Prokop Závada

• PhD.
• The Czech Academy of Sciences

The Zagros Fold and Thrust Belt (ZFTB), characterized by its numerous salt diapirism and active tectonic deformation, presents an exceptional natural laboratory for examining the sedimentological and structural impacts of diapiric movement within compressional regimes. Our study focused on a representative salt stocked-basin, where we meticulously...

The Ediacaran Period, a pivotal era in Earth's history, witnessed monumental shifts in global climate, atmospheric oxygenation, and biotic innovation, setting the stage for the Cambrian explosion of complex life. This study focuses on the Hormuz Complex within the Zagros Mountains' salt diapir caprock mélange in southern Iran, offering fresh insigh...

In southern Madagascar two main tectono-metamorphic events, corresponding to the East African Orogeny (ca. 630–610 Ma) and the Kuunga Orogeny (ca. 580–515 Ma) were recognized. An early structures include recumbent folds and sub-horizontal foliation S1 that were transposed during a regional east–west shortening resulting into north–south-oriented up...

Salt caves occur mostly in hyperarid and arid climates and are typically a few thousand years old. There is little data on the evolution of salt caves in semiarid climates, and no data on caves developed in salt glaciers, i.e., salt masses spreading under their own weight, similar to ice glaciers. The age of salt caves and the incision rates of cav...

Salt diapirs in southern Iran provide excellent exposures of the host rock sedimentary sequences that record salt diapiric growth in compressional settings. This study addresses the reactivation of one particular diapir in the core of an anticline of the Zagros Fold and Thrust Belt (ZFTB) using the classical concept of halokinetic sequences. These...

Stringers represent fragments of competent, brittle layers, formerly interstratified within a layered evaporite sequence (LES) that are entrained and deformed by viscous flow. To resolve the impact of the stringers on the deformation style of an extrusive salt sheet, an array of decameter-thick, carbonate stringers, preserved in the caprock matrix...

The formation of Neoproterozoic cap carbonate is linked to the "Snowball Earth" hypothesis, which suggests that the Earth was covered by ice during two or more prolonged glaciations. The melting of the glaciers led to a rapid rise in sea level and the subsequent deposition of carbonate-rich sediments. The presence of dolomite in the Hormuz Formatio...

Carbonate units in the Paskhand salt diapir (Zagros Mts., Iran) exhibit field relationships and rock fabrics similar to classical carbonate caprock (CCR) from around the world, but also have features that are in marked contrast to such examples. The most noticeable difference is that its atypical CCR (aCCR) is mostly made up of multigenerational do...

Abstract: Growth rate of salt diapirs usually oscillates depending on several factors. The growth can be arrested by depletion of the source layer or diapir burial, conversely, diapir reactivation occurs througherosionoftheoverburdenand/orintroductionoftectonicforces.Examplesofreactivated diapirs can be observed in the Zagros Mountains in Iran. The...

The eastern Zagros Fold and Thrust Belt (ZFTB) in Iran includes a salt tectonic province with roughly 130 salt-gypsum diapirs emerging within the Neoproterozoic-Early Cambrian Hormuz Complex. The diapirs in the ZFTB differ in composition and in their distribution of exposed caprock mélanges (CRMs). Although there are numerous studies focused on the...

The Zagros Fold and Thrust Belt in southern Iran is a well-known area for its impressive salt diapirs outcrops which are sourced from the Pre-Cambrian to Early Cambrian Hormuz Formation. The positive and negative accommodation spaces adjacent to the salt diapir result from the salt movement-sedimentation interaction that creates unconformity-bound...

Detachment folding can be defined as the displacement and buckling of a competent layer above a rheologically weak horizon during tectonic shortening, frequently addressed in the context of salt tectonics. More recent studies have focused on influence of detachments in large-scale lithospheric deformation where the detachment horizon is represented...

The Zagros Fold and Thrust Belt (ZFTB) is 1800 km long, which trends as NW-SE part of the orogeny interpolating the Alpine-Himalayan Orogenic Belt. The tectonic history of these parallel belts generally consists of three steps: stable platform in Paleozoic, extension and rifting in the ocean in Jurassic-Early Cretaceous; ophiolite emplacement in La...

Basin-scale salt flow and the evolution of salt structures in rift basins is mainly driven by sub- and supra-salt faulting and sedimentary loading. Crustal extension is often accompanied and followed by thermal subsidence leading to tilting of the graben flanks, which might induce an additional basinward-directed driver for salt tectonics. We desig...

Two iconic salt diapirs in the Zagros Mountains in Iran – Karmostaj (Gach) and Siah Taq – are regarded as world-class examples of salt extrusions and are frequently called ‘salt glaciers’. However, our field survey revealed that their glacier-like parts are formed by thick, variegated and deformed caprock, only locally mixed with salt. Caprock is a...

Basin-scale salt flow and the evolution of salt structures in rift basin is mainly driven by sub- and supra-salt faulting and sedimentary loading. Crustal extension is often accompanied and followed by thermal subsidence leading to tilting of the graben flanks, which might induce an additional basinward directed driver for salt tectonics. We design...

Coupled age and trace element mapping in monazite grains using the Laser-Ablation Split-Stream ICP-MS technique was carried out for a sequence of samples from (U)HP crustal section in the Eger Crystalline Complex interpreted as a Variscan continental subduction wedge. The sampled section comprises banded orthogneiss with monazite protolith ages of...

In this contribution we highlight the importance of in‐situ monazite geochronology linked to P−T modelling for identification of timescales of metamorphic processes. Barrovian‐type micaschists, migmatites and augengneiss from the Gumburanjun dome in the south‐eastern extremity of the Gianbul dome, NW Himalaya, have been studied in order to correlat...

High-pressure granitic orthogneiss of the south-eastern Orlica–Śnieżnik Dome (NE Bohemian Massif) shows relics of a shallow-dipping foliation, reworked by upright folds and a mostly pervasive N-S trending subvertical axial planar foliation. Based on macroscopic observations, a gradual transition from banded to schlieren and nebulitic orthogneiss wa...

The Kutná Hora crystalline complex (KHCC) in the Bohemian Massif is a HP/HT complex adjacent to the magmatic arc. It is dominated by migmatite, orthogneiss and granulite with bodies of eclogite and peridotite. The KHCC migmatite consists of K-feldspar, plagioclase, quartz, phengite, biotite, garnet and kyanite. Melting conditions were estimated at...

Monazite is an abundant accessory mineral in metasedimentary rocks and their anatectic products. Trace element analysis combined with U-Pb dating of monazite is widely used to reconstruct P-T-t histories of high-grade metamorphic terranes. This approach relies on interpreting U-Pb dates, which requires understanding the processes that cause isotopi...

This dataset provides friction data from ring-shear tests (RST) for a quartz sand used as standard analogue material for simulating brittle upper crustal rocks in the analogue laboratory of the Institute of Geophysics of the Czech Academy of Science (IGCAS) (Kratinová et al., 2006; Závada et al., 2009; Lehmann et al., 2017; Krýza et al., 2019). It...

The PIV (particle image velocimetry) method became a standard tool for the calculation of displacement fields in physical geodynamic models. For understanding the deformation dynamics of geodynamic models, in our study, we implemented several post-processing algorithms on the derived displacement field and calculated the velocity and strain(-rate)...

Understanding of the processes of magmatic fabric formation in crystal-rich magmas and their reflection in rock magnetic properties are important for understanding pluton formation and intrusion mechanisms. On the example of small concentrically zoned Castle Crags pluton in the Klamath Mountains (CA, USA) we provide reconstruction of the flow/defor...

The salt diapirs in the Zagros Fold and Thrust Belt (ZFTB; southeastern Iran) represent sensitive indicators of the interplay between tectonic forces governing their uplift and climate controlling their degradation. The diapirs contain Infracambrian evaporitic sequences of the Hormuz Formation and were initiated and reactivated during multiple tect...

A section of anatectic felsic rocks from a high-pressure (> 13 kbar) continental crust (Variscan Bohemian Massif) preserves unique evidence for coupled melt flow and heterogeneous deformation during continental subduction. the section reveals layers of migmatitic granofels interlayered with anatectic banded orthogneiss and other rock types within a...

We use structural, petrographic, and geochronological data to examine processes of exhumation of partially molten crust in the Late Devonian-early Carboniferous Chandman dome in the Mongolian tract of the Central Asian Orogenic Belt. The dome is composed of a magmatite-migmatite core and a low-grade metamorphic envelope of early Paleozoic metasedim...

Four volcanic geoheritage sites in the Czech Republic were selected to showcase new technologies for communicating the recent results of scientific research to a wider nonprofessional public. The selected volcanic sites are scoria cones with late intrusive plugs, phonolite lava-dome erupted within a maar crater, phonolite laccolith, and a nested gr...

New approach involving evaluation of anisotropy of magnetic susceptibility (AMS) data in stereoplots and Jelinek's Pj–T space, Vollmer's eigenvalue and microstructural analyses is proposed to discriminate between homogeneous and superposed deformation in granites. This method is used to decipher the internal AMS fabric and microstructural evolution...

Magma emplacement in extended brittle crust was simulated by injecting plaster of Paris (magma) into a large sandbox with a central deformable rubber sheet. During the experiments, analog magma was injected through small circular inlet cut in the center of the elastic sheet. Injection force recorded during the experiments with the steadily evacuati...

The mode of emplacement of Devils Tower phonolite porphyry is questioned in terms of field survey, revised tectonomagmatic evolution of the region, degree of erosion estimates, dating of the Devils Tower and nearby group of phonolite Missouri Buttes and their geological setting, respectively. A new genetic interpretation of volcaniclastic rocks in...

The Eger crystalline unit (ECU) represents a rapidly (1.1-2.5 mm/year) exhumed lower felsic crust that extruded along the Teplá-Barrandian – Saxothuringian suture zone at ~340 Ma. The ECU consists of high-grade gneisses and migmatites, granites, granulites and metasediments. Peak metamorphic conditions were established at ca. 740-845°C and 14-16 kb...

We have investigated the mode of emplacement of iconic Devils Tower, which is a phonolite porphyry monolith in the state of Wyoming in the western United States. Our field survey of this structure and its geological setting, its radiometric dating and the tectonomagmatic evolution of the region suggest a new genetic interpretation of the volcanicla...

Viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between ‘weak’ second phase bearing rock salt and ‘strong’ pure rock salt types are studied for deformation mechanisms using detailed quantitative microstructural study. While the solid inclusions rich (“dirty”) rock salts contain disaggregated siltstone...

We have investigated the mode of emplacement of iconic Devils Tower, which is a phonolite porphyry monolith in the state of Wyoming in the western United States. Our field survey of this structure and its geological setting, its radiometric dating, and the tectonomagmatic evolution of the region suggest a new genetic interpretation of the volcanicl...

The Northern Alvand granite pluton is located at northern part of the Sanandaj-Sirjan zone (SSZ) and west of Hamadan city in Western Iran. During the Mesozoic, the oceanic crust of the Neotethys was subducted beneath the Eurasian plate, then magmatic-metamorphic belt, namely, SSZ with 1500 km length along strike and 150-200 km in width was formed (...

A rock salt-lamprophyre dyke contact zone (sub-vertical, NE-SW strike) was investigated for its petrographic, mechanic and physical properties by means of anisotropy of magnetic susceptibility (AMS) and rock magnetic properties, coupled with quantitative microstructural analysis and thermal mathematical modelling. The quantitative microstructural a...

a b s t r a c t Microstructural study revealed that the ductile flow of intensely folded fine-grained salt exposed in an underground mine (Zechstein-Werra salt sequence, Neuhof mine, Germany) was accommodated by coupled activity of solution-precipitation (SP) creep and microcracking of the halite grains. The grain cores of the halite aggregates con...

This contribution presents a microstructural study of samples from the Qum Kuh salt glacier (Central Iran) and a salt mine of Neufhof (Germany) representing the extruded part and the source layer of the salt diapiric system, respectively. The main objectives are to identify the active deformation mechanisms and to track the in-situ distribution of...

This contribution presents a microstructural study of samples from the Qum Kuh saltglacier (Central Iran) and a salt mine of Neufhof (Germany) representing the extruded part and the source layer of the salt diapiric system, respectively. The main objectives are to identify the active deformation mechanisms and to track the in-situ distribution of f...

The Devils Tower is an exceptional igneous rock formation and a dominating landmark of the northern plains in Wyoming (USA). It rises 250 m above the surrounding sedimentary formations. Previous hypotheses suggested that the Devils Tower was originally part of a magmatic intrusion; volcanic conduit, magmatic stock or a laccolith. Our review of the...

The Klamath Mountains represent an accreationary complex on the northwest California and southwestern Oregon. It consists of four arcuate belts representing terranes of former island archipelago environments that span in age from Paleozoic to Jurrasic and are divided by eastward dipping thrust faults (Snoke and Barnes, 2006). During and after the a...

Emplacement mode and original shape and dimensions of a well exposed phonolite body in the Ceske stredohori Mountains (Czech Republic) were reconstructed using combined techniques of structural analysis of magmatic fabrics and columnar jointing together with analogue and thermal mathematical modeling of cooling for different shapes of experimental...

We have completed a preliminary investigation using surface gravity data and 3D geology to detect one or more magma chambers at Devils Tower, Wyoming, U.S.A. By comparison to the complete Bouguer anomaly, we use a local 3D geologic interpretation to estimate the observed Free-air anomaly. Since the Free-air anomaly is the result of the Earth's geol...

Anisotropy of magnetic susceptibility (AMS) and Electron back-scattered diffraction (EBSD) of magnetite and sanidine fabrics throughout an eroded trachyte lava dome in Tertiary volcanic province of the NW Czech Republic revealed two fabric types. The high degree of AMS fabric is associated with sanidine textural domains similar to normal kink bands...

Active deformation mechanisms in salt rock are greatly dependent on the structural level of the salt body. An important switch from dislocation creep dominated dynamic recrystallization to solution-precipitation controlled grain boundary sliding (SP-GBS) takes place in salt glaciers fed by vertical stems from the source layer. In this study we carr...

Viscous lava extrusions were modeled using plaster of Paris with admixed magnetite dust which served as a tracer of the internal anisotropy of magnetic susceptibility fabric in model lava domes. Used analogue material showed pseudoplastic behavior and yield strength level proportional to increasing mixing ratio of plaster powder and water. A series...

High-grade orthogneisses from granulite-bearing lower crustal unit show extreme finite strains of both K-feldspar and plagioclase with respect to weakly deformed quartz aggregates. K-feldspar aggregate in the most intensely deformed sample shows interstitial grains of quartz and albite, which also mark some intragranular fractures within K-feldspar...

Development of magnetic fabric within a diapirically ascending columnar body was investigated using non-scaled analogue model made of plaster of Paris containing small amount of fine-grained homogeneously mixed magnetite. The apparatus for the modelling consists of a manual squeezer with calibrated spring and a Perspex container. Set of weak colour...

The degree of the anisotropy of magnetic susceptibility (AMS) of basaltic rocks, as is known from the large AMS database of these rocks, is generally very low, while in more acidic volcanic rocks such as andesites, trachytes and phonolites, which have been investigated much less frequently, it is in general much higher. In the present study, the AM...

Development of magnetic fabric within a pluton during its diapiric ascent was investigated using an analogue non-scale model of plaster of Paris containing small amount of fine-grained (less than 0.09 mm) homogeneously mixed magnetite, with resulting bulk susceptibility being in the order of 10-3 [SI]. The apparatus for this modelling consists of a...

Volcanic domes and laccoliths are typical features of monogenic volcanic fields and are formed by highly viscous magmas either due to magma composition (andezites and rhyolites) and/or high crystal content (e.g. trachytes and phonolites). Although the evo-lution of shapes of extrusive domes and laccoliths was modelled for ideal newtonian fluids (Ta...