A subaerial arthropod trackway from the Upper Silurian Clam Bank Formation of Newfoundland

1995 ◽  
Vol 32 (3) ◽  
pp. 304-313 ◽  
Author(s):  
J. L. Wright ◽  
L. Quinn ◽  
D. E. G. Briggs ◽  
S. H. Williams
Keyword(s):  
Lower Devonian ◽  
Trace Fossil ◽  
Environment Analysis ◽  
Fine Grained ◽  
Body Drag ◽  
Upper Silurian ◽  
First Time ◽  
Parallel Series

Trackways are reported for the first time from Silurian rocks in Newfoundland. They occur in the Clam Bank Formation of the Port au Port Peninsula. At least one of the trackways represents one of the earliest known occurrences of a large subaerial arthropod trace fossil. It is preserved in hyporelief in a red fine-grained sandstone. The trackway, Diplichnites Dawson, 1873, consists of two parallel series of clearly defined imprints. It is attributed to a myriapod similar to the Lower Devonian Eoarthropleura. The sandstone contains halite pseudomorphs that indicate that the sediment horizon had been subject to desiccation immediately prior to the formation of the trackway. The arthropod walked on a red siltstone deposited in an alluvial flats environment. Analysis of the trackway suggests that the arthropod was approximately 23 cm long and had 17 pairs of walking appendages. It appears that a high-geared gait with a ratio of forestroke:backstroke of 8:2 was used in walking across the substrate, that is, approximately 20% of walking appendages were in contact with the substrate at any one time. This rapid gait, and the lack of a body drag mark, indicates that the arthropod was well adapted to subaerial locomotion. Knowledge of modern myriapod gaits has been used to extrapolate a theoretical trail, which compares well with the fossil trackway. Smaller, less well preserved trackways occur elsewhere in the Clam Bank Formation and may have been made by a similar arthropod.

SEDIMENTOLOGY AND CARBON ISOTOPE (δ13C) STRATIGRAPHY OF SILURIAN–DEVONIAN BOUNDARY INTERVAL STRATA, APPALACHIAN BASIN (PENNSYLVANIA, USA)

Palaios ◽  
2019 ◽  
Vol 34 (9) ◽  
pp. 405-423
Author(s):  
ANYA V. HESS ◽  
JEFFREY M. TROP
Keyword(s):  
New York ◽  
Carbon Isotope ◽  
Lower Devonian ◽  
Appalachian Basin ◽  
Sediment Supply ◽  
Fine Grained ◽  
Marine Strata ◽  
Central Pennsylvania ◽  
Storm Wave ◽  
Upper Silurian

ABSTRACT Silurian–Devonian boundary interval strata deposited during the expansion of land plants record a major perturbation of the carbon cycle, the global Klonk Event, one of the largest carbon isotope excursions during the Phanerozoic. In the Appalachian Basin, these marine strata record the regional buildup to the Acadian Orogeny. This study reports new sedimentologic, paleontologic, ichnologic, and carbon isotope data from an exceptional quarry exposure in central Pennsylvania, USA, a historically understudied area between better-documented outcrops >500 km away to the southwest (West Virginia, Virginia, Maryland) and northeast (New York). Facies spanning the continuous 113-m thick outcrop are dominantly carbonate and fine-grained siliciclastic strata interpreted as being deposited in supratidal through subtidal environments, including oxygen-limited environments below storm wave base. They record parts of three transgressive-regressive cycles, in the (1) upper Silurian Tonoloway Formation, (2) upper Silurian–Lower Devonian Keyser Formation through lower Mandata Member of the Old Port Formation, and (3) Lower Devonian Mandata through Ridgeley Members of the Old Port Formation. Micrite matrix δ13Ccarb analyses exhibit a large, positive δ13Ccarb excursion (>5‰ amplitude). Outcrops of this interval in the Appalachian Basin occur in two belts, between which correlation has been historically challenging. The regional correlation presented herein is based on carbon-isotope trends and is more consistent with published conodont biostratigraphy and volcanic ash ages, an improvement over published correlations based on lithostratigraphy. Transgressive-regressive trends at the central Pennsylvania study site are not consistent with regional trends, indicating that local controls (tectonics, sediment supply) rather than global (eustasy) dominated depositional patterns in the Silurian–Devonian boundary interval in the Appalachian Basin.

The Somerset Island Formation: an upper Silurian to ?Lower Devonian intertidal/supratidal succession, Boothia Uplift region, Arctic Canada

1978 ◽  
Vol 15 (2) ◽  
pp. 181-189 ◽  
Author(s):  
A. D. Miall ◽  
J. Wm. Kerr ◽  
M. R. Gibling
Keyword(s):  
Lower Devonian ◽  
Alluvial Fan ◽  
Similar Sequence ◽  
Island Formation ◽  
Fine Grained ◽  
Rock Types ◽  
Sandstone Rock ◽  
Upper Silurian ◽  
Somerset Island ◽  
Cornwallis Island

The Somerset Island Formation of Somerset Island is a newly defined unit consisting of interbedded fine-grained, grey, planar-laminated dolomite and limestone, grey mottled limestone and dolomite, red quartzose siltstone and red dolosiltite. It forms a transitional unit between the limestone and dolomite of the underlying Read Bay Formation and the sandstone and conglomerate of the overlying Peel Sound Formation, and ranges in thickness from 150 to more than 400 m. The formation was formed predominantly in intertidal and supratidal environments and forms the lowest part of a regressive sequence that culminates in boulder conglomerates of alluvial fan origin in the Peel Sound Formation. The Somerset Island Formation is predominantly Pridolian in age, but may include some strata of Ludlovian and Gedinnian age.The regressive sequence reflects a major pulse of the Cornwallis Disturbance of Boothia Uplift. A similar sequence occurs in Prince of Wales Island, although the lower part of the succession there contains conglomerate and sandstone, rock types that are absent in Somerset Island. These rocks are formally assigned to the Lower Peel Sound Formation but are of similar age to the Somerset Island Formation of the type area.Rocks of similar facies to the Somerset Island Formation of Somerset Island comprise the upper member of the Drake Bay Formation on Russell Island and Member D of the Read Bay Formation on Cornwallis Island. The latter unit is younger than the Somerset Island Formation, reflecting a later commencement of regression in that area.

scholarly journals Electrodeposition of Copper and Brass Coatings with Olive-Like Structure

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1762
Author(s):  
Artur Maciej ◽  
Natalia Łatanik ◽  
Maciej Sowa ◽  
Izabela Matuła ◽  
Wojciech Simka
Keyword(s):  
Corrosion Resistance ◽  
Cathodic Current Density ◽  
Bath Composition ◽  
Cathodic Current ◽  
Corrosion Properties ◽  
Fine Grained ◽  
Electrodeposited Coating ◽  
Copper Zinc ◽  
New Generation ◽  
First Time

One method of creating a brass coating is through electrodeposition, which is most often completed in cyanide galvanic baths. Due to their toxicity, many investigations focused on the development of more environmentally friendly alternatives. The purpose of the study was to explore a new generation of non-aqueous cyanide-free baths based on 1-ethyl-3-methylimidazolium acetate ionic liquids. The study involved the formation of copper, zinc, and brass coatings. The influence of the bath composition, cathodic current density, and temperature was determined. The obtained coatings were characterized in terms of their morphology, chemical composition, phase composition, roughness, and corrosion resistance. It was found that the structure of the obtained coatings is strongly dependent on the process parameters. The three main structure types observed were as follows: fine-grained, porous, and olive-like. To the best knowledge of the authors, it is the first time the olive-like structure was observed in the case of an electrodeposited coating. The Cu-Zn coatings consisted of 19–96 at. % copper and exhibited relatively good corrosion resistance. A significant improvement of corrosion properties was found in the case of copper and brass coatings with the olive-like structure.

The first finding of a Greek amphora in Poland

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sylwester Czopek ◽  
Katarzyna Trybała-Zawiślak ◽  
Joanna Trąbska ◽  
Barbara Trybalska ◽  
Joanna Adamik-Proksa ◽  
...  
Keyword(s):  
Trace Elements ◽  
Forest Steppe ◽  
Iron Compounds ◽  
Fine Grained ◽  
Tof Sims ◽  
First Finding ◽  
High Calcium ◽  
The University ◽  
First Time ◽  
North Western

Abstract In 2017, an expedition of the Institute of Archeology of the University of Rzeszów (Poland) carried out excavations on a hillfort belonging to the Scythian cultural circle (its forest-steppe variant) in Chotyniec, in south-eastern Poland. The hillfort is the central and most important point of a large settlement cluster, which is the furthest north-western enclave of this cultural circle. In an excavated cult object – the so-called ‘zolnik’ – we made an interesting discovery. Here we show this unique finding for the first time: a Greek wine amphora, from the beginning of the sixth century BC. We were able to explore and reconstruct it almost entirely. Amphora is the only artefact of this type found in the present Polish borders. The amphora was subjected to archaeometric research with the use of PLM, SEM/EDS, TXRF and ToF SIMS. The massive fabric was made of high calcium clay enriched in quartz and volcanic lithoclasts. The lack of chromium and nickel among trace elements makes the vessel different from the amphoras from the Eastern Meditteranean analysed so far, suggesting a specific workshop. Red painting was executed with very fine grained iron compounds predominantly based on aluminosilicates, enriched in phosphorus. Obviously, since it is associated with the presence of Scythians in Eastern Europe, it simultaneously delimits (geography-wise) the borders of Greek influence.

Plant Taphonomy and Paleoecology of Late Pennsylvanian Intramontane Wetlands in the Graissessac-Lodève Basin (Languedoc, France)

Palaios ◽  
2005 ◽  
Vol 20 (3) ◽  
pp. 249-265 ◽  
Author(s):  
CARLES MARTÍN-CLOSAS ◽  
JEAN GALTIER
Keyword(s):  
Detailed Comparison ◽  
Alluvial Fans ◽  
Fluvial Sediments ◽  
Tree Fern ◽  
Massif Central ◽  
Fine Grained ◽  
Tree Ferns ◽  
First Time ◽  
Diverse Plant

Abstract The Late Pennsylvanian Graissessac-Lodève basin is a small, fluvio-palustrine depocenter located in the southern part of the Massif Central (France). A taphonomic and sedimentologic study carried out in this area allows a reconstruction of Late Carboniferous vegetation in an intramontane context. The paleoecology of such limnic settings is poorly known, and this study permits detailed comparison with paralic basins for the first time. The Graissessac peat mires developed in abandoned fluvial channels, in floodplains, and above distal alluvial fans. The vegetation was dominated by monospecific stands of the arborescent lycopsid Sigillaria brardii, whereas the tree fern Psaronius occurred during the later stages of mire accretion. This is in contrast to coeval North American peat mires, which generally were dominated by tree ferns and pteridosperms throughout the mire profile. Stephanian floodplains and distal alluvial fans of the Graissessac-Lodève Basin were devoid of vegetation, with the exception of isolated thickets of sphenopsids that were composed of Calamites and Sphenophyllum. These plants were found growing in situ in the floodplain mudstones as well as in fine-grained sands of secondary channels. Parautochthonous foliage assemblages of ferns and pteridosperms found in floodplain mudstones represent the most diverse plant community. The plants supplying these remains were growing in exposed areas close to floodplains. Large logs attributed to cordaitaleans and monotypic assemblages of large Cordaites leaves were found in fluvial sediments, and suggest that the plants were riparian elements in the basin.

Martian stick-like structures are not trace fossils: a new protocol for testing ichnogenicity synthesized from paleosol ichnology

2021 ◽  
pp. 1-8
Author(s):  
Jorge F. Genise
Keyword(s):  
Surface Morphology ◽  
Trace Fossils ◽  
Trace Fossil ◽  
The Future ◽  
Study Case ◽  
First Time

Abstract There are different criteria that are usually analysed independently before identifying a new trace fossil, such as morphological regularity, completeness, dispersion, recurrence and complexity, surface morphology, and context. The synthesis of these criteria, as utilized in paleosol ichnology, composes a protocol that is presented herein for the first time and can be used for testing the ichnogenicity of trace-like structures in any paleoenvironment of Earth or Mars. As a study case, the Martian ‘stick-like structures’ do not fulfil any of the requirements posed by this protocol to be postulated as trace fossils. The ichnogenicity test, focussed exclusively on morphology and context, is simpler but equally useful as the biogenicity ones. It may be applied in the future with other potential cases before carrying on more complex analyses or to evaluate the astrobiological interest of trace-like structures.

scholarly journals Entrepreneurial self-efficacy in a multicultural society: Measures and ethnic differences

2006 ◽  
Vol 32 (1) ◽  
Author(s):  
Boris Urban
Keyword(s):  
South African ◽  
Ethnic Differences ◽  
Self Efficacy ◽  
Entrepreneurial Activity ◽  
Single Factor ◽  
Multicultural Society ◽  
Factor Solution ◽  
Fine Grained ◽  
African Context ◽  
First Time

Deficits in self-beliefs lower entrepreneurial activity in the broader South African context. A brief theoretical analysis preceded establishing the psychometric evaluations of the entrepreneurial self-efficacy (ESE) and general selfefficacy (GSE) measures. Participants representing different major ethnic groups in SA were sampled. Results indicate that the GSE scale remains a single factor solution thereby confirming the unidimensionality and reliability of this measure. The different ESE sub-domains provide a far more fine-grained approach to understanding self-efficacy. ANOVA determined significant differences in self-efficacy scores between the different groups. Apart from introducing the ESE construct to the SA literature, it is the first time that a study has united the general and specific measures of self-efficacy as well as measuring both the magnitude and strength dimensions of self-efficacy beliefs. Opsomming Tekortkominge in selfgeloofwaardigheid doen afbreuk aan entrepreneuriese aktiwiteite in die breër Suid Afrikaanse konteks. ’n Samevattende teoretiese analise het die vasstelling van strukturele ekwivalensie van die entrepreneuriese ESE en GSE skale voorafgegaan. ’n Steekproef van MBA respondente, verteenwoordigend van die hoof etniese groepe binne SA, is vir die studie gebruik. Bevindinge dui daarop dat die GSE skaal ’n enkel faktor oplossing is bevestigend van die enkel dimensionaliteit en betroubaarheid van hierdie maatstaf. ANOVA dui daarop dat merkbare verskille bestaan tussen die ESE tellings van die verskillende groeperinge. Benewens die bekendstelling van die ESE konsep, aan die SA literatuur, verenig hierdie studie vir die eerste keer die breë en spesifieke maatstawwe van selfgeloofwaardigheid, en meet dit ook die grote en sterkte van hierdie verandelikes.

scholarly journals Thermal properties of large main-belt asteroids observed by Herschel PACS

2020 ◽  
Vol 638 ◽  
pp. A84
Author(s):  
V. Alí-Lagoa ◽  
T. G. Müller ◽  
C. Kiss ◽  
R. Szakáts ◽  
G. Marton ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Thermal Inertia ◽  
Physical Models ◽  
Absolute Calibration ◽  
Calibration Error ◽  
Main Belt ◽  
Infrared Observations ◽  
Fine Grained ◽  
Shape Models ◽  
First Time

Non-resolved thermal infrared observations enable studies of thermal and physical properties of asteroids via thermo-physical models provided the shape and rotational properties of the target are well determined. We used calibration-programme Herschel PACS data (70, 100, 160 μm) and state-of-the-art shape models derived from adaptive-optics observations and/or optical light curves to constrain for the first time the thermal inertia of twelve large main-belt asteroids. We also modelled previously well-characterised targets such as (1) Ceres or (4) Vesta as they constitute important benchmarks. Using the scale as a free parameter, most targets required a re-scaling ~5% consistent with what would be expected given the absolute calibration error bars. This constitutes a good cross-validation of the scaled shape models, although some targets required larger re-scaling to reproduce the IR data. We obtained low thermal inertias typical of large main belt asteroids studied before, which continues to give support to the notion that these surfaces are covered by fine-grained insulating regolith. Although the wavelengths at which PACS observed are longwards of the emission peak for main-belt asteroids, they proved to be extremely valuable to constrain size and thermal inertia and not too sensitive to surface roughness. Finally, we also propose a graphical approach to help examine how different values of the exponent used for scaling the thermal inertia as a function of heliocentric distance (i.e. temperature) affect our interpretation of the results.

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