Tobias Stephan

• Dr. rer. nat.
• Postdoctoral fellow at Lakehead University

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...

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 Franconian Platform of SE Germany and the underlying Permian and Triassic rocks that developed from latest Permian to Triassic time were affected by multiple compressional and extensional events that created a complex fracture, fault and stylolite network. We reconstructed the spatio-temporal variations of post-Triassic palaeostress fields in t...

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...

The Lausitz Block, located in the northernmost part of the Bohemian Massif, hosts a large number of dike- to stock-shaped gabbroic intrusions that mainly comprise brown hornblende-poor (Group I; i.e. olivine gabbronorite, olivine gabbro, gabbro and diorite) and subordinately brown hornblende-rich lithologies (Group II; i.e. olivine-hornblende gabbr...

The Logan fault is one of many dextral faults that strike generally parallel to the NW-trend of the Northern Canadian Cordillera. Though widely documented, the timing and magnitude of displacement on many of these orogen-parallel faults are not well-constrained. Here, we present new low-temperature thermochronology data and thermal history models f...

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...

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...

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...

The Lausitz Block, located in the northernmost part of the Bohemian Massif, hosts a large number of dike- to stock-shaped gabbroic intrusions that mainly comprise brown hornblende-poor (Group I; i.e. olivine gabbronorite, olivine gabbro, gabbro and diorite) and subordinately brown hornblende-rich lithologies (Group II; i.e. olivine-hornblende gabbr...

Global tectonic and climatic models for the Permian-Triassic boundary (PTB) are highly debated. One of the most disputed topics is the temperature increase associated with CO2 emissions generated by the Siberian Trap volcanism and its potential influence on chemical weathering and associated variations in sediment fluxes. By integrating crustal arc...

Detailed knowledge on the temporal and spatial distribution of faults and fractures not only reveals the geodynamic and tectonic evolution of the lithosphere. It is also of increasing importance with regard to economic, social, and environmental challenges such as nuclear waste disposal, gas storage, geothermal energy, natural hazards, and mineral...

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...

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 geodynamic activity of the NW-Bohemia / Vogtland region with its earthquake swarm activity is always studied in relation to the local emission of juvenile fluids, in particular of CO2. Based on a 3D interpretation of the geological setting, geophysical results, and new evaluation of existing data, our approach suggests a spatial separation of t...

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...

Die Schwarmbebenaktivität in NW-Böhmen ist in den zurückliegenden Jahrzehnten vorwiegend an eine N- S streichende Bruchzone im Rahmen des Leipzig-Regensburger-Lineamentes gebunden, speziell an die lokal ausgebildete Počátky-Plesná-Zone (PPZ). Das für Europa typisch ausgeprägte NW-SE orientierte Spannungsfeld kann als treibendes geodynamisches Eleme...

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 Minerogenic Map of Tanzania summarises the available knowledge about the geological and tectonic structure and the mineral wealth of the country. While the printed map is a static product its data content is a part of the Tanzanian Geological and Mineral Information System (GMIS) being frequently upgraded as new information becomes available. T...

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...

As one of its efforts to scale up promotional programs for attracting investments in the development and utilization of Tanzania’s mineral resources, the Geological Survey of Tanzania has made major review of the previously existing Mineral Occurrence Map of Tanzania through verification of location of known occurrences of minerals coupled with tho...

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...

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 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...