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361.
Ichnodiversity and ichnoabundance: Revealing depositional trends in a confined turbidite system 总被引:1,自引:0,他引:1
Ichnological studies are still in their infancy when it comes to the interpretation of deep‐marine deposits. The Eocene–Oligocene turbidite system of the Grès d'Annot Formation in south‐east France is well‐studied sedimentologically, but its trace‐fossil content is poorly known. Here, an integrated ichnological–sedimentological study is presented from the Annot sub‐basin for the first time, which demonstrates its value for interpreting proximal to distal and axial to marginal trends in confined turbidite systems. A comprehensive trace‐fossil data set was collected from seven outcrops situated in the southern part of the basin. These data are presented following a morphology‐based classification scheme to allow easy recognition and characterization of ichnotaxa. Ichnodiversity and the abundance of ichnotaxa are regarded as important parameters in such interpretations. Instead of simply counting ichnotaxa per outcrop or stratigraphic unit, an equation has been developed in which the ‘ichnoabundance’ (new term) of each counted ichnotaxon is calculated. An exponential growth factor is applied to the increase of the frequency of trace fossils, and is assumed in this equation to better reflect the population dynamics of benthic organisms. A comparison of the solution for pre‐turbidite and post‐turbidite trace‐fossil suites seems to be more suitable for revealing regional and stratigraphic trends compared with conventional approaches. Despite varying size and conditions of the studied outcrops, the results achieved from the Grès d'Annot Formation can help in the reconstruction of sedimentary processes acting in this confined turbidite basin. 相似文献
362.
Paweł Zieliński Robert J. Sokołowski Stanisław Fedorowicz Iwan Zaleski 《Boreas: An International Journal of Quaternary Research》2014,43(3):712-721
The nature of permafrost and related environmental conditions in the Weichselian Late Pleniglacial and Lateglacial are reconstructed based on the assessment of frost structures that are best documented in the Loess Belt and in plateau areas composed of glacial till. Investigations were conducted in the central‐eastern part of the European Sand Belt (SE Poland and NW Ukraine) on a fluvio‐aeolian sedimentary succession and took into account its chronological context given by luminescence dating. Various generations of periglacial structures found in these deposits indicate not only the development of permafrost (ice‐wedge pseudomorphs) and decreased humidity (composite wedge casts) but also the degradation of permafrost (large‐scale involutions) and, finally, the establishment of deep seasonal frost (frost cracks). The diversity of structures in the study region appears to result from local conditions rather than increasing continentality of climate towards the east. 相似文献
363.
Vaduvescu O. Aznar Macias A. Wilson T. G. Zegmott T. Pérez Toledo F. M. Predatu M. Gherase R. Pinter V. Pozo Nunez F. Ulaczyk K. Soszyński I. Mróz P. Wrona M. Iwanek P. Szymanski M. Udalski A. Char F. Salas Olave H. Aravena-Rojas G. Vergara A. C. Saez C. Unda-Sanzana E. Alcalde B. de Burgos A. Nespral D. Galera-Rosillo R. Amos N. J. Hibbert J. López-Comazzi A. Oey J. Serra-Ricart M. Licandro J. Popescu M. 《Earth, Moon, and Planets》2022,126(2):1-26
Earth, Moon, and Planets - The Perseverance rover (Mars 2020) mission, the first step in NASA’s Mars Sample Return (MSR) program, will select samples for caching based on their potential to... 相似文献
364.
Ambrožová Klára Láska Kamil Matějka Michael Reuder Joachim 《Theoretical and Applied Climatology》2022,148(3-4):967-983
Theoretical and Applied Climatology - Air temperature inversions are common features in Antarctica, especially in the interior where they are observed nearly year-round. Large temporal variability... 相似文献
365.
Adamiec-Wójcik Iwona Brzozowska Lucyna Drąg Łukasz Wojciech Stanisław 《Boundary-Layer Meteorology》2022,184(3):423-440
Boundary-Layer Meteorology - Space–time correlations are fundamental to statistical theories and turbulence modelling. However, experimental studies of space–time correlations are often... 相似文献
366.
Zdzisław M. Migaszewski Agnieszka Gałuszka Artur Michalik Sabina Dołęgowska Andrzej Migaszewski Stanisław Hałas Andrzej Trembaczowski 《Aquatic Geochemistry》2013,19(4):261-280
The paper presents the results of determinations of stable S and O isotopes of dissolved sulfates and O and H stable isotopes of waters from three ponds, that is, Marczakowe Do?y acid pond, Marczakowe Do?y fish pond and Podwi?niówka acid pit pond, located in the Holy Cross Mountains (south-central Poland). The δ34SV-CDT and δ18OV-SMOW of SO4 2? in waters of three ponds (n = 14) varied from ?16.2 to ?9.5 ‰ (mean of ?13.6 ‰) and from ?8.1 to ?3.2 ‰ (mean of ?4.8 ‰), respectively. The mean δ34S–SO4 2? values were closer to those of pyrite (mean of ?25.4 ‰) and efflorescent sulfate salts (mean of ?25.6 ‰), recorded previously in the Podwi?niówka quarry, than to sulfates derived from other anthropogenic or soil and bedrock sources. The SO4 2? ions formed by bacterially induced pyrite oxidation combined with bacterial (dissimilatory) dissolved sulfate reduction, and presumably with subordinate mineralization of carbon-bonded sulfur compounds, especially in both Marczakowe Do?y ponds. In addition, the comparison of δ18O–SO4 2? and δ18O–H2O values indicated that 75–100 % of sulfate oxygen was derived from water. Due to the largest size, the Podwi?niówka acid pit pond revealed distinct seasonal variations in both δ18O–H2O (?9.2 to ?1.6) and δD–H2O (?29.7 to ?71.3) values. The strong correlation coefficient (r 2 = 0.99) was noted between δ18O–H2O and δD–H2O values, which points to atmospheric precipitation as the only source of water. The sediments of both acid ponds display different mineral inventory: the Marczakowe Do?y acid pond sediment consists of schwertmannite and goethite, whereas Podwi?niówka acid pit pond sediment is composed of quartz, illite, chlorite and kaolinite with some admixture of jarosite reflecting a more acidic environment. Geochemical modeling of two acid ponds indicated that the saturation indices of schwertmannite and nanosized ε-Fe2O3 (Fe3+ oxide polymorph) were closest to thermodynamic equilibrium state with water, varying from ?1.44 to 3.05 and from ?3.42 to 6.04, respectively. This evidence matches well with the obtained mineralogical results. 相似文献
367.
We discuss computational engineering and science (CES) methodologies and tools applicable to a variety of subsurface models and their couplings. First we overview both basic and widely recognized multiphase and multicomponent models. In the CES methodologies area we focus on accurate and robust numerical algorithms and linear and nonlinear solvers with parallel scalability. In the CES tools area, we discuss a few representative programming tools and technologies. We present several simulation examples which reflect the experiences of the research group at the Center for Subsurface Modeling at The University of Texas at Austin. 相似文献
368.
Based on observations of polar plume kinematics in the white-light corona during the total solar eclipse in 2006, the images obtained during multi-station observation of the eclipses of 2006, 2008, 2009 and 2010 were analysed. Several polar plumes showing similar kinematics were identified. The speeds of these dynamic features were found by comparing images obtained at different times along the path of totality. A possible connection with erupting spicules and macrospicules is discussed. 相似文献
369.
Spotless days (i.e., days when no sunspots are observed on the Sun) occur during the interval between the declining phase of the old sunspot
cycle and the rising phase of the new sunspot cycle, being greatest in number and of longest continuous length near a new
cycle minimum. In this paper, we introduce the concept of the longest spotless segment (LSS) and examine its statistical relation
to selected characteristic points in the sunspot time series (STS), such as the occurrences of first spotless day and sunspot
maximum. The analysis has revealed statistically significant relations that appear to be of predictive value. For example,
for Cycle 24 the last spotless day during its rising phase should be about August 2012 (± 9.1 months), the daily maximum sunspot
number should be about 227 (± 50; occurring about January 2014±9.5 months), and the maximum Gaussian smoothed sunspot number
should be about 87 (± 25; occurring about July 2014). Using the Gaussian-filtered values, slightly earlier dates of August
2011 and March 2013 are indicated for the last spotless day and sunspot maximum for Cycle 24, respectively. 相似文献
370.
Environmental and land use factors affecting phosphate hysteresis patterns of stream water during flood events (Carpathian Foothills,Poland) 总被引:1,自引:0,他引:1
Flood events play a substantial role in the circulation of catchment phosphate (PO43?). The purpose of the research was to analyze the factors determining PO43? hysteresis patterns (direction and width) during four types of floods: short and long rainfall floods and snowmelt floods on frozen and thawed soil. The research took place in small catchments (forested, agricultural, mixed‐use) in the Carpathian Foothills in Poland. Anticlockwise hysteresis was identified in the forested catchment during short and long rainfall floods. Under the same conditions, the clockwise direction was observed in the agricultural catchment. In the mixed‐use catchment, the direction of PO43? hysteresis loops was various, driven by the share of water flowing from each part of the catchment. For snowmelt floods, the PO43? hysteresis pattern was similar in all the streams studied (usually clockwise). The direction of PO43? hysteresis loops depends on water circulation patterns, which are determined by the different influx times of particular runoff components. The stream recharge mechanism during a flood event is affected both by the factor initiating the event (precipitation, snowmelt) as well as by land use in the given catchment. Hysteresis loop width was determined by the pool of PO43? in a given catchment during the time period immediately preceding a flood event as well as by the quantity of PO43? flushed out of the soil. The greater a catchment's pool of PO43? and the greater its ability to flush PO43? out of the soil and into surface flow, the wider the hysteresis loops. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献