Uwe Kroner

Technische Universität Bergakademie Freiberg · Institute of Geology

The formation and destruction of supercontinents requires prolonged convergent tectonics between particular plates, followed by intra-continental extension during subsequent breakup stages. A specific feature of the Late Paleozoic supercontinent Pangea is the prolonged and diachronous formation of the collisional belts of the Rheic suture zone coev...

Phanerozoic primary tin and tungsten deposits and lithium–cesium–tantalum (LCT) type pegmatites define discontinuous belts that reach several thousand kilometers length. Mineralization along these belts is irregularly distributed, diachronous, and occurs in different tectonic settings on both sides of major sutures. Although these deposits formed d...

Abstract The Variscides of Europe and N-Africa are the result of the convergence of the plates of Gondwana and Laurussia in the Paleozoic. This orogen is characterized by the juxtaposition of blocks of continental crust that are little affected by the Variscan orogeny. These low strain domains principally consist of Neoproterozoic/Cambrian Cadomia...

The Saxo-Thuringian zone of the European Variscides contains the record of the Cadomi-an and Variscan orogenies and a Paleozoic marine transition stage. The classical view of a relatively simple, double-vergent folded sedimentary basin at the end of the Early Carboniferous is challenged by the widespread occurrence of Late Devonian to Early Carboni...

The Urals are characterized by a depression of the Moho to a depth of 57 km. This structure is interpreted as a relic orogenic root, which has been conserved because no significant post-collisional processes occurred. However, there is evidence that voluminous post-collisional magmatism affected the lower crust. In this paper, we use thermal finite...

The spatial analysis of horizontal stress orientation is important to study stress sources and understand tectonics and the deformation of the lithosphere. Additional to the stress sources, the geometry of stress fields depends on the underlying coordinate reference system, which causes spatial distortions that bias the analysis and interpretation...

GeoBerlin"023 Topics: 3.28 Developments and progress in regional geology Title: On the nonexistence of a Saxo-Thuringian Ocean – a review Abstract: As demonstrated by the Saxo-Thuringian Ocean, some regional geological models originated prior the advent of plate tectonics and evolved little since. Despite the abundance of facts that neither prov...

To be a quantitative and testable tectonic model, plate tectonics requires spherical geometry and spherical kinematics in terms of finite rotations conveniently parametrized by their angle and axis and described by unit quaternions. In treatises on ’Plate Tectonics’ infinitesimal, instantaneous, and finite rotations, absolute and relative rotations...

Major tin (Sn) deposits within the Variscan orogen are closely related to 325-270 Ma postkinematic granites that intruded the metamorphic rocks of the former precollisional accretionary wedge of the Gondwana margin. In the Erzgebirge (Germany), some of these metasedimentary rocks have high Sn contents (locally more than 1000 ppm Sn). We report cass...

The Berga Antiform represents one of the key areas of the Saxo-Thuringian Zone of the Central-European Variscides. The geological record constrains early Palaeozoic marine sedimentation on a post-Cadomian Peri-Gondwana shelf, interrupted by Frasnian magmatism, and eventually followed by Lower Carboniferous synorogenic sedimentation. Variscan tecton...

Late Cretaceous granitic rocks occur in the Gejiu ore district to the east and west of the N-S striking Gejiu Fault, whereas major Sn deposits are only known to occur to the east of the Gejiu Fault. Comparison of the whole-rock chemistry, the apatite trace-element chemistry, and zircon Hf and O isotope data of the various granites demonstrates that...

The spatial location and the specific character of tectonic lines is crucial for numerous practical applications such as hydrogeology, exploration and for infrastructural projects. In order to significantly improve our understanding of the available tectonic data set of Saxony, a series of cooperation projects named ARTUS has been performed by the...

Granites appear to be isotropic, which qualifies them as suitable crystalline host rocks for nuclear disposal sites. However, despite their optical appearance, granites show a primary anisotropy [1, 2] that evolved during emplacement and crystallization of the melt. Hypothetically, it is expected that different tectonic environments, i.e. different...

For permanent nuclear waste disposal sites, crystalline rocks, especially granite, are considered appropriate host rocks. The crystalline basement of Germany consists of pre-, syn- and post- Variscan felsic plutons, which were consolidated during different tectonic regimes. It is expected that the tectonic environment during intrusion influenced th...

New analytical and field techniques, as well as increased international communication and collaboration, have resulted in significant new geological discoveries within the Appalachian-Caledonian-Variscan orogen. Cross-Atlantic correlations are more tightly constrained and the database that helps us understand the origins of Gondwanan terranes conti...

New analytical and field techniques, as well as increased international communication and collaboration, have resulted in significant new geological discoveries within the Appalachian-Caledonian-Variscan orogen. Cross-Atlantic correlations are more tightly constrained and the database that helps us understand the origins of Gondwanan terranes conti...

For permanent nuclear waste disposal sites, crystalline rocks, especially granitic/granodioritic batholiths, are considered an appropriate host rock. Principally, three types of granitic plutons occur in the extra-alpine crystalline basement of Germany that were consolidated during the late Paleozoic Variscan orogeny of Central Europe: (i) Pre-Vari...

The Saxothuringian Zone of the Central European Variscides preserves the sedimentary record of the post-Cadomian shelf and an Early Carboniferous synorogenic basin. Thus, this area reflects the transition from a passive continental margin setting to an active plate boundary zone. Particularly the record of the so called “Wrench-and-Thrust Zone” (WT...

Felsic rocks of the Erzgebirge in the Central European Variscides experienced ultra-high pressure metamorphism at ∼340 Ma, followed by nearly isothermal decompression during channel like rapid exhumation within ∼10 Ma. Despite the general time frame of exhumation and emplacement within mid-crustal levels is known, available geochronological data do...

Late Mesozoic-Cenozoic plate convergence led to widespread intraplate deformation in Western-Central Europe during the Late Cretaceous-Paleogene and the Miocene until today reflecting the collision of Eurasia with Iberia-Africa and Adria, respectively. The resulting complex deformation pattern inside the plate boundary zone contrasts with a rather...

Three supercontinents have been suggested to have existed in the last 1 Gyr. The supercontinent status of Pangea and Rodinia is undisputed. In contrast, there is an ongoing controversy whether Pannotia existed at all. Here we test the hypothesis of a Pannotian supercontinent. Using first order tectonic constraints we reconstruct the Paleozoic kinem...

The “Bergaer Sattel” of the Saxo-Thuringian Zone of the Central European Variscides constitutes a NE-SW striking antiformal structure. The striking feature of the Berga antiform is the juxtaposition of greenschist facies metamorphic rocks with very low grade lithologies of Paleozoic age. Classically, the entire region is described as a simple south...

Sea-level rise after the Hirnantian glaciation resulted in the global inundation of continental shelf areas and the widespread formation of early Silurian black shales. Black shales that were deposited on shelves receiving drainage from earlier glaciated areas have high uranium (U) contents because large-scale glacial erosion brought rocks with lea...

The Late Paleozoic Variscan Orogen of Europe and North Africa comprises reworked Neoproterozoic to Early Paleozoic crust of the northern Gondwanan shelf that collided with Laurussia. The orogen is characterized by an arcuate trend of the Rheic suture along two orthogonal orogenic arcs and an apparently arbitrary juxtaposition of contrasting paleoge...

The Hämmerlein polymetallic deposit is hosted in skarn, schists, and gneisses that reached their metamorphic peak at ~ 340 Ma during the Variscan orogeny. The deposit is spatially closely associated with one of the most voluminous granites of the Erzgebirge, the Eibenstock granite which intruded the metamorphic units at ~ 320 Ma, and locally also d...

The possibility to date detrital heavy minerals and, therefore, to constrain the age of igneous and/or high-grade metamorphic protoliths of sedimentary rocks gains growing significance. The increasing datasets demand statistical and quantitative evaluation tools that allow a fast comparison of data. However, the objective extraction of provenance i...

Phanerozoic magmatic Sn-W deposits are concentrated at ancient convergent plate boundaries. The formation of the deposits is controlled by a sequence of sedimentary and tectonic accumulation eventually followed by crustal melting processes. The sedimentary processes include protolith enrichment by intense chemical weathering (loss of Ca and Na) fol...

The formation of Phanerozoic magmatic Sn-W deposits is controlled by a sequence of sedimentary, tectonic, and eventually crustal melting processes. The sedimentary processes include protolith enrichment by intense chemical weathering followed by sediment redistribution from the continent interior towards its margin. Hence, the spatial distribution...

Plate-tectonic reconstructions require precise and reliable knowledge of the pre-orogenic architecture of the involved plate margins. The Variscan-Appalachian orogeny reworked the entire shelf of northern Gondwana, which dominantly comprises Early Palaeozoic passive margin sequences. Due to complex Variscan orogenic processes and the Alpine overpri...

Geophysics combined with 3D modelling may significantly contribute to address and visualize geological problems. Nevertheless, in orogenic complexes, such as the Saxo-Thuringian Zone, existing geophysical and geological methods (reflection and refraction seismics, drillings etc.) were not able to shed light into the lower parts of the crust. Modern...

Supplementary Material Supplementary Table S1. Lithology, stratigraphic age, and coordinates of samples with dated detrital zircon populations. Supplementary Table S2. Re-processed detrital zircon U–Pb ages of samples listed in Table S1. Supplementary Material S3. Data sources for compilations in Supplementary Tables S1, 2 and Supplementary Mate...

We present a statistical approach to data mining and quantitatively evaluating detrital age spectra for sedimentary provenance analyses and palaeogeographic reconstructions. Multidimensional scaling coupled with density-based clustering allows the objective identification of provenance end-member populations and sedimentary mixing processes for a c...

The distribution of Au mineralization in the Appalachians and Variscides is irregular. Major segments of the belt do not show significant Au mineralization. Segments with major Au deposits, however, show a complex history of repeated endogenic and exogenic metal redistribution. Major sources for Au occurrences in the Appalachians and Variscides are...

Zircon U-Pb dating of detrital minerals has become the most applied approach in provenance analyses and has produced the largest database of provenance and, thus, palaeogeographic indicators. However, the subjective comparison of individual zircon age spectra with each other or with likely source areas is in many cases inadequate, as pattern may be...

To test plate-tectonic constellations in consideration of the long-term development of sedimentary transport paths, temporally and spatially highly resolved records of provenance analysis are mandatory. The interpretation of existing studies focus on small-scale areas within an orogen thereby neglecting the differing distribution of provenance data...

The Erzgebirge, SW England and NW Iberia are famous examples for Sn-W enriched granites that intruded into a thick pile of tectonically accumulated sediments (Romer and Kroner, 2014). For example, in the Erzgebirge the emplacement of such granites is associated with the exhumation of hot (ultra)high-pressure rocks. In contrast, the Cornubian Bathol...

The various allochthonous units of the Saxo-Thuringian Zone displays the Variscan evolution between 400-300 Ma characterized by multiple subduction, exhumation and continental collision processes. During the late Carboniferous, the Saxo-Thuringian Zone was intruded by several granitic rocks. Subsequent reactivations of initially Variscan structures...

The late- to post-Variscan (325-295 Ma) peraluminous, transitional I-S granites of the Erzgebirge (Krušné hory) – Vogtland – Fichtelgebirge (Smrčiny) are subdivided into five different groups based on compositional and mineralogical properties (Förster et al., 1999): (i) low-F biotite granites; (ii) low-F two-mica granites; (iii) high-F, high-P2O5...

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Transpressional tectonics is manifested in oblate strain geometry. In multiply deformed regions, the finite strain ellipsoid may be the expression of different deformational episodes. As demonstrated from the Rheno-Hercynian–Saxo-Thuringian boundary of the Central European Variscides, particularly in the Saxo-Thuringian Zone, there is ample evidenc...

The formation of major granite-hosted Sn and/or W deposits and lithium–cesium–tantalum (LCT) type pegmatites in the Acadian, Variscan, and Alleghanian orogenic belts of Europe and Atlantic Northern America involves weathering-related Sn and W enrichment in the sedimentary debris of the Cadomian magmatic arc and melting of these sedimentary source r...

The two-plate model for the Variscides (Kroner & Romer, 2013) proposes for the NE-SW striking Rheic suture zone between Saxo-Thuringia (Gondwana plate) and Rheno-Hercynia (Laurussia plate) an initial transform plate boundary that finally changed to a late Variscan fold and thrust belt. Here we test this model in the Schwarzburg Unit of the Saxo-Thu...

During the Variscan orogeny prolonged subduction-exhumation processes represent one of the most important tectono-metamorphic features lasting from 400-330 Ma (Kroner and Romer, 2013 and references therein). For these processes the Allochthonous Domain of the Saxo-Thuringian Zone (subdivision after Kroner et al., 2007) constitutes one of the key ar...

Romer and Kroner (2012) stated "the core of the Harlech Dome (i) in part is made up of Ordovician deposits and (ii) contains tectonic repetitions". In their comment, Schofield et al. (this issue) distort this statement and state that (i) we claim the entire sedimentary sequence of the Harlech Dome is Ordovician and (ii) we misinterpreted their zirc...

In their comment, Waldron and White state that manganese-rich sedimentary rocks of Nova Scotia and Wales are Cambrian and were deposited in a deep-water turbidite basin called “Megumia” rather than on the Avalonian shelf. Available geochronological data are not in conflict with an Early Ordovician deposition age for manganese-rich sedimentary rocks...

The guidebook contains a thematic description an background information for each field day. The overall setting and development of the Saxo-Thuringian zone within the Variscan orogen is presented in Kroner and Romer (2010). This material is not included in this guide book (because of copyright reasons) and will be handed out to field trip participa...

Mn-rich (3.26–15.6 wt.% MnO) sedimentary layers (coticules, Strohschiefer) occur in Ordovician siliciclastic sedimentary rocks that were deposited on the Avalonian shelf and subsequently metamorphosed between 340 and 380 Ma. The Mn-rich layers formed during periods of restricted clastic input, when Mn concentrated by a redox-controlled dissolution–...

In the southern Uralides, Permian magmatism, tectonism and metamorphism concentrate in the East Uralian Zone, such that this zone provides the key for understanding of the late phase of the Uralian orogeny. Carboniferous distal marine sediments and lenses of amphibolite–serpentinite associations show that the lithospheric precursor of the East Ural...

The Lodève basin, which contains an exceptional long and nearly uninterrupted profile of Early to Late Permian continental red beds, is well correlated to the other European Permocarboniferous basins. Together they cover the time span from the Late Pennsylvanian to the Permian–Triassic boundary. Although these basins were placed within the equatori...

Geochemical and radiogenic age data are incompatible with the idea that the gneiss-complexes of the East Uralian Zone are microcontinental blocks that collided with the Magnitogorsk island arc during the Uralian orogeny. Field and microstructural data from the Dzhabyk and Suunduk complexes presented in this paper enable us to suggest an alternative...

The Uralian organic root has been stabilized by the post-collisional migration of granitic magmas causing the redistribution of heat producing elements. At least 80 % of the heat producing elements of the Uralian root have been concentrated in a melt fraction of 20- 30% and transported to the upper crust. Thus, the lower crust is 0.2 times depleted...

The Lambert Graben is the largest known rift structure within the East Antarctic Craton. The north-western shoulder segment, the northern Prince Charles Mountains (PCM), experienced two major denudational episodes during the Permo-Carboniferous and the Cretaceous that are apparently related to the initial rifting and graben formation, and its react...

Bis heute wird bei regionalgeologischen Abhandlungen über die mittel- und westeuropäischen Varisziden die Kossmatsche Gliederung von 1927 zugrunde gelegt. Die Region von Sachsen und Thüringen kann als deren locus typicus bezeichnet werden: „Da gerade das sächsische Gebirge einen der theoretisch wichtigsten Abschnitte des variszischen Bogens darstel...

The southern East Uralian Zone consists of granite-gneiss complexes that are embedded in geological units with typical oceanic characteristics. These gneisses have been interpreted as parts of a microcontinent that collided during the Uralian orogeny. The gneiss-plate of Kartali forms the south eastern part of the gneiss mantle surrounding the Dzha...

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The Saxonian Granulites represent a major exposure of high-pressure rocks within the mid-European Variscan belt. The granulites emerge in an extensional dome structure beneath a low-grade Paleozoic cover. The boundary between the granulites and their cover is a crustal-scale shear zone with transport top to the SE, juxtaposing high-pressure (HP) gr...

The structural setting of the northern Shackleton Range is dominated by west to south-west directed Ross-age thrusting leading to stacking of the following main units (I) remobilized northern basement, (II) ophiolite complex, (III-north) low-grade meta-sediments. The latter form a lithological link across the ice-covered centre (Fuchs Dome) to the...

Metamorphic rocks of the northern Haskard Highlands, NW Shackleton Range, form two crustal blocks that show distinct pressure-temperature-deformation-time (P-T-D-t) evolutions. The more northerly block comprises metadiorite and metasediments of the Nostoc Lake Formation. The more southerly block includes the Mount Weston Gneiss, Mount Gass Formatio...

Geological mapping and new structural observations during the 1994/95 EUROSHACK Expedition lead us to propose a new lithological subdivision of the Proterozoic Read Group, which is exposed in a tectonic window framed by the Ross-age low-grade Mount Wegener Nappe in the southern Shackleton Range. The oldest rock-units of the Read Group comprise seve...

U—Pb and Pb—Pb zircon ages for metamorphic zircons from granulites in the Saxonian granulite complex are reported, using the SHRIMP ion microprobe, conventional multigrain and single-gain techniques and the evaporation method. This is comp-lemented by a Pb—Pb evaporation age for a post-granulite granite emplaced into the schist mantle around the gr...

U–Pb and Pb–Pb zircon ages for metamorphic zircons from granulites in the Saxonian granulite complex are reported, using the SHRIMP ion microprobe, conventional multigrain and single-gain techniques and the evaporation method. This is complemented by a Pb–Pb evaporation age for a post-granulite granite emplaced into the schist mantle around the gra...

The Saxonian Granulites represent an exotic element of the Saxothuringian zone. The juxtaposition of rocks with different metamorphic grades is an essential feature of this area. The aim of this study is the reconstruction of the tectonometamorphic process connected with this phenomena. The major conclusions are: high grade metamorphism as well as...