Evidence for two stages of back-arc compression in the late Cretaceous fold-and-thrust belt in the Precordillera of northern Chile (24°30′S–25°30′S)

2020 ◽  
Vol 103 ◽  
pp. 102706
Author(s):  
Rodrigo González ◽  
Daniela Espinoza ◽  
Francisca Robledo ◽  
Vicente Jeria ◽  
Mauricio Espinoza ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Northern Chile ◽  
Thrust Belt ◽  
Fold And Thrust Belt ◽  
Two Stages ◽  
Back Arc

scholarly journals Late Cretaceous Uplift in the Malargüe fold-and-thrust belt (35ºS), southern Central Andes of Argentina and Chile

2013 ◽  
Vol 40 (1) ◽  
Author(s):  
Jose Francisco Mescua ◽  
Laura Beatriz Giambiagi ◽  
Victor Alberto Ramos
Keyword(s):  
Late Cretaceous ◽  
Central Andes ◽  
Thrust Belt ◽  
Fold And Thrust Belt ◽  
Southern Central

Inversion tectonics, intracontinental fold-and-thrust belts and complex stress fields in central Europe: the history of the Franconian Basin revealed by paleostress analysis, geological maps and field observations.

2020 ◽  
Author(s):  
Saskia Köhler ◽  
Florian Duschl ◽  
Hamed Fazlikhani ◽  
Daniel Köhn
Keyword(s):  
Stress Field ◽  
Late Cretaceous ◽  
Complex Stress ◽  
Strike Slip ◽  
Stress Fields ◽  
Thrust Belt ◽  
Slip Regime ◽  
Geological Maps ◽  
Fold And Thrust Belt ◽  
Paleostress Analysis

<p>The Franconian Basin in SE Germany has seen a complex stress history indicative of several extensional and compressional phases e.g. the Iberia-Europe collision acting on a pre-faulted Variscan basement. Early Cretaceous extension is followed by Late Cretaceous inversion with syntectonic sedimentation and deformation increasing progressively from SW to NE culminating in the Franconian Line where basement rocks are thrusted over the Mesozoic cover. The development of this intracontinental fold-and-thrust belt is followed by Paleogene extension associated with the formation of the Eger Graben, which is then succeeded by a new compressional event as a consequence of the Alpine orogeny.</p><p>We use existing data from literature and geological maps and new field data to construct balanced cross-sections in order to reveal the architecture of the Cretaceous fold-and-thrust belt. In addition, we undertake paleostress analysis using a combination of fault slip information, veins and tectonic and sedimentary stylolites to identify stress events in the study area, as well as their nature and timing. Furthermore, we try to understand how basement faults influence younger faults in the cover sequence.</p><p>Our paleostress data indicates that at least five different stress events existed in Mesozoic to Cenozoic times (from old to young): (1) an N-S directed extensional stress field with E-W striking normal faults, (2) a NNE-SSW directed compressional stress field causing thrusting and folding of the cover sequence, (3) a strike slip regime with NE-SW compression and NW-SE extension, (4) an extensional event with NW-SE extension and the formation of ENE-WSW striking faults according to the formation of the Eger Graben in the E, and finally (5) a strike slip regime with NW-SE compression and NE-SW extension related to Alpine stresses. The geometry of faulting and deformation varies significantly over the regions with respect to the influence of and distance to inherited Variscan structures.</p><p>We argue that the extensional event of stress field (1) provides spacing for Early Cretaceous sedimentation in the Franconian Basin. This is followed by the creation of an intracontinental fold-and-thrust belt during stress fields (2) and (3) with a slight rotation of the main compressive stress during these events in Late Cretaceous. We associate the following extension to the development of the Eger Graben in Miocene time. Finally, a NW-SE directed compression related to Alpine stresses in an intracontinental strike-slip regime is following. Reconstruction of the Cretaceous fold-and-thrust belt reveals mainly fault propagation folding with deep detachments sitting below the cover sequence indicating thick-skinned tectonics. We argue that the Franconian Line is a thrust with a steeply dipping root that belongs to the same fold-and-thrust belt.</p>

From arc evolution to arc-continent collision: Late Cretaceous–middle Eocene geology of the Eastern Pontides, northeastern Turkey

2019 ◽  
Vol 131 (11-12) ◽  
pp. 1889-1906 ◽  
Author(s):  
Özgür Kandemir ◽  
Kenan Akbayram ◽  
Mehmet Çobankaya ◽  
Fatih Kanar ◽  
Şükrü Pehlivan ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Middle Eocene ◽  
Structural Data ◽  
Massive Sulfide ◽  
Arc Volcanism ◽  
Eastern Pontides ◽  
The North ◽  
Fold And Thrust Belt ◽  
Volcaniclastic Rocks ◽  
Back Arc

Abstract The Eastern Pontide Arc, a major fossil submarine arc of the world, was formed by northward subduction of the northern Neo-Tethys lithosphere under the Eurasian margin. The arc’s volcano-sedimentary sequence and its cover contain abundant fossils. Our new systematical paleontological and structural data suggest the Late Cretaceous arc volcanism was initiated at early-middle Turonian and continued uninterruptedly until the end of the early Maastrichtian, in the northern part of the Eastern Pontides. We measured ∼5500-m-thick arc deposits, suggesting a deposition rate of ∼220 m Ma–1 in ∼25 m.y. We have also defined four different chemical volcanic episodes: (1) an early-middle Turonian–Santonian mafic-intermediate episode, (2) a Santonian acidic episode; when the main volcanic centers were formed as huge acidic domes-calderas comprising the volcanogenic massive sulfide ores, (3) a late Santonian–late Campanian mafic-intermediate episode, and (4) a late Campanian–early Maastrichtian acidic episode. The volcaniclastic rocks were deposited in a deepwater extensional basin until the late Campanian. Between late Campanian and early Maastrichtian, intra-arc extension resulted in opening of back-arc in the north, while the southern part of the arc remained active and uplifted. The back-arc basin was most probably connected to the Eastern Black Sea Basin. In the back-arc basin, early Maastrichtian volcano-sedimentary arc sequence was transitionally overlain by pelagic sediments until late Danian suggesting continuous deep-marine conditions. However, the subsidence of the uplifted-arc-region did not occur until late Maastrichtian. We have documented a Selandian–early Thanetian (57–60 Ma) regional hiatus defining the closure age of the İzmir-Ankara-Erzincan Ocean along the Eastern Pontides. Between late Thanetian and late Lutetian synorogenic turbidites and postcollisional volcanics were deposited. The Eastern Pontide fold-and-thrust belt started to form at early Eocene (ca. 55 Ma) and thrusting continued in the post-Lutetian times.

scholarly journals Structural inversion of back-arc basins–The Neogene Adjara-Trialeti fold-and-thrust belt (SW Georgia) as a far-field effect of the Arabia-Eurasia collision

2021 ◽  
Vol 803 ◽  
pp. 228702
Author(s):  
Thomas Gusmeo ◽  
William Cavazza ◽  
Victor M. Alania ◽  
Onise V. Enukidze ◽  
Massimiliano Zattin ◽  
...  
Keyword(s):  
Field Effect ◽  
Far Field ◽  
Thrust Belt ◽  
Fold And Thrust Belt ◽  
Structural Inversion ◽  
Back Arc

scholarly journals Tectonic setting of Cretaceous porphyry copper deposits of northern Chile (28°-30° S) and its relations with magmatic evolution and metallogeny

2020 ◽  
Vol 47 (3) ◽  
pp. 469
Author(s):  
Christian Creixell ◽  
Javier Fuentes ◽  
Hessel Bierma ◽  
Esteban Salazar
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Porphyry Copper ◽  
Northern Chile ◽  
Porphyry Copper Deposits ◽  
The West ◽  
Copper Deposits ◽  
Magmatic Arc ◽  
Fault Systems ◽  
Back Arc

Cretaceous porphyry copper deposits of northern Chile (28º-29º30’ S) are genetically related with dacitic to dioritic porphyries and they represent a still poorly-explored target for Cu resources. The porphyries correspond to stocks distributed into two separated discontinuous NS trending belts of different age. The location of these porphyries is generally adjacent to orogen-parallel major fault systems that extend along the studied segment and also have a marked temporal relationship with deformation events registered along these structures. A first episode of Cu-bearing porphyry emplacement took place between 116 and 104 Ma (Mina Unión or Frontera, Cachiyuyo, Punta Colorada, Dos Amigos, Tricolor porphyries). These Early Cretaceous dacite to diorite porphyries are spatially associated with the eastern segments of the Atacama Fault System, which records sinistral transpression that started at 121 Ma producing ground uplift, consequent denudation and exhumation of the Early Cretaceous magmatic arc. This resulted in a change from marine to continental deposition with an angular unconformity in the site of the back-arc basin after of eastward migration of the deformation around 112-110 Ma. At the scale of the continental margin, this deformation is correlated with early stage of the Mochica Orogenic event described in Perú. A second episode of Cu-bearing porphyry emplacement occurred between 92 and 87 Ma (Elisa, Johana, Las Campanas and La Verde deposits), which are spatially and temporally associated with the regional-scale Las Cañas-El Torito reverse fault, active between 89 and 84 Ma, during the Peruvian Orogenic Phase. This fault up thrust to the west part of the Chañarcillo Group rocks (Lower Cretaceous) over the younger upper levels of the Cerrillos Formation (Upper Cretaceous). The integrated geological mapping and geochemical data of the Early to Late Cretaceous volcanic rocks indicates that both Early Cretaceous sinistral transpression and Late Cretaceous east-west compression were not significant in promote changes in magma genesis, except for slight changes in trace element ratios (increase in Th/Ta, Nb/Ta and La/Yb) suggesting that the Late Cretaceous deformation event produced only slightly increase in crustal thickness (>40 km), but far from being comparable to major Cenozoic orogenic phases, at least along the magmatic arc to back-arc domains in the study area. Finally, our study give insights about regional geological parameters that can be used as a first order guide for exploration of Cu resources along Cretaceous magmatic belts of northern Chile, where both Early and Late Cretaceous Cu-bearing porphyry intrusions are restricted to a large structural block bounded to the west and east by Cretaceous fault systems.

Analogue modeling and tectono-stratigraphic evolution of the eastern Sicilian fold-and-thrust belt

2020 ◽  
Author(s):  
Maxime Henriquet ◽  
Stéphane Dominguez ◽  
Giovanni Barreca ◽  
Jacques Malavieille ◽  
Carmelo Monaco
Keyword(s):  
Large Scale ◽  
Middle Miocene ◽  
General Structure ◽  
Foreland Basin ◽  
Accretionary Wedge ◽  
Thrust Belt ◽  
Central Mediterranean ◽  
Fold And Thrust Belt ◽  
Structural Architecture ◽  
Back Arc

<p>            In Central Mediterranean, the Sicilian Fold and Thrust Belt (SFTB) and Calabrian Arc, as well as the whole Apennine-Maghrebian belt, result from the subduction and collision with drifted micro-continental terranes. These terranes detached from the European margin and migrated southeastward in response to Neogene slab roll-back and associated back-arc extension. From N to S, the SFBT is divided in 4 main tectono-stratigraphic domains: (1) the Calabro-Peloritani terrane, drifted from the European margin and detached from the Corso-Sarde block since the back-arc opening of the Tyrrhenian basin, (2) the Neotethyan pelagic cover, constituting the remnants of the Alpine Tethys oceanic accretionary wedge, (3) the folded and thrusted platform (Panormide) and basinal (Imerese-Sicanian) series of the down-going African margin, and (4) the undeformed african margin foreland (Hyblean).</p><p>            The scarce good quality outcrops of key tectono-stratigraphic units and crustal scale seismic lines makes the structural architecture of the SFTB very controversial, as testified by the wide variety of tectonic interpretations (Bianchi et al., 1987; Roure et al., 1990; Bello et al., 2000; Catalano et al., 2013). Major outstanding issues particularly concern: (1) the occurence of Alpine Tethys units far from the region where the remnants of the Tethyan accretionary wedge outcrop (Nebrodi range); in a forearc position above the Peloritani block north of the SFTB and in an active foreland context along the southern front of SFTB; (2) the diverging suggested tectonic styles, from stacked large-scale tectonic nappes to foreland imbricated thrust systems rooted into a main basal décollement; and (3), the deposition environnement of substantial units such as the widespread Numidian Flyschs, from syntectonic foreland basin to wedge-top sedimentation.</p><p>            We used 2D analogue models to investigate the mechanical processes involved in the formation of the SFTB starting from the Oligocene Tethys subduction to the Middle Miocene - Late Pliocene continental collision with the African paleo-margin. Based on a detailed tectono-stratigraphic synthesis, complemented by field observations, we reproduce the first-order mechanical stratigraphy of the sedimentary and basement units involved in the SFTB as well as the structural inheritance of the African margin. Our models also include: syntectonic erosion and sedimentation, syn-orogenic flexure and adjustable material output via a “subduction channel“.  </p><p>            The analog models succeed in reproducing the general structure of the SFTB and main tectono-stratigraphic correlations. For instance, the Panormide platform is underthrusted beneath the Alpine Tethys accretionary wedge, then stacked above the Imerese basinal units and belatedly exhumed in response to basement anticlinal stack. Our results also suggest that the Alpine Tethys units couldn’t overthrust the whole African foreland in the Middle Miocene, nor be back-thrusted over the forearc basin during the Burdigalian. We rather favor a gravity-induced sedimentation process inducing reworking of the tethysian sediments at specific building stages of the accretionary wedge. The structural architecture of the modeled orogenic wedge is also consistent with a SFTB growing by frontal accretion and basal underplating of mechanically resistant stratigraphic units rather than by large-scale nappe overthrusting.  </p>

Late Cretaceous-Paleocene stratigraphic and structural evolution of the central Mexican fold and thrust belt, from detrital zircon (U-Th)/(He-Pb) ages

2019 ◽  
Vol 95 ◽  
pp. 102264 ◽  
Author(s):  
Edgar Juárez-Arriaga ◽  
Timothy F. Lawton ◽  
Daniel F. Stockli ◽  
Luigi Solari ◽  
Uwe Martens
Keyword(s):  
Late Cretaceous ◽  
Detrital Zircon ◽  
Structural Evolution ◽  
Thrust Belt ◽  
Fold And Thrust Belt
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