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Wyświetlanie 1-15 z 92
Tytuł:
Effects of different shelf storage conditions of chicory on the colour change using digital image processing
Autorzy:
Zhang, M.
De Baerdemaeker, J.
De Busscher, R.
Schrevens, E.
Powiązania:
https://bibliotekanauki.pl/articles/26058.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
chicory
colour change
head
Cichorium intybus
leaf
storage condition
shelf storage
Źródło:
International Agrophysics; 1996, 10, 1
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluating the Frasnian-Famennian mass extinction: Comparing brachiopod faunas
Autorzy:
Copper, P
Powiązania:
https://bibliotekanauki.pl/articles/22494.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
brachiopod fauna
global loss
Palmatolepis linguiformis
climate cycle
Palmatolepis rhenana
Atrypida
water setting
mass extinction
Brachiopoda
South America
Famennian
shelf area
Frasnian
atrypid extinction
Late Devonian
Devonian
reef habitat
paleontology
Opis:
The Frasnian-Famennian (F-F) mass extinctions saw the global loss of all genera belonging to the tropically confined order Atrypida (and Pentamerida): though Famennian forms have been reported in the literafure, none can be confirmed. Losses were more severe during the Givetian (including the extinction of the suborder Davidsoniidina, and the reduction of the suborder Lissatrypidina to a single genus), but origination rates in the remaining suborder surviving into the Frasnian kept the group alive, though much reduced in biodiversity from the late Early and Middle Devonian. In the terminal phases of the late Palmatolepis rhenana and P. linguiformis zones at the end of the Frasnian, during which the last few Atrypidae dechned, no new genera originated, and thus the Atrypida were extirpated. There is no evidence for an abrupt termination of all lineages at the F-F boundary, nor that the Atrypida were abundant at this time, since all groups were in decline and impoverished. Atypida were well established in dysaerobic, muddy substrate, reef lagoonal and off-reef deeper water settings in the late Givetian and Frasnian, alongside a range of brachiopod orders which sailed through the F-F boundary: tropical shelf anoxia or hypoxia seems implausible as a cause for atrypid extinction. Glacial-interglacial climate cycles recorded in South America for the Late Devonian, and their synchronous global cooling effect in low latitudes, as well as loss of the reef habitat and shelf area reduction, remain as the most likely combined scenarios for the mass extinction events.
Źródło:
Acta Palaeontologica Polonica; 1998, 43, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Genetic analysis of selected tomato [Lycopersicon esculentum Mill.] traits in crosses between cultivated lines and the nor mutant
Autorzy:
Seroczynska, A
Niemirowicz-Szczytt, K.
Powiązania:
https://bibliotekanauki.pl/articles/2044241.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inheritance
shelf life
polygalacturonase gene
Lycopersicon esculentum
nor gene
mutant
heterozygote
tomato breeding
yield
hybrid
ripening
cross
earliness
genetic analysis
fruit weight
Opis:
The aim of the study was to investigate the delayed ripening caused by the nor gene and its possible interaction with selected traits observed in two combinations, namely, Dw₄ x nor and C36 x nor. The lines Dw₄ and C36 differed from each other in the majority of examined characters. There was no significant effect of reciprocal crosses on these characters (total yield, number of fruits, fruit weight, locule number, earliness and fruit shelf life). In Dw₄ x nor fruit weight was inherited with incomplete dominance of small fruit, while in C36 x nor the inheritance proved to be intermediate. This important statement made it possible to distinguish the hybrids characterised by fruit weight intermediate in relation to the parental forms. The experiments attested to the high significance of additive effects for fruit weight, periods from sowing to ripening and from flowering to ripening in both combinations and for locule number in Dw₄ x nor. It was also found that the nor gene slightly delayed the onset of fruit ripening but did not affect such traits as total yield, number and weight of fruits, locule number and period from sowing to flowering. In its homozygous state the nor gene totally inhibited fruit ripening. However, as a heterozygote it revealed an intermediate action, slowing down fruit ripening and prolonging shelf life 2-3 times as compared with standard tomato. The expression of the nor gene was also found to be dependent on the genetic background. Line C36 positively influenced the flavour and firmness of hybrid fruits, while Dw₄ had a negative effect on fruit quality.
Źródło:
Journal of Applied Genetics; 1998, 39, 3; 259-273
1234-1983
Pojawia się w:
Journal of Applied Genetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The continental shelf in the law of the sea conventions of 1958 and 1982 and the principal of natural prolongation
Autorzy:
Wasilewski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1920339.pdf
Data publikacji:
1998
Wydawca:
Instytut Morski w Gdańsku
Tematy:
continental shelf
Geneva Convention
Opis:
The subject of the paper is the evolution of the concept of the continental shelf in international law, shown in the context of natural prolongation of the land territory of a coastal state co-creating this concept. The starting point for the analysis are the determinations of such specialised disciplines of science as: geography, oceanography and geology, and in consequence a possibly accurate topographic description of the sea and ocean floor, determination of the most important physiographic zones and of their characteristic features. This, only formally distinguished, but treated as one whole for meritoric and structural reasons three-element sequence, formed in the order: continental shelf in geographic/physical approach - continental slope -foot of continental slope, forms a common topographic feature called the continental margin. However, the reconstruction of the continental shelf concept in international law is not limited only to the description and characteristic of the continental margin in the horizontal plane. Appropriately to the needs of the paper, and to the extent the competence of the Author allowed, the margin is also described in the vertical dimension, i.e. going deeper into the essence of the natural factor, contained basically in the geomorphologic and geologic structure of the main physiographic provinces forming the continental margin. Such a view of the above problem allowed to obtain knowledge of motivations and of various arguments forming the essence and reach of the external limit of the continental shelf in the Geneva Convention on the continental shelf of I958, called further in text the GC IV ( I958). However, most important was to show and prove the thesis that it was the natural factor that dictated and shaped stipulations in international law with respect to the discussed subject, and that this factor played an extremely important role in the evolution and development of the continental shelf concept during the period after CG IV ( I958) was adopted. The principle, contained in the ITJ ruling on the continental shelf of the North Sea that the continental shelf is a natural prolongation of the territory of a coastal state, the natural prolongation principle, was well substantiated by the geomorphology and geophysical characteristics of the continental margin. This principle was also of primary importance for the shaping of the concept of the continental shelf and of its external boundary in the United Nations Convention on the Law of the Sea of 1982, called below UNCLOS (1982).
Źródło:
Biuletyn Instytutu Morskiego w Gdańsku; 1998, 25, 2; 15-32
1230-7424
2450-5536
Pojawia się w:
Biuletyn Instytutu Morskiego w Gdańsku
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sea-bottom relief versus differential compaction in ancient platform carbonates: a critical reassessment of an example from Upper Jurassic of the Cracow-Wielun
Relief dna morskiego a zróżnicowana kompakcja w kopalnych platformach węglanowych: krytyczne przeszacowanie przykładu z górnej jury Wyżyny Krakowsko-Wieluńskie
Autorzy:
Matyszkiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/191314.pdf
Data publikacji:
1999
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
sea bottom relief
carbonate buildup
bedded facies
compaction
Tethyan shelf
Late Jurassic
Opis:
The growth of carbonate buildups in the northern, stable shelf of the Tethyan Ocean was the principal factor in the development of diversified sea-bottom relief in the Late Jurassic basin. Reconstruction of this relief has been a matter of numerous controversies. This paper provides an analysis of published data on elevation differences on sea bottom along the SW margin of the Holy Cross Mts. and in the Cracow-Wielun Upland. Moreover, methods of reconstruction of synsedimentary relief are presented. In the Late Oxfordian the elevations on basin floor in the Czestochowa area (Cracow-Wielun Upland) were about 100 meters at most, and were presumably even lower. The largest (over 200 meters) elevation differences of sea-bottom relief existing in the Czestochowa area at the Oxfordian/Kimmeridgian have been postulated when the recently observed differences in thickness between the deposits of carbonate buildup and of equivalent basinal facies were identified as a relief. In fact, different thickness is, in considerable part, an effect of differential compaction.
Wzrost budowli węglanowych na północnym, stabilnym szelfie Tetydy był główną przyczyną powstania urozmaiconego reliefu dna w basenie późnojurajskim. Rekonstrukcja tego reliefu jest przedmiotem licznych kontrowersji. Praca analizuje dane literaturowe o wielkości deniwelacji dna z rejonu SW-obrzeżenia Gór Świętokrzyskich i Wyżyny Krakowsko-Wieluńskiej oraz omawia metodykę rekonstrukcji reliefu synsedymentacyjnego. Deniwelacje dna basenu u schyłku oksfordu w rejonie Częstochowy wynosiły co najwyżej około 100 m a przypuszczalnie były jeszcze mniejsze. Postulowane wcześniej, ponad dwustumetrowe deniwelacje w basenie w rejonie Częstochowy na przełomie oksfordu i kimerydu były oparte na utożsamianiu z deniwelacjami dna aktualnej różnicy miąższości między utworami budowli węglanowej a ekwiwalentnymi jej utworami facji basenowej. Różnica ta jest w znacznej części wynikiem zróżnicowanej podatności osadów na kompakcję.
Źródło:
Annales Societatis Geologorum Poloniae; 1999, 69, No. 1-2; 63-79
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameterization of light scattering for solving the inverse problem of determining the concentrations of the principal light scattering and absorbing admixtures in shelf waters
Autorzy:
Pelevin, V.N.
Rostovtseva, V.V.
Powiązania:
https://bibliotekanauki.pl/articles/48226.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
bio-optical modelling
backscattering
sea water
shelf water
light absorption
irradiance
Opis:
A method for estimating the water backscattering coefficient was put forward on the basis of experimental data of diffuse attenuation coefficient for downwelling irradiance and irradiance reflectance. Calculations were carried out for open sea waters of different types and the spectral dependencies were found (‘anomalous’ spectra) and explained. On this basis, a new model of light backscattering on particles in the sea is proposed. This model may be useful for modelling remote sensing reflectance spectra in order to solve the inverse problems of estimating the concentration of natural admixtures in shelf waters.
Źródło:
Oceanologia; 2001, 43, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Siliceous biota [radiolarians and sponges] and the Late Devonian biotic crisis: The Polish reference
Autorzy:
Vishnevskaya, V
Pisera, A.
Racki, G.
Powiązania:
https://bibliotekanauki.pl/articles/22703.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Astroentactinia stellata
Trilonche nigra
Polska
biotic crisis
Astroentactinia paronae
Trilonche echinata
mass extinction
taxonomy
Famennian
Frasnian
siliceous fauna
Late Devonian
Devonian
Radiolaria
carbonate shelf
Holy Cross Mountains
Trilonche grandis
paleoecology
distribution
paleontology
Opis:
The radiolarian species Astroentactinia paronae, A. stellata, Trilonche echinata, T. grandis, T. nigra, Haplentactinia inaudita, and H. rhinophyuosa are common in late Frasnian to early Famennian rhythmic, calcareous−marly sequence of the southern Holy Cross Mts., Poland. They are known also from coeval abundant siliceous biota assemblages from the carbonate shelf of East European Platform including more than 150 taxa of radiolarians. However, in ecological terms, the moderately diverse Polish microfaunas (34 species of 12 genera) are more similar to these from Kolyma and Alaska, also marked by abundance of sphaerical entactiniids and near−absence of bilateral−symmetric Ceratoikiscidae and Palaeoscenididae. A succession of two distinctive siliceous sponges associations is established in the incipiently submerged Holy Cross carbonate platform: from an ephemeral, diverse, mostly rigid−skeletal lithistid−hexactinosan foreslope assemblage (initial phase of the late Frasnian Kellwasser Crisis), to long−lasting, basinal loose−skeletal hexactinellid−demosponge faunas (appearing abundantly just prior the Frasnian–Famennian boundary in the late Palmatolepis linguiformis Zone). Such regional blooms of marine siliceous biotas, parallel to temporary retreat of calcareous biota, are demonstrated worldwide for the Kellwasser Crisis. These suggest probable causal links with cooling pulses and at least regional, volcanically induced eutrophication.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of waxing on the water balance and keeping qualities of cut anthuriums
Autorzy:
Mujaffar, S.
Sankat, C.K.
Powiązania:
https://bibliotekanauki.pl/articles/24151.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
flower
shelf life
anthurium
cut
waxing
keeping quality
transpiration
fruit wax
water balance
Źródło:
International Agrophysics; 2003, 17, 2
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Czerstwienie pieczywa i sposoby przedłużania jego swieżości
Autorzy:
Fik, M
Powiązania:
https://bibliotekanauki.pl/articles/827126.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Technologów Żywności
Tematy:
trwalosc przechowalnicza
pieczywo
czerstwienie pieczywa
termin przydatnosci do spozycia
przedluzanie trwalosci
storage durability
bread
staling process
term shelf
durability prolongation
Opis:
Pieczywo charakteryzuje się krótkim okresem trwałości i przydatności do spożycia, co jest związane z szybkim jego czerstwieniem. W pracy przedstawiono obecny stan wiedzy z zakresu czerstwienia i omówiono wpływ tego procesu na jakość oraz przydatność chleba do spożycia. Szczególnie wiele miejsca poświęcono na omówienie roli w tym procesie niektórych składników chemicznych takich, jak: skrobia, białka, woda i węglowodany nieskrobiowe. Wyjaśniono również znaczenie poszczególnych substancji (preparaty enzymatyczne, emulgatory i hydrokoloidy, związki lipidowe, białka, węglowodany nieskrobiowe) bądź procesów (mrożenie, pakowanie i przechowywanie w modyfikowanej atmosferze) w przedłużaniu świeżości i trwałości pieczywa.
Generally, bakery products are characterized by a short-term stability and shelf life as a result of a fast running process of staling. This review presents the current state of knowledge on staling process and its effect on the quality and storing time of bread. A role of some chemical compounds participating in this process, such as starch, proteins, water, and non-starch carbohydrates, was expressly emphasized. Furthermore, it was explained the significant effect of some substances (e.g.: enzyme preparations, emulsifiers and hydrocolloids, lipids, proteins, and non-starch carbohydrates) or processes (e.g.: freezing, packaging, and storage in modified atmosphere) on prolonging the freshness of bakery products, as well as their shelf life.
Źródło:
Żywność Nauka Technologia Jakość; 2004, 11, 2; 5-22
1425-6959
Pojawia się w:
Żywność Nauka Technologia Jakość
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Outline of lithostratigraphy, sedimentation and tectonics of the Tsodilo Hills Group, a Neoproterozoic-Lower Palaeozoic siliciclastic succession in NW Botswana
Litostratygrafia, sedymentacja i tektonika grupy tsodilo hills, neoproterozoiczno-dolnopaleozoicznej sukcesji silikoklastycznej w nw Botswanie
Autorzy:
Wendorff, M.
Powiązania:
https://bibliotekanauki.pl/articles/973688.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
siliciclastic shelf
Neoproterozoic
Pan-African
Damara belt
Botswana
Opis:
The Tsodilo Hills Group is an association of meta-quartzites, meta-conglomerates and quartz-mica schists altered to kyanite metamorphic grade and outcropping in NW Botswana. The unit is a part of the regional Neoproterozoic–Lower Palaeozoic succession deformed during the Pan-African orogenesis and present in the Damara belt of Namibia to the west, in which the main orogenic event occurred at ca. 534–516 Ma, and in the Katangan suite of the Lufilian arc in Zambia and the Democratic Republic of Congo to the north-east. Sedimentary structures, textures, mineral composition, facies trends and palaeocurrent patterns suggest that the deposition of the Tsodilo Hills Group strata took place on an open continental shelf influenced by tides and supplied with siliciclastic material derived from a source area elevated to the south of the depository. The ongoing sedimentation was punctuated by two regressive stages. The older one is reflected by an association of red mudstone, siltstone and sandstones/quartzites, and incised in them channel-fill sandstone bodies with bimodalbipolar palaeocurrent patterns, which are interpreted here as deposits of tidal mudflats intersected by tidal creeks. Enrichment of these rocks in phosphorous was probably caused by upwelling of deep ocean waters reflecting sea-level changes. The second regression was related to an increased input of terrigenous material and is indicated by a conglomerate marker bed. Numerous shear zones, a few small-scale reverse faults and one major thrust, displacing strata towards the south-west, deform the succession. The degree of deformation evolves laterally along the strike of this structure from a prominent thrust in the southern part of the Tsodilo Hills to a thin shear zone in the north.
Praca prezentuje w zarysie nowe wyniki badań nad grupą Tsodilo Hills, odsłaniającą się w północno-zachodniej części Botswany. Jednostka ta reprezentowana jest przez zmetamorfizowane skały terrygeniczne: kwarcyty, piaskowce, zlepieńce i łupki muskowitowe będące cześcią sukcesji deponowanych od neoproterozoiku, a następnie zdeformowanych we wczesnym paleozoiku podczas orogenezy panafrykańskiej, której maksimum w orogenie Damara w Namibii, bezposrednio na zachód od dyskutowanego obszaru, przypada na okres ok. 534-516 Ma. Skały te reprezentują kyanitową fację metamorficzną. Grupa Tsodilo Hills leży w obrębie pasma orogenicznego Damara, które ciągnie się z Namibii poprzez Botswanę. Jego przedłużenie ku północnemu wschodowi znane jest jako orogeniczny łuk lufilianski (“Lufilian arc”) rozciągający się pomiędzy Zambią na południu a Demokratyczną Republika Konga (DRC) na północy. Struktury i tekstury sedymentacyjne, systemy paleoprądów oraz kierunkowe zmiany facjalne sugerują iż depozycja grupy Tsodilo Hills przebiegała na obszarze otwartego szelfu pozostającego pod wpływami pływów i zaopatrywanego w materiał terrygeniczny dostarczany ze strefy źródlowej położonej na południe od obszaru sedymentacji. Postępująca depozycja została przerwana przez dwa epizody regresywne. Świadectwem pierwszej regresji jest kompleks czerwonych mułowców, pyłowców i piaskowców/kwarcytów erozyjnie rozciętych przez kanały wypełnione piaskowcami o dwukierunkowym warstwowaniu skośnym, interpretowane tutaj jako osady równi pływowych. Wzbogacenie tych skał w fosfor spowodowane było prawdopodobnie przez ‘upwelling’ głębinowych wód oceanicznych wywołany eustatycz nymi zmianami poziomu morza. Druga regresja, której odbiciem jest poziom zlepieńcowy, wywołana była wzrostem intensywności dostawy materiału klastycznego. Sukcesja osadowa jest zdeformowana przez liczne fałdki ciągnione, małoskalowe uskoki wsteczne oraz jedno nasunięcie. Stopień deformacji zmienia się stopniowo wzdłuż biegu tej struktury tak, że wyraźna strefa nasunięcia w południowym sektorze Tsodilo Hills ewoluuje lateralnie w cienką strefę skał nieznacznie zdeformowanych przez ścinanie w obszarze północnym. Kierunkowe struktury tektoniczne wskazują, iż lokalne ruchy nasuwcze skierowane były ku południowemu zachodowi.
Źródło:
Annales Societatis Geologorum Poloniae; 2005, 75, 1; 17-25
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Brachiopods and their response to the Early-Middle Frasnian biogeochemical perturbations on the South Polish carbonate shelf
Autorzy:
Balinski, A
Powiązania:
https://bibliotekanauki.pl/articles/20277.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
brachiopod
brachiopod response
paleontology
Early-Middle Frasnian
Frasnian
biogeochemical perturbation
Southern Poland
Polska
carbonate shelf
Brachiopoda
Flabellulirostrum
Thomasaria
carbon isotope
diversity dynamics
Opis:
The brachiopod faunas from deposits recording the Early–Middle Frasnian transition of Poland are poorly known. The present report describes these faunas that were recovered from Wietrznia and Kostomłoty (Holy Cross Mountains) and Dębnik (Silesian−Cracow Upland) regions positioned on the southern Polish carbonate shelf. The brachiopod distribution was analysed relative to a significant δ¹³C excursion, referred recently to as Palmatolepis punctata Event. The sporadic occurrence of brachiopods at Dębnik makes it difficult to analyse the biotic response to this geochemical anomaly. However, higher brachiopod frequency in the topmost part of the section coincides with a gradual decrease of δ¹³C down to the Frasnian background values. At two studied sections at Wietrznia the greatest taxonomic diversity and abundance of brachiopods (Flabellulirostrum–Coeloterorhynchus assemblage) are confined to the Palmatolepis transitans Zone. In the following Pa. punctata Zone brachiopods are rare (Biernatella lentiformis assemblage) or absent, which suggests a serious deterioration of the environmental conditions linked probably with periods of benthic anoxia−dysoxia and oligotrophic conditions in the basin. In two Kostomłoty sections brachiopods faunas of this age are members of the mostly monospecific rhynchonellid−dominated Phlogoiderhynchus polonicus assemblage which inhabited deeper−water environments characteristic of intrashelf oxygen−depleted basins of ŁysogóryKostomłoty region. In some horizons large shells of P. polonicus were frequently colonised by discinoid Romerella? sp. Among 28 species described in this report new forms include: Flabellulirostrum kielcensis sp. nov., F. rackii sp. nov., and Thomasaria ventosa sp. nov.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 647-678
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conodont ecology in the Early-Middle Frasnian transition on the South Polish carbonate shelf
Autorzy:
Sobstel, M
Makowska-Haftka, M.
Racki, G.
Powiązania:
https://bibliotekanauki.pl/articles/23066.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
conodont
ecology
Early-Middle Frasnian
Frasnian
Southern Poland
carbonate shelf
paleoecology
Holy Cross Mountains
deposit
Palmatolepis transitans
Palmatolepis punctata
Opis:
Well exposed Early–Middle Frasnian (E–MF, Palmatolepis transitans to Palmatolepis punctata zonal interval) deposits of the Holy Cross Mountains, in particular the reference Wietrznia section at Kielce, were studied in terms of conodont biofacies dynamics. Frequency of the conodont elements has been controlled mostly by depositional rate in hemipelagic muddy lithofacies and post−mortem gravity sorting during lateral redeposition in storm−generated, talus−like and encrinite layers. The conodont assemblages are dominated by a highly varying proportion of polygnathid, icriodontid, and ancyrodellid fauna. Major biofacies turnovers coincided with the deepening pulses corresponding to Timan, Middlesex, and early Rhinestreet global events. Trends in the conodont dynamics, mortality, and diversity point that the biotic shifts also coincide with the large−scale δ¹³C excursions as a record of changing trophic conditions during the major biogeochemical perturbation. A gradual decline of the Early Frasnian Ancyrodella reef−dwelling community correlates with the minor positive and succeeding larger negative δ¹³C excursion, and this is paired with a replacement by, mostly sparse, polygnathid and polygnathid−icriodontid biofacies, as well as with a short−term Belodella acme in mud−mounds areas. The distinctive habitat deterioration in pelagic and reef ecosystems is broadly correlative with the Domanik Crisis. The progressive biofacies unification is a conodont response to onset of the prolonged (ca. 0.5 Ma) δ¹³C enrichment, probably linked with high−stress life conditions due to eutrophication and partly anoxic regimes. A negative carbon isotope excursion in the late Pamatolepis punctata Zone is marked by the second major biofacies turning point during the Rhinestreet transgression, as recorded primarily in a final mesotaxid extinction, and highlighted also by decrease of conodont size and increased mortality of juveniles. After stabilization of δ¹³C values and a return to the background level across the Palmatolepis punctata–Palmatolepis hassi zonal transition, renewed biofacies diversification, in particular re−appearance of reef−related ancyrodellid fauna, took place. In addition, a large−scale migration event among palmatolepids and polygnathids during sea−level rise, mainly from the East European Platform, characterised this Middle Frasnian interval.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 719-746
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conodont-based event stratigraphy of the Early-Middle Frasnian transition on the South Polish carbonate shelf
Autorzy:
Pisarzowska, A
Sobstel, M.
Racki, G.
Powiązania:
https://bibliotekanauki.pl/articles/22673.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
conodont association
stratigraphy
Early-Middle Frasnian
Frasnian
Polska
carbonate shelf
biostratigraphy
carbon isotope
paleoecology
Devonian
Palmatolepis transitans
Palmatolepis punctata
Opis:
Early to Middle Frasnian (E–MF) epicontinental sequences are investigated in five representative localities of the Holy Cross Mountains and Cracow region, with emphasis on conodont biostratigraphy, to evaluate the regional stratigraphic and biotic context of a major biogeochemical perturbation in global carbon cycling. Conodont associations from the Palmatolepis transitans to Palmatolepis punctata Zone boundary beds are dominated by the shallow−water polygnathid and ancyrodellid fauna in the South Polish epicontinental successions, and first appearances of index palmatolepid species are delayed due to facies control of pelagic environments during intermittent drowning of the carbonate shelf. Thus, identification of the zonal boundary is based mainly on species of Ancyrodella, and five distinctive ancyrodellid levels in the succession across the E–MF interval enable refined correlation of the sections studied, especially when paired with chemostratigraphic proxies. Prominent conodont biofacies shifts coincided with eustatic deepening, which is correlated with the Timan, Middlesex, and early Rhinestreet events, respectively. Trends in the conodont dynamics, mortality and diversity, partly replicated by the benthic biota (especially shelly faunas and crinoids), indicate that the faunal turnovers correlate also with the main δ¹³C excursions and related changes in trophic conditions. The E–MF transitional interval, marked by short−term sea−level fluctuations, is distinguished by a change from relatively diversified biofacies to more homogenous, mostly impoverished faunas. The latter change is a biotic response to the beginning of a prolonged (ca. 0.5 Ma) positive δ¹³C anomaly, probably paired with unsteady eutrophic and partly anoxic regimes. The late Pa. punctata Zone negative carbon isotope anomaly is synchronous with the second large−scale pelagic biofacies remodelling, including mesotaxid extinction. A stabilization of the carbon cycle and its return to normal background values at the start of the Early Palmatolepis hassi Zone coincide with conodont biofacies diversification and recovery of reef−related biofacies. With the exception of collapsed, endemic Kadzielnia−type mud−mound biota and a moderate biodiversity depletion due to overall ecosystem stagnation, no significant extinction events can be demonstrated, even if the large−scale changes in carbon cycling during the E–MF timespan are of higher−amplitude than the celebrated carbon isotopic anomalies related to the Frasnian–Famennian mass extinction. Thus, this regional succession in detail confirms that the large−scale punctata Isotopic Event (= Pa. punctata Event) is correlated neither with catastrophic enviromental nor radical biotic changes.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 609-646
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early and Middle Frasnian brachiopod faunas and turnover on the South China shelf
Autorzy:
Ma, X -P
Becker, R.T.
Li, H.
Sun, Y.-Y.
Powiązania:
https://bibliotekanauki.pl/articles/21029.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Early Frasnian
Middle Frasnian
Frasnian
paleontology
brachiopod fauna
South China shelf
Devonian
Brachiopoda
Cyrtospirifer
faunal turnover
Opis:
The first appearance of the brachiopod Cyrtospirifer and related forms in the Late Devonian of South China significantly postdates the beginning of the Frasnian and the entry of the group in other parts of the world. Scattered data from different sections suggest that its first entry, associated with the emergence of other plicate spiriferids, such as theodossid and conispiriferid brachiopods, was late in the Middle Frasnian. At the same time, many rhynchonellids disappeared or became extinct locally in South China. This brachiopod faunal overturn near the Palmatolepis punctata–Early Pa. hassi zonal boundary is the most significant event in the Early–Middle Frasnian of South China, characterized by about a 35% loss of existing species and the flourishing of the plicate spiriferids, which was coeval with the end of a major biogeochemical perturbation recently recognized in the Pa. punctata Zone. By contrast, atrypid brachiopods do not seem to show any significant diversity change. The brachiopod faunal change was probably related to a (local?) transgressive event in South China, which also brought new pelagic faunas northwards into some intra−shelf deeper water areas, such as the Shetianqiao area in central Hunan Province. Fifteen brachiopod species are described and illustrated, which include some taxa that are first recorded or recognized in South China, e.g., the spiriferid Pyramidaspirifer, which is now known from both North America and South China. One new species, Desquamatia qiziqiaoensis, is erected.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 789-812
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Znaczenie przepływów hiperpyknalnych i klinoform deltowych dla interpretacji sedymentologicznych formacji z Machowa (miocen zapadliska przedkarpackiego
Hyperpycnal flows and deltaic clinoforms - implications for sedimentological interpretations of late Middle Miocene fill in the Carpathian Foredeep Basin
Autorzy:
Porębski, S.J.
Warchoł, M.
Powiązania:
https://bibliotekanauki.pl/articles/2074464.pdf
Data publikacji:
2006
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
miocen
przepływ hiperpyknalny
klinofroma deltowa
zapadlisko przedkarpackie
Carpathian Foredeep
Miocene
hyperpycnal flow
shelf-margin delta
Opis:
The Middle to early Upper Miocene Machów Formation represents the youngest and little to non-deformed increment in the Carpathian Foredeep Basin that was initiated during the Paleocene in response to thrust loading of the North European craton. The onset of the Machów Formation was associated with the late Badenian (lateMiddle Miocene) flexural subsidence (ca 12.5 Ma BP) that resulted in underfilled-basin conditions recorded in the emplacement of submarine fans and shelf-margin deltas, up to 400 m in relief. These systems were fed from the south by a net of small, suspended-load dominated rivers, which resulted in the strongly heterolithic nature of the basin infill. There is a striking absence of large-scale traction structures, and thick sandstone/mudstone packages intercalated with thick-bedded massive sandstones provide evidence of deposition mainly from sustained turbidity currents typified by oscillations in velocity and sediment concentration within a flow. The evidence in both submarine-fan and delta-front deposits includes the abundance of climbing ripples, thick flat-laminated intervals within the otherwise massive thick-bedded sandstones, and inverse to pensymmetrical grading associated with a succession of structural divisions, which departs from that generated by harmonic energy dissipation typical for surge-type (semi-constant volume) turbidity currents. This evidence is interpreted to reflect deposition mainly from hyperpycnal flows, whose oscillatory behaviour reflected chiefly changing flood stages in the sourcing fluvial flow. The inferred semi-permanent flow feeding is also supported by the very high sedimentation rate (locally up to 24 cm/a) of the Machów Formation. Four clinoform types have been distinguished in the formation. Type 1 is most common and corresponds to platform (“shallow-water”) deltas of subseismic scale. The remaining three are shelf-margin (“deepwater”) deltas. The latter types differ one form another in the height and internal structure of clinoforms, as well as in the degree of downdip segregation of sand that either dominates in slope increments (type 2), forms shingled clinoform toes (type 3), or is concentrated in basin-floor fans in the front of a muddy clinoform slope. The basinward sand segregation is facilitated by the dissection of a clinoform’s top during the maximum fall in relative sea level and by long slopes that ease the transformation of hyperpycnal flows into high-efficiency turbidity currents. Numerous internal onlap unconformities make the shelf-margin deltas interesting targets for hydrocarbon search in stratigraphic traps. The identified type 4 clinoforms, up to 200 m high, in the Quinqueloculina reusii zone point to a major deepening in the upper part of the Machów Formation. This suggests a rise in flexural accommodation at ca 11 Ma BP, and contradicts the common view on uniform upward-shallowing throughout the formation.
Źródło:
Przegląd Geologiczny; 2006, 54, 5; 421-429
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
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