48 research outputs found

    Constraining long-term denudation and faulting history in intraplate regions by multisystem thermochronology: An example of the Sudetic Marginal Fault (Bohemian Massif, central Europe)

    Get PDF
    The Rychlebské hory Mountain region in the Sudetes (NE Bohemian Massif) provides a natural laboratory for studies of postorogenic landscape evolution. This work reveals both the exhumation history of the region and the paleoactivity along the Sudetic Marginal Fault (SMF) using zircon (U-Th)/He (ZHe), apatite fission track (AFT), and apatite (U-Th)/He (AHe) dating of crystalline basement and postorogenic sedimentary samples. Most significantly, and in direct contradiction of traditional paleogeographic reconstructions, this work has found evidence of a large Cretaceous sea and regional burial (to >6.5 km) of the Carboniferous-Permian basement in the Late Cretaceous (~95–80 Ma). During the burial by sediments of the Bohemian Cretaceous Basin System, the SMF acted as a normal fault as documented by offset ZHe ages across the fault. At 85–70 Ma, the basin was inverted, Cretaceous strata eroded, and basement blocks were exhumed to the near surface at a rate of ~300 m/Ma as evidenced by Late Cretaceous–Paleocene AFT ages and thermal modeling results. There is no appreciable difference in AFT and AHe ages across the fault, suggesting that the SMF acted as a reverse fault during exhumation. In the late Eocene–Oligocene, the basement was locally heated to <70°C by magmatic activity related to opening of the Eger rift system. Neogene or younger thermal activity was not recorded in the thermochronological data, confirming that late Cenozoic uplift and erosion of the basement blocks was limited to less than ∼1.5 km in the study area

    Glaciolacustrine deposits formed in an ice-dammed tributary valley in the south-central Pyrenees: new evidence for late Pleistocene climate

    Get PDF
    Combined geomorphic features, stratigraphic characteristics and sedimentologic interpretation, coupled with optically stimulated luminescence (OSL) dates, of a glacio-fluvio-lacustrine sequence (Linás de Broto, northern Spain) provide new information to understand the palaeoenvironmental significance of dynamics of glacier systems in the south-central Pyrenees during the Last Glacial Cycle (≈130 ka to 14 ka). The Linás de Broto depositional system consisted of a proglacial lake fed primarily by meltwater streams emanating from the small Sorrosal glacier and dammed by a lateral moraine of the Ara trunk glacier. The resulting glacio-fluvio-lacustrine sequence, around 55 m thick, is divided into five lithological units consisting of braided fluvial (gravel deposits), lake margin (gravel and sand deltaic deposits) and distal lake (silt and clay laminites) facies associations. Evolution of the depositional environment reflects three phases of progradation of a high-energy braided fluvial system separated by two phases of rapid expansion of the lake. Fluvial progradation occurred during short periods of ice melting. Lake expansion concurred with ice-dam growth of the trunk glacier. The first lake expansion occurred over a time range between 55 ± 9 ka and 49 ± 11 ka, and is consistent with the age of the Viu lateral moraine (49 ± 8 ka), which marks the maximum areal extent of the Ara glacier during the Last Glacial Cycle. These dates confirm that the maximum areal extent of the glacier occurred during Marine Isotope Stages 4 and 3 in the south-central Pyrenees, thus before the Last Glacial Maximum. The evolution of the Linás de Broto depositional system during this maximum glacier extent was modulated by climate oscillations in the northern Iberian Peninsula, probably related to latitudinal shifts of the atmospheric circulation in the southern North-Atlantic Ocean, and variations in summer insolation intensity

    Agro-amelioration in forestry

    No full text

    Determinates of fire risks in the historic means of transport

    No full text
    W artykule przedstawiono główne przyczyny zagrożeń pożarowych w zabytkowych środkach transportu. Do przyczyn tych należą: zmniejszenie wytrzymałości izolacji obwodów elektrycznych - oświetleniowych, procesy zmęczeniowe elementów pojazdów i układów elektrycznych a także zły stan techniczny pojazdów w szczególności zbiorników i przewodów doprowadzających paliwo do silnika. W artykule zaprezentowano założenia analiz technicznych zjawisk eksploatacyjnych w zabytkowych środkach transportu. Podano zależności matematyczne wykorzystywane w modelowaniu oceny stanu technicznego obiektu wraz z wyznaczeniem zakresu, czasu miejsca przeglądu lub naprawy.The article presents the main causes of fires in the historic means of transport. The reason for this are: a reduction in insulation resistance of electrical circuits – lightning, processes fatigue vehicle parts and electrical systems as well as the bad technical condition of vehicles, in particular thanks and fuel hoses in the engine. The article presents the assumptions of technical analysis of phenomena operating in the historic means of transport. Given depending on the mathematical modeling used in the assessment of the technical state of the object with the determination of scope, time, place or repair

    Lithostratigraphy of tills and proglacial deposits in the Szczecin vicinity, northwestern Poland

    No full text
    W regionie szczecińskim występuje 9 poziomów różnowiekowych glin lodowcowych, które zdefiniowano na podstawie ich składu petrograficznego oraz pozycji w sukcesji litostratygraficznej. Poziomy te reprezentują najstarsze zlodowacenie (jedna glina), zlodowacenia południowopolskie (2 gliny), zlodowacenia środkowopolskie (3 gliny) oraz zlodowacenia północnopolskie (2 gliny o regionalnym zasięgu i jedna glina występująca lokalnie, w strefie moren czołowych fazy poznańskiej). Dla wszystkich poziomów glin dokonano formalizacji litostratygraficznej. Niektóre poziomy glin regionu szczecińskiego posiadają cechy, które pozwalają korelować je z glinami o podobnych cechach z zachodniej i centralnej Polski. Wiek innych poziomów glin określono na podstawie ich pozycji w stosunku do horyzontów przewodnich. Kierunki transportu glacjalnego dla wczesnych stadiałów zlodowaceń są zazwyczaj z NW na SE, podczas gdy w młodszych stadiałach zmieniają się na NE-SW, a w najmłodszych na ENE-WSW. W regionie szczecińskim nie udokumentowano istnienia żadnych osadów interglacjalnych lub interstadialnych, natomiast występują powszechnie osady proglacjalne, w tym bardzo miąższe serie zastoiskowe. Te ostatnie udokumentowano prawie dla wszystkich awansów lądolodów i reprezentują one głównie zbiorniki z faz transgresywnych zlodowaceń. W badanym regionie wydzielono dwie główne kopalne powierzchnie erozyjno-denudacyjne, jedną z okresu międzylodowcowego pomiędzy zlodowaceniami południowopolskimi a środkowopolskimi, a drugą z okresu interglacjału eemskiego i wczesnego Vistulianu. Różniły się one intensywnością erozji i charakterem dominujących procesów: w pierwszym okresie przeważała denudacja i powierzchniowe obniżanie terenu, a w drugim prawdopodobnie bardziej intensywna była głęboka erozja rzeczna. Starsze i młodsze serie glacjalne zawierają domieszki materiału wczesnokenozoicznego, podczas gdy osady ze zlodowaceń środkowopolskich takich domieszek nie mają. Świadczy to o występowaniu licznych wychodni podłoża neogeńskiego, a pośrednio też o intensywnej erozji przed i w czasie zlodowaceń najstarszych, południowopolskich i północnopolskich. Natomiast w czasie zlodowaceń środkowopolskich lądolody nasuwały się na obszar z ciągłą pokrywą starszych osadów glacjalnych.In the vicinity of Szczecin, NW Poland, 9 till horizons occur which have been defined by their petrographic composition and position in lithostratigraphic succession. The tills include to the "oldest glaciation", two tills to Elsterian, three tills to Saalian and three tills to Weichselian (two of them with regional extent, and one local, connected with the marginal zone of the Pomerania Phase). This stratigraphic subdivision was formalized. Some tills of the Szczecin region indicate features which are correlative with till horizons in western and central Poland. The age of other tills has been established in relation to these index horizons. Glacial palaeotransport was usually from NW to SE during the first stadials of each glaciation, then changed from NE to SW in the middle, and finally to ENE-WSW in the final stadials. There are no interglacial or interstadial deposits near Szczecin, but proglacial sediments have a widespread occurrence, particularly glaciolacustrine series. The latter are quite thick and occur in almost all glacial horizons. Glaciolacustrine deposits were formed mainly during the ice sheet advances. Two regional, buried palaeosurfaces have been documented in the studied area. They were formed during the Mazovian (Holstein) Interglacial (Elsterian/Saalian ice free period) and during the Eemian and early Vistulian. Each of them was formed by different processes, the first one by regional denudation and slow lowering of the surface, and the second one probably also by more intensive and deep fluvial erosion. The sediments from the oldest glaciations (San 1 and San 2) and Vistulian contain admixtures of early Cenozoic material, whereas Middle Polish (Saalian) deposits do not. From this it follows that during the first there were many outcrops of older sediments, exposed due to intensive erosion, whereas the Middle Polish (Saalisan) ice sheets advanced to the area covered by continuous cover of older glacial deposits

    Momentum-based load prescriptions: applications to jump squat training

    No full text
    Velocity-based training is often applied to ballistic exercises, like the barbell jump squat, to improve vertical jump performance. However, determining the ideal training load based on velocity data remains difficult, as load prescriptions tend to be limited to subjective velocity loss thresholds, velocity ranges, or both. Using data from jump squats performed with 0%, 15%, 30%, 45%, and 60% of the 1-repetition maximum squat, we explored subjective and objective methods to determine the ideal training load. Specifically, we explored takeoff velocity and a related metric only recently discussed in the literature, system momentum (i.e., takeoff velocity multiplied by the mass of the athlete-load system). At the group level, an ideal training load could not be revealed objectively using takeoff velocity. With individual participants, the process remained challenging using takeoff velocity. Conversely, an ideal training load could be revealed easily and objectively using system momentum at the group average and individual participant levels. System momentum at takeoff is well-suited to assist practitioners seeking to identify appropriate training loads for jump squat training, and potentially other ballistic exercises. We suggest a pivot from velocity to system momentum when seeking to objectively establish training loads for the jump squat and related exercises

    The results of new studies of Quaternary sediments in the Kleszczów Graben, Szczerców Outcrop, Bełchatów Lignite Opencast Mine

    No full text
    The paper presents the results of new studies of Quaternary deposits filling the Kleszczów Graben in the Szczerców outcrop, Bełchatów Lignite Opencast Mine. Sedimentary successions were profiled in the fieldwork. Moreover, the borehole data were studied. Laboratory studies included: grain size analyses, analyses of shape and morphology of quartz grain (morphoscopy), analyses of anisotropy of magnetic susceptibility (AMS), palynological, malacological and ostracodological studies, as well as geochronometric (C14) and geochemical (δ18O/δ16O) measurements. The studies were carried out in 2009–2013 and resulted in discovering of some sedimentary formations as well as arranging geological cross-sections and synthetic lithostratigraphic profile. The following sedimantary formations have been distinguished: Folwark, Kuców, Czyżów, Ławki, Rogowiec, Aleksandrów, Piaski and Widawka, arranged into two structural units: the lower one – deformed, and the upper one – undeformed
    corecore