Jhon-Meyer Munoz

• Arcila, Paula; n Luco, Rafael Robertson & Munoz, Jhon-Meyer (2025). Relationship between Neogene volcanic centers and the foreland advance of deformation: The Malargüe fold-and-thrust belt 35°-36°S, 69°50′W, Southern Central Andes, Argentina. Journal of South American Earth Sciences. ISSN 0895-9811. 166. doi: 10.1016/j.jsames.2025.105732. Fulltekst i vitenarkiv Vis sammendrag

  The presence of Neogene volcanic centers have been poorly studies between 35° and 36°S, 69°50′W in the Malargüe Fold-and-Thrust Belt, Argentina. This work used field observations, stratigraphic sections, whole-rock geochemistry, and 40Ar/39Ar geochronology to characterize three polygenetic volcanic successions: Butamallín, Fiero, and Picudo de la Ventana and their relationship with the synorogenic deposits. Their emplacement spans from the Early Miocene (16.7 ± 1.7 Ma), through the Late Miocene (9.8 ± 1.0 Ma), to the Pliocene (6.5 ± 0.5 Ma), with each center displaying distinctive geochemical signatures associated with retroarc magmatism, arc-related magmatism, and retroarc magmatism with depleted mantle affinities. The volcanic successions unconformably overlie synorogenic units, acting as sediment sources and influencing basin architecture. The relationship with synorogenic successions, together with paleoflow indicators and clast compositions, reveals four evolutionary stages: (1) a foreland basin in the Early Miocene, (2) the development of wedge-top basins during the Middle Miocene, (3) arc migration and volcanic expansion in the Late Miocene, and (4) the formation of piggyback basins associated with mantle-derived magmatism from the Late Miocene to the Pliocene. These results support a model of forelandward (eastward) propagation of the Malargüe Fold-and-Thrust Belt (MFTB) in the southern Central Andes of Argentina.

• montes, camilo; Rosero, C.A.; Felipe, Lamus; . Perez-Angel, L.C.; Bayona, Germán & Munoz, Jhon-Meyer (2025). Panoramic Transect of the Western Flank of Eastern Cordillera Fold and Thrust Belt, Northern Andes, Colombia. Journal of South American Earth Sciences. ISSN 0895-9811. 171. doi: https:/www.sciencedirect.com/science/article/pii/S0895981125005802?via%3Dihub. Fulltekst i vitenarkiv Vis sammendrag

  A ∼23 km-long, hiking-kayaking, panoramic transect along the Rionegro Canyon in the western flank of the Eastern Cordillera of Colombia reveals two deformed belts with contrasting structural styles separated by a regional fault (La Salina Thrust). East of the fault, a deformed belt is characterized by tight, horizontal and upright concentric and box folds with pervasive axial-planar cleavage within a Lower Cretaceous, mostly sandy sequence. West the fault, the structural style is characterized by thrust sheets with prominent footwall deformation and isoclinal folding in the hanging wall. At least four stacked thrust sheets that repeat Upper Cretaceous sequences define a regional-scale duplex (El Trigo-Bituima anticlinal stack duplex). Immediately west of the anticlinal duplex, a regional syncline (Guaduas) folds a ∼1.5 km-thick, middle Eocene to Oligocene molasse deposit. The western flank of the syncline is thrusted (Cambras Thrust) on to a ∼2 km-thick Miocene molasse deposit repeated by the frontal thrust of the Eastern Cordillera (Honda Thrust). Line-balancing of a 30 km-long cross-section that includes the Honda Thrust results in a shortening value of ∼60 % (∼45 km) not considering layer-parallel shortening. Reconstruction of the original geometry suggests the presence of two rift-fault systems: one to the east, where the thickness of Cretaceous sequence changes from ∼4 to 3 km, and another one ∼50 km to the west, where the ∼3 km-thick Cretaceous sequence thins to nothing. The former is reactivated as the La Salina Thrust and likely contains pre-Cretaceous basement rocks in its hanging wall, and the latter is not reactivated, as previous studies had proposed. All of this is consistent with a main pulse of growth of the Eastern Cordillera and major surface elevation gain starting in middle Eocene times.

• Barrera, Jhon Meyer Munoz; Gawthorpe, Rob; Cullen, Timothy; Pechlivanidou, Sofia; Henstra, Gijs Allard & Rotevatn, Atle [Vis alle 7 forfattere av denne artikkelen] (2024). Tectono-sedimentary evolution of high-displacement crustal-scale normal faults and basement highs on rifted margins: Klakk Fault Complex and Frøya High, Mid-Norwegian Margin. Basin Research. ISSN 0950-091X. 36(4). doi: 10.1111/bre.12889. Fulltekst i vitenarkiv Vis sammendrag

  Crustal-scale high-displacement (>10 km) normal faults are not captured in existing tectono-sedimentary models of rift basins. We used 2D and 3D seismic reflection and well data to perform a structural and source-to-sink analysis of the southern part of the Klakk Fault Complex and the western part of the Vingleia Fault Complex, Mid-Norwegian rifted margin. The north–south trending Klakk Fault Complex has a zig-zag to sinuous plan-view geometry, forming a series of structural recesses and salients along strike. In cross-section, the fault complex has a listric to convex-up or low-angle planar geometry with displacements above 20 km. This fault complex exhumed basement highs, the Frøya High and Sklinna Ridge, in its footwall and created a series of supradetachment basins, for example, the Rås Basin, in its hanging wall. In contrast, the northeast-southwest trending Vingleia Fault Complex has a zig-zag geometry in plan view and planar to listric geometry in cross-section and displacement of up to 5 km. This fault has the Frøya High in its footwall and the southern Halten Terrace in its hanging wall. Restoration of selected structural cross-sections shows a prominent fault-parallel ridge, up to 15 km east of the Klakk Fault Complex interpreted as a palaeodrainage divide. This divide separates steep drainages developed along the west-dipping footwall scarp to the Klakk Fault Complex, from broader, gentler east-dipping drainages up to ca. 10 km long developed on a back-tilted dip slopes along the eastern side of the Frøya High and Sklinna Ridge. Progressive headward erosion of active flank catchments was enhanced around topographically elevated structural salients to the point of capturing previous dip-slope-directed drainages during the earliest Cretaceous. A network of submarine canyons develop down-dip of the drainage catchments along the Klakk Fault Complex scarp, whose geometries and length are controlled by their location with respect to the structural salients or recesses, and the presence of fault terraces. The middle Jurassic-earliest Cretaceous synrift deposits form two seismic sequences that are filled with five distinctive seismic facies that record the evolution from a linked normal fault during rift climax to a high-displacement stage. During the high displacement stage, exhumed local continental core complexes formed structural salients, separated along strike by structural recesses at the heads of supradetachment basins. Key elements of the high-displacement fault stage include (i) the development of structural salients at sites of rift climax displacement maxima, (ii) development of supradetachment basins in rift climax displacement minima and (iii) migration of major depocentres away from the centre of rift climax fault segments. We synthesise these observations into a generic tectono-sedimentary model for high-displacement faults.

• Koehl, Jean-Baptiste P.; Jolley, David W.; Peace, Alexander L.; Barrera, Jhon Meyer Munoz & Foulger, Gillian R. (2024). Impact of sub-basalt thrust systems on the Faroe continental shelf for the late Paleoproterozoic–Cenozoic tectonic evolution of the margin. Open Research Europe. 4. doi: 10.12688/openreseurope.18284.2. Fulltekst i vitenarkiv Vis sammendrag

  Background The Faroe margin in the northeastern Atlantic is segmented by margin-orthogonal, WNW–ESE-striking lineaments extending several hundred kilometers out to the continent–ocean transition. Despite several earlier studies speculating that these features are the product of reactivation of pre-Cenozoic basement-seated structures at depth, the thick Cenozoic volcano-sedimentary sequences deposited along the margin mask the underburden, thus rendering the identification and interpretation of such structures and resolving the pre-Cenozoic history of the area challenging. The present study documents for the first time the existence of margin-orthogonal basement-seated thrust systems and describes their detailed geometry, kinematics, and tectonic evolution. Methods We interpreted basement-seated tectonic structures on seismic reflection data from TGS on the Faroe Platform and the Wyville–Thomson and Munkagrunnur ridges using the newly established seismic facies of major thrust systems. Results The data show that the Wyville–Thomson Ridge, Munkagrunnur Ridge, and Faroe Platform are cored by WNW–ESE-striking thrust systems hundreds of kilometers long and 30–50 km wide, showing dominantly top-SSW kinematics. The thrusts were reworked into NE–SW-striking folds during the Caledonian Orogeny and controlled the formation of Caledonian thrusts, which in turn controlled the formation of post-Caledonian faults. The pre-Caledonian nature of the WNW–ESE-striking thrusts and their geometry and kinematics suggest a relationship with late Paleoproterozoic Laxfordian shear zones onshore northern Scotland and the continuation of the coeval Nagssugtoqidian Orogen in southeastern Greenland, the Ammassalik Belt. The thrust systems also align with the Tornquist Zone in eastern Europe and the North Sea, thus suggesting either that they controlled the formation of the Tornquist Zone or a possibly much longer (Paleoproterozoic?) tectonic history for the Tornquist Zone. Conclusions The Faroe Island margin is crosscut by late Paleoproterozoic Laxfordian–Nagssugtoqidian thrust systems, which controlled further tectonic development of the margin.

• Koehl, Jean-Baptiste P.; Stokmo, Eirik & Barrera, Jhon Meyer Munoz (2024). On the Billefjorden fault zone in Garmdalen, central Spitsbergen: implications for the mapping of major fault zones during geological fieldwork and for the tectonic history of Svalbard. Open Research Europe. 4(147). doi: 10.12688/openreseurope.17826.2. Fulltekst i vitenarkiv Vis sammendrag

  Background: The present contribution reexamines the geometry of a segment of a presumably long-lived fault in Svalbard, the Balliolbreen Fault segment of the Billefjorden Fault Zone, along which presumably two basement terranes of Svalbard accreted in the early–mid Paleozoic after thousands of kilometers strike-slip displacement. Methods: We performed structural fieldwork to Billefjorden in central Spitsbergen and interpreted satellite images. Results: Field observations demonstrate that the Balliolbreen Fault formed as a top-west thrust fault in the early Cenozoic and that weak sedimentary units such as shales of the Lower Devonian Wood Bay Formation and coals of the uppermost Devonian–Mississippian Billefjorden Group partitioned deformation, resulting in significant contrast in deformation intensity between stratigraphic units. For example, tight early Cenozoic folds are localized in shales of the Wood Bay Formation and contemporaneous top-west brittle–ductile thrusts within coals of the Billefjorden Group, whereas Pennsylvanian deposits of the Hultberget (and/or Ebbadalen?) Formation are simply folded into gentle open folds. Rheological contrasts also resulted in the development of décollements locally, e.g., between tightly folded strata of the Wood Bay Formation and Billefjorden Group and flat-lying, brecciated limestone-dominated strata of the Wordiekammen Formation. Despite the limited quality and continuity of outcrops in the area, the eastward-thickening character (i.e., away from the fault) of Pennsylvanian deposits of the Hultberget, Ebbadalen, and Minkinfjellet formations suggests that the fault did not act as a normal fault in Pennsylvanian times. Conclusions: The study suggests that strain partitioning of early Cenozoic Eurekan contraction alone may explain the deformation patterns in Paleozoic rock units in central Spitsbergen, i.e., that Late Devonian Svalbardian contraction is not required, and that a major segment of the Billefjorden Fault Zone formed in the early Cenozoic. The present work illustrates the crucial need for interdisciplinary approaches and composite educational backgrounds in science.

• Henstra, Gijs Allard; Cullen, Tim; Gawthorpe, Robert Leslie; Barrera, Jhon Meyer Munoz; Muravchik, Martin & Rotevatn, Atle (2023). The evolution of catchment-depositional system relationships on the dip slopes of intra-rift basement highs: An example from the Frøya High, Mid-Norwegian rifted margin. Basin Research. ISSN 0950-091X. 35(4), s. 1259–1287. doi: 10.1111/bre.12753. Fulltekst i vitenarkiv Vis sammendrag

  Basement highs form one of many potential sediment source areas during the evolution of continental rifts and rifted margins and add to the topographic complexity typical of active rifts. Footwall basement highs acting as a source area to sedimentary systems in the hangingwall of major faults have been documented in many systems worldwide. However, the back-tilted footwall dip slopes of such highs have received comparatively little attention. Here, we investigate a subsurface case study from the Norwegian continental shelf, where catchments and shallow marine syn-rift sedimentary systems on a dip slope are preserved due to early transgression of an intra-rift high. At the onset of Late Jurassic rifting, the Frøya High emerged as a prominent, N-S trending, 25 km-wide basement high tilted towards the east in response to several kilometres of displacement along the Klakk Fault Complex, a major normal fault zone at the Frøya High's western edge. Using well-calibrated 3D seismic reflection data, we observe a series of conspicuous Upper Jurassic wedges along the eastern edge of the Frøya High along the margin of the Froan Basin. Internally, these wedges show sigmoidal geometries marking top and foresets of clinoform packages with a maximum thickness of ca. 200 m with foresets between 30 and 200 m high, dipping ca. 10° towards the east, southeast and northeast. We interpret these wedges to represent a series of eastward prograding deltas positioned along a constructional shoreline, connected to E-W trending valleys and river catchments up-dip. The deltas show strong progradation, interpreted to reflect the impact of the continued uplift of their catchments prior to the abrupt termination of sediment supply from drainage capture by footwall scarp drainages. The presence of a connected, largely constructional shoreline has implications for Late Jurassic sediment distribution around the Frøya High, providing primary sedimentary input for longshore-driven sedimentary systems in the Draugen Ridge to the north. Comparisons with other syn-rift dip slope systems highlight a broadly similar evolution but shows a distinct lack of the protracted backstepping observed in other dip slope systems. We postulate that different structural configurations of dip slope systems, being footwall uplift or hangingwall subsidence driven, may drive the strongly progradational character of the deltaic systems on the Frøya High. The Frøya High example highlights the need to constrain primary sediment input points to aid the interpretation of volumetrically significant, but short-lived and subtle depositional systems, especially within complex, tectonically active settings.

• Barrera, Jhon Meyer Munoz; Rotevatn, Atle; Gawthorpe, Rob; Henstra, Gijs Allard & Kristensen, Thomas Berg (2021). Supradetachment basins in necking domains of rifted margins: Insights from the Norwegian Sea. Basin Research. ISSN 0950-091X. 34(3). doi: 10.1111/bre.12648. Fulltekst i vitenarkiv Vis sammendrag

  Supradetachment basins at passive rifted margins are a key witness of major-continental extension, and they may preserve a record from which the amount and rates of extension and metamorphic core complex exhumation may be reconstructed. These basins have mainly been recognised in back-arc and orogenic collapse settings, with few examples from rifted margins. Using 2D and 3D seismic reflection, wellbore, and gravity anomaly data, we here characterise the three-dimensional structural and tectonosedimentary evolution of a spoon-shaped supradetachment basin that was formed in the necking domain of a rifted margin, at the southern limit of the Møre and Vøring segments of the Norwegian rifted margin. The basin, with an areal extent of ca. 2400 km2, and a landward-rotated syn-tectonic succession up to ca. 30 km thick (true stratigraphic thickness), is separated from footwall continental margin core complex basement culminations by major large-offset (>30 km) normal fault complexes characterised by a cross-sectional geometry whereby an upper, steeper part of the fault gives way to a low-angle detachment fault at depth. These fault complexes are associated with a tectonic thinning of the continental crust to ca. 11 km, compared with a crustal thickness of ca. 27 km in the proximal domain. The basin is filled by a succession of pre-, syn- and post-tectonic deposits, that accumulated over time as the basin evolved over a series of rift- and detachment faulting events. The 30 km thick syn-tectonic succession reflects deposition during two separate rifting events, which are disconnected by deposits reflecting a relative short period of tectonic quiescence. The results are discussed in light of examples of supradetachment basins on other rifted margins globally, as well as in the context of the evolution of the Norwegian margin overall.

• Barrera, Jhon Meyer Munoz; Rotevatn, Atle; Gawthorpe, Rob; Henstra, Gijs Allard & Kristensen, Thomas Berg (2020). The role of structural inheritance in the development of high-displacement crustal faults in the necking domain of rifted margins: The Klakk Fault Complex, Frøya High, offshore mid-Norway. Journal of Structural Geology. ISSN 0191-8141. 140. doi: 10.1016/j.jsg.2020.104163. Fulltekst i vitenarkiv Vis sammendrag

  The role of inherited structures during the development of normal faults in continental rifts and proximal domains of passive margins have been extensively studied. Few studies, however, have a focus on deciphering the role of inheritance in the development of high-displacement (>10 km), low-angle (<30°) normal faults in necking domains of passive margins. We integrated and interpreted potential field, 2D and 3D reflection seismic, and well data to study the role of structural inheritance in controlling the location and development of the southern part of the Klakk Fault Complex, offshore mid-Norway. The down-to-the-west Klakk Fault Complex is an N-S non-collinear fault complex that separates the Frøya High in its footwall from the Rås Basin in its hanging wall. The fault segments vary from low-angle planar to listric fault geometries in cross-section, with displacements of 17 km–34 km. These displacements led to syn-rift basement thinning of 12–14 km toward the west, which consequently, also affected the crustal wedge geometry of the necking domains. We identify three intra-acoustic-basement structures based on seismic facies and define their 3D geometry: (i) a bowl-shaped basin, (ii) a hyperbolic surface, and (iii) a domal structure. We discuss their origin and elucidate their role during later rifting. We conclude that pre-existing basement structures controlled the rift-related structures during the second rift phase (thinning), and affected the location, geometries, orientation and segmentation of the high-displacement low-angle faults in the necking domains. The results of this work offer new insights into the development of necking domains in areas where a thick continental crust (>25 km) is present during rifting.

• Koehl, Jean-Baptiste P. & Barrera, Jhon Meyer Munoz (2018). From widespread Mississippian to localized Pennsylvanian extension in central Spitsbergen, Svalbard. Solid Earth (SE). ISSN 1869-9510. 9, s. 1535–1558. doi: 10.5194/se-9-1535-2018. Fulltekst i vitenarkiv Vis sammendrag

  In the Devonian–Carboniferous, a rapid succession of clustered extensional and contractional tectonic events is thought to have affected sedimentary rocks in central Spitsbergen, Svalbard. These events include Caledonian post-orogenic extensional collapse associated with the formation of thick Early–Middle Devonian basins, Late Devonian–Mississippian Ellesmerian contraction, and Early–Middle Pennsylvanian rifting, which resulted in the deposition of thick sedimentary units in Carboniferous basins like the Billefjorden Trough. The clustering of these varied tectonic settings sometimes makes it difficult to resolve the tectono-sedimentary history of individual stratigraphic units. Notably, the context of deposition of Mississippian clastic and coal-bearing sedimentary rocks of the Billefjorden Group is still debated, especially in central Spitsbergen. We present field evidence (e.g., growth strata and slickensides) from the northern part of the Billefjorden Trough, in Odellfjellet, suggesting that tilted Mississippian sedimentary strata of the Billefjorden Group deposited during active (Late/latest?) Mississippian extension. WNW–ESE-striking basin-oblique faults showing Mississippian growth strata systematically die out upwards within Mississippian to lowermost Pennsylvanian strata, thus suggesting a period of widespread WNW–ESE-directed extension in the Mississippian and an episode of localized extension in Early–Middle Pennsylvanian times. In addition, the presence of abundant basin-oblique faults in basement rocks adjacent to the Billefjorden Trough suggests that the formation of Mississippian normal faults was partly controlled by reactivation of preexisting Neoproterozoic (Timanian?) basement-seated fault zones. We propose that these preexisting faults reactivated as transverse or accommodation cross faults in or near the crest of transverse folds reflecting differential displacement along the Billefjorden Fault Zone. In Cenozoic times, a few margin-oblique faults (e.g., the Overgangshytta fault) may have mildly reactivated as oblique thrusts during transpression–contraction, but shallow-dipping, bedding-parallel, duplex-shaped décollements in shales of the Billefjorden Group possibly prevented substantial movement along these faults.

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• Munoz, Jhon-Meyer; Torabi, Anita; Basa, Abhisek; Hansen, Torsten Hundebøl & Skurtveit, Elin (2026). Fault-core in overburden section: geomechanical and geo chemical characterisation of the Baza fault core, southern Spain. I Ziegler, Martin; Nicol, Romain; Jaeggi, David & Nussbaum, Christophe (Red.), Caprock Integrity & Gas Storage Symposium 2026. Swiss Federal Office of Topography. s. 41–45. doi: https:/www.swisstopo.admin.ch/dam/en/sd-web/jwHxgZfGm5AB/Conference%20Proceedings%20CIGSS%202026.pdf. Fulltekst i vitenarkiv
• Munoz, Jhon-Meyer (2024). Tectono-stratigraphic model for high-displacement crustal normal faults on continental rifts : The Late Jurassic and earliest Cretaceous on and around the Frøya High, Norwegian Sea. Universitetet i Bergen. ISSN 9788230869123. Fulltekst i vitenarkiv Vis sammendrag

  Nye seismiske refleksjonsdata og forbedringer i prosessering av seismikk i løpet av de siste to tiårene har forbedret muligheten for å se strukturer i necking- og distaldomenet i riftede marginer. Osmundsen og Peron-Pinvidic (2018) har dokumentert at normalforkastninger med høyt sprang (> 30 km) skiller de ulike strukturelle domenene på riftede marginer. Disse normalforkastningene, eller grenseforkastningskompleksene, kontrollerer kildeområdet for sedimenter, avsetningsrute og avsetningsområde gjennom rift-fasen og i flere millioner år etter den tektoniske hendelsen. Til tross for den viktige rollen normalforkastninger med høyt sprang spiller, finnes det lite kunnskap om hvordan deres vekst skiller seg fra andre forkastninger, og hvordan de samhandler med andre strukturer for å kontrollere arkitekturen og utviklingen av sedimentære systemer. Gjennom denne forskningen har det blitt benyttet seismikk og brønndata lokalisert på den sørlige delen av den norske riftmarginen for å undersøke tre viktige temaer knyttet til den tektonostratigrafiske utviklingen på og rundt Frøyahøyden under sen Jura og de tidligste riftfasene fra Kritt. Arbeidet starter med å undersøke hvilken rolle strukturer i grunnfjellet spiller når det kommer til plassering, geometri, orientering og segmentering av forkastningskomplekset Klakk vest for Frøyahøyden. Det andre temaet for arbeidet tar for seg den tredimensjonale geometrien og utviklingen av et skjeformet supradetachment-basseng utviklet i neckingdomenet til en riftmargin. Det tredje temaet omfatter en «source-to-sink»-analyse (S2S) for å syntetisere den geomorfologiske og tektonostratigrafiske utviklingen av avsetningssystemene på og rundt Frøyahøyden, Norskehavet. Resultater fra disse studiene viser (i) at en kombinasjon av nedarvede strukturer og reologi kontrollerer den tredimensjonale geometrien til grenseforkastningskompleksene, (ii) at normalforkastninger med høyt sprang genererer to typer supradetachment-bassenger, skjeformede og grensetype, (iii) hvordan størrelsesorden på sprang og samhandling mellom forkastningssegmenter styrer lokalisering av både grunne og dype avsetningssystemer, og (iv) normalforkastninger med høyt sprang viser to typer «source-to-sink» systemer som kan relateres til aktive og passive eller de hellende flankene. Avhandlingen presenterer utviklingen av en tektono-sedimentær modell for normalforkastninger med høyt sprang, utviklet i neckingdomener med tykk kontinentalskorpe. Funnene i avhandlingen vil bidra til å identifisere plasseringen og arkitekturen til silisiklastiske reservoarer, som videre vil bedre kunnskap om utviklingen av riftsystemer og leting etter hydrokarboner.

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