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1

Insights into the palaeoenvironments, structure and stratigraphy of the lower Miocene of the Eastern Carpathians Bend Zone, Romania

Bercea Răzvan-Ionuţ, Bălc Ramona, Tămaș Alexandra, Filipescu Sorin, Mircea Tămaș Dan, Guillong Marcel, Flavius Szekely Flavius, Lukács Réka

Geological Quarterly

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2023

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Vol. 67, No. 1

art. no. 2

EN

The ages of several Oligocene to Miocene sedimentary formations from the Eastern Carpathians Bend Zone are poorly constrained due to palaeoenvironmental factors, reworking of fossils, structural complexity and limited exposure. To help overcome these issues, this study integrates calcareous nannoplankton and foraminifera biostratigraphy with isotopic age dating (U-Pb) of volcaniclastic zircons, and sedimentological and structural observations/interpretations. Our study was carried out along an ~6-km-long section made from a series of outcrops along the Bizdidel River which exposes several formations such as the Pucioasa, Fusaru, Vinețișu, Starchiojd and Slon. We show that the Fusaru Formation consists of coarse-grained rocks deposited as confined longitudinal channel successions that migrated laterally. It is bounded by the mud-rich Pucioasa and Vinețișu formations which are lateral equivalents of the Fusaru confined channels deposited as levee/overbank units. These genetically related formations appear to reach younger ages – of the lower to middle Burdigalian based on calcareous nannoplankton and foraminifera biostratigraphy – than previously thought (upper Oligocene to lower Burdigalian). The dominant organic-rich mudstones of the Starchiojd Formation represent pelagites/hemipelagites deposited in anoxic conditions. Their middle Burdigalian age is established by a 17.41 ±0.27 Ma zircon U-Pb age of zircons from the Bătrâni Tuff in the Starchiojd Formation. Based on the similar phenocryst content, zircon U-Pb age and zircon trace element composition, the source of the tuff is suggested to be the 17.3 Ma Eger ignimbrite-forming eruption, which has proximal, near-caldera deposits in the Bükkalja Volcanic Field, Hungary. The mud-rich Slon Formation seems to be related to shelf edge/upslope failure that formed cohesive debrite avalanches resulting from foreland propagation of compression. The Slon Formation extends in this area to at least the upper part of the lower Miocene to middle Miocene. These results highlight the need to revise ages of those parts of the sequence which are poorly constrained or different in other parts of the Carpathian Basin. Such revised ages help to better constrain the understanding of the deformation history of the Carpathians.

2

Structural control on the initiation and development of the Biała Wisełka Landslide Complex (Silesian Beskid, Outer Carpathians, Southern Poland)

Sikora R.

Geology, Geophysics and Environment

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2018

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Vol. 44, no. 1

31--48

EN

The numerous landslides which have developed in the mostly Cretaceous to Eocene turbiditic rocks of the Silesian Beskid are genetically and geometrically controlled by bedrock structural features, the Biała Wisełka Landslide Complex being no exception. Its location is in the headwater area of the Wisła River, on the slopes of Mt. Barania Góra (1220 m a.s.l.). The bedrock is represented by flysch strata of the Silesian Nappe (Outer Carpathian Fold-and-Thrust Belt), or, more specifically, the Upper Cretaceous turbiditic Upper Godula and Lower Istebna Beds of the Godula Thrust Sheet. The research work consisted in their mapping and structural analysis, facilitated by the use of a high-resolution digital elevation model based on LiDAR data. A comparative analysis enabled the determination of the relationships between landslides and the bedrock structure. The study results point to significant roles being played by the joint network, fault systems, the structural arrangement and the lithology of rock strata in the initiation and evolution of the studied landslide complex. An additional result of the methods applied methods was the identification and characterization of previously unknown fault zones in the study area.

3

Miocene transpression effects at the boundary of Central Carpathian Paleogene Basin and Pieniny Klippen Belt - examples from Polish-Slovakian borderland

Ludwiniak M.

Geology, Geophysics and Environment

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2018

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Vol. 44, no. 1

91--100

EN

A geological structural study has been conducted along the tectonic contact zone of the Central Carpathian Paleogene Basin (CCPB) and Pieniny Klippen Belt (PKB) in the eastern Podhale and western Spišska Magura areas. It concerned mostly the Central Carpathian Paleogene flysch strata and, to a lesser degree, the Upper Cretaceous rocks of the PKB. Tectonic deformation structures genetically related to the important tectonic boundary in question occur within a c. 1.5–2 km-wide strip of the Paleogene flysch rocks adjacent from the south to the PKB. Two parallel structural domains have been distinguished within this strip: the contact zone proper in the north and the peri-Pieniny monocline in the south. Most of the minor faults documented in the Paleogene flysch bear a record of dextral motion parallel to the contact zone. Some dextral-reverse oblique slip faults of NE-SW and W-E trends have also been recognized. Discrepancies in the orientation and sense of movement on strike-slip faults in the Paleogene flysch rocks and those in marlstones of the “klippen envelope” of the PKB were encountered. They probably reflect differences in the structural history of both the adjacent rock complexes, as the Upper Cretaceous deposits of the PKB must have experienced more deformation events and, in general, were affected by much more intense strain than those of the CCPB. Contractional structures, such as south-vergent reverse faults and recumbent folds which point to ca N-S tectonic shortening, have also been found in the Paleogene rocks. The entirety of the structural features found in the CCPB is characteristic of a transpressional regime. The regionally consistent coexistence of structures resulting from strike-slip movements and tectonic shortening, as well as features pointing directly to a transpressional regime, prove the transpressional dextral nature of the contact between the CCPB and PKB.

4

What are cleats? Preliminary studies from the Konin lignite mine, Miocene of central Poland

Widera M.

Geologos

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2014

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Vol. 20, No. 1

3--12

EN

Cleats (fractures, joints) are discontinuities in coals, including lignites. They are important in mining activity because of their gas and water permeability in hard coal, and mainly because of their water permeability in lignites. As opposed to hard-coal cleats, lignite cleats have not been studied in detail before. The present contribution does so, using as an example the 1st Middle-Polish Lignite Seam (MPLS-1) in the Jóźwin IIB opencast mine in central Poland. It should be mentioned here that any remarks in the present contribution concerning MPLS-1 refer exclusively to this lignite seam in the Jóźwin IIB opencast mine. The investigated discontinuities consist of two sets, i.e. the face and butt cleats, which are roughly oriented NW–SE and NE–SW, respectively. The mean spacing of the face cleats is ~12.4 cm, while the mean spacing of the butt cleats is ~12.8 cm. The maximum average aperture is ~4.9 mm for the face cleats and ~4.1 mm for the butt cleats. The cleat spacing and aperture do not depend on the lignite thickness, but the cleat spacing increases with increasing mineral-matter and xylite content, whereas the aperture increases when the contents decrease. The regional folding and local salt diapirism tentatively explain the formation of the orthogonal system of the lignite cleats, partly because of the parallelism of the face cleats and the major tectonic directions in central Poland.

5

Udostępnione pogórnicze obiekty podziemne Dolnego Śląska jako zaplecze geoturystyczne

Zagożdżon P. P., Zagożdżon K. D.

Przegląd Geologiczny

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2013

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Vol. 61, nr 1

19–-24

EN

Tourist routes in the historic underground mining workings are an ideal base for geotourism. Lower Silesia is an area favoured in this respect, due to the amount and variety of such objects. They allow observation of different geological units: diversity of their lithology, mineralization, types of deposits, tectonics, as well as very interesting aspects of mining. This paper presents proposals of geotourist routes or observation sites in underground facilities described for Złoty Stok, Krobica, Kowary, Kletno and Osówka. Long and continuous lithological profiles, interesting rocks (e.g. rheomorphic granites in Osówka), signs of mineralization (löllingite in Złoty Stok, fluorite and amethyst in Kletno), numerous dislocation zones and folds, well-preserved historic mining workings (16th and 18th- century adits in Krobica) and many others are available for observation in these objects.

6

Fault network in Rio Colca valley between Maca and Pinchollo, Central Andes, southern Peru

Żaba J., Małolepszy Z., Gaidzik K., Ciesielczuk J., Paulo A.

Annales Societatis Geologorum Poloniae

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2012

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Vol. 82, No. 3

279-–290

EN

The network of faults and joints within the Mesozoic, Miocene and Pleistocene–Holocene formations was studied in the Rio Colca valley, in the Pinchollo–Lari–Maca area (Central Andes, southern Peru). A complex, multi-phase development of these structures was revealed. The results show that the structural framework of the Rio Colca valley consists of WNW–ESE and NE–SW faults, and a few W–E faults. The strike of the most common fault sets is approximately parallel (longitudinal) or perpendicular (transverse) to the W–E oriented strike of stratification surfaces in the Mesozoic sedimentary series and the W–E fold macro-structures, developed in these strata. Diagonal faults and joints are less common, although at some localities they are numerous. The recurrence of major fault systems throughout the Mesozoic and Miocene series and the Pleistocene–Holocene (mainly colluvial) deposits is proof of recent, tectonic activity in the study area. The recent faulting has led to the development of a system of distinct, primary fault scarps, tectonic grabens and horsts, as well as open fissures, which are well marked in the surface morphology, and in many cases have not yet been eroded.

7

Analiza strukturalno-kinematyczna kompleksu deformacji glacitektonicznych w strefie rowu Kleczewa (elewacja konińska, wschodnia wielkopolska)

Włodarski W.

Prace Państwowego Instytutu Geologicznego

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2009

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T. 194

75--100

PL

Przedmiotem artykułu jest analiza strukturalno-kinematyczna kompleksu deformacji glacitektonicznych, wyodrębniającego się jako osobne piętro strukturalne w strefie rowu Kleczewa (elewacja konińska). Analiza makrostrukturalna pozwoliła zdefiniować trzy podjednostki strukturalne A, B i C. Analiza strukturalno-kinematyczna mezostruktur wykazała znaczące różnice w rozwoju strukturalnym poszczególnych podjednostek. Podjednostkę strukturalną A reprezentują głównie fałdy i nasunięcia, rozwijające się w polu kompresji horyzontalnej przed czołem nasuwającego się lądolodu zlodowacenia Odry. Deformacjom podlegały głównie osady starsze od zlodowacenia Odry, tj. iły formacji poznańskiej miocenu górnego, węgle brunatne formacji poznańskiej miocenu środkowego a podrzędnie gliny T1 zlodowacenia południowopolskiego. Niewielki udział w deformacjach miały dolne partie serii glacifluwialnej z Jóźwina z fazy anaglacjalnej zlodowacenia Odry. Podjednostka strukturalna B obejmuje wyższe partie serii glacifluwialnej z Jóźwina, które przykrywają, a miejscami rozcinają erozyjnie, struktury podjednostki A. Osady podjednostki B są pocięte uskokami normalnymi powstałymi w efekcie pionowych przemieszczeń podścielających je struktur podjednostki A. Podjednostka strukturalna C jest reprezentowana głównie przez struktury wskazujące na ścinanie proste w płaszczyźnie (sub)horyzontalnej w warunkach subglacjalnych. Obejmuje ona glinę T2 zlodowacenia Odry oraz strefy kontaktu z podłożem. Pod względem mezostrukturalnym glina T2 reprezentuje melanż typu block in matrix. Podrzędną rolę w rozwoju strukturalnym podjednostki C odgrywała ekstensja horyzontalna w efekcie aktywizacji makrostruktur podłoża w trakcie rozpadu lądolodu zlodowacenia Odry.

EN

The complex of glaciotectonic deformations within Kleczew graben zone (Konin Elevation) is the object of present study. The analysis of macrostructures was the basis for definition of three structural sub-units A, B and C. Mesostructures were studied in detail within each of these sub-units. The structural sub-unit A is mainly represented by folds and thrusts produced by horizontal compression in front of advanced Odranian ice-sheet. These structures developed mainly within the Upper Miocene Poznań Formation clays, the Middle Miocene Poznań Formation brown coals and the South Polish glacial tills. The structural sub-unit B is composed of the glaciofluvial series from Jóźwin of the Odranian Glaciation, which cover discordantly deformed sediments of the sub-unit A. The sediments of the sub-unit B are dissected by lot of normal faults and high angle reverse faults. These structures were produced by horizontal extension related to vertical uplift of structures of sub-unit A. The structural sub-unit C is represented mainly by glacial till T2 of the Odranian Glaciation and contact zone between this till and the older sediments. The style of deformation of these sediments shows (sub)horizontal simple shearing under subglacial conditions. Within the complex of glaciotectonic deformations, the horizontal extension was the youngest deformation event produced by vertical uplift of the basement during decaying of the Odranian ice-sheet.

8

Late Eocene to Quaternary deformation and stress field evolution of the Orava region (Western Carpathians)

Peskova I., Vojtko R., Starek D., Sliva L.

Acta Geologica Polonica

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2009

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Vol. 59, no. 1

73-91

EN

The northern part of theWestern Carpathians suffered polyphase deformation at the boundary between their Central and Outer parts. Palaeostress analysis in the Orava region revealed the existence of five different stress fields in the period from the Late Eocene to the Quaternary. The evolution of the stress fields was determined by detailed structural analysis of the fault slip and fold orientation data. The orientation of the stress fields shows an apparent clockwise rotation from the Late Eocene to the Quaternary. During the Late Eocene to Oligocene, E-W compression and perpendicular tension affected this area. This was the time when the Central Carpathian Palaeogene Basin formed. After this compression, the palaeostress field rotated approximatly 40-50[degrees], and NW-SE compression and NE-SW tension took place in the Early Miocene. The Middle Miocene to Pliocene was characterised by progressive rotation of the palaeostress field from NW-SE to the NE-SW direction of the maximum principal compressional stress axis ([sigma][1]). This clockwise rotation of the Oligocene to Quaternary palaeostress fields here is explained by the effect of the counterclockwise rotation of the ALCAPA microplate, and by the regional stress field changes in this region. The Quaternary stress field was reconstructed on the basis of structural measurements in the Pliocene sedimentary formations of the Orava-Nowy Targ Basin. The results of the palaeostress analysis show that the Quaternary stress field is characterised by E-W-oriented S[h] (minimum horizontal compression) and N-S-oriented S[H] (maximum horizontal compression).

9

Development of fault pattern in the Silesian Nappe : Eastern Outer Carpathians, Poland

Rubinkiewicz J.

Geological Quarterly

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2000

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Vol. 44, Nr 4

391-403

EN

The development of fault pattern in the Silesian Nappe (Central Carpathian Depression) in the eastern part of Polish Outer Carpathians is outlined, from field observations and interpretation of air photos and radar images. Fault slip analysis and palaeostress reconstruction was applied to determine different systems of strike-slip, reverse and normal faults and the relative age of each system was determined. The results show a consistent evolution of fault systems which occurred as several episodes. Some of these episodes are local but others represent a regional pattern of faulting across the whole Polish Eastern Outer Carpathians. The beginning of fault evolution took place in Late Oligocene to Late Miocene times. The oldest phase is represented by reverse and thrust faults of system R1 with SW-NE compression; a younger phase involves origination of strike-slip faults belonging to system S1 (with the same direction of compression). Reverse (system R2) and strike-slip (system S2) faults were formed locally during a N-S compressional event. Dextral strike-slip faults of system S3 with simultanous opening of a dextral set of fault system S1 originated subsequently. The youngest events are represented by normal faults N1, N2, and N3 systems during NW-SE, and SW-NE to N-S extension.

10

Geometric reconstruction of thrusts in the Sierra de los Organos Massif (western Cuba)

Piotrowska K., Piotrowski J.

Kwartalnik Geologiczny

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1999

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Vol. 43, Nr 3

277-284

EN

A developmental scheme of fold-thrusts against a palaegeographic background is presented, basing upon a spatial analysis of the Sierra de los Organos structures in the Gauniguanico Cordillera (western Cuba). Thrusting which took place within the Sierra de los Organos terrane (Ch. W. Hatten et al., 1988; K. Piotrowska, 1993) resulted from deep-seated processes of a regional extent. The thrusting process was initiated during the early Middle Eocene (K. Piotrowska, 1978; A. Pszczółkowski, 1978). Initial detachment of the whole Jurassic-Tertiary sequence from its basement occurred in the basal part of the sandstone-shale San Cayetano Formation. Within this huge mass detached from its basement, another detachment took place. This occurred at top parts of the San Cayetano Formation which is overlain by a considerably thick carbonate sequence. An essential role in the process of nappes formation was played by a difference in competency (strength) of rock formations. Two nappes were formed: the Mogote and Alturas de Pizarras del Sur nappes. Due to compressive conditions existing all the time and related to a migration of the Sierra de los Organos terrane towards the north, both these nappes were subjected to a process of imbrication and duplexing. A stack of imbrications of the Mogote nappe was formed, over which duplex structures of the San Cayetano Formation composing the Alturas de Pizarras del Sur nappe were thrusted. As a result a structural inversion was taking place. The highest position is occupied by tectonic units of the metamorphosed nappe (J. Piotrowski, 1976). They come from the southern part of the terrane which underwent metamorphic processes (greenschist facies).

PL

Masyw górski Sierra de los Organos jest położony w zachodniej części Kuby, w prowincji Pinar del Rio. W obrębie tego masywu można wyróżnić trzy grupy jednostek strukturalnych: -płaszczowinę mogotową, znajdującą się w najniższej pozycji strukturalnej, zbudowaną głównie ze skał wapiennych (oksford-eocen); -płaszczowinę Alturas de Pizamas del Sur, zbudowaną z piaskowców i łupków formacji San Cayetano (jura dolna?-środkowa), nasuniętą na płaszczowinę mogotową; -płaszczowinę zmetamorfizowaną, zajmującą najwyższą pozycję strukturalną. W opracowaniu oparto się na klasycznych opracowaniach modelowych eksperymentalnych i teoretycznych dotyczących mechanizmu genezy i rozwoju struktur płaszczowinowych (S. E. Boyer, D. Elliott, 1982; P. B. Jones, 1995). Proces nasunięć rozpoczął się od inicjalnego odkłucia, które nastąpiło w najniższej części sekwencji osadowej reprezentowanej przez piaskowcowo-łupkową formację San Cayetano. Po powstaniu inicjalnego odkłucia w transportowanej sekwencji doszło do dalszego jej różnicowania na mniejsze płaszczowiny cząstkowe na granicy zespołów o różnym stopniu podatności. W wyniku drugiego odkłucia powstały dwie płaszczowiny: wyższa- mogotowa- i płaszczowina Alturas de Pizarras del Sur. Płaszczowina mogotowa dzieli się na mniejsze segmenty, które wspinają się na rampę i tworzą spiętrzenie łusek w postaci stosu płaszczowinowego Niższa pierwotnie płaszczowina Alturas de Pizarras del Sur, pozostająca tyle mogotowego stosu płaszczowinowego, dzieli się na mniejsze struktury dupleksowe nasunięte następnie na mogotowy stos płaszczowinowy. Zachodzi tu zjawisko inwersji strukturalnej. Najwyższą pozycję zajmuje płaszczowina zmetamorfizowana, interpretowana jako wachlarz łusek. W świetle takiej interpretacji w strukturze Sierra de los Organos można wyróżnić najniżej leżący mogotowy stos płaszczowinowy, wywodzący się z wachlarza łusek, struktury dupleksowe płaszczowiny Alturas de Pizarras del Sur oraz wachlarz łusek płaszczowiny zmetamorfizowanej, znajdujący się w najwyższej pozycji strukturalnej.

11

The Upper Cretaceous succession (Cenomanian - Santonian) of the Staffhorst Shaft, Lower Saxony, northern Germany: integrated biostratigraphic, lithostratigraphic and downhole geophysical log data

Niebuhr B.

Acta Geologica Polonica

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1999

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Vol. 49, no. 3

175-213

EN

The Cenomanian to Santonian succession of the Staffhorst shaft, ca. 50 km south of Bremen, because of its structural position in the northern German Upper Cretaceous basin, is intermediate in character and fossil content between the pelagic sediments characterizing the Pompeckj Block in the north and the proximal sediments of the Lower Saxony Block in the south. The biostratigraphic subdivision of the shaft is based on inoceramids, echinoids, belemnites and foraminifera. The various biozonations and zonal boundaries used in the Boreal Realm are compared and applied to the zonation of the shaft succession, and the biostratigraphy of the individual fossil groups is described. A new inoceramid zone, that of Inoceramus gibbosus, is proposed for the topmost Lower Coniacian; and an echinoid assemblage zonation is introduced. The existing benthic foraminiferal zonation of the Middle Turonian to Santonian has been modified, with changed age assignments based on the macrofossil zonation. The proposed basal stage boundary criteria of the "Second International Symposium on Cretaceous Stage Boundaries" (Brussels, 1995) could be applied only in some cases. The proximity of the Staffhorst shaft to the trial borehole, situated only 39 m away, has permitted the Self Potential (SP) and Resistivity (R) logs to be uniquely directly calibrated against the lithostraligraphical and biostratigraphic succession of the shaft. The previous identification of some stage and substage boundaries on the logs of northern German boreholes based on foraminiferal zonation will need to be shifted by several tens of metres as a result of thid calibration.

12

Sedimentological and tectonic features of the Poprad sandstone member, Eocene, Magura Nappe: case study of the Klikuszowa quarry, Outer West Carpathians, Poland

Cieszkowski M., Zuchiewicz W., Schnabel W.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1998

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Vol. 46, nr 1

55-74

EN

This paper gives an overview of principal sedimentological and structural features observed within the uppermost Eocene, thick-bedded turbidites of the Krynica subunit, Magura Nappe, that are exposed at Klikuszowa in a zone of change of the dominant orientation of thrusts and folds, from NE-SW in the west, to W-E in the east. The succession exposed in the Klikuszowa quarry represents the middle-fan distributary channel depositional system. Flute casts indicate palaeocurrent directions from the south-east and south. The distribution of transparent heavy minerals in these sandstones is characterised by the predominance of garnet, which content distinctly increases as compared to that of the underlying Szczawnica Formation and the lower part of the Magura Formation, with mixed garnet-zircon-tourmaline-rutile-apatite spectra. The presence of chromite throughout the entire succession of the Krynica subunit is noteworthy. The specific location of the study area enabled us to reconstruct a sequence of structural events recorded by small-scale tectonic features. The following post-folding episodes of faulting have been recognised: submeridional compression and thrust-wrenching, pure strike-slip faulting, N 20 degrees W extension and wrenching, and three subsequent events of normal faulting, associated with the WNW-, ENE- and NE-orientated extension. These events took place between the early Oligocene and late Serravallian times.