induced dedolomitisation and altered geochemical signals. Our findings show that the δ 13 C carb of calcite-rich intervals are the most altered, with values between -16.9 to 0.6‰, whereas the dolomite-dominated parts retain the best-preserved (i.e. most original) values. Those define a trend of steadily ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T 2increasing δ 13 C carb , from -6 to +0.5‰, which we interpret as a return to normal marine conditions and carbonate-carbon values following the Lomagundi-Jatuli Event.

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“…Diagenetic facies (Diagenetic Carbonate Subunit), as here described, are characteristic products of meteoric diagenesis in near-surface environments [34,[61][62][63][64][65], whose formation may be related to water table fluctuations [66] and/or major changes in basin paleogeography [35,62,67]. Additionally, several features demonstrate the subaerial and pre-burial nature of the Intra-Vallesian paleokarst such as (i) breccia deposits that include pseudospar and speleothem fragments, together with fluvial deposits capping the karst surface; and (ii) cave-fill deposits (clays, subarkoses and flowstones) within the subsurface karst system.…”

Section: Evolutionary Model Of the Intra-vallesian Paleokarstmentioning

confidence: 85%

Tectono-Sedimentary Evolution of the Madrid Basin (Spain) during the Late Miocene: Data from Paleokarst Profiles in Diagenetically-Complex Continental Carbonates

et al. 2020

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An intra-Vallesian (Upper Miocene) paleokarst developed at the top of the Intermediate Miocene Unit in the continental intracratonic Madrid Basin is recognized. This paleokarst is an early shallow, tabular-shaped karst that shows a marked control by the depositional facies pattern and lithologies. By integrating morphological, petrological, and geochemical data, three hydrogeological zones were established throughout the paleokarstic profiles: (i) a paleo-vadose zone, characterized by vertically elongated caves and vadose cementation; (ii) a 3–7 m thick paleo-epiphreatic zone (paleo-water table fringe), with development of stratiform breccia bodies, the superimposition of both vadose and phreatic features, and the lowest Fe and Mn contents in host-rock carbonates; and (iii) a paleo-phreatic zone characterized by an increase in δ13C values and the predominance of phreatic cementation. The paleogeographic reconstruction for the intra-Vallesian paleokarst using profiles revealed relative topographic highs to the north and topographic lows to the south, drawing the paleokarst landscape. Immediately overlaying the paleokarst surface are fluvio-lacustrine facies belonging to the Miocene Upper Unit (Late Vallesian to Late Turolian). Their lowermost deposits consist of fluvial terrigenous facies deposited by approximately N–S fluvial streams, and pass upward into fluvio-lacustrine fresh-water limestones. This paleokarstic surface represents a major change in the evolution of sedimentary patterns of basin, from endorheic to exorheic conditions, as the result of a change from compressive to extensional conditions in the tectonic regime.

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Dedolomitization: review and case study of uncommon mesogenetic formation conditions

Cited by 41 publications

References 70 publications

Stylolites and stylolite networks as primary controls on the geometry and distribution of carbonate diagenetic alterations

Stylolites and stylolite networks as primary controls on the geometry and distribution of carbonate diagenetic alterations

Hydrothermal dedolomitisation of carbonate rocks of the Paleoproterozoic Zaonega Formation, NW Russia — Implications for the preservation of primary C isotope signals

Tectono-Sedimentary Evolution of the Madrid Basin (Spain) during the Late Miocene: Data from Paleokarst Profiles in Diagenetically-Complex Continental Carbonates

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