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1

The K-Pg boundary section at Nasiłów, Poland : stratigraphic reassessment based on foraminifers, dinoflagellate cysts and palaeomagnetism

Remin Zbyszek, Cyglicki Michał, Barski Marcin, Dubicka Zofia, Roszkowska-Remin Joanna

Geological Quarterly

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2021

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Vol. 65, No. 3

art. no. 45

EN

The Nasiłów section represents the uppermost part of the Middle Vistula River section, a classical Polish extra-Carpathian Cretaceous section, and gives access to the Cretaceous-Paleogene (K-Pg) boundary interval. Despite many papers that have been published so far, our newly collected data shed new light on the completeness of biostratigraphic and sedimentary records of the K-Pg at that site. The Nasiłów section encompasses the upper Maastrichtian regional XII and XIII foraminiferal assemblage zones and the lower Danian P0?-Pα standard planktonic foraminiferal zones. The K-Pg boundary is placed at the top of a phosphatic layer. The grey marly chalk unit, never before subjected to examination of biostratigraphically important taxa, displays blooms of guembelitrids pointing to the uppermost Maastrichtian (XIII foraminiferal assemblage Zone) as well as of planktonic and benthic foraminifers of a reduced test size. Such foraminiferal dwarfism is commonly observed near the end of the Cretaceous and interpreted as a response to the Deccan volcanism (possible 2nd phase) that caused climate changes and ocean acidification. The terminal Maastrichtian age of the marly chalk unit is additionally supported by an acme of the dinoflagellate cyst Palinodinium grallator, together with Tallasiphora pelagica and Disphaerogena carposphaeropsis. The “Greensand”, a distinct glauconite-quartz sand unit, contains exclusively terminal Maastrichtian planktonic foraminifers and dinoflagellate cyst assemblages. Individual specimens of Danian age are interpreted to be either an effect of contamination or were translocated down by burrowers into the Greensand. The lowermost portion of the Siwak (informal lithostratigraphic unit) demonstrates an early Danian age based on the co-occurrence of the common planktonic foraminifers Globoconusa daubjergensis, Guembelitria cretacea, Muricohedbergella monmouthensis, M. planispira, Planoheterohelix globulosa, Parvularuglobigerina extensa and P. alabamensis. The last occurrence of Palynodinium grallator and the first occurrences of Carptella cornuta and Senoniasphaera inornata, recorded directly above the phosphatic layer, support the same age assignment. The new palaeomagnetic data cannot prove remagnetization at the boundary interval, in contrast to previous research which gave support to a hiatus in the critical interval.

2

The loess section in Wąchock as the key site of Vistulian loesses and palaeosols in the Holy Cross Mountains (Poland)

Dzierżek Jan, Lindner Leszek, Nawrocki Jerzy

Geological Quarterly

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2020

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Vol. 64, No. 2

252--262

EN

The Wąchock section (N part of the Holy Cross Mountains) is bipartite, with a sub-loess lower part and a loess upper part. The sub-loess part lying on Lower Triassic sandstones includes fluvial, glacial and ice-dammed lake deposits, TL-dated at 352 ky BP to 157 ±23 ky BP. They represent the Mazovian (MIS 11) (Zbójnian?, MIS 9?) Interglacial and the Odranian Glaciation (MIS 6). The upper part comprises loesses intercalated with palaeosols, which reach a total thickness of 9 m and have TL ages at 148 ±23 ky BP to 15.8 ±8 ky BP. This part of the succession begins with horizon B of a brown soil from the Eemian Interglacial (MIS 5e) with an interstadial black soil from the oldest Vistulian (MIS 5c). Four younger loess horizons from the middle and younger Vistulian occur above; loesses with arctic and tundra palaeosols correspond to younger isotope stages (MIS 5b-MIS 2). The loess and palaeosol horizons distinguished in Wąchock were correlated with loess sections in Poland (Zwierzyniec and Polanów Samborzecki) and western Ukraine (Kolodiiv 3), showing large similitarities of both loesses and palaeosols. Due to this, the Wąchock site is proposed as a one of key sections for Vistulian loess sequences not only in the Holy Cross Mts. region but also in Central Europe. Palaeomagnetic studies of the Wąchock loesses have registerered palaeomagnetic inclinations with values lower than the average values expected in this locality (63°).

3

New evidences of Holocene tectonic and volcanic activity of the western part of Lake Sevan (Armenia)

Avagyan Ara, Sahakyan Lilit, Meliksetian Khachatur, Karakhanyan Arkadi, Lavrushin Vasily, Atalyan Tatul, Hovakimyan Hayk, Avagyan Seda, Tozalakyan Petros, Shalaeva Evgenia, Chatainger Christine, Sokolov Sergey, Sahakov Arkadi, Alaverdyan Gagik

Geological Quarterly

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2020

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Vol. 64, No. 2

288--303

EN

The purpose of this paper is to present new data on active geological processes in the Lake Sevan Basin and to show its multidisciplinary aspects. The investigations of its structures, recent lake sediments, and lake floor gas emission allow a better understanding of the history of geological development and the recent tectonic and volcanic activity of the basin. This paper summarizes underwater investigations of active geological features of Lake Sevan, undertaken for the first time in Armenia. More than 30 aligned underwater-source related gas emission points were discovered. The gas contains carbon dioxide of volcanic or volcanogenic-metamorphogenic origin and can be related to unloading of deep fluid systems. This allows defining the Noratus-Kanagegh Fault segment trace below the recent Lake Sevan floor sediments. The discovery of the subaqueous segment of active fault shows the presence of another natural hazard of lake tsunami related to possible future co-seismic rupture. The recent sediments of the northwestern Lake Sevan coastline are sandwiched between two blocky lava flows. The radiocarbon dating of bones of bovine mammals (with entire skull), found ~15 cm from the cover of the lake sediments, suggests that the upper blocky basaltic-andesite layer can be a result of eruption younger than ~3400 years BP. About 80 m of the Noratus sequence sediments have been sampled for palaeomagnetic study and the age of 3.1-2.3 Ma for the lower part (42 m) is obtained. The upper and post-Gelasian activity of the Noratus-Kanagegh Fault is proven by a cross-cutscoria layer of 2.30 ±0.15 Ma K/Ar age.

4

Towards a consistent Oxfordian/Kimmeridgian global boundary: current state of knowledge

Wierzbowski A., Atrops F., Grabowski J., Hounslow M., Matyja B. A., Olóriz F., Page K., Parent H., Rogov M. A., Schweigert G., Villaseñor A. B., Wierzbowski H., Wright J. K.

Volumina Jurassica

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2016

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Vol. 14, no. 1

15--49

EN

New data are presented in relation to the worldwide definition of the Oxfordian/Kimmeridgian boundary, i.e. the base of the Kimmeridgian Stage. This data, mostly acquired in the past decade, supports the 2006 proposal to make the uniform boundary of the stages in the Flodigarry section at Staffin Bay on the Isle of Skye, northern Scotland. This boundary is based on the Subboreal-Boreal ammonite successions, and it is distinguished by the Pictonia flodigarriensis horizon at the base of the Subboreal Baylei Zone, and which corresponds precisely to the base of the Boreal Bauhini Zone. The boundary lies in the 0.16 m interval (1.24–1.08 m) below bed 36 in sections F6 at Flodigarry and it is thus proposed as the GSSP for the Oxfordian/ Kimmeridgian boundary. This boundary is recognized also by other stratigraphical data – palaeontological, geochemical and palaeomagnetic (including its well documented position close to the boundary between magnetozones F3n, and F3r which is placed in the 0.20 m interval – 1.28 m to 1.48 m below bed 36 – the latter corresponding to marine magnetic anomaly M26r). The boundary is clearly recognizable also in other sections of the Subboreal and Boreal areas discussed in the study, including southern England, Pomerania and the Peri-Baltic Syneclise, Russian Platform, Northern Central Siberia, Franz-Josef Land, Barents Sea and Norwegian Sea. It can be recognized also in the Submediterranean-Mediterranean areas of Europe and Asia where it correlates with the boundary between the Hypselum and the Bimmamatum ammonite zones. The changes in ammonite faunas at the boundary of these ammonite zones – mostly of ammonites of the families Aspidoceratidae and Oppeliidae – also enables the recognition of the boundary in the Tethyan and Indo-Pacific areas – such as the central part of the Americas (Cuba, Mexico), southern America, and southern parts of Asia. The climatic and environmental changes near to the Oxfordian/Kimmeridgian boundary discussed in the study relate mostly to the European areas. They show that very unstable environments at the end of the Oxfordian were subsequently replaced by more stable conditions representing a generally warming trend during the earliest Kimmeridgian. The definition of the boundary between the Oxfordian and Kimmeridgian as given in this study results in its wide correlation potential and means that it can be recognized in the different marine successions of the World.

5

A new stratigraphic position of some Early Pleistocene deposits in central Poland

Bujak Ł., Woronko B., Winter H., Marcinkowski B., Werner T., Stachowicz-Rybka R., Żarski M., Woźniak P. P., Rosowiecka O.

Geological Quarterly

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2016

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Vol. 60, No. 1

238--251

EN

A new borehole in Rożce (SW Mazovian Lowland) drilled in 2012, combined with a wide variety of research methods (palaeomagnetism, palynological analysis, studies of plant macroremains and textural features of deposits) shed new light on the age and stratigraphic position of the Early Pleistocene deposits, formerly assigned as the Lower Pleistocene. The study focuses on the deposits from 50.7-104.0 m depth, between glacial till of the Nidanian Glaciation (ca. 0.9 Ma) and the Poznań Clays (ca. 5.322 Ma). The deposits situated directly underneath the till (50.7-60.2 m) are related to the Nidanian Glaciation and show a reversed polarity and correlate with the end of the Matuyama Epoch. The deposits from 60.2-104.0 m depth were accumulated during the Early Pliocene, i.e. approximately 5.332-4.6 million years ago. They appear to correlate with the middle part of the Gilbert Palaeomagnetic Epoch and thus they are considerably older than previously thought. The cored section indicates a stratigraphic gap of about 3.5 Ma from the Lower Pliocene to the first advance of the Scandinavian ice sheets into Poland, which are thought to have occurred in the early Middle Pleistocene. The analysed deposits accumulated under variable climatic conditions showing two periods with significant aridity alternated with two periods of increased humidity. Deposits of the arid periods contain no pollen, butaeolian sand quartz grains are found. During periods of more humid climate the area was covered by various types of mixed forest.

6

Palaeomagnetism of Middle Ordovician Carbonate Sequence, Vaivara Sinimäed Area, Northeast Estonia, Baltica

Plado J., Preeden U., Joeleht A., Pesonen L. J., Mertanen S.

Acta Geophysica

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2016

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Vol. 64, no. 5

1391--1411

EN

The hill range of Vaivara Sinimäed in northeast Estonia consists of several narrow east- to northeast-trending glaciotectonic fold structures. The folds include tilted (dips 4-75°) Middle Ordovician (early Darriwilian) layered carbonate strata that were studied by mineralogical, palaeomagnetic, and rock magnetic methods in order to specify the postsedimentational history of the area and to obtain a better control over the palaeogeographic position of Baltica during the Ordovician. Mineralogical studies revealed that (titano)magnetite, hematite, and goethite are carriers of magnetization. Based on data from 5 sites that positively passed a DC tilt test, a south-easterly downward directed component A (Dref = 154.6°± 15.3°, Iref = 60.9°± 9.7°) was identified. The component is carried by (titano)magnetite, dates to the Middle Ordovician (Plat = 17.9°, Plon = 47.3°, K = 46.7, A95 = 11.3°), and places Baltica at mid-southerly latitudes. Observations suggest that in sites that do not pass the tilt test, the glaciotectonic event has caused some rotation of blocks around their vertical axis.

7

Paleomagnetyzm, a odrodzenie teorii Wegenera : synopsis

Lewandowski M.

Przegląd Geologiczny

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2015

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Vol. 63, nr 11

1284--1291

EN

This article envisages turning points in the process of implementation of the continental drift hypothesis to the knowledge on the development of the Earth’s crust. In the author’s opinion, they were most of all linked with the development of palaeomagnetism, a discipline integrating methods of geophysics and geology. Alfred Wegener has been included into the Science Hall of Fame, thanks to studies by Brunhes on inversely magnetized rocks of Auvergne, discovery of geomagnetic inversions of Icelandic lavas by Hospers, polar wander paths construction by Creer and Irving, ending with Pangea reconstruction by Bullard, Everett and Smith, bridging the concept of continental drift and plate tectonics theory.

8

Palaeomagnetism of Late Cretaceous-Paleocene igneous rocks from the western part of the Antarctic Peninsula (Argentine Islands Archipelago)

Bakhmutov V., Shpyra V.

Geological Quarterly

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2011

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Vol. 55, No. 4

285-300

EN

A collection of 360 oriented samples of igneous rocks from the western part of the Antarctic Peninsula (Argentine Islands Archipelago, Penola Strait area), has yielded well-defined palaeomagnetic directions. Age determinations by various methods showed a Late Cretaceous-Paleocene time interval for the rocks studied. The characteristic remanent magnetisation (ChRM) was isolated by a stepwise thermal demagnetisation mostly in the temperature interval 450-580 degreesC. It is evidently a primary magnetisation. The rocks along the coastline of the western part of the Antarctic Peninsula (AP) were emplaced during the Cretaceous Normal Superchron while the rocks from the islands with reversed polarity are of Paleocene. New Cretaceous (112-85 Ma) and Paleocene (60 Ma) palaeomagnetic poles for the passive continental margin of the Antarctic Peninsula fit well with a synthetic East Antarctica apparent polar wander path and confirms that the AP did not undergo latitudinal displacement for the last 100 Ma. The palaeomagnetic pole for 60 Ma shows a slight shift from palaeopoles obtained for the South Shetland Islands which implies that the South Shetland block is characterized by own tectonic evolution and probable anticlockwise rotation during the Paleocene.

9

Palaeomagnetic and petromagnetic study of uranium-bearing polymetallic-fluorite mineralization in the Orlík-Kladsko crystalline complex (near Kletno, Lower Silesia, Poland)

Sobień K., Nawrocki J.

Geological Quarterly

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2010

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Vol. 54, No 3

325-336

EN

Palaeomagnetic measurements of polymetallic-uranium ore in the Old Uranium Kletno Mine were carried out. Thermal and alternating field (AF) demagnetizations of the rocks studied (fluorite and quartz veins, cataclased gneisses, calcareous-silicate rocks with epidote/grossular) enabled isolation of two well-defined magnetization components. A normal polarity palaeomagnetic direction was preserved in magnetite and coarse hematite, whereas reversed polarity is linked with fine hematite grains. Both statistically well-defined components do not differ within limits of error. The calculated mean palaeomagnetic pole was compared with the European apparent polar wander path. This comparison points unambiguously, within limits of statistical error, for an Early Cretaceous to Paleogene age of characteristic components of magnetization. Consequently this age limit constrains the time of uranium-bearing polymetallic-fluorite mineralisation.

10

Palaeomagnetic age constraints indicate post-Varis can orgin of massive breccia in Wietrznia Quarry (Holy Cross Mountains, Central Poland)

Szaniawski R., Lewandowski M.

Geological Quarterly

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2009

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Vol. 53, No 3

357-362

EN

Palaeomagnetic study has been carried out to resolve the controversy over the age and origin of the massive breccia body exposed in Wietrznia Quarry in the Holy Cross Mountains. The breccia studied consists of variously sized angular fragments of Frasnian and Fammenian limestone and shale infilling a palaeodepression within Frasnian limestone. Forthis purpose, the conglomerate test has been applied that enables determination of the relative age of remanence components and formation of the breccia. Palaeomagnetic analysis of breccia clasts reveals the presence of two characteristic components of magnetization. The observed components are akin to those previously described from in situ rocks at Wietrznia Quarry and from other Devonian carbonates from the Holy Cross Mountains. Such components have been interpreted as early synfolding and postfolding over prints of Viséan and Early Permian age. The palaeomagnetic conglomerate test performed in this study are positive results, indicating that the breccia postdates both components. This implies that the breccia is not of synsedimentary character and postdates Variscan de formation.

11

Wyniki badań paleomagnetycznych osadów jeziornych z profilu Czarnucha (Równina Augustowska, północno-wschodnia Polska)

Nawrocki J.

Biuletyn Państwowego Instytutu Geologicznego

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2009

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nr 435

69--74

PL

Przedmiotem badań paleomagnetycznych było 51 fragmentów rdzenia z otworu wiertniczego Czarnucha. Badane osady jeziorne zostały w głównej swej masie przemagnesowane w wyniku procesów diagenetycznych, prowadzących do powstania wtórnych nośników namagnesowania. Pojedyncze próbki o inklinacji ujemnej, znajdujące się głównie w dolnej części profilu, reprezentują najprawdopodobniej pierwotny zapis paleomagnetyczny. Ich obecność może wskazywać, że co najmniej ta część profilu powstawała w chronie odwrotnego namagnesowania Matuyama.

EN

Paleomagnetic analysis was performed on 51 core samples from the Czarnucha borehole. The lacustrine deposits were mostly remagnetized as a results of diagenetic processes leading to the formation of secondary magnetization carries. Single samples of negative inclination, found mainly in the lower portion of the section, most likely represents the original palaeomagnetic record. Their presence can indicate that at least part of the sequence was deposited during the Matuyama chrone of reverse magnetization.

12

Synthrusting remagnetization of the Krizna nappe: high resolution palaeo- and rock magnetic study in the Strazovce section, Strazovske vrchy Mts, Central West Carpathians (Slovakia)

Grabowski J., Michalik J., Szaniawski R., Grotek I.

Acta Geologica Polonica

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2009

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Vol. 59, no. 2

137-155

EN

Palaeomagnetic studies of the uppermost Jurassic to lower Cretaceous pelagic carbonates in the Krizna nappe in the Strazovske vrchy Mts (Central West Carpathians, Slovakia) revealed the presence of secondary magnetite-related magnetization of exclusively normal polarity (component B), which was most probably acquired during the thrusting episode in the late Cretaceous. Three formations exposed in the Strazovce section were the subject of investigation: Jasenina Kimmeridgian.Tithonian), Osnica (Lower.Middle Berriasian) and Mraznica (Upper Berriasian.Hauterivian). Component B is ubiquitous throughout the section but is strongest in the Mraznica Formation. This formation contains a lot of superparamagnetic particles and shows rock magnetic characteristics typical of chemically remagnetized carbonates. The remaining two formations, although also remagnetized, bear traces of an older, probably primary magnetization (component C). The fold test for component B is apparently positive; however the inclination in pre-folding coordinates is too steep for any expected palaeoinclination of Jurassic to recent age. Additional tectonic correction must be applied to match the palaeoinclinations with expected values. Although there is some uncertainty in this additional correction, all plausible options suggest that the rocks must have been magnetized when they dipped in the opposite direction to the thrusting direction. This interpretation is concordant with the internal tectonics of the Krizna nappe, consisting of imbricated units of duplex-type structure.

13

Palaeomagnetic age of remagnetizations in Silurian dolomites, Rástla quarry (Central Estonia)

Plado J., Preeden U., Puura V., Pesonen L. J., Kirsimäe K., Pani T., Elbra T.

Geological Quarterly

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2008

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Vol. 52, No 3

213-213

EN

Alternating field and thermal demagnetization of dolomite samples from the Silurian (Llandovery) horizontally-bedded sequence of central Estonia reveal two secondary magnetization components (A and B) both of chemical origin. A low-coercivity (demagnetized at -50 mT) component A (D = 60.7°, I = 7.7°, alfa95 = 16.6°) with high dispersion (k = 14.2), yields a palaeopole at 18.2°N and 139.5°E that points towards the Late Devonian — Mississipian segment of the Baltica APWP (Apparent Polar WanderPath). A high-coercivity component B (D = 13.5°, I = 60.7°, k = 67.0, alfa 95 = 4.7°) carries both normal and reversed polarities. Comparing the palaeopole (71.1°N and 173.3°E) with the European APWP reveals a Cretaceous age. These two remagnetizations are linked to mineral assemblages of magnetite and maghemite (A), and hematite (B) determined from mineralogical (X-ray, SEM and optical microscopy) and rock magnetic (acquisition and thermal demagnetization of a 3-component IRM; Lowrie-test) studies. The results suggest that the first (A) Palaeozoic remagnetization was caused by low-temperature hydrothermal circulation due to the influence of the Caledonian (more likely) or Hercynian Orogeny after the diagenetic dolomitization of carbon ates. Hematite, carrying the component B, and goethite, are the latest ferromagnetic minerals that have precipitated into the existing pore space (hematite) and walls of microscopic fractures (goethite) that opened to allow ac cess for oxygen-rich fluids during the Late Mesozoic.

14

New palaeomagnetic results from the Polish part of the Pieniny Klippen Belt, Carpathians - ev i dence for the palaeogeographic position of the Czorsztyn Ridge in the Mesozoic

Grabowski J., Krobicki M., Sobień K.

Geological Quarterly

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2008

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Vol. 52, No 1

31-44

EN

Middle and Upper Juras siclime stones from the Polish part of the Pieniny Klippen Belt (PKB) were palaeomagnetically studied at six localities. The Middle Jurassic redcrinoidal lime stones of the Krupianka Lime stone Formation and Oxfordian radiolarites of the Czajakowa Radiolarite Formation, sampled in the eastern part of the Polish section of the PKB, were ei ther unsuitable for palaeomagnetic studies (Krupianka Klippe) or remagnetized in the Neogene (Baba and Zaskalskie-Bodnarówka klippen). The Czorsztyn Lime stone Formation was investigated at the localities of Krempachy (up per Mid dle Jurassic: upper most Bajocian?-Callovian?), Obłazowa (mid dle Oxfordian) and Rogoźnik (Rogoża Coquina Member- Kimmeridgian). A pre-folding, mixed polarity component of magnetization was revealed, which was interpreted as primary. Palaeoinclinations differ slightly, but not significantly, between localities. The palaeolatitude of the Polish sector of the PKB, averaged for the Middle/Upper Jurassic, amounts to 22°N (± 5°). It corresponds to the estimated palaeolatitudes of the northern margins of the Adriatic microplate and indicates a significantly large distance from the European plate. There is a growing evidence for a northward drift of the PKB in the Late Jurassic up to the earliest Cretaceous: from the palaeolatitude of 22°N in the Late Jurassic up to 28°N in the western part, in Po land/W Slovakia, and from 28° up to 36°N in the eastern part of the PKB in Ukraine. Systematically lower palaeolatitudes in the west combined with exsting palaeogeographic and geotectonic scenarios would account for a NE-SW orientation of the Czorsztyn Ridge in the Late Juras sic/earliest Cretaceous.

15

New palaeomagnetic data from the Palaeozoic carbonates of the Moravo-Silesian Zone (Czech Republic): evidence for a timing and origin of the late Variscan remagnetization

Grabowski J., Bábek O., Nawrocki J., Tomek Č.

Geological Quarterly

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2008

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Vol. 52, No 4

321-321

EN

Palaeomagnetic studies were carried out in the Devonian–Early Carboniferous carbonates of the Moravo-Silesian Zone — MSZ (Czech Republic) in order to evaluate the timing and origin of late Variscan magnetic over printing. Sampling localities were spread out along the strike of the MSZ from the SW to NE. Previously published thermal maturity data have demonstrated a significant gradient from SW (burial temperatures 150–200gradeC) to NE of the region (250–300gradeC). A late Variscan remagnetization direction (component A), carried by magnetite, was identified in 6 localities. Three phases of the remagnetization in the MSZ might be distinguished which might be assigned to Early to Late Carboniferous, Late Carboniferous and Early Permian. They are coeval with remagnetization events distinguished in Ardennes. A correlation exists between thermal indices and un blocking temperature spectra of component A. Thermal activation nomograms show that component A might be either a thermoviscous or thermochemical remanent magnetization acquired due to a thermal event (deep burial) of 1–10 My duration and stabilized during subsequent uplift. A more ancient component B, identified in the SW part, previously interpreted as primary, is shown to be a synfolding remagnetisation. Itindicates 70grade clockwise rotations before the acquis tion of the component A .

16

Palaeomagnetic studies of the loess-palaeosol sequence from the Kolodiiv section (East Carpathian Foreland, Ukraine)

Nawrocki J., Boguckyj A., Łanczont M.

Geological Quarterly

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2007

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Vol. 51, No 2

161-166

EN

The Upper Pleistocene loess-palaeosol sequence from the Kolodiiv section (East Carpathian Fore land) has been palaeomagnetically studied. Almost all samples displayed moderate to high positive palaeomagnetic inclinations and declinations en closed between 320° and 40°. How ever, one sample from the fossil soil of the last inter glacial pedocomplex (at 16.6 m pro file depth) was reverse magnetized and there fore can be correlated with the Blake Palaeomagnetic Event. Consequently that palaeosol can be related to (Oxygen Isotope Stage) OIS 5e1. An other sample from the Dubno 1 interstadial palaeosol demonstrated southern declination and significant lowering of inclination (up to 40°). This might be a record of the Laschamp Palaeomagnetic Event or of any Late Pleistocene palaeomagnetic excursion. The magnetic susceptibility and anhysteretic remanent magnetization data reflect the presence of several soils forming during the warm conditions of OIS 5 and the complex nature of the Eemian warming. Two palaeosols that developed between ca.115 ka and 120 ka indicate at least two climatic optima during the Eemian. High values of magnetic susceptibility (up to 300 Ą 10-6 SI units) noted in the middle of the section that contains slump deposits (9.5 m to 11m of depth) suggest that this material was derived from older soils of inter glacial type.

17

Radiometric dating of the Tertiary volcanics in Lower Silesia, Poland. V. K-Ar and palaeomagnetic data from Late Oligocene to Early Miocene basaltic volcanics of the North-Sudetic Depression

Birkenmajer K., Pécskay Z., Grabowski J., Lorenc M. W., Zagożdżon P. P.

Annales Societatis Geologorum Poloniae

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2007

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Vol. 77, No 1

1-16

EN

This is the fifth contribution to geochronological, petrologic-geochemical and palaeomagnetic studies of the Tertiary basaltoids of Lower Silesia, Poland. It covers the area of the North-Sudetic Depression close to its contact with the Fore-Sudetic Block (6 new sites). The oldest K-Ar date was obtained from basanite plug at Sichów (BP-34: 27.80ą1.27 Ma) located exactly on the Sudetic Marginal Fault. It determines the age of the fault as Late Oligocene. Five other sites (BP-35-39) yielded radiometric ages between 20.07ą0.90 Ma and 18.72ą0.81 Ma (Early Miocene). The volcanics investigated are typical within-plate basaltoids represented by ankaratrite and basanite. The Late Oligocene Sichów intrusion (BP-34) is normally magnetized, the Early Miocene basaltic rocks (ankaratrite BP-39 and basanites: BP-35-38) reveal reversed magnetization.

PL

Piąta część datowań K-Ar i badań paleomagnetycznych trzeciorzędowych wulkanitów Dolnego Śląska obejmuje odsłonięcia tych skał w obszarze niecki północnosudeckiej, w sąsiedztwie sudeckiego uskoku brzeżnego. Otrzymano sześć dat w granicach 27,80š1,27 Ma (późny oligocen: Sichów, BP-34) – 18,72š0,81 Ma (niższy miocen = burdygał: Wilków, BP-37). Późnooligoceńska data dla ankaratrytowego czopu Sichowa (BP-34), który znajduje się na sudeckim uskoku brzeżnym, określa taki wiek tego uskoku. Zbadane skały bazaltowe – bazanity i ankaratryty (melabazanity) są typowymi przedstawicielami wulkanizmu sródpłytowego. Skład chemiczny ogniska magmowego podlegał ewolucji, co przejawiło się w badanych skałach wzrostem zawartości potasu i kobaltu w okresie czasu między wyższym oligocenem a niższym miocenem. Czopy ankaratrytu i bazanitu zostały zbadane pod względem paleomagnetycznym: najstarszy z nich, 27,80 Ma (BP-34: ankaratryt) wykazuje namagnesowanie normalne, pozostałe pięć, 20,07–18,72 Ma (BP-39: ankaratryt; BP-35–38 – bazanity) wykazuje namagnesowanie odwrócone.

18

New palaeomagnetic results from the Polish part of the Pieniny Klippen Belt: further evidence for low palaeolatitudes in the Late Jurassic

Grabowski J., Krobicki M., Sobień K.

Volumina Jurassica

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2006

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Vol. 4, no. 1

44-44

EN

Middle and Upper Jurassic limestones from the Polish part of the Pieniny Klippen Belt were palaeomagnetically investigated. Samples were collected from four localities: Obłazowa Klippe (Czorsztyn Limestone Formation - Upper Oxfordian), Rogoźnik Klippe (Rogoża Coquina Member of the Czorsztyn Limestone Formation - Kimmeridgian), Krupianka Creek and Baba Klippe (Krupianka Limestone Formation - Upper Bajocian). During thermal demagnetization samples from Rogoźnik Klippe and Obłazowa Klippe indicate one distinct, high temperature component with normal polarity, an inclination ca 40° and a counterclockwise rotated declination of about 20° from the present north. Because the fold tests between Obłazowa and Rogoźnik are positive, we conclude that the obtained direction is pre-folding. Good quality data enable determination of the magnetic remanence age as Mesozoic, Late Jurassic or Early Cretaceous and a palaeolatitude calculation of 22 ± 5°. It might be compared to recently obtained data from the Ukraine section (Veliky Kamenets) of the Pieniny Klippen Belt (Lewandowski et al. 2005), where palaeolatitude for the Late Jurassic (Oxfordian) was estimated as 28 ± 6°. In Baba Klippe one direction with reversed polarity and steep inclination has been defined. Fold test was impossible because the layers are in a horizontal position, but we assume that it is secondary. Component with reversed polarity was acquired probably during thermal changes of rocks related to andesite intrusion (about 300 m to the south) of Sarmatian age. This direction resembles Neogene data with reversed polarity acquired from the Pieniny andesites (Birkenmajer & Nairn 1968; Marton et al. 2004).

19

Lithology and palaeomagnetic record of Late Weichselian varved clays from NW Russia

Bakhmutov V., Kolka V., Yevzerov V.

Geological Quarterly

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2006

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Vol. 50, No. 3

353-368

EN

A lithological and palaeomagnetic analysis of Late Weichselian glaciolacustrine deposits from two ancient periglacial lakes was carried out in the valley of the Shuja (S Karelia) and Ust-Pjalka (S-E Kola Peninsula) rivers, NW Russia. The rhythmic structure of the varved clays is interpreted as turbiditic with systematic differences between the proximal and distal areas of accumulation. In the proximal area the textural and structural properties of the deposits towards both distal and (partly) lateral directions are described. It is shown that the proximal varve successions are incomplete while distally they are continuous. The accumulation of one varve (DE rhythm, second order cycle) during one year is consistent with palaeomagnetic data. Significant differences in magnetic parameters and in the palaeomagnetic "records" of declination-inclination between proximal and distal varves are established. Analysis of palaeomagnetic properties was combined with lithological analysis in all sections. Locally, the varved clays in the proximal area could be used for palaeomagnetic research. Taking into account the erosion of underlying deposits by turbidity currents and inclination shallowing, these sediments could not precisely record palaeosecular variation (PSV). The distal varved clays (represented by the DE rhythms) are clearly most useful both for varve-clay chronology and PSV recovery. The palaeomagnetic declination and inclination records are correlated with chrono- and magnetostratigraphy scheme of NW Russia. This paper also examines lithology-dependent "inclination error" and anisotropy of magnetic susceptibility in glaciolacustrine sediments.

20

New Late Vendian palaeogeography of Baltica and the TESZ

Nawrocki J., Boguckyj A., Katinas V.

Geological Quarterly

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2004

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Vol. 48, No 4

309--316

EN

New palaeomagnetic poles obtained from the Vendian tuffs and basalts of western Ukraine indicate the necessity of a substantial revision of the Late Vendian-Early Cambrian palaeogeography of the Baltic plate. The palaeopole calculated for the most stable component isolated from the Vendian tuffs and basalts is far away from the Vendian-Cambrian apparent polar wander path (APWP), constructed on the basis of Scandinavian poles but is very close to the pole recently isolated from the Vendian sediments of the White Sea Region. Depending on the polarity of the newly-determined Late Vendian pole, two palaeogeographic models of the Baltic plate in the Late Vendian-Early Cambrian are possible. In our preferred model the Baltic plate moved at that time from the moderate southern latitudes to the equator rotating anticlockwise of ca. 120 degrees Celsius. This reconstruction explains the geological structures of the marginal zones of Baltica better than the previously proposed stationary model of the Late Vendian-Cambrian Baltica. According to the new late Vendian palaeogeographic scenario, the European, passive margin of Baltica was separated from an active, Avalonian margin of Gondwana. The Late Neoproterozoic tectonic structures of the Brunovistulian Terrane and the Małopolska Block were developed near the present day southwestern corner of Baltica that was tectonically active at that time. Alternative reconstruction shows the Baltic platemoving from the moderate northern latitudes in the Vendian, crossing palaeoequator in the latest Vendian, and reaching moderate southern palaeolatitudes in the Late Cambrian. This model, however, would have required exceptionally high plate velocity (ca. 33 cm/year).