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Midtkandal, Ivar; Zuchuat, Valentin; Petrie, Elizabeth & Liberty, Lee
(2021).
COTEC.
Show summary
The multi-disciplinary, multi-institution approach to monitoring CO2-flow in the subsurface is presented, and represented by examples from sedimentology, structural geology, and seismic monitoring.
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Zuchuat, Valentin; Steel, Elisabeth; Mulligan, Ryan P.; Collins, Daniel S. & Green, J.A. Mattias
(2021).
Variations in physiography, tidal forcing, and bottom shear stress in palaeo-seas: lessons learned from numerical modelling.
Show summary
The physiography (geometry and bathymetry) of a basin and its latitude are the primary parameters that dictate the tidal dynamics in shoreline–shelf systems. Understanding the impact that changes in physiography have on tides allows researchers to 1) improve interpretations of historical sedimentary processes in shallow-marine basins, and 2) better predict potential variations in tidal dynamics in response to an anthropogenic-driven relative sea level change.
Here, we present an analysis of numerical modelling of tidal propagation in the Upper Jurassic Sundance and Curtis Seas demontrating that basin-scale amplification and dampening of tides occurred in different palaeophysiographic configurations, and more localised amplification relating to tidal harmonics occurred in certain physiographic scenarios. Consequently, palaeophysiography was the primary control on both the magnitude and location of tidal amplification, flow speed, and bed shear stress, whereas secondary controls were initial tidal forcing and bottom drag coefficient.
Simulation results for the palaeophysiography with a 600 m depth at the mouth of the system suggest a distribution of sedimentary facies comparable to those documented in the Upper Jurassic lower Curtis Formation, apart from the innermost Curtis Sea, near to the palaeoshoreline. Sediments potentially supplied by aeolian processes during regression and increased aridity were likely reworked by tides during a subsequent a transgression as the climate became more humid. The palaeophysiography with a 600 m depth at the mouth of the system can therefore be considered a realistic palaeophysiographic configuration for the Sundance and Curtis Seas given the similarities that exist between the predicted distribution of sedimentary facies and their actual distribution in the lower Curtis Formation. In this palaeophysiography, the Sundance Sea and the Curtis Sea would have thus attained a maximum depth of ~240 m and 40-45 m, respectively. In this context, the simulated tidal range in the Curtis Sea would have reached 2.60 m, which would classify the Curtis Sea as a meso-tidal system (2x 1.30 m tidal amplitude).
Finally, using change in palaeophysiographic configuration as a proxy for relative sea-level variations revealed the non-uniqueness (sensu Burgess & Prince, 2015) of sedimentary successions deposited in tide-dominated basin, given that tidal amplification in the system was controlled by palaeophysiographic configuration: one specific succession could be the product of several, equally-valid relative sea-level histories. Reciprocally, the impact of relative sea-level change on different successions is non-unique, since local tidal harmonics and the characteristics of coeval deposition may vary significantly during relative sea level changes.
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Zuchuat, Valentin; Steel, Elisabeth; Mulligan, Ryan P.; Collins, Daniel S. & Green, Mattias J.A.
(2021).
Curtis Wars, episode IV: Return of the (Je)tide: Tidal dynamics in palaeo-seas in response to long-term changes in bathymetry, tidal forcing, and bottom shear stress.
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Zuchuat, Valentin; Liberty, Lee; Petrie, Elizabeth; Hafner, Alison; Arvesen, Brock & Alterskjær, Camilla
[Show all 10 contributors for this article]
(2021).
On CO2 monitoring techniques and the importance of collaborating during times of crisis.
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Zuchuat, Valentin; Steel, Elisabeth; Mulligan, Ryan P.; Collins, Daniel S. & Green, J.A. Mattias
(2021).
A quick a robust numerical modelling method to study the propagation of tides in palaeo-seas.
Show summary
Tidal dynamics in shoreline-shelf systems are dependent on the physiography (geometry and bathymetry) of a basin and its latitude. Researchers can increase their understanding of sedimentary processes in ancient shallow-marine basins, and incorporate potential variations in tidal dynamics in response to an anthropogenically-driven relative sea level change by studying the impact that changes in physiography have on tides.
In order to conduct such an analysis in the epicontinental Upper Jurassic Sundance and Curtis Seas, we developed a workflow that everyone can use to model the propagation of tides in ancient basins, to understand the evolution of tidal dynamics in a basin with respect to change in its physiography, or to test the feasibility of certain geological interpretations.
The numerical simulations of tides are run in the open-source Deltares Delft3D software, and one of the primary input that the software requires is palaeobathymetric data. Since these data might not exist for the study of ancient marine systems, we developed a simple Python code that extracts the colour-value of every pixel in a georeferenced image, before attributing it a depth value depending on how light- or dark-colour the pixel was: the lighter-coloured the pixel is, the shallower the attributed depth is (and vice-versa). Various tidal constituents can then be forced into the system, either at the same time, if the control on the different tidal constituents in the system is robust, or individually in order for example to minimise assumptions. Such a workflow can quickly test if and how tides can propagate in any given ancient seas, which allows for the testing of certain geological interpretation of the rock record.
Our Python-code allows for the very quick generation of multiple palaeobathymetries, by varying the maximum depth attributed to the darkest-coloured pixel of the image, which can then be used to study by proxy the impact of relative sea-level variations on the propagation of tides in ancient seas. The sensitivity of the models can then be tested by varying different input parameters, such as the initial open-ocean tidal forcing, or the bottom drag coefficient values.
Delft3d can notably simulate the tidal amplitude and the flow speed anywhere in the system and at any time, but the distribution of sedimentary facies can be predicted for each of the simulation, using the modelled maximum bed shear stress as a proxy. The map of the predicted distribution of sedimentary facies can then be compared to the real distribution of sedimentary facies in the rock record.
The study of the Upper Jurassic Sundance and Curtis Sea using this simple but robust workflow allowed us to identify the primary control that the physiographic configuration had on the propagation of tides in the system. This workflow also allowed quantifying how tidal dynamics would evolve with respect to change in palaeophysiographic configuration, which has highlighted the importance of considers the effects of palaeophysiographic changes related to relative sea-level variations and their associated impact on tidal dynamics, which will certainly help improving and refining models of tide-dominated basins and their evolution.
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Zuchuat, Valentin; Steel, Elisabeth; Mulligan, Ryan P.; Collins, Daniel S. & Green, J.A. Mattias
(2021).
Ancient tides and physiography: time to update sequence-stratigraphic models?
Show summary
Tidal dynamics are dependent on the physiography (geometry and bathymetry) of a basin and its latitude. By studying the impact that changes in physiography have on tides, scientists can improve their understanding of sedimentary processes that occurred in palaeo-seas, and incorporate potential variations in tidal dynamics in response to relative sea level changes to their interpretation.
We developed a workflow that everyone can use to model the propagation of tides in ancient basins, to understand the evolution of tidal dynamics in a basin with respect to change in its physiography, or to test the feasibility of certain geological interpretations. This methods was tested in the epicontinental Upper Jurassic Sundance and Curtis Seas, which extended from today’s British Columbia to today’s east-central Utah, where tidal currents strongly impacted the deposition of certain sedimentary units preserved in the rock record.
The numerical simulations of tides were run in the open-source Delft3D software by Deltares, and one of the initial input that the software requires is palaeobathymetric data. Because palaeobathymetry data might not exist for the study of ancient seaways, we developed a simple Python code that extracts the colour-value of every pixel in a georeferenced image, before attributing it a depth value depending on how light- or dark-colour the pixel was: the lighter-coloured the pixel is, the shallower the attributed depth is (and vice-versa).
The results of numerical modelling of tidal propagation show that changing the palaeophysiographic configuration of the basin controls both the magnitude and the location of tidal amplification. Some palaeophysiographic configurations resulted in an overall increase in tidal amplitude in the seaway (with various degrees of amplification) but potentially link to the onset of resonance in (part of) the basin, whereas other palaeophysiographic configurations led to a general decrease of the tidal amplitude. Further, certain palaeophysiographic configurations resulted in a heterogeneous spatial distribution of the tidal amplification across the basin as additional tidal harmonics only appeared in certain parts of the basin, but were absent from others. This results in the resurgence of tidal amplification or dampening with different periods at different locations, with increasing spatial variations the deeper the basin is. As a result, the stacking pattern of the various architectural elements would differ from one margin of the basin to the other, despite a similar relative sea-level history. Consequently, the interpretation of the relative sea-level history across an entire basin necessitates caution when tides are one of the main process active at the time of deposition, especially when data points are scarce or limited to a portion of the basin only.
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Zuchuat, Valentin; Augland, Lars Eivind; Jones, Morgan Thomas; Twitchett, Richard; Rodríguez-Tovar, Francisco J. & Hammer, Øyvind
[Show all 11 contributors for this article]
(2021).
Facies changes, volcanism, and mass extinction conundrum: the Permian-Triassic boundary across the Barents Sea Shelf.
Show summary
The most dramatic mass extinction the Earth has ever experienced occurred 252 million years ago, at the end of the Permian. It was likely triggered by the volcanic eruptions and magmatic intrusions associated with the Siberian Traps Large Igneous Province (LIP), leading to dramatic climatic changes, with consequences lasting well into the Early Triassic.
Here, we present a summary of the findings from the study of several sedimentary successions distributed across the Barents Sea that spanned the End Permian Mass Extinction (EPME) and the Permian-Triassic boundary. The four studied successions included the renowned Festningen section in the outer part of Isfjorden, western Spitsbergen; the DD-1 core and the associated river section in Deltadalen, central Spitsbergen; a core drilled offshore Kvitøya in northern Svalbard, and a core drilled on the Horda Platform in the Barents Sea. Datasets of various research lines were collected from these sections including sedimentology, organic geochemistry, isotope, geochronology, XRF, mineralogy, ichnology, palaeontology, palynology and digital outcrop data.
Historically, the Permian-Triassic boundary exposed today in Svalbard (and at various places across the High Arctic regions) was placed at the very prominent and abrupt facies change occurring between the siliceous mudstones or spiculites of the Kapp Starostin Formation, and the overlying soft, non-siliceous mudstones and siltstones of the Vardebukta and Vikinghøgda formations. The abruptness of this facies change, which also marks the demise of sponges, led to the belief that it represented a hiatus or a gap of several million years, with the uppermost Permian strata missing from the sedimentary record, while the mudstones of the Vardebukta and Vikinghøgda formations were definitely of Lower Triassic age, based on ammonoid biostratigraphy.
Hindeodus parvus, the conodont that defines the base of the Triassic, was for the first time identified in Svalbard a few meters above the lithostratigraphic boundary, which is therefore of Upper Permian age. Additionally, our new data show that sedimentation was continuous across this lithostratigraphic boundary. This transition from the Kapp Starostin Formation to the Vardebukta and Vikinghøgda formations was accompanied by a major reorganisation/inversion of the basin(s), but its exact nature remains puzzling.
Further, all measured sections record the EPME, which is associated with a 6-8 ‰ δ13CVPDB negative excursion, and measured between the lithostratigraphic and the Permian-Triassic boundaries. These negative isotopic excursions are found in close vicinity to several tephra layers that have been precisely dated at 252.13 ± 0.62 Ma, strongly suggesting a connection to the Siberian Traps LIP event. The mass extinction is also confirmed by the very rapid decreasing of trace fossil abundance and diversity, as anoxia spread across the water from proximal and shallow water to deeper settings. Geochemical and ichnological data indicate the occurrence of several anoxic pulses, intersected by very brief episodes of improved oxygenation levels. It took ca. 145 Kyr for life to recover after the extinction event, based on sedimentation rate calculations. Data also suggest that a shift towards more arid climatic conditions and increased eutrophication on land accompanied the EPME.
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Zuchuat, Valentin
(2021).
The Good, the Bad, and the Ugly, Permian-Triassic edition.
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Zuchuat, Valentin; Midtkandal, Ivar; Poyatos More, Miquel; Da Costa, Sigrid; Brooks, Hannah Louise & Halvorsen, Kristine
[Show all 9 contributors for this article]
(2021).
Mind The Gap: Composite and diachronous stratigraphic surfaces in low-gradient, transitional settings: The J-3 “unconformity” and the Curtis Formation, east-central Utah, U.S.A.
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Anell, Ingrid Margareta; Serck, Christopher Sæbø; Zuchuat, Valentin & Braathen, Alvar
(2020).
Structural influence on Triassic deposition on the Northern Barents Shelf.
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Zuchuat, Valentin; Steel, Elisabeth; Mulligan, Ryan P.; Collins, Daniel S. & Green, Mattias J.A.
(2020).
Does it still make sense to apply classical, sequence-stratigraphical concepts to tide-dominated basins?
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Zuchuat, Valentin
(2020).
If Cream knew how to code: psychedelic simulations of tides in the Proto-Western Interior Seaway.
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Zuchuat, Valentin; Sleveland, Arve; Sprinkel, Douglas; Pettigrew, Ross P.; Dodd, Thomas J.H. & Clarke, Stuart M.
[Show all 8 contributors for this article]
(2020).
When Utah was a blue state: the sedimentology of the tidally-influenced Upper Jurassic Curtis Formation.
Show summary
The sedimentary record of east-central Utah during the Middle/Late Jurassic shows that arid conditions prevailed, punctuated by episodic incursions of the Sundance Sea from the north. It is some of these incursions that terminated the Entrada aeolian system, and deposited the overlying shallow-marine Curtis Formation in a tide-dominated, semi-enclosed basin. The shallow-marine system was neighboured by a coastal aeolian system belonging to the Moab Member of the Curtis Formation, and a fluvially-starved, sporadically-flooded, paralic belt of the Summerville Formation. These paralic deposits progressively blanketed the shallow-marine strata of the Curtis Formation as the sea regressed northward. This study deconstructs and analyses the continental to shallow-marine deposition during one transgressive-regressive cycle.
Our analysis sub-divides the Curtis Formation into three informal units: the lower, middle and upper Curtis. Allocyclically-driven, short-lived relative sea-level variations, along with episodes of uplift and deformation, dominated over autocyclic processes of the Curtis Sea as the lower Curtis was deposited. The system entered into tidal resonance following the onset of the major transgression that defines the base of the middle Curtis, as the flooded basin reached an optimal length that corresponded to an odd multiple of one quarter tidal wavelength. This high-energy resonant system overprinted the effects of allocyclic forcing within the middle Curtis. By contrast, the neighbouring coastal systems continued to record allocyclic signals preserved as five stacked aeolian sequences of the Moab Member of the Curtis Formation, and a cyclical pattern recognised within the supratidal Summerville Formation.
By documenting a resonant stage in a tide-influenced basin that overprints the otherwise dominant allocyclic processes, this study highlights the importance of assessing coeval depositional systems in order to build complete stratigraphic basin histories.
Keywords: allocyclic, autocyclic, Curtis Formation, stratigraphic surfaces, tidal resonance, aeolian sequences, Utah.
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Zuchuat, Valentin; Midtkandal, Ivar; Poyatos More, Miquel; Da Costa, Sigrid; Brooks, Hannah L & Halvorsen, Kristine
[Show all 9 contributors for this article]
(2020).
Brexit, Megxit, and the J-3 Unconformitexit: how they all lost it.
Show summary
Unconformities, by definition, correspond to non-depositional or erosive surfaces, separating older strata below, from younger rocks above, and encapsulating significant time gaps. However, recent studies have emphasized the composite nature of some unconformities, as well as their heterochronous and diachronous character, which restricts the use of such a definition to a near one-dimensional setting.
This study analyses the nature of the J-3 Unconformity, which separates the Middle Jurassic Entrada Sandstone from the Late Jurassic Curtis Formation (and laterally equivalent units) in east-central Utah (USA). Our detailed mapping and characterization indicates the J-3 “Unconformity” is in fact a composite surface generated by either erosion-related processes such as eolian deflation, and water-induced erosion, or by deformational processes. These multiple mechanisms interacted and overlapped in time and space, which demonstrates the composite and diachronous and non-unique nature of such boundaries. This contact has been historically interpreted as an unconformity, but our results show that this key stratigraphic surface is a time-transgressive flooding-ravinement surface that formed shortly before and during a series of transgressions that flooded the area during the Late Jurassic. Consequently, the regionally extensive, composite, heterochronous, and diachronous J-3 Unconformity does not fit the classic unconformity definition, after which an unconformity universally separates older from younger strata basin-wide.
The J3 “Unconformity” case study highlights the fact that one process can be represented by varying expressions in the stratigraphic record, and conversely many processes may result in the same stratigraphic expression. Consequently a revised definition of unconformity is discussed, focusing on processes and associated environmental changes, while abandoning its time-barrier aspect. This investigation also exemplifies some of the implications on subsurface analyses that the inaccurate characterization of the subseismic complex characters of such major stratigraphic bounding surfaces can have. These inaccuracies may lead to imprecise timing and sediment budget predictions, and ultimately have strong implications for basin evolution and reservoir models.
Key words: Unconformity, transitional basin, composite surface, ravinement, time-transgressive
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Zuchuat, Valentin; Hafner, Alison; Osmond, Johnathon L.; Liberty, Lee; Petrie, Elizabeth & Arvesen, Brock
[Show all 11 contributors for this article]
(2020).
CO2 containment and monitoring techniques along Little Grand Wash Fault, east-central Utah, USA.
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Zuchuat, Valentin; Sleveland, Arve Rein Nes; Pettigrew, Ross P.; Dodd, Thomas J.H.; Clarke, Stuart M. & Braathen, Alvar
[Show all 7 contributors for this article]
(2019).
Why you should care about neighbouring sedimentary systems: Overprinted allocyclic processes by tidal resonance in the Upper Jurassic Curtis Formation, Utah, USA.
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Zuchuat, Valentin; Osmond, Johnathon L.; Sundal, Anja; Midtkandal, Ivar; Skurtveit, Elin & Petrie, Elizabeth
[Show all 9 contributors for this article]
(2019).
CO2 containment and monitoring techniques along Little Grand Wash Fault, east-central Utah, USA.
Show summary
Our current understanding of sub-surface CO2 sequestration feasibility derives mainly from valuable small-scale projects, which have mostly been working at injection or human time scales. These projects, however, have not been operational long enough to fully assess flow and/or seepage at longer time scales relevant for subsurface CO2 storage (e.g. > 10 kY). Many examples of fluid escape have been documented in the offshore subsurface environment (e.g. seismic chimneys), and natural seeps found on land, both active and relict, offer informative analogues to subsurface fluid migration. Of note are the natural seeps located in east-central Utah, USA that are easily accessible and represent suitable onshore counterparts to the offshore fluid escape features. These seeps can improve our understanding of geological and geomechanical factors controlling subsurface CO2 containment and the expression of fluid escape in geophysical images. A critical concern is how to account for features that are detrimental to subsurface storage containment and are at scales below seismic resolution. This multidisciplinary project aims to address the challenge by collecting surface and subsurface datasets at mesoscopic scales that, through viable upscaling, will be implemented in seismic investigations and reservoir-seal models. Moreover, the project builds upon previous studies detailing the complex development of the Jurassic sedimentary basin in question (Zuchuat et al. 2018; 2019; in press) but is also relevant for the Horda Platform region (Aurora and Smeaheia) or other prospective North Sea CO2 storage sites. Overall, this next research phase specifically focuses on the detailed, post-depositional history of the targeted interval in Utah, addressing one fundamental question: what are the thresholds for detecting CO2 seeps in the subsurface? This encompasses more targeted questions:
• What is the detailed geological footprint of CO2 flow along strata, faults, and fractures?
• How did the CO2 flow migrate through a heterogeneous and transitional, faulted reservoir-seal complex?
• Can seepage from the storage compartment be identified by seismic imaging?
• Can detailed geological datasets and related geophysical models verify the existence of – and facilitate quantification of CO2 volumes (saturation) required to create offshore geophysical chimneys, and thereby improve integrity assessment of prospective North Sea CO2 reservoirs?
Zuchuat, V., Sleveland, A. R., Sprinkel, D. A., Rimkus, A., Braathen, A., & Midtkandal, I. (2018). New Insights on the Impact of Tidal Currents on a Low-gradient, Semi-enclosed, Epicontinental Basin—the Curtis Formation, East-central Utah, USA. Geology of the Intermountain West, 5, 131-165.
Zuchuat, V., Sleveland, A.R.N., Pettigrew, R.P, Dodd, T.J.H., Clarke, S.M., Braathen, A., & Midtkandal, I. (2019). Overprinted Allocyclic Processes by Tidal Resonance in an Epicontinental Basin: the Upper Jurassic Curtis Formation, East-Central Utah, USA. The Depositional Record, 5(2), 272-305.
Zuchuat, V., Midtkandal, I., Poyatos-Moré, M., Da Costa, S., Brooks, H.L., Halvorsen, K., Cote, N., Sundal, A., & Braathen, A. (in press.). Composite and Diachronous Stratigraphic Surfaces in Low-Gradient, Transitional Settings: the J-3 “Unconformity” and the Curtis Formation, East-Central Utah, U.S.A. Accepted in The Journal of Sedimentary Research.
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Zuchuat, Valentin; Midtkandal, Ivar; Miquel, Poyatos-More; Da Costa, Sigrid; Halvorsen, Kristine Årland & Sundal, Anja
[Show all 8 contributors for this article]
(2018).
Unconformities matter: The spatial and temporal information contained in the J-3 Unconformity and the Curtis Formation, east-central Utah, USA.
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Bromander, Nikoline; da Costa, Sigrid; Skurtveit, Elin; Evans, Jim; Midtkandal, Ivar & Zuchuat, Valentin
[Show all 8 contributors for this article]
(2018).
Regional evaluation of structural collapse in sandstone reservoirs and impact on reservoir quality: a case study from the Entrada Sandstone, Utah, USA.
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Zuchuat, Valentin; Sleveland, Arve Rein Nes; Rabbel, Ole; Braathen, Alvar; Midtkandal, Ivar & Pettigrew, Ross P.
[Show all 8 contributors for this article]
(2018).
Why you should care about neighbouring sedimentary systems: Overprinted allocyclic processes by tidal resonance in the Upper Jurassic Curtis Formation, Utah, USA.
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daCosta, Sigrid Østmo; Bromander, Nikoline; Zuchuat, Valentin; Braathen, Alvar; Sundal, Anja & Midtkandal, Ivar
(2018).
Topographic Development as a result of regional incision, faulting, and
deposition at the onset of relative sea-level rise; The upper Entrada
Sandstone and the lower Curtis Formation, Utah, USA.
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Midtkandal, Ivar; Sundal, Anja; Braathen, Alvar; Petrie, Elizabeth; Evans, James R. & Zuchuat, Valentin
[Show all 10 contributors for this article]
(2018).
Project summary: CO2 seal bypass - a multidisciplinary approach to CO2 migration and storage.
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Skurtveit, Elin; Sundal, Anja; Sauvin, Guillaume; Soldal, Magnus; Zuchuat, Valentin & Braathen, Alvar
(2017).
Fracture flow experiments addressing CO2 migration in fault zone.
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Sleveland, Arve Rein Nes; Zuchuat, Valentin; Rimkus, Algirdas; Midtkandal, Ivar; Sundal, Anja & Braathen, Alvar
(2017).
Spatial and temporal distribution of tidally modified sandstone reservoirs – implications for CCS and petroleum exploration.
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Zuchuat, Valentin; Sleveland, Arve Rein Nes; Rimkus, Algirdas; Braathen, Alvar & Midtkandal, Ivar
(2017).
Modelling the Sequence Stratigraphic Development of the Upper Jurassic Curtis Formation along the NE Margin of the San Rafael Swell, Central-Eastern Utah, USA: an Example of a Low-Gradient Tidal Basin.
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Midtkandal, Ivar; Zuchuat, Valentin; Braathen, Alvar; Sundal, Anja & Evans, James
(2017).
Syn-sedimentary subsurface liquefaction and collapse; injectites, pseudo-channels and pseudo-clinoforms in the Jurassic Entrada and Curtis Formations, Utah, USA.
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Zuchuat, Valentin; Midtkandal, Ivar; Da Costa, Sigrid; Sundal, Anja & Braathen, Alvar
(2017).
Schizophrenia in sedimentology: The J-3 Unconformity and the Curtis Formation, Central-Eastern Utah, USA.
Show summary
The tide-dominated, Upper Jurassic Curtis Formation crops out in Eastern-Central Utah, overlying the continental to marginal marine Entrada Sandstone. The contact between the two sedimentary formations is formally identified as the J-3 Unconformity, which can be traced over significant distances. It has since been regarded as a “simple” subaerial unconformity, followed by a third order transgression within an enclosed basin and the resulting deposition of the tide-influenced Curtis Formation. However, careful inspection of the different facies and their sub-regional correlation clearly shows that the essence of the J-3 Unconformity is not merely characterised by a long-lasting phase of subaerial exposure. It instead displays evidence of an intricate poly-erosional history, happening during short-lived syn-depositional transgressive and regressive periods. The initial bounding surface was locally altered by processes associated with development of the Curtis Formation, and the nature of their impact is strongly process-dependent. Pre-Curtis erosional processes mainly involved aeolian deflation and fluvial incision, creating a basinwide gentle relief. Syn-Curtis erosional mechanisms were controlled by the distribution and magnitude of tidal forces within the basin, resulting in a steeper and more localised relief in comparison with pre-Curtis widespread denudation. Furthermore, sedimentary processes alone can’t explain the present-day relief observed with the J-3 Unconformity. Indeed, tectonic played, at various scale, a key role in the funnelling of the various erosional forces and the distribution of the depocentres, with (i) m-scale grabens and horsts structures, and (ii) hydroplastic sand remobilisation, both observed within the uppermost strata of the Entrada Sandstone, as well as (iii) syn-Curtis sub-regional tectonic uplift. This study shows that reducing an unconformity to a single process is insufficient. Instead, careful mapping and understanding of such a schizophrenic surface can provide a non-negligible amount of information regarding the dynamic of a basin and its subsequent infill.
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Planke, Sverre; Zuchuat, Valentin; Svensen, Henrik; Hammer, Øyvind; Braathen, Alvar & Silkoset, Petter
[Show all 27 contributors for this article]
(2016).
Coring and High-Resolution Imaging of the Permian-Triassic Boundary in Deltadalen, Svalbard.
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Sundal, Anja; Miri, Rohaldin; Hellevang, Helge; Tveranger, Jan; Midtkandal, Ivar & Zuchuat, Valentin
[Show all 7 contributors for this article]
(2016).
Movement of CO2 charged fluids in
low permeability rocks during deformation:
migration patterns in the Carmel Formation, Utah.
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Planke, Sverre; Twitchett, Richard; Zuchuat, Valentin; Svensen, Henrik; Hammer, Øyvind & Braathen, Alvar
[Show all 22 contributors for this article]
(2015).
Coring the Permian-Triassic Boundary in Deltadalen, Svalbard.
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Algirdas, Rimkus; Sundal, Anja; Sleveland, Arve Rein Nes; Zuchuat, Valentin & Midtkandal, Ivar
(2015).
Sedimentology and reservoir quality of a tidally modified marginal marine succession; the Middle Jurassic Curtis Formation, southeastern Utah, USA.
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Rimkus, Algirdas; Sundal, Anja; Sleveland, Arve Rein Nes; Zuchuat, Valentin; Braathen, Alvar & Midtkandal, Ivar
(2015).
Sedimentology and reservoir quality of a Middle Jurassic marginal marine succession; the Curtis Formation, southeastern Utah, USA.
Show summary
The objective of this study is to investigate the depositional architecture of the Curtis Formation, and evaluate how the observed facies distributions would affect overall reservoir quality. This tidally influenced marginal marine succession is well exposed in southeastern Utah (Humbug Flats, San Rafael Swell) and provides a high-resolution analogue to subsurface reservoirs. In order to constrain the distribution of reservoir-grade sandstone bodies and characterize their heterogeneities, traditional sedimentological field methods were applied and LIDAR-scan data were collected. Permeability, porosity and diagenetic imprint parameters were evaluated from thin sections and used to constrain the model.
The Middle Jurassic (Callovian) Curtis and Summerville formations represent a complex set of vertical and lateral facies transitions from tidal shallow marine and supratidal sabkha deposits, respectively. The Curtis Formation developed in a transgressive to regressive, low-gradient epicontinental setting where vertical stacking of sandstone bodies was limited by accommodation. Determining reservoir quality in tidal sediments is extremely challenging due to complex and heterogeneous sand distribution.
In this study of the Curtis Formation, sub-seismic scale reservoir heterogeneities are the main focus. Sedimentological characterization is used for classification of significant structures and layers forming potential baffles to fluid flow within genetically related units. Excellent outcrop quality allowed lateral correlation between log sites, supplemented by conventional photographs and LIDAR imagery.
The reservoir quality of Curtis Formation shows a general water-depth related trend: sand-to-mud ratio increases with increasing water-depth during the transgressive phase. The lower succession contains channelized sandstone bodies in a heterolithic matrix, leading to limited connectivity. Tidal flat settimg. High permeability
A cleaning upwards trend towards the middle part, corresponds with a transition into a deeper shoreface environment, which in turn represents improved reservoir quality with laterally extensive relatively homogeneous sandstones.
The uppermost part displays a dirtying-upwards trend into increasingly heterolithic strata.
Lateral connectivity is generally high, whereas siltstone interlayers provide frequent vertical flow baffles. Locally, mud-drapes and shifts in depositional transport directions cause high variance in directional permeability. This depositional model for the Curtis Formation is an inter-well-scale analogue with respect to reservoir property distributions in tidally influenced, heterogeneous reservoirs (e.g. the Tilje, Cook and Knurr formations on the Norwegian continental shelf). Evaluation of the diagenetic imprint proved essential, as reservoir behavior at the original burial depth has to be characterized for relevant comparison.
Further studies aim to investigate facies distribution within the succession on a regional scale.
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Zuchuat, Valentin
(2019).
Continental to Shallow Marine Transition in a Tide-Dominated, Low Accommodation basin - Controlling Factors and Depositional Architecture.
University of Oslo.
Full text in Research Archive
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Zuchuat, Valentin; Midtkandal, Ivar & Braathen, Alvar
(2019).
Continental to Shallow Marine Transition in a Tide-Dominated, Low Accommodation Basin - Controlling Factors and Depositional Architecture.
University of Oslo.
Show summary
Modern tide-dominated, regressive shorelines featuring deltas estuaries and lagoons are well characterised and distinctive from wave or fluvial dominated systems. However, some ancient tidedominated basins and their associated sedimentary successions do not relate well to any of the above-mentioned, present-day systems. The Utah-Idaho Trough a semi-enclosed, narrow, and shallow foreland basin flooded during the Upper Jurassic by the Curtis Sea is one of these exceptions. The main target of this doctoral thesis is the Upper Jurassic, tide-dominated Curtis Formation, which outcrops in east-Central Utah, where it overlies the Middle Jurassic, aeolian deposits of the Entrada Sandstone. The Curtis Formation is defined at its base by the J-3 Unconformity and is conformably overlain by supratidal sabkha deposits of the Summerville Formation. The Entrada-Curtis-Summerville is subdivided into eight facies associations (FA 1-8), with six subfacies associations (FA 1a, 1b, 3a, 3b, 4a, 4b). Based on the specific three-dimensional arrangement of these facies associations, it is proposed to separate the Curtis Formation into three informal subunits: The lower, middle and upper Curtis. The lower Curtis, which consists of upper shoreface to beach deposits (FA 2), mud- (FA 3a) and sand-dominated heterolithic subtidal flat sediments (FA 3b),
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Tveterås, Susanne; Braathen, Alvar; Midtkandal, Ivar & Zuchuat, Valentin
(2018).
Fault style and deformation mechanisms caused by sand mobility in the Entrada Sandstone.
UIO.
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Halvorsen, Kristine; Braathen, Alvar; Midtkandal, Ivar & Zuchuat, Valentin
(2018).
Sand tectonics – sand mobility linked to faulting and the influence on depositional systems.
UIO.
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Halvorsen, Kristine; Zuchuat, Valentin; Midtkandal, Ivar & Braathen, Alvar
(2018).
Sand tectonics – sand mobility linked to faulting and the influence on depositional systems.
University of Oslo.
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Tveterås, Susanne; Braathen, Alvar; Midtkandal, Ivar & Zuchuat, Valentin
(2018).
Fault style and deformation mechanisms caused by sand mobility in the Entrada Sandstone and Curtis Formation, Utah, USA.
University of Oslo.
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Da Costa, Sigrid; Zuchuat, Valentin & Midtkandal, Ivar
(2018).
The complexity of regional erosion; incision, faulting, and deposition during the development of the J-3 unconformity, Utah, USA.
University of Oslo.
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Bromander, Nikoline; Sundal, Anja; Midtkandal, Ivar & Zuchuat, Valentin
(2018).
Facies-controlled reservoir quality and preferential deformation in sandstone reservoirs; a case study from the Entrada Sandstone, Utah, USA.
University of Oslo.
