Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
Link to record
Permanent link

Direct link
Alternative names
Publications (10 of 185) Show all publications
Jeanneret, P., Klonowska, I., Barnes, C., Majka, J., Holmberg, J., Gilio, M., . . . Koyi, H. (2023). Deciphering the tectonometamorphic history of subducted metapelites using quartz‐in‐garnet and Ti‐in‐quartz (QuiG–TiQ) geothermobarometry: A key for understanding burial in the Scandinavian Caledonides. Journal of Metamorphic Geology, 41(2), 235-270
Open this publication in new window or tab >>Deciphering the tectonometamorphic history of subducted metapelites using quartz‐in‐garnet and Ti‐in‐quartz (QuiG–TiQ) geothermobarometry: A key for understanding burial in the Scandinavian Caledonides
Show others...
2023 (English)In: Journal of Metamorphic Geology, ISSN 0263-4929, E-ISSN 1525-1314, Vol. 41, no 2, p. 235-270Article in journal (Refereed) Published
Abstract [en]

The Seve Nappe Complex is a subduction-related high-grade metamorphic unit that was emplaced onto the margin of Baltica during Caledonian orogenesis. In this paper, the tectonometamorphic evolution of the Lower Seve Nappe in the Scandinavian Caledonides was characterized with the help of the continuous Collisional Orogeny in the Scandinavian Caledonides (COSC-1) drill core, using a combination of various P–T estimation techniques based on garnet–quartz mineral pairs (quartz-in-garnet and Ti-in-quartz [QuiG–TiQ]), conventional thermobarometry and thermodynamic modelling of phase equilibria. This multi-method approach yields complementary results and delivers critical data to constrain a comprehensive pressure–temperature–deformation–time (P–T–D–t) evolutionary path for the metasedimentary rocks of the Lower Seve Nappe. In the garnetiferous metasedimentary rocks, quartz inclusions in garnet preserve the P–T conditions of three distinct garnet growth stages corresponding to three metamorphic stages Ms1 to Ms3, including prograde and peak metamorphic conditions. Ms1 and Ms2 stages were constrained via quartz inclusions in garnet core and mantle. They are relatively close in the P–T space and could be considered as one single continuous prograde event occurring at epidote–amphibolite facies conditions of 460–520°C and 0.6–0.85 GPa. The growth of the garnet outermost rim defines the Ms3 stage at amphibolite facies conditions of 590–610°C and 1.13–1.18 GPa and corresponds to the peak metamorphic conditions. The microstructural analysis shows that the finite ductile strain pattern of the Lower Seve Nappe results from the superposition of four deformation phases. The initial phase D1 is defined by the S1 foliation that is still preserved as a curved inclusion trail in the garnet core. The D2 phase initiated contemporaneously with garnet core growth and the development of muscovite–biotite–plagioclase S2 foliation. Garnet outermost rim growth marks the end of the prograde path and peak metamorphic conditions. This stage is overprinted by the D3 phase and Ms4 stage associated with the development of the main regional metamorphic and mylonitic fabric S3 associated with C′-type shear bands along the retrograde path. Ms4 stage, which was constrained using traditional thermobarometric techniques, corresponds to the chemical re-equilibration of the metasedimentary minerals and occurred under amphibolite facies conditions at ~570–610°C and 0.78–1.00 GPa. The D3 phase is then generally weakly to strongly overprinted by later lower grade deformation D4 phase at greenschist facies conditions (Ms5). 40Ar/39Ar ages of syn-kinematic white mica and biotite indicate that the final stage of the thrusting of the Lower Seve Nappe and thus the timing of its emplacement onto the Offerdal Nappe occurred at c. 423 Ma. Collectively, these results are consistent with previous estimates of the timing and conditions of metamorphism derived from the Lower Seve Nappe especially in west-central Jämtland. However, application of QuiG–TiQ thermobarometry demonstrated that quartz inclusions in garnet can preserve different aspects of garnet growth, which are not accessible by traditional methods especially in complex terranes, and therefore provided new significant insights into the Lower Seve prograde evolution.

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
40Ar/39Ar dating, P–T–D–t evolution, quartz-in-garnet, Scandinavian Caledonides, Ti-in-quartz thermobarometry
National Category
Geology Geochemistry
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-496712 (URN)10.1111/jmg.12693 (DOI)000884256100001 ()
Funder
Swedish Research CouncilThe Geological Survey of Sweden (SGU), 36-2012/2015
Available from: 2023-02-20 Created: 2023-02-20 Last updated: 2023-02-20Bibliographically approved
Ali, M., Koyi, H., Bosworth, W., Ligi, M., Ball, P. J. & Decarlis, A. (2023). Geometry and kinematics of the Middle to Late Miocene salt tectonics, central Egyptian Red Sea margin. Journal of Structural Geology, 176, Article ID 104955.
Open this publication in new window or tab >>Geometry and kinematics of the Middle to Late Miocene salt tectonics, central Egyptian Red Sea margin
Show others...
2023 (English)In: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201, Vol. 176, article id 104955Article in journal (Refereed) Published
Abstract [en]

The Red Sea basin includes a thick Middle to Late Miocene evaporitic succession that underwent halokinesis and caused intensive reshaping of the seafloor and the development of salt-tectonic structures. However, the ge-ometry and kinematics of these structures are still poorly understood. This study uses 2D and 3D seismic surveys and well data of the northern Egyptian Red Sea to systematically describe the distribution and morphology of salt structures, discuss their initiation, and construct a kinematic model for their origin. Our results indicate that the massive salt layer developed into five major NW-SE to NNE-SSW trending salt walls, characterized by relatively irregular crests and moderately dipping flanks. In addition, several symmetrical and asymmetrical folds and two categories of normal faults (subsalt and suprasalt) have been recognized. Based on our observations, salt mobilization in the study area started in the Late Miocene, during the precipitation of layered evaporites, and continued until the present day. In the northern Egyptian Red Sea, seismic interpretation indicates that hal-okinesis was triggered by a combination of thin-and thick-skinned systems, where the latter played a major role. The salt layer was welded during the Quaternary as several sags and grabens developed above the salt diapirs. Thick-skinned physical models are compatible with our observations, supporting the impact of basement faulting on Red Sea diapirism.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Salt tectonics, Salt walls, Evaporites, Quseir province, Northern red sea
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-518345 (URN)10.1016/j.jsg.2023.104955 (DOI)001088958200001 ()
Available from: 2023-12-19 Created: 2023-12-19 Last updated: 2023-12-19Bibliographically approved
Schöfisch, T., Koyi, H. & Almqvist, B. (2023). Magnetic fabric analyses of basin inversion: a sandbox modelling approach. Solid Earth, 14(4), 447-461
Open this publication in new window or tab >>Magnetic fabric analyses of basin inversion: a sandbox modelling approach
2023 (English)In: Solid Earth, ISSN 1869-9510, E-ISSN 1869-9529, Vol. 14, no 4, p. 447-461Article in journal (Refereed) Published
Abstract [en]

A magnetic fabric analysis is a useful tool to dis- play deformation in nature and in models. In this study, three sandbox models represent basin inversion above a veloc- ity discontinuity (base plate). After complete deformation of each model, samples were taken in different parts of the models (along faults and areas away from faults) for mag- netic fabric analysis. Model I, which simulates basin for- mation during extension, shows two kinds of magnetic fab- ric: an “undeformed”/initial fabric in areas away from faults and a normal fault-induced fabric with a magnetic foliation that tends to align with the fault surface. Models II and III were extended to the same stage as Model I but were sub- sequently shortened/inverted by 1.5 cm (Model II) and 4 cm (Model III). Both inverted models developed “thrusts” during inversion. The thrusts show an alignment of magnetic folia- tion parallel to the fault surfaces that depends on the maturity of the thrust. Our results highlight that thrusting is more ef- ficient in aligning the magnetic fabric along them compared to normal faults. Moreover, models II and III reveal a mag- netic fabric overprint towards a penetrative strain-induced fabric (magnetic lineation perpendicular to shortening direc- tion) with increasing strain in areas away from thrusts. Such overprint shows a gradual transition of a magnetic fabric to a penetrative strain-induced fabric and further into a thrust- induced fabric during shortening/inversion. In contrast, ex- tension (Model I) developed distinct magnetic fabrics with- out gradual overprint. In addition, pre-existing normal faults are also overprinted to a penetrative strain-induced fabric during model inversion. They define weak zones within the main pop-up imbricate and steepen during model inversion. Steepening influences the magnetic fabric at the faults and,in general, the strain propagation through the model during inversion. The magnetic fabric extracted from the models presentedhere reflect the different stages of basin development and in- version. This study is a first attempt of applying magnetic fabric analyses on models simulating inverted basins. This study illustrates the possibility of applying a robust tool, i.e. magnetic fabric analyses, to sandbox models, whose initial, intermediate, and final stages are well documented, to under- stand fabric development in inverted tectonic regimes.

Place, publisher, year, edition, pages
European Geosciences Union (EGU), 2023
Keywords
AMS, Magnetic Fabric Analysis, Analogue Modelling, Basin Inversion
National Category
Geosciences, Multidisciplinary
Identifiers
urn:nbn:se:uu:diva-503294 (URN)10.5194/se-14-447-2023 (DOI)000979561200001 ()
Funder
Swedish Research Council, 2017-04519
Available from: 2023-06-02 Created: 2023-06-02 Last updated: 2023-06-07Bibliographically approved
Abdelmaksoud, A., Ali, M. Y., Al Suwaidi, A. & Koyi, H. (2023). Petroleum system of the fold-and-thrust belt of the United Arab Emirates: New insights based on 1D and 2D basin modeling. Marine and Petroleum Geology, 158, Article ID 106567.
Open this publication in new window or tab >>Petroleum system of the fold-and-thrust belt of the United Arab Emirates: New insights based on 1D and 2D basin modeling
2023 (English)In: Marine and Petroleum Geology, ISSN 0264-8172, E-ISSN 1873-4073, Vol. 158, article id 106567Article in journal (Refereed) Published
Abstract [en]

The hydrocarbon potential of the fold-and-thrust belt (FTB) in the United Arab Emirates (UAE)-Oman mountains has received limited attention to date, leading to a poor understanding of the petroleum systems in this region. Despite the existence of hydrocarbon fields within the FTB, the source rock potential has not been adequately studied. This study aims to address this knowledge gap using 1D and 2D basin modeling approaches to evaluate the petroleum system of the FTB. In addition, gas chromatographs are also used to correlate hydrocarbon occurrences with their source rock. This study's findings identify the Silurian, Upper Cretaceous, Paleocene-Eocene, and Oligocene formations as the primary source rocks in the study area. Silurian shales, encountered in a well in the northern UAE, are currently considered overmature. The Cenozoic source rocks exhibit a spectrum of Total Organic Carbon (TOC) content, ranging from less than 1 to as high as 2 wt%, leading to variable degrees of expulsion efficiency. The maturity of these rocks varies based on their position in relation to the FTB and foredeep, with increasing maturity towards the north. The Upper Cretaceous sequences display low TOC and Hydrogen Index, indicating very low expulsion efficiency. The present-day distribution of maturity is largely influenced by Late Cretaceous and Oligocene-Miocene compressional events that affected the northern and northeastern Arabian Plate. This analysis shows that hydrocarbon expulsion from the Silurian source rocks was initiated during the Middle-Late Jurassic. These hydrocarbons are presumed to have migrated through Upper Permian, Jurassic, and Lower and middle Cretaceous reservoirs. Westward hydrocarbon migration, towards a regional bulge, may have also occurred following compressional events that resulted in lithospheric flexure and formation of the foreland basin. Notably, certain exceptions to migration towards the bulge include structural entrapment of hydrocarbons beneath the main frontal thrust zone of FTB and some structural traps beneath the Lower Fiqa Formation.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Qusaiba, Thamama, Petroleum system, 1D basin model, 2D basin model, Fold-and-thrust belt, United Arab Emirates
National Category
Geology Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-517507 (URN)10.1016/j.marpetgeo.2023.106567 (DOI)001105519400001 ()
Available from: 2023-12-11 Created: 2023-12-11 Last updated: 2023-12-11Bibliographically approved
Qadir, H. O., Baban, E. N., Aziz, B. Q. & Koyi, H. A. (2023). Potential field survey of subsurface structures of the NW segment of the Zagros Fold-Thrust Belt, Kurdistan Region. Geophysical Prospecting, 71(8), 1673-1690
Open this publication in new window or tab >>Potential field survey of subsurface structures of the NW segment of the Zagros Fold-Thrust Belt, Kurdistan Region
2023 (English)In: Geophysical Prospecting, ISSN 0016-8025, E-ISSN 1365-2478, Vol. 71, no 8, p. 1673-1690Article in journal (Refereed) Published
Abstract [en]

This study reports results of gravity and magnetic surveys conducted for the first time in the western segment of the Zagros Fold-and-Thrust Belt in the Kurdistan Region. This study attempts to delineate deep structures in an area, which has not been surveyed before. CG-5 Autograv gravimeter and G-857 portable proton-precession magnetometer were used to acquire gravity and magnetic data from 750 stations along over eleven traverses across and parallel to the Zagros trend (NW-SE). Six of these traverses are parallel to the Zagros trend, whereas the others are perpendicular to the trend of the other traverses and can be tied where they intersect. The total length of the traverses is about 1000 km. Tilt Angle of horizontal gradient method is used to detect regional gravity and magnetic lineaments. The mapped lineaments from regional gravity and magnetic surveys are divided into two categories: the NE-SW lineaments, which represent transversal faults in the study area, and the NW-SE lineaments, which represent the Zagros Thrust Faults, some of which may be linked to the inverted basement normal faults of Arabian passive margin (the NW-SE Najd Fault system). The results show that there is a relationship between the regional gravity and magnetic lineaments outlining the same deep geological features. The data presented here confirm the presence of regional longitudinal and transversal lineaments documented in other studies (e.g. Anah-Qalat Dizeh Fault, Surdash-Tikrit Fault, Sirwan Fault, Khanaqin Fault, Zagros Mountain Front Fault, Baranan Back Thrust Fault and High Zagros Reverse Fault) and outlines new lineaments not mapped before. Most of the detected regional lineaments in the current study coincide with the previously confirmed lineaments, which have played a significant role in the tectonic evolution of the Zagros Fold-and-Thrust Belt. As such, this study contributes to a better understanding of the subsurface structure of the Kurdistan segment of the Zagros Fold-and-Thrust Belt and probably the rest of the belt.

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
Kurdistan Region, lineaments, NW Zagros, potential field methods
National Category
Geotechnical Engineering
Identifiers
urn:nbn:se:uu:diva-518657 (URN)10.1111/1365-2478.13401 (DOI)001028697200001 ()
Funder
Swedish Research Council
Available from: 2023-12-22 Created: 2023-12-22 Last updated: 2023-12-22Bibliographically approved
Feng, Q., Qiu, N., Wu, H. & Koyi, H. (2023). Thermo-Kinematic Constraints on Restoration of the Eastern Sichuan Fold-And-Thrust Belt, South China. Tectonics, 42(9), Article ID e2022TC007630.
Open this publication in new window or tab >>Thermo-Kinematic Constraints on Restoration of the Eastern Sichuan Fold-And-Thrust Belt, South China
2023 (English)In: Tectonics, ISSN 0278-7407, E-ISSN 1944-9194, Vol. 42, no 9, article id e2022TC007630Article in journal (Refereed) Published
Abstract [en]

Kinematic restoration of the eastern Sichuan fold-and-thrust belt (ESFTB) in South China is calibrated with a new thermo-kinematic model combining analog models, discrete element method, and thermochronology data. Thermo-kinematic analysis provides constraints on the onset, rate, and lateral variation of deformation and exhumation. Results show that the ESFTB experienced a northwestward thrusting and periodic exhumation. Its evolution was characterized by five major stages based on the deformation characteristics; (a) Shortening above a basal decollement and formation of large imbricates separated by narrow synclines during 170-130 Ma; (b) Transition stage during 130-100 Ma; (c) Stepping up of deformation to shallow decollement levels and shaping of the thick-skinned domain during 100-70 Ma; (d) Shaping of the thin-skinned domain during 70-20 Ma; and (e) Continuous exhumation and structural modification from 20 Ma to present. The changes in the exhumation rate have been tectonic responses to the subduction retreat of the Paleo-Pacific Plate and the eastward growth of the Tibetan Plateau. The westward subduction of the Paleo-Pacific Plate resulted in northwestward shortening across South China, progressive deformation of the ESFTB, and rapid exhumation from the Late Jurassic to the Late Cretaceous. The crustal extension associated with the rollback of the Paleo-Pacific slab accounted for the Mesozoic exhumation rate decrease until the Miocene. The accelerated cooling of the thin-skinned domain of the ESFTB since the Miocene was a response to the eastward growth of the Tibetan Plateau, while the continuous slow exhumation in the thick-skinned domain was related to the continuous crustal extension in South China. New thermo-kinematic method combining analog modeling, discrete element method, balanced reconstruction, and thermochronology dataEastern Sichuan fold-and-thrust belt (ESFTB) experienced northwestward thrusting and periodic exhumation and its evolution can be subdivided into five stagesExhumation rate changes are responses of ESFTB to subduction retreat of the Paleo-Pacific Plate and eastward growth of the Tibetan Plateau

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2023
Keywords
kinematic restoration, eastern Sichuan fold-and-thrust belt, analog model, low-temperature thermochronology, thermo-kinematic modeling, South China
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-514376 (URN)10.1029/2022TC007630 (DOI)001066638600001 ()
Available from: 2023-10-20 Created: 2023-10-20 Last updated: 2023-10-20Bibliographically approved
Lescoutre, R., Almqvist, B., Koyi, H., Berthet, T., Hedin, P., Galland, O., . . . Juhlin, C. (2022). Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny. Geological Society of America Bulletin, 134(11-12), 3022-3048
Open this publication in new window or tab >>Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny
Show others...
2022 (English)In: Geological Society of America Bulletin, ISSN 0016-7606, E-ISSN 1943-2674, Vol. 134, no 11-12, p. 3022-3048Article in journal (Refereed) Published
Abstract [en]

The Fennoscandian Shield in central Sweden displays a complex structural and compositional architecture that is mainly related to the Proterozoic history of the Baltica paleocontinent. In its western parts, the Precambrian basement is covered by the allochthonous rocks of the Caledonide orogen, and direct information about the underlying crust is restricted to a few unevenly distributed basement windows in western Sweden and Norway. In this study, we use preliminary results from the second borehole of the Collisional Orogeny in the Scandinavian Caledonides project (COSC-2), new gravity data, forward gravity, and magnetic modeling and interpretation of seismic reflection profiles to assess the 3-D architecture of the basement. Our results reveal a wide (∼100 km) and dense network of mainly flat-lying and saucer-shaped dolerites intruding the volcanic and granitic upper crustal rocks of the Transscandinavian Igneous Belt. Similar intrusion geometries related to 1.2 Ga dolerites can be recognized in the Fennoscandian Shield. We discuss that the formation of these sill complexes occurred in a lithologically and structurally heterogeneous crust during transtension, which is in disagreement with the current understanding of sill emplacement that involves crustal shortening, layering, or anisotropy of the host rock. Our seismic interpretation and the structural observations from the COSC-2 drilling show that part of the Caledonian-related basement deformation was localized along the margins of the dolerite sheets. We propose that the dolerite intrusion geometry, akin to a flat-ramp geometry, guided the basement deformation during the Caledonian orogeny.

Place, publisher, year, edition, pages
Geological Society of America, 2022
Keywords
Baltica, orogeny, Caledonian, mafic intrusion
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-470029 (URN)10.1130/B36202.1 (DOI)000966241900016 ()
Projects
Collisional Orogeny in the Scandinavian Caledonides (COSC)
Funder
Swedish Research Council, 2018-03414
Available from: 2022-03-18 Created: 2022-03-18 Last updated: 2023-05-05Bibliographically approved
Schöfisch, T., Koyi, H. & Almqvist, B. (2022). Magnetic fabric signature within a thrust imbricate: an analogue modelling approach. Tectonics, 47(7), Article ID e2021TC007054.
Open this publication in new window or tab >>Magnetic fabric signature within a thrust imbricate: an analogue modelling approach
2022 (English)In: Tectonics, ISSN 0278-7407, E-ISSN 1944-9194, Vol. 47, no 7, article id e2021TC007054Article in journal (Refereed) Published
Abstract [en]

In this study, we report results from three analogue models with similar initial setup and different amounts of bulk shortening, to simulate a development of a pop-up structure in fold-and-thrust belts at different stages. Samples are taken in different places of the deformed models for analysis using anisotropy of magnetic susceptibility. Shortening of the models resulted in the formation of a pop-up structure, which is bounded by backthrust(s) and complex forekink zone(s). Several forethrusts at different degrees of maturity developed in front of the pop-up structure. Three distinct types of magnetic fabric can be identified throughout the models: (i) a compactional oblate fabric that changes as function of distance towards a localized deformation zone (e.g., thrust or kinkzone), (ii) a thrust-induced fabric with magnetic foliation parallel to the thrust surface, and (iii) a complex forekink zone fabric with broad girdle distributions of principal axes and magnetic lineation perpendicular to shortening direction. The latter indicate interplay between folding and thrusting of the shortened sand layers. Additionally, a decrease in degree of anisotropy with appearance of a quantitatively more prolate fabric can be observed towards the thrusts and kinkzones. Additionally at thrusts, a variation in strain is reflected by the magnetic fabric and can be inherited in a thrust-induced fabric. In conclusion, strain is changing as function of distance towards localized deformation zones with characteristic fabric, and differences in magnetic fabric are distinct between data away and within deformation zones as deformation zones mature.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2022
Keywords
analog model, magnetic fabric analysis, pop-up structure, anisotropy of magnetic susceptibility, strain distribution, thrust imbricate
National Category
Geology
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-451972 (URN)10.1029/2021TC007054 (DOI)000826955100001 ()
Funder
Swedish Research Council, 2017-04519
Available from: 2021-09-01 Created: 2021-09-01 Last updated: 2023-06-04Bibliographically approved
Amri, Z., Masrouhi, A., Naji, C., Bellier, O. & Koyi, H. (2022). Mechanical relationship between strike-slip faulting and salt tectonics in the Northern Tunisian Atlas: The Bir-El-Afou salt structure. Journal of Structural Geology, 154, Article ID 104501.
Open this publication in new window or tab >>Mechanical relationship between strike-slip faulting and salt tectonics in the Northern Tunisian Atlas: The Bir-El-Afou salt structure
Show others...
2022 (English)In: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201, Vol. 154, article id 104501Article in journal (Refereed) Published
Abstract [en]

Wide variety of salt structures -from typical diapirs to large allochthonous salt sheets- are recognized in the Northern Tunisian Atlas. In this study, we present for the first time the presence of a diapiric structure, Bir-ElAfou Salt Structure (BEASS), which has formed in response to strike-slip tectonics. Structural mapping, mesoscale field observations, fault kinematic analysis, and interpretation of gravity data are used to interpret BEASS, which is currently associated with a restraining bend. The present-day NNE- trending restraining stepover is formed as a result of E-W dextral fault system. We assume that the restraining stepover is a product of the inversion of a pre-existing pull-apart basin that formed during the Cretaceous South Tethyan extension. Tectono-sedimentary relationship is used to argue for an early Cretaceous NW-SE regional extension and local transtension. During the opening of the pull-apart basin, salt movement took place in the southwestern corner of the basin which must have thinned due to its extension facilitating diapiric emplacement. Diapir growth during Aptian was followed by brief salt flow from the diapir crest towards the basin forming a salt sheet. A period of Tertiary contraction resulted in the inversion of the pull-apart basin and consequently, squeezing of BEASS.

Place, publisher, year, edition, pages
ElsevierElsevier BV, 2022
Keywords
Salt diapir, Pull-apart, Restraining bend, Inversion, Tunisia
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-465902 (URN)10.1016/j.jsg.2021.104501 (DOI)000742547800001 ()
Available from: 2022-01-24 Created: 2022-01-24 Last updated: 2024-01-15Bibliographically approved
Carboni, F., Koyi, H., Bicocchi, A. & Barchi, M. R. (2022). Modelling the 4D kinematics of extensional structures developed above discontinuous inclined ductile basal detachments. Journal of Structural Geology, 157, Article ID 104570.
Open this publication in new window or tab >>Modelling the 4D kinematics of extensional structures developed above discontinuous inclined ductile basal detachments
2022 (English)In: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201, Vol. 157, article id 104570Article in journal (Refereed) Published
Abstract [en]

A series of scaled analogue models were used to a preliminary study on the influence of the basal detachment configuration on the evolution of extensional systems, developed above an inclined basal ductile detachment. Three different basal configurations were aimed to test extension above: i) a homogeneously distributed ductile detachment; ii) two sectors with a different distribution of the ductile detachment, separated by an abrupt, transversal boundary; ii) a laterally variable width of the ductile detachment, driven by an abrupt oblique boundary. Fault activity was monitored through a series of digital elevation models obtained from the laser scanning of the models' surface. Results of the models analysis show how the geometry, the distribution, the kinematic, and the timing of faulting is strongly controlled by the geometry and orientation of the ductile-brittle interface in respect to the extension direction. Faults close to the brittle-ductile interface develop following the interface geometry, whose effect is reduced moving away from it. In addition, we observe a major number of faults which accommodates lower amount of extension and are less closely spaced above longer ductile detachments. Our results can be compared with natural case-histories along continental passive margins, where extension occurs above a dipping salt detachment, with inhomogeneous distribution (e.g., the northern Gulf of Mexico, central Brazilian margin, Angola margin).

Place, publisher, year, edition, pages
ElsevierElsevier BV, 2022
Keywords
Analogue modelling, Salt tectonics, Normal faults, Kinematic analysis
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-474821 (URN)10.1016/j.jsg.2022.104570 (DOI)000792416900002 ()
Funder
Swedish Research Council
Available from: 2022-05-23 Created: 2022-05-23 Last updated: 2024-01-15Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1872-052x

Search in DiVA

Show all publications