Description: Devonian-Carboniferous sedimentary and volcanic rocks are exposed in the Badenweiler-Lenzkirch Zone (BLZ) of the Southern Schwarzwald and in the Southern Vosges (Central Europe). Several lithostratigraphic units are recognized. Sedimentary or tectonic relations between some of the units can be realized by comparing sedimentary and volcanic facies associations as well as petrographic and geochemical datasets. During the Variscan orogenesis the sediments were deposited in different kinds of basins along an active margin setting. Their deformation was studied in the Markstein area of the Southern Vosges and is presented here in detail. Some arguments favour a northward underthrusting of a narrow and oceanic pre-Upper Devonian back-arc basin beneath the crystalline units of the Central Vosges and Schwarzwald. Accretion of continental crust continued from the Upper Devonian to the late Lower Carboniferous along with a characteristical evolution of a deep marine retro-arc foreland basin. It has accumulated about 3500 m of turbidite sandstones, shales and conglomerates of volcano-plutonic origin, assembling now the Markstein Group in the Southern Vosges. To the south of the Markstein Group, deep marine mud-rich turbidite systems and a shallowing-upward succession of fluvio-deltaic sediments filled in the Oderen Basin, which subsided in the late Tournaisian and early Viséan. A subduction type volcanism occurred in form of tholeiitic basalts, K-calcalkaline island arc andesites and continental arc sandstones. In contrast to former models, a genetical relationship between the Markstein and the Oderen Group is rejected here. Instead, different subduction systems in space and time have caused the development of the active margin basins. The Variscan deformation of the exposed sedimentary units started in the upper Viséan. Structural analysis of kinematic indicators and macroscopic fabrics in the Markstein Group give evidence for thrusting and dextrally transpressive shearing, forming a positive flower structure along the southern border of the Central Vosges crystalline units. This was broadly synchronous with dextrally transpressive deformation along the Lalaye-Lubine/Baden Baden fault at the northern border of the Central Vosges and Schwarzwald and along the "Transition Complex" between the Central and the Southern Schwarzwald. The high-K-calcalkaline Metzeral granite intruded postkinematically into the principal displacement zone and has a position similar to the dextrally sheared Randgranite association along the northern border of the BLZ. A juxtaposition between the Oderen and the Markstein Groups was achieved in the upper Viséan due to the dextral transpressive motion along the ESE-trending Markstein Fault. The exhumation of high grade metamorphic rocks of the Central Vosges and Schwarzwald during the upper Viséan is discussed in the context of long lasting accretionary tectonics and the two-sided dextral transpression, favouring crustal extrusion as a main exhumation process. A thorough examination of the supracrustal rocks and their mode of deformation in the Southern Vosges helps us to determine the relationships with the BLZ and contributes also to the paleogeographic reconstruction of the Armorica - Proto-Alpine - Gondwana connection.

Description: Turbidites and debris-flow deposits are exposed in the Upper Devonian to late Lower Carboniferous Markstein Group of the Southern Vosges Mountains (NE-France). Medium to coarse-grained sandstones are the dominating lithology alternating with fine-grained units. Sedimentary facies and their stacking patterns indicate a prograding evolution of sandy submarine fans from an outer-fan facies to channel-lobe-transional deposits and coarse conglomerates. Sedimentological and tectonical data confirm the strong geological relationship between the sedimentary units of the Southern Vosges and the Badenweiler-Lenzkirch Zone in the southern Schwarzwald.The grain composition of the turbidite sandstones is of metagranodioritic and volcanic origin. It reflects the erosion of an uplifted plutonic basement, episodically mixed with detritus from basaltic to dacitic active volcanoes. Trace element patterns and element ratios in sandstones from mafic-volcanic as well as from non-volcanic stratigraphic levels point to a subduction related setting. Trace element patterns in sandstones from dacite-volcanic active stages have normalized values, which can be compared with those from overthickened active margins or collisional belts. However, large-scale frontal collisional processes between the Protoalpine and the Moldanubian Zone cannot be evidenced by tectonic or provenance data. Instead, the favoured plate tectonic scenarios for the depositional setting are an arc-hinterland collision followed by dextral transpressive deformation through largescale wrench faults or a transpressively deformed active margin basin. In the first case a prograding retro-arc foreland is regarded as the tectonic setting of the submarine fans, in the second case an extensional or strike-slip setting in the fore-arc or back-arc area can also be imagined. Some turbidite complexes share petrographic and sedimentological similarities which in combination with the occurrences of overturned units point to an accretionary tectonic environment. Therefore the first model is favoured here. Our results are of interest for the paleogeographic reconstruction of the southern border of the Variscan Moldanubian Zone.