Wyniki wyszukiwania - Biblioteka Nauki

1

Combined analysis of faults and deformation bands reveals the Cenozoic structural evolution of the southern Bukk foreland (Hungary)

100%

Petrik A. , Beke B. , Fodor L.

Geologia Sudetica

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2014

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tom Vol. 42

72--74

2

Cenozoic dynamic evolution of the Polish Platform

70%

Jarosiński M. , Porawa P. , Ziegler P. A.

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2009

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tom Vol. 53, No 1

3-26

EN

The Cenozoic tectonic evolution of the Polish Platform reflects repeated changes in loading conditions at the Alpine–Carpathian and Arctic–North Atlantic margins of the European continent. After the Late Creta ceous–Paleocene main phase of the Mid-Polish Basinin - version, a second phase of limited uplift of the Mid-Polish Swell occurred during the Middle–Late Eocene. End Eocene and Early Oligocene subsidence of narrow grabens on the Fore-Sudetic Monocline was coeval with normal faulting in the East Alpine foredeep basin and the development of the Central European rift system. At the same time the Outer Carpathian flysch basins were rearranged, presumably in response to the build-up of compressional stresses at crustal levels, whilst subsidence and erosion patterns changed in the Carpathian Foreland from being dominated by the NW–SE trending Mid-Polish Swell to being controlled by the development of the W–E trending Meta-Carpathian Swell. At the end of the Oligocene the Fore-Sudetic graben system propagated into the area of the Trans-European Suture Zone and the Sudetes and remained active during the Early and Middle Miocene. This was paralleled by intensified subduction activity and thrusting of the Carpathians and the development of their flexural foredeep basin. A short early Sarmatian episode of basement in volving transpression along the SW margin of the Mid-Polish Swell correlates with the termination of north-directed nappe transport in the Outer Carpathians. This was followed by eastward migration of the subsidence centre of the Carpathian Foredeep Basin and the gradual termination of tectonic activity in the grabens of the Polish Lowlands. After a period of post-orogenic relaxation the present-day compressional stress regime built up during the Pliocene and Quaternary. Intensified ridge push forces exerted on the Arctic–North Atlantic passive margins contribute to this compressional stress field that is dominated by collision-related stresses reflecting continued indentation of the Adriatic Block. This sequence of events is interpreted in terms of changing tectonic loads in the Carpathians, Alps and at the NW passive margin of Europe. The complex and diachronous interaction of mechanically coupled and uncoupled plates along collision zones probably underlies the temporally varying response of the Carpathian Foreland that in addition was complicated by the heterogeneous structure of its lithosphere. Progressively increasing ridge push on the passive margin played a secondary role in the stress differentiation of the study area.

3

A deep palaeovalley in the floor of Polish Carpathian Foredeep Basin near Pilzno and its control on facies of Badenian (Middle Miocene) evaporite facies

60%

Głuszyński A. , Aleksandrowski P.

Geological Quarterly

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2016

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tom Vol. 60, No. 2

493--516

EN

The Pogórska Wola palaeovalley of combined tectonic and erosional origin dissects the Mesozoic floor of the Carpathian Foredeep Basin to a depth exceeding 1200 m. It formed during Paleogene times presumably due to fluvial and submarine erosion, concentrated along a local pre-Late Badenian graben system. All members of the foredeep’s Badenian-Sarmatian sedimentary fill attain distinctly greater values inside the palaeovalley than on top of elevated plateaux on palaeovalley shoulders. The fill comprises the Early to Late Badenian sub-evaporite Skawina Formation, the laterally equivalent Late Badenian evaporite Krzyżanowice and Wieliczka formations and the supra-evaporite Late Badenian to Early Sarmatian Machów Formation. Over the plateaux and in the highest palaeovalley segment, the evaporites are developed in the sulphate facies Krzyżanowice Formation, whereas in the lower palaeovalley segments chloride-sulphate facies evaporites of the Wieliczka Formation occur. The rock salt-bearing rocks are involved in thrusting and folding at the Carpathian orogenic front, which helps to assess the lateral extent of the Wieliczka Formation in seismic records. The deep palaeotopographic position of the evaporites inside the palaeovalley, combined with their lithological and sedimentary features, point to their formation via subaqueous gravity flow-driven redeposition of originally shallow-water evaporites, preferentially halite-bearing, presumably combined with precipitation from sulphate and chloride brines at the palaeovalley floor. Both the redeposited sediments and the brines must have come from the adjacent plateaux and from a thrust-sheet top basin, approaching from the south on top of the Cretaceous-Paleogene Carpathian flysch thrust wedge.

4

Cenozoic synthem stratigraphic architecture of the SE Brazilian shelf and its global eustatic context: evidence from the Pelotas Basin (offshore Brazil)

60%

Zerfass G. d. S. d. A. , Ruban D. A. , Chemale F. J. , Zerfass H.

Geologos

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2013

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tom Vol. 19, No. 4

273--290

EN

The Pelotas Basin, located on the SE Brazilian shelf, has evolved since the Aptian. Stratigraphical data from the basin can be used for delineation of the unconformity-bounded units (synthems) on the shelf, which is a first step towards a full understanding of its stratigraphic architecture, evolution, and hydrocarbon potential. Hiatuses in the Cenozoic succession of the Pelotas Basin are established with both biostratigraphic (planktonic foraminifers and calcareous nannofossils) and isotopic (87Sr/86Sr) data. The seven recognised hiatuses are dated respectively as (1) Palaeocene (Danian-Thanetian), (2) Palaeocene/Eocene boundary (Thanetian-Ypresian), (3) Eocene (Ypresian-Lutetian), (4) Eocene-Oligocene (Lutetian-Rupelian), (5) early-late Oligocene (Rupelian-Chattian), (6) early Miocene (Aquitanian-Burdigalian), and (7) middle-late Miocene (Serravallian-Tortonian). These intervals between the hiatuses are correlated with those of the Santos and Campos Basins north from the Pelotas Basin. The breaks in sedimentation that these basins have in common occurred (1) at the Palaeocene-Eocene and (2) Eocene-Oligocene transitions, (3) in the early Miocene, and (4) in the middle-late Miocene. These main unconformities outline five synthems on the SE Brazilian shelf, viz. the SEBS-1 (Palaeocene), SEBS-2 (Eocene), SEBS-3 (Oligocene), SEBS-4 (early-middle Miocene) and SEBS-5 (late Miocene-Holocene). The above unconformities are correlated with those established in the Cenozoic sedimentary successions of different regions such as Western Siberia, Arabia, NW and NE Africa, peninsular India, S Australia, the Gulf of Mexico, NW Europe, and South Africa. The only regional unconformity, near the Oligocene/Miocene boundary, coincides with the nearly-global sedimentation break. The latter was resulted from a climatic event, i.e., the ‘Mi-1 glaciation’. Thus, a eustatic origin is supposed for this regional unconformity. The other regional unconformities also correspond to global sea-level falls (probably with an exception for the Palaeocene/Eocene surface), which suggests that global eustatic movements controlled the development of the regional synthem architecture.

5

Reconstructing an eroded scoria cone : the Miocene Soonica Hill volcano (Lower Silesia, SW Poland)

60%

Awdankiewicz M.

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2005

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tom Vol. 49, No. 4

439--448

EN

The basaltic rocks of Sośnica Hill near Targowica (Fore-Sudetic Block) belong to the Cenozoic Central European Volcanic Province. The volcanic succession at Sośnica is over 40 m thick and comprises pyroclastic fall deposits (mainly tuff breccias), subvolcanic intrusions (plug, dykes and other intrusive sheets) and aa-type lavas. Field relationships and structural data enable a detailed reconstruction of the vent location, morphology and eruptive history of the original volcano. Initial Hawaiian to Strombolian-type explosive eruptions produced a pyroclastic cone. Subsequently subvolcanic intrusions and lavas were emplaced. The lavas were fed from the central vent of the volcano, breached the cone and flowed southwards. Later eruptions resumed at a new vent on the western slopes of themain cone. The final volcanic edifice-a breached Strombolian scoria cone with a lava flow and a parasitic cone-was 500-1000 m in diameter at the base and 90-180mhigh. The preserved SWsector of this volcano, where the pyroclastic deposits were protected from erosion by the surrounding plugs and lavas, corresponds to ca. 1/2 of the height and 1/8 of the volume of the original volcano. Compared with many other remnants of Cenozoic volcanic centres in Lower Silesia, this volcano is exceptionally well preserved and exposed.

6

First Cenozoic glaciers in West Antarctica

60%

Birkenmajer K. , Gazdzicki A. , Krajewski K. P. , Przybycin A. , Solecki A. , Tatur A. , Yoon H. I.

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nr 1

3-12

EN

One of the most significant global climatic events in the Cenozoic was the transition from greenhouse to icehouse conditions in Antarctica. Tectonic evolution of the region and gradual cooling at the end of Eocene led to the first appearance of ice sheets at the Eocene/Oligocene boundary (ca. 34 Ma). Here we report geological record of mountain glaciers that preceded major ice sheet formation in Antarctica. A terrestrial- valley-type tillite up to 65 metres thick was revealed between two basaltic lava sequences in the Eocene- Oligocene Point Thomas Formation at Hervé Cove - Breccia Crag in Admiralty Bay- King George Island- South Shetland Islands. K-Ar dating of the lavas suggests the age of the glaciation at 45-41 Ma (Middle Eocene). It is the oldest Cenozoic record of alpine glaciers in West Antarctica- providing insight into the onset of glaciation of the Antarctic Peninsula and South Shetland Islands.

7

Tectonic evolution of the late Cretaceous Nysa Kłodzka Graben, Sudetes, SW Poland

60%

Don J. , Gotowała R.

Geologia Sudetica

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2008

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tom Vol. 40

51-63

EN

The Nysa Kłodzka Graben, located in the Sudetes of SW Poland, developed as a result of Coniacian (middle Upper Cretaceous) N-trending faulting of the Variscan crystalline basement rocks that comprise the crest of the Orlica-Śnieżnik Dome. The graben was transgressed by a late Cretaceous sea that encroached during the Cenomanian from the northwest. Up to 700 m of Coniacian shales, sandstones and conglomerates were deposited in the graben, with shales (the ~500 m thick Idzików 'clays') dominating the graben's central section. On the western side of the graben, shales grade upwards to greywackes in a style that resembles a turbidite sequence; on the eastern side, shales are overlain by sandstones and conglomerates (the Idzików conglomerates) that represent extensive late Cretaceous fan deltas. These within-graben fan deltas date the onset of fault-block movements that uplifted the Sudetes region during the late Cretaceous-Cenozoic. By the end of the Cretaceous, both the sedimentary infill and the underlying Cenomanian and Turonian strata were steepened at the graben margins and were gently folded, the fold axes paralleling the graben's marginal faults. Subsequent Cretaceous-Paleocene ('Laramian') deformations resulted in NW-trending reverse faulting, which restructured the earlier N-S template of the graben, and in transcurrent faults, which cut the N-trending folds, modified the north and south ends of the graben and strongly affected the graben's western walls. The total thickness of the Upper Cretaceous strata of the Nysa Kłodzka Graben is 3 times that of the Intra-Sudetic Synclinorium, implying that the two units developed independently.

8

Overview of magmatism in Northwestern Vietnam

60%

Khuong H.

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tom Vol. 80, No 2

185-226

EN

Amalgamation of tectonic plates of Southeast Asia occurred in northwestern Vietnam. Six groups of magmatic rocks are related to the tectonic events. The first group corresponds to the major episodes of crustal formation in the South China block, or is linked with the formation of Gondwana. The second group includes granitoids in connection with the collision and formation of the Caledonian-Hercynian folding event. The third group contains Upper Permian ophiolites, as well as the Permian extrusives, formed in intraplate setting, related to back-arcs spreading. The fourth group is related to Triassic Indosinian orogeny, the fifth group comprises Jurassic-Cretaceous intraplate granitoids. Finally, during Cenozoic times, magmatic rocks were represented by alkaline granitoids - the effect of strike-slip faulting related to the collision of India and Eurasia plates.

9

An overview of lithotype associations of Miocene lignite seams exploited in Poland

51%

Widera M.

Geologos

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2016

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tom Vol. 22, No. 3

213--225

EN

Currently, three stratigraphically distinct lignite seams of Early to Middle Miocene age are exploited in Poland, namely the third Ścinawa lignite seam (ŚLS-3), the second Lusatian lignite seam (LLS-2) and the first Mid-Polish lignite seam (MPLS-1). All of these are composed of numerous macroscopically distinguishable layers defined as lignite lithotypes. In the present paper, the lithotypes of Polish lignites are grouped into seven major lithotype associations that originated in various types of mire. Therefore, an approximate reconstruction of mire type can be based on lignite lithotypes. Within the Polish lignite seams examined, the commonest in order of importance are: xylodetritic (XDL), detroxylitic (DXL), detritic (DL) and xylitic (XL) lithotype associations, mostly with a massive (m) or horizontal (h) structure. They are particularly dominant in lignite opencasts belonging to the Konin and Adamów mines. However, in the lowermost seams at the Turów and Bełchatów mines, a substantial part of the seams comprises the bitumen-rich (BL) lithotype association. These seams also lignite lithotypes that in large quantities have a gelified (g) and/or nodular (n) structure. In contrast, lignites from the Sieniawa mine are characterised by an admixture of the best-developed lithotype associations of both fusitic (FL) and weathered (WL) lignites. Moreover, the vast majority of these lignites have a folded (fo) and/or faulted (fa) structure, because they were completely deformed by glaciotectonics.

10

Ksylity w kenozoicznych osadach drobnokrystalicznych z odkrywek KWB Konin S.A. i KWB Adamów S.A.

51%

Widera M.

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2012

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tom R. 53, nr 1-2

119-122

PL

Fragmenty kopalnego drewna wśród osadów drobnoziarnistych są spotykane w wielkopolskich odkrywkach węgla brunatnego. Obecność ksylitów w osadach neogeńskich udokumentowano w odkrywkach Kazimierz N i Drzewce (KWB Konin S.A.), a pochodziły prawdopodobnie ze stropowych części niżej zalegających torfów i/lub z roślinności porastającej brzegi basenu sedymentacyjnego.

EN

Fragments of fossil wood among fine-grained deposits are found in Wielkopolska lignite opencasts. The presence of xylites in Neogene sediments have been documented in the opencasts Kazimierz N and Drzewce (Konin Lignite Mine), and Paleogene sediments in the opencast Koźmin N (Adamów Lignite Mine). Fragments of wood, which later became xylites, probably came from the upper part of the lower lying peat and/or from the vegetation growing in the areas surrounding the sedimentary basin.

11

Mineralogy and geochemistry of rare earth elements in the Moyil Valley alteration zones, Meshkinshahr (northwest Iran)

51%

Naseri H. , Jamadi M. , Radmard K. , Alavi G.

Geologos

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2020

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tom Vol. 26, No. 3

219--231

EN

Sabalan Mountain (northwest Iran) witnessed intense volcanic activity during the Cenozoic (Plio-Pleistocene). The result of this manifests itself in the conical geometry of the Sabalan stratovolcano and ahigh hydrothermal gradient around it, which can be detected by geological phenomena such as hot springs, smoke gases and steam outlet pores. The high hydrothermal slope and upward migration of hot water in this area have caused extensive alteration zones in the host rocks. A mineralogical study of alteration zones in thewells drilled in the Moyil Valley to the northwest of Sabalan Mountain has revealed the presence of phyllic, argillic, calcitic and propylitic alterations in volcanic rocks (trachyandesite) and alteration phyllic and propylitic ones in monzonite rocks. In chondrite-normalised rare-earth-element diagrams, trachyandesite rocks exhibit an HREEs enrichment when compared to MREEs and LREEs in propylitic and calcitic alteration zones. This result can be explained by the acidic nature of hydrothermal fluids containing complex ions such as (SO-2, Cl-). The (La/Yb)cn, (La/Sm)cn and (Tb/Yb)cn ratios for argillic, phyllic, propylitic and calcitic alteration zones have revealed that they are higher in fresh rocks compared to altered rocks, suggesting the enrichment of HREEs in comparison to LREEs and MREEs. The anomalies of Eu do not change remarkably in the argillic and propylitic alteration zones of trachyandesite rocks; apparently, alteration hadno effect on them. Such behaviour reflects the presence of gold cations in Eu+3 formed at temperatures below 250°C. Eu anomalies increased in propylitic alteration zones in monzonite rocks and calciticand phyllic alteration zones in trachyandesiterocks.

12

Ascending speleogenesis of Sokola Hill: a step towards a speleogenetic model of the Polish Jura

51%

Gradziński M. , Hercman H. , Kicińska D. , Pura D. , Urban J.

Acta Geologica Polonica

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2011

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tom Vol. 61, no. 4

341-365

EN

The paper deals with the origin of caves in Sokola Hill (Polish Jura). The caves abound in solution cavities in the walls and ceilings, many of them arranged hierarchically, some others arranged in rising sets. Blind chimneys and ceiling half-tubes are also present. These features collectively indicate that the caves originated under Phreatic conditions by an ascending flow of water, probably of elevated temperature. Phreatic calcite spar, crystallized from water of elevated temperature, lines the cave walls. During the formation of the caves the Jurassic limestone aquifer was confined by impermeable cover. Three possible scenariosfor the origin of the caves are suggested. The firstscenario pointsto formation of the caves during the Palaeogene prior to the removal of the confining Cretaceous marls. The second connectsthe origin of the caves with regional palaeoflow driven by tectonic loading by Carpathian nappes to the south, while the third refers to local topographically driven palaeoflow. Both the second and third scenarios assume that the Polish Jura had a cover of Miocene impermeable clastics. All the scenarios account for the origin of the caves in Sokola Hill and explain the common occurrence of ascending caves throughout the Polish Jura. In the subsequentstages of evolution the caves were partly filled with various deposits. Conglomerates composed of Jurassic limestone clasts, quartz sands and sandstones are preserved as erosional remnants, locally covered by or interfingered with calcite flowstones. The clastic deposits were laid down by surface streams that invaded the caves earlier than 1.2 Ma. The caves were not invaded by water from Pleistocene glaciers, which is proved by the assemblage of heavy minerals in the cave clastics.

13

Cape Roberts Project: investigating the Cenozoic history of Antarctica

51%

Majewski W.

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tom 21

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nr 2

14

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

41%

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

Acta Geologica Polonica

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2009

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tom 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).

15

Biotic interaction between spionid polychaetes and bouchardiid brachiopods: Paleoecological, taphonomic and evolutionary implications

41%

Rodrigues S. C. , Simoes M.G. M. G. , Kowalewski M. , Petti M. A. V. , Nonato E. F. , Martinez S. , del Rio C. J.

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nr 4

EN

Shells of Bouchardia rosea (Brachiopoda, Rhynchonelliformea) are abundant in Late Holocene death assemblages of the Ubatuba Bight, Brazil, SW Atlantic. This genus is also known from multiple localities in the Cenozoic fossil record of South America. A total of 1211 valves of B. rosea, 2086 shells of sympatric bivalve mollusks (14 nearshore localities ranging in depth from 0 to 30 m), 80 shells of Bouchardia zitteli, San Julián Formation, Paleogene, Argentina, and 135 shells of Bouchardia transplatina, Camacho Formation, Neogene, Uruguay were examined for bioerosion traces. All examined bouchardiid shells represent shallow−water, subtropical marine settings. Out of 1211 brachiopod shells of B. rosea, 1201 represent dead individuals. A total of 149 dead specimens displayed polychaete traces (Caulostrepsis). Live polychaetes were found inside Caulostrepsis borings in 10 life−collected brachiopods, indicating a syn−vivo interaction (Caulostrepsis traces in dead shells of B. rosea were always empty). The long and coiled peristomial palps, large chaetae on both sides of the 5th segment, and flanged pygidium found in the polychaetes are characteristic of the polychaete genus Polydora (Spionidae). The fact that 100% of the Caulostrepsis found in living brachiopods were still inhabited by the trace−making spionids, whereas none was found in dead hosts, implies active biotic interaction between the two living organisms rather than colonization of dead brachiopod shells. The absence of blisters, the lack of valve/site stereotypy, and the fact that tubes open only externally are all suggestive of a commensal relationship. These data document a new host group (bouchardiid rhynchonelliform brachiopods) with which spionids can interact (interestingly, spionid−infested sympatric bivalves have not been found in the study area despite extensive sampling). The syn−vivo interaction indicates that substantial bioerosion may occur when the host is alive. Thus, the presence of such bioerosion traces on fossil shells need not imply a prolonged post−mortem exposure of shells on the sea floor. Also, none of the Paleogene and Neogene Bouchardia species included any ichnological evidence for spionid infestation. This indicates that the Spionidae/ Bouchardia association may be geologically young, although the lack of older records may also reflect limited sampling and/or taphonomic biases.

16

Nowe dane o wieku i petrologii kenozoicznych bazaltoidów dolnośląskich

41%

Badura J. , Pécskay Z. , Koszowska E. , Wolska A. , Zuchiewicz W. , Przybylski B.

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tom Vol. 54, nr 2

145-153

EN

Fifteen samples of basaltoid rocks have been analysed from the Lower Silesia, SW Poland, some of them from localities close to the Sudetic Marginal Fault. K-Ar datings have been made on whole rock samples, using the methodology applied by the Institute of Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary. Most of the samples give ages ranging between 21- 38 Ma, whereas that derived from a borehole in the Mokrzeszów Graben has been dated to 44 Ma. Another borehole sample (Jeżów Sudecki B-5), close to the Intrasudetic Fault, is of 59 Ma age. On the other hand, the supposedly "Quaternary" basaltoids from Dębowiec area fall into the interval of 29–30 Ma. The southeasternmost occurrences of the Lower Silesian basaltoids at Nowa Cerekiew display two generations of effusive activity: the older lava flows (26 Ma) are cut by plugs dated to 22 Ma. The Oligocene–Lower Miocene (26-33 Ma, 20'24 Ma) rocks represent alkali basalts and basanites. The alkali basalts consist of phenocrysts of olivine (chrysolite), altered to a different degree, and clinopyroxene (salite). In the matrix, clinopyroxene (Ti-salite), olivine (hyalosiderite), plagioclases (labradorite–andesine), and opaque minerals (titanomagnetite, ilmenite) occur. The basanites contain phenocrysts of altered olivine (chrysolite) and clinopyroxene (salite). Their matrix consists of clinopyroxene (Ti-salites), olivine (hyalosiderite), nepheline, plagioclases (bytownite–andesine), and opaque minerals. On the TAS diagram, samples of the studied basaltoids plot mainly in the fields of basalts and basanites/tephrites. The bimodality of some samples falling into two fields of basalts and basanites/nephelinites on the TiO2/Zr-Nb/y diagram results from their distinct geochemical signature.

17

Pre-Quaternary geomorphological history and geoheritage of Britain

41%

Migon P. , Goudie A.

Quaestiones Geographicae

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2012

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tom 31

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nr 1

18

Zapis lądowych etapów historii geologicznej Gór Świętokrzyskich w osadach i formach krasowych – wybrane przykłady

41%

Urban J.

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2013

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tom nr 454

77--101

PL

Artykuł prezentuje trzy przykłady interpretacji zdarzeń geologicznych oraz warunków paleogeograficznych i paleośrodowiskowych dokonanych na podstawie badań form krasowych w skałach węglanowych dewonu Gór Świętokrzyskich. Pierwszy relacjonowany kierunek badań dotyczy kopalnych form krasowych w dwu stanowiskach Wietrznia oraz Jaworznia i dokumentuje późnopermską ewolucję rzeźby i jej tektoniczne odmłodzenie na początku triasu. Następne interpretacje dotyczą form krasu kenozoicznego. Analiza przestrzennego rozwoju podziemnych systemów krasowych umożliwiła określenie poziomów stabilizacji bazy erozyjnej w neogenie. Najwyższy poziom krasowy (Łagów) był zapewne związany z poziomem neogeńskiego zbiornika morskiego w zapadlisku przedkarpackim. Z kolei badania osadów piaszczystych w wypełnieniach form krasowych, w tym przede wszystkim analiza obtoczenia i kształtu ziarn pozwoliły na wyróżnienie pięciu typów ziarn piasków o różnym pochodzeniu, w tym pochodzących z lokalnych zwietrzelin różnych skał oraz ziarn pirogenicznych. Analiza ta stała się podstawą do określenia zasięgu pokrywy dolnotriasowej, oceny rozwoju krasu w czwartorzędzie, a także do sformułowania sugestii dotyczących paleośrodowiska neogenu.

EN

The paper presents three examples of interpretations of geological events and paleogeographic and paleoenvironmental conditions made on the basis of studies of karst forms in Devonian carbonate rocks of the Świętokrzyskie (Holy Cross) Mountains, central Poland. The first study concerns paleokarst forms in two sites: Wietrznia and Jaworznia which record the Late Permian relief evolution and its tectonic rejuvenation at the beginning of the Triassic period. The next two interpretations concern the Cenozoic karst forms. Analysis of spatial development of subsurface karst systems made possible to determine of erosional base stabilization levels during the Neogene. The highest karst horizon (Łagów) was most probably related to the level of one of the transgressions in the Fore-Carpathian marine basin. In turn, the study of sand sediments filling karst forms, particularly analysis of roundness and shape of sand grains enables to distinguish five types of sand grains of different genesis, among which are grains originated from various local weathered rocks as well as pyrogenic particles. On the basis of this analysis the extent of Lower Triassic cover was determined and karst development during the Quaternary period was assessed, as well as some suggestions on the Neogene paleoenvironment were formulated.

19

First tillodont from India: Additional evidence for an early Eocene faunal connection between Europe and India?

41%

Rose K. D. , Rana R. S. , Sahni A. , Kumar K. , Singh L. , Smith T.

Acta Palaeontologica Polonica

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2009

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tom 54

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nr 2

351-355

EN

Vastan Lignite Mine in southeastern Gujarat, India, produces the oldest known Cenozoic land−mammals and the only early Eocene continental vertebrate fauna known from India (e.g., Bajpai et al. 2005; Rana et al. 2005, 2008; Rose et al. 2006, 2008, 2009; Smith et al. 2007; Rage et al. 2008). The fauna comes from the Cambay Shale Formation and has been dated as middle Ypresian (~52 Ma, early Cuisian) based on a common nummulitid foraminiferan from about 15 m above the vertebrate−producing layer (Sahni et al. 2006; Rana et al. 2008). However, a recent study of dinoflagellate cysts from the section suggests that the deposits may be as old as 54–55 Ma (Garg et al. 2008). Although some elements of the fauna, such as anthracobunids and lagomorphs, have Asian affinities, a surprising number of taxa among the snakes, bats, insectivores, primates, rodents, and artiodactyls appear to be most closely related to early Eocene European or North American taxa. This may simply reflect the poor state of knowledge of contemporary south Asian vertebrate faunas; alternatively, it might be evidence of previously unsuspected early Eocene faunal exchange between Europe and southwest Asia. We report here two teeth of a tillodont from Vastan Mine, which constitute the first record of the mammalian order Tillodontia known from India. Despite the much greater generic diversity of tillodonts in Asia than elsewhere, the Vastan tillodont shows clear affinities with Euramerican esthonychines.

20

Cenozoic tectonic evolution of the Poznań-Oleśnica Fault Zone, central-western Poland

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Widera M. , Ćwikliński W. , Karman R.

Acta Geologica Polonica

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2008

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tom Vol. 58, no. 4

455-471

EN

The Poznań-Oleśnica Fault Zone (P-OFZ) of central-west Poland is an over 150 km long, up to 10 km wide, and up to 200 m deep graben that developed during Early Oligocene to Pliocene times on the flank of the NE-dipping Fore-Sudetic Homocline. Fault systems of this extensional structure appear to reach pre-Zechstein basement in the area ofthe Fore-Sudetic Homocline that forms an integral part of the Bohemian Massif. The P-OFZ was affected by several stages of subsidence, separated by periods of inversion and/or tectonic quiescence between the Triassic and Cenozoic. Structurally, this dislocation zone can be linked with the Variscan faults, reactivated at that time. During the second half of the last century, the northern parts of the P-OFZ graben were intensively explored by cored boreholes because of their lignite content. Conventional back-stripping methods could not be applied to the tectonic analysis of the POFZ due to the limited thickness of the graben fill, its poor dating and the presence of relatively thick lignite seams. Therefore, phases of accelerated subsidence were determined by comparing the thickness of individual lithostratigraphic units within the graben and on its flanks. The total subsidence of the different graben segments was quantified by determining the aggradation coefficient (AC) and by taking the consolidation coefficient (CC) of lignite seams into consideration. Subsidence analyses indicate that the initial Early Oligocene extensional phase of the P-OFZ was followed by an Early.Middle Miocene extensional subsidence phase and a probably latest Miocene.Pliocene final extensional phase.