6 research outputs found

    Refining the Early Devonian time scale using Milankovitch cyclicity in Lochkovian–Pragian sediments (Prague Synform, Czech Republic)

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    The Early Devonian geological time scale (base of the Devonian at , Becker et al., 2012) suffers from poor age control, with associated large uncertainties between 2.5 and 4.2 Myr on the stage boundaries. Identifying orbital cycles from sedimentary successions can serve as a very powerful chronometer to test and, where appropriate, improve age models. Here, we focus on the Lochkovian and Pragian, the two lowermost Devonian stages. High-resolution magnetic susceptibility ( – 5 to 10 cm sampling interval) and gamma ray spectrometry (GRS – 25 to 50 cm sampling interval) records were gathered from two main limestone sections, Požár-CS (118 m, spanning the Lochkov and Praha Formations) and Pod Barrandovem (174 m; Praha Formation), both in the Czech Republic. An additional section (Branžovy, 65 m, Praha Formation) was sampled for GRS (every 50 cm). The and GRS records are very similar, so variations are driven by variations in the samples' paramagnetic clay mineral content, reflecting changes in detrital input. Therefore, climatic variations are very likely captured in our records. Multiple spectral analysis and statistical techniques such as: Continuous Wavelet Transform, Evolutive Harmonic Analysis, Multi-taper method and Average Spectral Misfit, were used in concert to reach an optimal astronomical interpretation. The Požár-CS section shows distinctly varying sediment accumulation rates. The Lochkovian (essentially equivalent to the Lochkov Formation (Fm.)) is interpreted to include a total of nineteen 405 kyr eccentricity cycles, constraining its duration to . The Praha Fm. includes fourteen 405 kyr eccentricity cycles in the three sampled sections, while the Pragian Stage only includes about four 405 kyr eccentricity cycles, thus exhibiting durations of and respectively. Because the Lochkov Fm. contains an interval with very low sediment accumulation rate and because the Praha Fm. was cross-validated in three different sections, the uncertainty in the duration of the Lochkov Fm. and the Lochkovian is larger than that of the Praha Fm. and Pragian. The new floating time scales for the Lochkovian and Pragian stages have an unprecedented precision, with reduction in the uncertainty by a factor of 1.7 for the Lochkovian and of ∼6 for the Pragian. Furthermore, longer orbital modulation cycles are also identified with periodicities of ∼1000 kyr and 2000–2500 kyr

    Climate instability and tipping points in the Late Devonian: Detection of the Hangenberg Event in an open oceanic island arc in the Central Asian Orogenic Belt

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    Sedimentary petrology and trace element geochemistry indicate that the Late Devonian to Early Carboniferous Heishantou Formation near Boulongour Reservoir (NW Xinjiang, China) was deposited on a steep slope, mid-latitude accreting island arc complex in an open oceanic system. Bulk 87Sr/86Sr ratios show excursion patterns that are consistent with excursions at the Devonian-Carboniferous (D-C) boundary in epicontinental margin sediments. Sedimentation rates for the Boulongour Reservoir sediments show highly variable rates that range from 0.5 cm/ky to 10 cm/ky, consistent with other Late Devonian sections and modern arc environments. Multiple whole rock geochemical proxies for anoxia and the size and distribution of pyrite framboids suggest the presence of the Hangenberg Event in the sediments associated with the D-C boundary, despite the lack of visible black shale. The presence of anoxia in an open ocean, island arc environment cannot be explained by upwelling of anoxic bottom waters at this paleolatitude, but can be explained by the global infliction of oceanic shallow water eutrophication on to a climate system in distress

    Personality, creativity and complexity of thought

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    Presented study introduce the correlation of creativity, personality and cognitive complexity. The structure of cognitive processess has been great topic since the turn of 20th century. The research on cognitive styles have brought many new findings on the interconectedness of personality and cognitive processes such as perception, thinking and decision making, memory etc. Theories of cognitive complexity represent one contribution of this period, which aims on how are the cognitive processess structured, how this structure affects the effectivity of decision making and how it’s affected by different internal or external factors such as sex, age, \npersonality, social context, time pressure etc . In the first part of our research we conducted an analysis of \ncorrelation between divergent thinking factors and cognitive complexity measures following the approach of P. \nSuefeld and P.E. Tetlock. Figural and verbal fluence, flexibility, elaboration and originality were measured by \nsubtests Torrance test of creative behaviour and Guilford Alternative uses test. Cognitive complexity was scored \non the Paragraph completion test data following the Integrative/Conceptual complexity scoring manual (Baker-Brown et al., 1992). In the second part of study we conducted correlation study of cognitive complexity and Big Five personality traits (measured by Czech version of NEO-FFI by Hřebíčková & Urbánek, 2001). The article gives a summary of main findings of our studies and briefly sketch out the questions and hypotheses for future research on the complexity of thought

    The model of adaptive behavior for the development of Czech assessment scales for children

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    We introduce results of cluster analysis conducted during the development of Czech assessment scales of adaptive behavior in children and adolescents. Within the frame of National Institute of Education we organized the group of experts on the topic of adaptive behavior, both from the academical and practical areas. Every member of the expert group obtained 300 items inspired by local or foreign methods of adaptive behavior assessment. The experts were instrued to cathegorize the items, which they found meaningful with regard to the construct of adaptive behavior and its manifestation on the Czech background. Based on results we compiled consequent model of adaptive behavior, that becomes the base structure for newly developed assessment scales. We compare this structure with the model of adaptive behavior used by DSM-V.\
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