Geologia Sudetica, 31 (1): 3-31.

Polyphase exhumation of eclogite-bearing high-pressure mica schists from the Fore-Sudetic Block, SW Poland

Izabella Nowak

Instytut Nauk Geologicznych PAN, ul. Podwale 75, 50-449 Wrocław, Poland; izanowak@twarda.pan.pl

Key words: mica schist, high-pressure, eclogite, exhumation, Fore-Sudetic Block.

Abstract
Mica schists with eclogite lenses appear within the Fore-Sudetic Block in the vicinity of Kamieniec Ząbkowicki. In this paper their metamorphic and structural evolution and geotectonic context is discussed. The mica schists registered a clockwise metamorphic P-T path with two peaks of metamorphism - a pressure peak and a temperature peak. This path indicates compression and crustal thickening during the initial stage of metamorphism, continuing until pressure peak conditions were achieved during continental collision. The minimum pressure and temperature conditions for the pressure peak of these mica schists (11-12 kbar and 400-430°C) and the presence of replacement pseudomorphs after lawsonite indicate that during HP metamorphism the mica schists were at shallower depths than the eclogites and the schists experienced borderline blueschist/eclogite facies conditions. In the mica schists, decompression took place under conditions of rising temperature until the temperature peak was achieved under amphibolite facies conditions (579+/-35°C and 7.4+/-0.2 kbar). This was connected to the upwelling of Variscan granitoid magmas. After the temperature peak of metamorphism further decompression was isothermal. The mica schists were deformed at least four times. The earliest structures (F1) are defined by a HP mineral assemblage (phengite, pseudomorphs after lawsonite, kyanite, rutile, chloritoid, paragonite). The exhumation of the mica schists mostly occurred in a low-angle (?) normal faulting regime (F2) producing SW-vergent structures, coeval with the upwelling of the granitoid magmas. Further uplift and exhumation during isothermal decompression went on by transpression and thrusting to the east (F3) in a continued collisional setting. Late orogenic extension (F4) in the Kamieniec Ząbkowicki area was accomplished by normal faulting on zonally reworked WSW-dipping S2 surfaces.

Geologia Sudetica, 31 (1): 33-59.

Litologia i geneza zmetamorfizowanych skał osadowych i wulkanicznych jednostki Chełmca (Góry Kaczawskie)
[The lithology and origin of the metasedimentary and metavolcanic rocks of the Chełmiec Unit (Góry Kaczawskie, Sudetes)]

Zdzisław Baranowski¹, Anna Haydukiewicz¹, Ryszard Kryza¹, Stanisław Lorenc², Andrzej Muszyński² & Zdzisława Urbanek³

¹ Uniwersytet Wrocławski, Instytut Nauk Geologicznych, ul.Cybulskiego 30, 50-205 Wrocław, Poland
² Uniwersytet Adama Mickiewicza, Instytut Geologii, ul. Maków Polnych 16, 61-606 Poznań, Poland
³ Polska Akademia Nauk, Instytut Nauk Geologicznych, ul. Podwale 75, 50-449 Wrocław, Poland

Key words: sedimentary succession, volcanic rocks, volcaniclastic rocks, mélange, Kaczawa complex, Sudetes,Variscan orogeny.

Abstract
Based on detailed drill core studies from fourteen boreholes (up to 1500 m deep) and on field observations, the Chełmiec tectonic unit in the northern part of the Kaczawa Mts appears to contain two types of tectonostratigraphic elements. The first is fragments of a stratigraphic sequence, composed mainly of dark muddy slates (metamudstones) and variegated laminated silty-clayey slates (both considered as Ordovician), and of volcaniclastic rocks, greenstones and dia-bases. The second element is represented by mélange bodies which consist of dark muddy slates (matrix) enclosing fragments of various lithologies: dark siliceous and graphitic slates, light siliceous slates, quartzites, greywackes, variegated silty-clayey slates etc. (probably Upper Devonian or Lower Carboniferous).
Due to the lack of biostratigraphic evidence, the stratigraphic subdivision is based on lithological criteria. Using e.g. the rule of superposition and analysis of lithological contacts and sedimentary and volcanogenic structures, the stratigraphic succession was defined, and three informal lithostratigraphic units were distinguished: (a) an association of metamudstones and diabases, (b) an association of metavolcaniclastic rocks (both within the stratigraphic sequence), and (c) a mélange association. The dark metamudstones and variegated silty-clayey slates of the association of metamudstones and diabases are interpreted as turbidites. The volcaniclastic rocks, of clearly epiclastic character, were delivered episodically from marginal parts of the basin or volcanic heights by denser turbiditic currents and other types of gravity flows. Simultaneously, volcanic activity occurred within the basin itself producing basaltic lavas (now observed as subvolcanic diabases and effusive greenstones), which geochemically correspond to recent mildly alkaline within-plate basalts. The geotectonic setting of the basin is difficult to define precisely but the sequence was probably emplaced in an outer fan or in a basin at a continental margin.
The mélange represents a later stage of the evolution of the Kaczawa Complex. Most probably, it was deposited from gravity flows and slumps in a trench or on a trench slope. Its origin is thought to have been connected within the formation of a Variscian accretionary prism in Late Devonian and Early Carboniferous times.
The rock complex of the Chełmiec Unit experienced several stages of deformation during the Variscian orogeny. The first event resulted in a system of thrusts (and associated folds?) and it was related to (or partly preceeded by) the formation of mélange. It is likely that deformation at this stage (and in particular in its later phase) took place under blueschist facies conditions. The second deformation event, probably under greenschist facies conditions, was associated with folding which steepened the earlier foliation and produced new asymmetric folds. The third deformation event, partly under semi-brittle/brittle conditions, is responsible for new thrusts cutting the earlier structures and the formation of large open folds, such as the Bolków-Wojcieszów antiform.
The deformation of the rocks of the Chełmiec Unit was associated with greenschist facies metamorphism. In general, primary sedimentary and volcanic structures are well preserved in the rocks of this unit which often seem to have suffered weaker deformation and metamorphism than that observed in other units of the Kaczawa Mts. No clear evidence of the early high-pressure episode which is widespread in other tectonic units of the Kaczawa Complex has been found in the Chełmiec Unit so far.

Geologia Sudetica, 31 (1): 61-68.

Latest Devonian conodonts from an olistolith in the northern part of the Góry Bardzkie, West Sudetes

Joanna Haydukiewicz

Instytut Nauk Geologicznych, Uniwersytet Wrocławski, ul. Cybulskiego 30, 24-205 Wrocław, Poland

Key words: conodont, Latest Famennian, deep-marine, olistolith, CAI.

Abstract
Latest Devonian conodonts have been recovered from siliceous rock at Bardo Śląskie, Góry Bardzkie (Mts), West Sudetes. The exposure in the Nysa Kłodzka river cut consists of several undisturbed intervals, separated by zones of fault breccia, interpreted as one large olistolith of Devonian rock embedded in a surrounding Lower Carboniferous graywacke. The siliceous rock shows signs of very low-grade contact metamorphism (300-360°C; conodont CAI = 5) attributed to the late Carboniferous granite intrusion. They represent intervals from Mid- to probably Late-expansa Zone, Mid-expansa to the Early-praesulcata Zones and undivided praesulcata-Zone, all suggesting the latest Famennian age for the siliceous host rocks, which appear the youngest Devonian sediments paleontologically documented to date in the allochthonous domain of the Góry Bardzkie. Palmatolepis and Polygnathus are the most frequent genera. The two genera are believed to indicate the deepest pelagic environment of the late Devonian sea. Both the biofacies and lithofacies of the investigated sediments strongly suggest their distal, deep-water basinal origin. The presence of the open-marine pelagic sediments in the uppermost Famennian seems to imply a continuous sedimentation rather, than a break at the Devonian-Carboniferous boundary in the Góry Bardzkie allochthonous domain.

Geologia Sudetica, 31 (1): 69-77.

Fluvial sedimentology of the Biały Kamień Formation (Upper Carboniferous, Sudetes, Poland)

Leszek Kurowski

Instytut Nauk Geologicznych, Uniwersytet Wrocławski, pl. Borna 9, PL 50-204 Wrocław, Poland

Key words: molasse, fluvial, Intra-Sudetic basin, Variscan, Carboniferous.

Abstract
The Biały Kamień Formation (Namurian B-C) is part of a molasse sequence deposited in the post-Variscan Intra-Sudetic basin. The formation differs from the adjacent deposits by its coarse-grained nature and possession of fining-up cycles, consistent with deposition in a braided gravel-bed river (GII and GIII facies of Miall's 1978 classification). Fine-grained sediments and coal seams are present in the upper part of the formation. The cyclicity mostly seems to reflect autocyclic depositional mechanisms within the tectonically controlled Intra-Sudetic molasse basin.

Geologia Sudetica, 31 (1): 79-91.

Genesis and evolution of Sudetic late Hercynian volcanic rocks inferred from trace element modelling

Kazimierz Dziedzic

Instytut Nauk Geologicznych, Uniwersytet Wrocławski, ul. Cybulskiego 30,  50-205 Wrocław, Poland

Key words: andesite, rhyolite, partial melting, modelling, AFC, lithospheric mantle, rifting, rift depressions, fracture zones.

Abstract
The late Hercynian volcanic complexes in the Sudetes originated due to decompressional melting of the subcontinental lithospheric source region. The volcanic activity started with the calc-alkaline andesite magma in an Early Permian, followed by the picritic relicts and the andesitic assemblage rocks both of tholeiitic affinity. The tholeiitic andesites originated by AFC processes involving mantle-and lower crust-derived material. The differentiation of the andesitic parental magma within high-level magma chamber(s) by AFC processes involving upper crust components yielded the acid volcanic varieties in the area. The geodynamic processes and geological relations correspond with those of continental rift zones.

Geologia Sudetica, 31 (1): 93-104.

Orthogneisses and metapelites from a polyphase tectonic zone - mesostructural versus microstructural evidence: an example from the Czerniawa Zdrój section (Izera-Karkonosze Block, West Sudetes)

Wojciech Czapliński

Instytut Nauk Geologicznych PAN, ul. Podwale 75, 50-449 Wrocław, Poland; wojtekcz@twarda.pan.pl

Key words: West Sudetes, Izera–Karkonosze Block, microstructures, quartz c-axis.

Abstract
Within the gneisses of the northern part of the Izera–Karkonosze Block (West Sudetes), there are 4 belts of schistose rocks. The Stara Kamienica schist belt in the Czerniawa section consists of a sequence of orthogneisses deformed to various degree, occurring concordantly with metapelitic mica schists. Structural analysis of these rocks, including quartz c-axis analysis, allows four stages of deformation, common for both lithologies to be recognized. The quartz c-axis microfabrics are often incompatible with other elements of the structural record, which is interpreted as having resulted from multiple overprinting of older microfabrics by younger ones in a heterogeneous deformation regime. This heterogeneity concerns the geometry of the deformation as well as the mechanisms, which included subgrain-rotation recrystallization, grain-boundary migration, microfracturing and pressure-solution processes.

Geologia Sudetica, 31 (1): 105-111.

Mesostructural and kinematic characteristics of core gneisses in western part of the Orlica-Śnieżnik Dome, West Sudetes

Marian Dumicz

Instytut Nauk Geologicznych, Uniwersytet Wrocławski, pl. M. Borna 9, 50-204 Wrocław, Poland

Key words: Orlica-Śnieżnik Dome, Sudetes, Variscides, gneiss, stretching lineation.

Abstract
The Orlica-Śnieżnik Dome in the West Sudetes consists of an orthogneissic core and a schist-phyllite mantle. It is subdivided into two parts tectonically separated by the Upper Cretaceous Nysa Graben. In this paper structures developed during polyphase deformation of the c. 500 Ma core gneisses in the western part (Orlické hory, Góry Orlickie, Góry Bystrzyckie) are compared with those of the eastern part (Śnieżnik massif). The effects of deformations D₁ to D₄ structures are, in general, mutually comparable in the gneissic series of the Góry Orlickie (Mountains) and the Śnieżnik complex. D₅ structures, manifested in the Góry Orlickie as S-C structures which show a top-to-the-south or top-to-the-southwest sense of displacement, are, however, not known in this shape from the eastern part. Structures of such geometry in the gneisses of the latter region were ascribed to deformation D₃. The C element of the S-C structures is represented in the Góry Orlickie by a rough S₅ domainal cleavage, spatially related to the NW-SE fault zone of Olešnice-Uhřínov, which separated the gneissic core from the Nové Město series and the Zabřeh series of the mantle. This relationship suggests that both the S₅ cleavage and the fault zone are associated with the same deformation event D₅ and originated under similar rheological and kinematic conditions. In both cases cataclastic deformation was accompanied by only local and limited recrystallization of white micas. Kinematic analysis of the D₅ tectonic structures shows that these structures were formed in a sinistral transtension regime. In the Góry Bystrzyckie the tabular crystals of microcline, usually preserving their original shapes, are, in general, arranged along the S₃ gneissosity planes in which they show a considerable scatter. They are more or less lenticularly deformed, in concordance with the SSW-trending L₃ mineral recrystallization lineation, and point to a top-to-the-north sense of shearing during D₃ event.

Geologia Sudetica, 31 (2): 133-155.

Late Cainozoic evolution of the Nysa Kłodzka river system between Kłodzko and Kamieniec Ząbkowicki, Sudetes Mts, southwestern Poland

Dariusz Krzyszkowski¹, Bogusław Przybylski² & Janusz Badura²

¹ Instytut Geografii, WSP Słupsk (correspondence: P.O. Box 202, 53-350 Wrocław, Poland
² Państwowy Instytut Geologiczny, Oddział Dolnośląski, ul. Jaworowa 19, 53-122 Wrocław, Poland

Key words: Fluvial terraces, neotectonics, stratigraphy, F. E. Zeuner, Sudetes.

Abstract
The Nysa Kłodzka river drainge basin in the Sudetes Mts, SW Poland, preserves a complex late Cainozoic sequence that includes eight fluvial series/terraces and deposits from two glacial episodes as well as locally volcanic rocks, slope covers and loess. Sedimentation took place during the late Pliocene and since early Middle Pleistocene (Cromerian), with a long erosion phase (hiatus) during the Early Pleistocene. Fluvial series occur in the late Pliocene, Cromerian, Holsteinian, late Saalian/Eemian, Weichselian and the Holocene. Glacial deposits are represented in the early Elsterian and early Saalian stages. The main tectonic uplift and strong erosion was during the Early Pleistocene, with displacement about 60-70 m. Tectonic uplift was documented also for the post-Elsterian and the post-early Saalian time, and these uplift phases are most probably due to glacio-isostatic rebound. The Quaternary terrace sequence has been formed due to base level changes, epigenetic erosion after glaciations and neotectonic movements. The Cromerian fluvial deposits/terraces do not reveal any tectonic influence. However, all other Quaternary terraces indicate clear divergence, and the post-early Saalian terraces also offset by fault scarps. The total Late Pleistocene displacement along the fault scarps is about 25 m. The fluvial pattern is stable, once formed during the Pliocene, it continued in the same place until recently, with only minor changes along the uplifted block surrounding the Bardo gorge which infers the antecedent origin of the Bardo gorge. During the post-glacial times, epigenetic incisions have only slightly modified the valley.

Geologia Sudetica, 31 (2): 157-170.

The preglacial fluvial deposits in the southern part of the Upper Nysa Depression, central Sudetes Mts, southwestern Poland

Waldemar Sroka & Anna Kowalska

Instytut Nauk Geologicznych, Uniwersytet Wrocławski, pl. Maxa Borna 9, 50-204 Wrocław, Poland

Key words: gravel-bearing rivers, stratigraphy, fluvial palaeoenvironments.

Abstract
Three fluvial series have been distinguished in the Upper Nysa Depression, Kłodzko Basin, central Sudetes. The oldest, the Červeny Potok series, of probable Late Pliocene age, contains fluvial facies, mainly gravelly but also sandy and silty. It is quartz-rich and characterized by strong chemical decomposition of gneiss clasts. The Lichkov series, of probable Early to early Middle Pleistocene age, contains similar lithofacies to the Červeny Potok series, with locally abundant debris-flow deposits. The Boboszów series, of probable late Middle Pleistocene age, consists of a monotonous series of fluvial gravels. The pebbles in both, the Lichkov and Boboszów series are gneiss-rich and are characterised by a lack of significant chemical clast decomposition. The coarse-grained fluvial sediments of the southern part of the Upper Nysa Depression were mainly deposited in gravel-dominated braided rivers of Donjek and Scott type, and locally on alluvial fans. The material was transported from N or NE to S or SW, with the source area only in the adjacent metamorphic massif, despite the fact that the series lie on Late Cretaceous rocks. The studied area constituted a small intramontane depression subjected to limited subsidence, surrounded by episodically active faults. The variability of sedimentary process reflected climatic changes rather than tectonic activity. The northern part of the studied area, which now belongs to the Baltic Sea drainage area, was drained to the south, either to the North or Black Seas, during the Late Pliocene to Middle Pleistocene. The capture of this area by the Nysa Kłodzka river took place in the Late Pleistocene as a result of upstream erosion reflecting glacio-isostatic rebound and fault activity after the early Saalian glaciation.

Geologia Sudetica, 31 (2): 171-196.

The preglacial Nysa Kłodzka fluvial system in the Sudetic Foreland, southwestern Poland

Bogusław Przybylski¹, Janusz Badura¹, Jerzy A. Czerwonka², Dariusz Krzyszkowski³, Katarzyna Krajewska⁴ & Teresa Kuszell⁵

¹ Państwowy Instytut Geologiczny, Odział Dolnośląski, ul. Jaworowa 19, 53-122 Wrocław, Poland
² Przedsiębiorstwo Geologiczne we Wrocławiu Proxima S.A., ul. Wierzbowa 15, 50-056 Wrocław, Poland
³ Instytut Geografii, WSP Słupsk (correspondence: P.O. Box 202, 53-350 Wrocław, Poland)
⁴ Muzeum Ziemi, Polska Akademia Nauk, Al. Na Skarpie 20/26, 00-488 Warszawa, Poland
⁵ Instytut Nauk Geologicznych, Uniwersytet Wrocławski, ul. Cybulskiego 30, 50-205 Wrocław, Poland

Key words: fluvial environments, stratigraphy, fluvial palaeogeography, Pliocene-Early Pleistocene.

Abstract
The preglacial series deposited by the Nysa Kłodzka river has a much wider extent in the Sudetic Foreland than hitherto supposed. It can be found in a 5-10 km wide belt near margin of the Sudetes Mts and an over 60 km wide belt in the Sudetic Foreland and the adjacent part of the Silesian Lowland. This series is porphyry-bearing and it is made up of four lithostratigraphic units that differ in their heavy mineral contents. The porphyry-free sediments deposited by other river systems of the Sudetic Foreland occur at the margins of the porphyry-bearing series or partially overlie it. Units I-III were deposited mainly by sinuous, suspended-load, low energy rivers and only locally by gravel-load, high energy rivers. The preglacial sediments of units I-III consist of strongly re-worked, quartz-rich material and some kaoline matrix, that most probably come from Tertiary weathering mantles of the Sudetes Mts. These fluvial sequences were deposited by rivers with widely migrating valleys and they probably reflect weak tectonic activity in the region. Unit IV was deposited by bed-load, high energy rivers which were formed during general landscape reorganisation caused by strong tectonic activity. The new valleys were incised, and as a result, local, kaolin-free material became dominant in the sequence. The vertical amplitude of tectonic movements in the Sudetic Foreland at that time was about 40-80 m, with simultaneous uplift of the Sudetes Mts of about 60-70 m. Units I-III are most probably of Late Pliocene age, whereas unit IV could have been deposited from the Early Pleistocene to the Cromerian Stage.

Geologia Sudetica, 31 (2): 197-211.

Late Quaternary evolution of the Nysa Kłodzka river valley in the Sudetic Foreland, southwestern Poland

Bogusław Przybylski

Państwowy Instytut Geologiczny, Oddział Dolnośląski, ul. Jaworowa 19, 53-122 Wrocław, Poland

Key words: Neotectonics, river terraces, stratigraphy, glaciation of the Sudetic Foreland.

Abstract
The late Quaternary Nysa Kłodzka river terrace system has developed since the retreat of the Early Saalian (Odranian) ice sheet, which entirely covered the Sudetic Foreland and partly the Sudetes Mts. There are four terraces in the river valley, where the oldest one, the Upper Terrace, developed during and immediately after the ice sheet retreat, other terraces were deposited during the subsequent cold and warm stages, Wartanian, Weichselian and the Holocene. At the initial stage, the present river valley formed at the margin of retreating ice sheet. Later, the valley developed due to several erosion and sedimentation phases. The Nysa Kłodzka river flows through a zone of moderate to distinct tectonic activity, which is confirmed by seismic activity and recent crustal movements in the eastern part of the Sudetic Foreland. The neotectonic movements influenced much the evolution of morphology of this zone throughout the Quaternary and led to the shaping of the valley into its current form. During the late Quaternary, neotectonics could have been strenghten due to post-glacial isostatic rebound. These vertical movements disturbed the terrace system of the Nysa Kłodzka river valley, with the strongest terrace tilt in the Upper Terrace level, but less deflections visible even in the Holocene terrace levels.

Geologia Sudetica, 31 (2): 213-220.

Late Weichselian and Holocene development of the small valleys in the SE part of the Niemcza Hills, Sudetic Foreland, southwestern Poland

Stefan Witold Alexandrowicz¹ & Dariusz Ciszek²

¹ Akademia Górniczo-Hutnicza, Al. Mickiewicza 30, 30-059 Kraków, Poland
² Instytut Geograficzny, Uniwersytet Wrocławski, pl. Uniwersytecki 1, 50-137 Wrocław, Poland

Key words: Loess redeposition, alluvial deposits, mollusc fauna.

Abstract
The deposits which fill the small valleys of the Niemcza Hills in the Sudetic Foreland were accumulated by meandering rivers. There are sequences that consist of both the channel and overbank facies, including lateral accretion deposits and soils. The overbank deposits are composed of redeposited loess, which forms the alluvial loam described in this paper as silty loam. Two main stages of accumulation occurred: Lateglacial/early to middle Holocene and late Holocene. During the first stage, accumulation rates were very low in spite of the drastic climatic change at the Weichselian/Holocene boundary. The second stage was characterised by very high accumulation rates and generally increased slope activity, which was probably a result of human impact and extensive agriculture, present in this area since ca 2300-2500 yrs BP. The mollusc fauna changes according to the valley evolution, at first (stage I) represented by poor, redeposited, mainly cold-tolerant loess fauna, and then (stage II) rich assemblages of snails living in shady and humid habitats.

Geologia Sudetica, 31 (2): 221-239.

The role of neotectonics in the Quaternary evolution of the landscape of the Sowie Mts, Sudetes, southwestern Poland

Dariusz Krzyszkowski¹ & Wioletta Olejnik²

¹ Instytut Geografii, WSP Słupsk (correspondence: P.O. Box 202, 53-350 Wrocław, Poland)
² Instytut Geograficzny, Uniwersytet Wrocławski, pl. Uniwersytecki 1, 50-137 Wrocław, Poland

Key words: Quaternary, neotectonics, mountain valleys, alluvial fans.

Abstract
The Sowie Mts range comprises distinct morphological features that may be related to active tectonics. These are large-scale scarps up to100-200 m high, with triangular facets, at the Sudetic Marginal Fault, which separates the mountain range from its foreland; stepped morphology in the mountain interior with 100-300 m high scarps between flat surfaces; and straight, asymmetric valleys. The last two features are related to differently oriented faults. Meso-scale tectonically induced morphological features are represented by localised steepening of longitudinal valley profiles at fault lines (breaks, knickpoints), distinct downstream divergence of terraces, offset terraces, and the formation of fault scarps, basal scarplets beyond the valleys, frequent occurrence of alluvial fans and their onlap, and stream deflections at the Sudetic Marginal Fault. Apart from incipient Neogene offset, two phases of subsequent Quaternary tectonic uplift are possible. Total neotectonic uplift of the Sowie Mts range is about 100-300 m and, most probably, major tectonic activity took place during the Early Pleistocene. Late Pleistocene uplift was much less (10-40 m), although it is much better documented. The late Pleistocene tectonic activity was related to post-early Saalian glacio-isostatic rebound. Generally, the central part of the Sowie Mts was uplifted at least twice as much as the northern and southern area during each tectonic event. As a result, all geomorphic surfaces, including the flat surfaces, are deflected, and the height of the large-scale scarps, valley fault scarps, basal scarplets and knickpoints in the valley longitudinal profiles changes regionally.

Geologia Sudetica, 31 (2): 241-258.

Terraces of the Bystrzyca river valley, Middle Sudetes, and their deformation along the Sudetic Marginal Fault

Dariusz Krzyszkowski¹ & Jacek Biernat²

¹ Instytut Geografii, WSP Słupsk (correspondence: P.O. Box 202, 53-350 Wrocław, Poland)
² Instytut Geograficzny, Uniwersytet Wrocławski, pl. Uniwersytecki 1, 50-137 Wrocław, Poland

Key words: fluvial terraces, neotectonics, fault scarps, Middle and Late Pleistocene stratigraphy.

Abstract
There are three stages in the evolution of the Bystrzyca river valley, dated to the Pliocene, the Early to late Middle Pleistocene, and the late Middle Pleistocene to recent. The Pliocene landscape was flat to hilly, with a weakly developed margin of the mountains. The valleys were shallow and wide, most probably with sinuous rivers, and are today represented by the 100-120 m high terrace. The scarp of the Sudetic Marginal Fault and the mountain landscape with deeply incised valleys were not formed until the Early Pleistocene tectonic phase, during which the uplift was about 60-70 m. The late Middle to Late Pleistocene stage of the valley development may be subdivided into several sub-stages, during each of which, one of three morphogenetic factors, namely fluvial activity, glacial erosion and sedimentation and tectonic uplift, prevailed. Five fluvial terraces have been found, one formed before glaciation and the other four during the post-glacial times. The valley was glaciated only once, during the early Saalian (Odranian) stage. The total postglacial uplift was about 40-50 m and fluvial activity that time was influenced by varying uplift rates. At first, erosion prevailed due to strong glacio-isostatic uplift. Then, it diminished quickly and was replaced by more localised tectonic uplift, which decreased with time. As a result, fluvial activity in the mountains and in the foreland became different, as is highlighted by the increased thickness of fluvial deposits in the foremoutain zone, the rapid change of terrace height, formation of a distinct, 25-30 m high, fault scarp along the Sudetic Marginal Fault, and the increased erodibility along the fault lines.

Geologia Sudetica, 31 (2): 259-288.

Late Quaternary evolution of the Czyżynka river valley, Wałbrzych Upland, Middle Sudetes Mts, southwestern Poland

Dariusz Krzyszkowski

Instytut Geografii, WSP Słupsk (correspondence: P.O. Box 202, 53-350 Wrocław, Poland)

Key words: mountain valley, slope deposits, fluvial sedimentation, late Quaternary

Abstract
The lower part of the Czyżynka river valley (Wałbrzych Upland, Sudetes) was formed entirely after the early Saalian (Odranian) stage. The subsequent, 60-80 m deep, valley was incised into the mountain plateau. The valley is generally narrow with an alternating wide and narrow segments, and characterized by steep slopes, including common subvertical rock walls. Three terraces, formed most probably during the Wartanian/Eemian, Middle Weichselian and Late Weichselian represent the main stages of fluvial activity. Fluvial sequences show that sinuous to meandering rivers were active throughout the late Quaternary. Two phases of loess deposition are inferred (Wartanian and Middle Weichselian), as the deposits of the older terraces contain large admixtures of loess-like deposits. Moreover, two phases of large angular debris production and formation of extensive slope covers and fans have been recognized. The older occurred during the Upper Pleniglacial of the Weichselian stage. A continuum of slope colluvium was formed at that time, from fine-grained sheet wash deposits (including redeposited loess) to coarse grained deposits formed by cohesive debris flows, noncohesive debris flows and grain flows, and open-work loose material formed by debris avalanches. Frost activity and permanently moist conditions have been reported for that time, most probably with permafrost. Also, all these slope deposits contain an admixture of loess, suggesting loess deposition that time, too. The second phase of coarse debris production occurred, most probably, during the the Younger Dryas forming less extensive slope covers.

Geologia Sudetica, 31 (2): 289-305.

Geomorphic evolution of the mountain front of the Sudetes between Dobromierz and Paszowice and adjacent areas, with particular reference to the fluvial systems

Piotr Migoń¹, Dariusz Krzyszkowski² & Katarzyna Gogół¹

¹ Instytut Geograficzny, Uniwersytet Wrocławski, pl. Uniwersytecki 1, 50–137 Wrocław, Poland
² Instytut Geografii, WSP Słupsk (correspondence: P. O. Box 202, 53–350 Wrocław, Poland)

Key words: neotectonics, fluvial terraces, alluvial fans, differential erosion, Quaternary.

Abstract
The morphology of the marginal part of the Sudetes between Dobromierz and Paszowice reflects above all lithological and structural differences within bedrock. Major landforms include watershed surfaces of low relief, monadnocks and intramontane basins. Drainage pattern changes were associated with the decay of the early Saalian (Odranian) ice-sheet, whilst stages of further development of fluvial systems are well documented by multiple terrace levels. The mountain front of the Sudetes, genetically related to the Sudetic Marginal Fault, is only up to 100 m high and overall strongly degraded. In contrast to southern sectors of the Sudetic mountain front, active Quaternary tectonics played minor part in the landscape development.

Geologia Sudetica, 31 (2): 307-316.

Geomorphological evidence of neotectonics in the Kaczawa sector of the Sudetic Marginal Fault, southwestern Poland

Piotr Migoń & Janusz Łach

Instytut Geograficzny, Uniwersytet Wrocławski, pl. Uniwersytecki 1, 50-137 Wrocław, Poland

Key words: neotectonics, fluvial morphology, planation surfaces, Quaternary, Sudetes.

Abstract
The Kaczawa sector of the marginal escarpment of the Sudetes Mts is 80-120 m high and separates upland denudation surfaces, probably Late Miocene in age, and flat foreland surfaces underlain by Cainozoic sediments. Genetically the scarp is related to the course of the Sudetic Marginal Fault. Scarp dissection by short, deeply incised valleys was the response to the Pliocene-Early Quaternary uplift of the Sudetes Mts relative to their foreland. Evidence for tectonic activity during the Late Quaternary is equivocal. Deformations of terrace levels have not been recorded whilst upper valley slope benches apparently cut off at the mountain front do not bear an alluvial cover.

Geologia Sudetica, 31 (2): 317-328.

The pre-Elsterian valley system in the Western Sudetes, southwestern Poland, and its later transformation

Marek Michniewicz

Państwowy Instytut Geologiczny, Oddział Dolnośląski, ul Jaworowa 19, 53-122 Wrocław, Poland

Key words: buried valleys, fluvial pattern, glacial deposits, Elsterian glaciation.

Abstract
This paper presents a reconstruction of the pre-Elsterian fluvial pattern in the Western Sudetes Mts using borehole and geophysical data. These valleys were blocked by the advancing Elsterian ice sheet, enabling the proglacial lakes to be formed, and most of them were later covered by the ice sheet which entered into the mountain interior. The valleys are now filled with 5-15 m of 'pre-glacial' fluvial gravels and a generally thick glacial series. The latter comprises a till and glaciofluvial and glaciolacustrine sediments, including varved clay. The former valleys occur along the axes of the present-day valleys or at their margins, or occur in watershed areas which have been recently abandoned. Post-Elsterian changes in valley pattern is due to the filling of old valleys and epigenetic incision of new valleys along the tributary valleys. The valley fragments which preserved their former position were deeply incised, with the almost complete removal of older deposits. Some fault activity has been documented for that time in the marginal zone of the Sudetes Mts. The Saalian ice sheet only entered the marginal part of the Sudetes Mts, and hydrographic changes from that time are smaller.