Stratigraphie sequentielle du Dinantien type (Belgique) et correlation avec le Nord de la France (Boulonnais, Avesnois)

2001 ◽  
Vol 172 (4) ◽  
pp. 411-426 ◽  
Author(s):  
Luc Hance ◽  
Eddy Poty ◽  
Francois-Xavier Devuyst
Keyword(s):  
Early Phase ◽  
Outer Shelf ◽  
Large Area ◽  
Third Order ◽  
Inner Shelf ◽  
Southern England ◽  
The North ◽  
Western Germany ◽  
Local Tectonics ◽  
Homoclinal Ramp

Abstract The relative influences of local tectonics and global eustasy in the architecture of the sedimentary units of the Namur-Dinant Basin (southern Belgium) are determined. Nine third-order sequences are recognised. During the Lower Tournaisian (Hastarian and lower Ivorian) a homoclinal ramp extended from southern Belgium through southern England (Mendips) and into southern Ireland. From the upper Ivorian to the lower Visean rapid facies changes occurred due to progradation and increasing prominence of Waulsortian mudmounds. Progradation gradually produced a situation in which inner shelf facies covered the Namur (NSA), Condroz (CSA) and southern Avesnes (ASA) sedimentation areas, whereas outer shelf facies were restricted to the Dinant sedimentation area (DSA). During the middle and late Visean a broad shelf was established from western Germany to southern Ireland. Because the shelf built up mainly by aggradation, parasequences can be followed over a large area. An early phase of Variscan shortening is perceptible during the Livian. The stratigraphic gap between the first Namurian sediments (E2 Goniatite Zone) and the underlying Visean varies from place to place, but is more important in the north.

scholarly journals Diversified calcimicrobes in dendrolites of the Zhangxia Formation, Miaolingian Series (Middle Cambrian) of the North China craton

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ming-Xiang Mei ◽  
Muhammad Riaz ◽  
Zhen-Wu Zhang ◽  
Qing-Fen Meng ◽  
Yuan Hu
Keyword(s):  
North China ◽  
Cyanobacterial Mats ◽  
Third Order ◽  
Depositional Sequence ◽  
Middle Cambrian ◽  
Forming Mechanism ◽  
The North ◽  
Biological Affinity ◽  
History Of ◽  
Group 3

AbstractAs a type of non-laminated microbial carbonates, dendrolites are dominated by isolated dendritic clusters of calcimicrobes and are distinct from stromatolites and thrombolites. The dendrolites in the upper part of the Miaolingian Zhangxia Formation at Anjiazhuang section in Feicheng city of Shandong Province, China, provide an excellent example for further understanding of both growth pattern and forming mechanism of dendrolites. These dendrolites are featured by sedimentary fabrics and composition of calcified microbes as follows. (1) The strata of massive limestones, composed of dendrolites with thickness of more than one hundred meters, intergrade with thick-bedded to massive leiolites, formimg the upper part of a third-order depositional sequence that constitutes a forced regressive systems tract. (2) A centimeter-sized bush-like fabric (shrub) typically produced by calcified microbes is similar to the mesoclot in thrombolites but distinctive from clotted fabrics of thrombolites. This bush-like fabric is actually constituted by diversified calcified microbes like the modern shrub as a result of gliding mobility of filamentous cyanobacteria. Such forms traditionally include: the Epiphyton group (which actually has uncertain biological affinity), the Hedstroemia group which closely resembles modern rivulariacean cyanobacteria, and the possible calcified cyanobacteria of the Lithocodium–Bacinella group. (3) Significantly, dense micrite of leiolite is associated with sponge fossils and burrows, and is covered by microstromatolite. The Lithocodium–Bacinella group is a controversial group of interpreted calcified cyanobacteria in the Cambrian that has also been widely observed and described in the Mesozoic. Therefore, dendrolites with symbiosis of leiolites in the studied section provide an extraordinary example for further understanding of growing style of bush-like fabrics (shrubs) of the dendrolites dominated by cyanobacterial mats. Furthermore, the present research provides some useful thinking approaches for better understanding of the history of the Early Paleozoic skeletal reefs and the microbe–metazoan transitions of the Cambrian.

New Evidence of the Late Neopleistocene Peopling of the Lower Ob Valley

2021 ◽  
Vol 49 (1) ◽  
pp. 9-20
Author(s):  
I. D. Zolnikov ◽  
A. A. Anoikin ◽  
E. A. Filatov ◽  
A. V. Vybornov ◽  
A. V. Vasiliev ◽  
...  
Keyword(s):  
Upper Paleolithic ◽  
The Arctic ◽  
Northern Eurasia ◽  
West Siberian Plain ◽  
Faunal Remains ◽  
Human Occupation ◽  
Large Area ◽  
Paleolithic Site ◽  
The North ◽  
Available Information

This study focuses on the early human occupation of the arctic part of the West Siberian Plain and introduces the finds at the Paleolithic site Kushevat (Shuryshkarsky District, Yamal-Nenets Autonomous Okrug), discovered in 2020. Geological and geomorphological characteristics of the Lower Ob region are provided, the chronology of the key Middle and Late Neopleistocene sequences is assessed, and criteria underlying the search for Paleolithic sites in the area are outlined. We describe the discovery and excavations at Kushevat, its stratigraphy and its faunal remains. On the basis of correlation with neighboring key Late Neopleistocene sections with a representative series of absolute dates, the age of the site is estimated at cal 50–35 ka BP. Results of a traceological study of a possibly human-modified reindeer antler are provided. Findings at Kushevat and the available information on the early peopling of northern Eurasia suggest that the boundary of the inhabited part of that region must be shifted ~200 km to the north. The Ob, therefore, is one of the last major Siberian rivers where traces of the Early Upper Paleolithic culture have been found. The discovery of a stratified site in its lower stretch is a milestone in the Paleolithic studies in the region. A large area over which faunal remains are distributed, and the presence of lithics among the surface finds, suggest that Kushevat is a highly prospective site for future archaeological studies of the early stages in the human peopling of the region.

Vowel raising in Basaa: a synchronic chain shift

Phonology ◽  
1996 ◽  
Vol 13 (2) ◽  
pp. 239-267 ◽  
Author(s):  
Deborah Schlindwein Schmidt
Keyword(s):  
Phonological Representation ◽  
Large Area ◽  
Bantu Languages ◽  
North East ◽  
The North ◽  
Equatorial Africa ◽  
Verb Forms ◽  
Vowel Raising

Like many of the zone A Bantu languages of western equatorial Africa, Basaa, which is spoken over a large area to the north-east and east of Douala, Cameroon, shows an inventory of seven surface vowels (Guthrie 1953). The Basaa forms cited in this article, all of which are found in the comprehensive Dictionnaire Basaa-Français (Lemb & de Gastines 1973), are transcribed using the vowel symbols in (1):These vowel symbols differ from those used by Guthrie only in that the hooks are eliminated from underneath his [i] and [u] and the dots are eliminated from underneath his [???] and [???]. I assume for these vowels the characteristics indicated in (1), where non-parenthesised feature specifications are a property of surface phonological representation and parenthesised feature specifications are default phonetic values. Following Hyman's (1988) analysis of Esimbi, another Cameroonian language containing these vowels in its inventory, I take [E] and [ɔ] to be low.The verb roots in (2) contain instances of each of the seven surface vowels of Basaa:Though bare verb roots may surface unsuffixed, suffixal extensions may also be added to give applied, passive, habitual, direct causative, indirect causative, simultaneous, associative, possessive, reversive, reflexive, stative and nominalised forms. Of interest to us is the vowel raising induced within the verb root when certain of these suffixal extensions are added. In (3) we see the CVC verb forms of (2) along with their corresponding applied and indirect causative forms:Other suffixal extensions that induce raising are the passive, direct causative, simultaneous, reversive and stative extensions. For example, these other suffixal extensions attach to /ten/, one of the verb roots in (3), to give [tina], [tinis], [tinha], [tinil] and [tiní], respectively.

scholarly journals Morphology and distribution of the freshwater mussel Diplodon granosus, a rare and poorly understood species

2020 ◽  
Vol 50 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Igor Christo MIYAHIRA ◽  
Maria Cristina Dreher MANSUR ◽  
Daniel Mansur PIMPÃO ◽  
Sheyla Regina Marques COUCEIRO ◽  
Sonia Barbosa dos SANTOS
Keyword(s):  
South America ◽  
Freshwater Mussels ◽  
Freshwater Mussel ◽  
Wide Distribution ◽  
Large Area ◽  
The North ◽  
Coastal Rivers ◽  
The Status ◽  
Long Time

ABSTRACT Diplodon granosus was one of the first freshwater mussels to be described for South America. However, the status of the species was confusing for a long time, receiving different taxonomic treatments. In this paper, we redescribe the shell, with new data on the soft parts and information on the distribution and conservation of D. granosus, a rarely recorded species. The shell is thin, not inflated; the macrosculpture is composed only by granules that cover the whole shell, not forming bars; the microsculpture comprises short spikes. In the soft parts we highlight the few, weak and irregularly distributed lamellar connections of the outer demibranch and some features of the stomach, such as the distally enlarged minor typhlosole. There are records of D. granosus over a large area of South America, from Guiana to Argentina. However, most of these records are related to other species and the distribution of D. granosus is restricted to the north of South America in the basins of the Amazonas and Orinoco rivers, and coastal rivers in between. Despite this wide distribution, the species occurs in specific habitats, mainly streams (igarapés), resulting in an extremely fragmented occurrence. Thus, any disturbance to these habitats can threat this freshwater mussel.

Inner shelf seismic stratigraphy off the north coast of Northern Ireland: new data on the depth of the Holocene lowstand

2002 ◽  
Vol 186 (3-4) ◽  
pp. 369-387 ◽  
Author(s):  
J.A.G Cooper ◽  
J.T Kelley ◽  
D.F Belknap ◽  
R Quinn ◽  
J McKenna
Keyword(s):  
Northern Ireland ◽  
Seismic Stratigraphy ◽  
North Coast ◽  
Inner Shelf ◽  
The Holocene ◽  
The North

scholarly journals Modelling the spread and connectivity of waterborne marine pathogens: the case of PaV1 in the Caribbean

2014 ◽  
Vol 72 (suppl_1) ◽  
pp. i139-i146 ◽  
Author(s):  
Andrew S. Kough ◽  
Claire B. Paris ◽  
Donald C. Behringer ◽  
Mark J. Butler
Keyword(s):  
Field Experiments ◽  
Significant Risk ◽  
Large Area ◽  
Larval Stages ◽  
The North ◽  
Risk Of Mortality ◽  
Rapid Spread ◽  
Waterborne Transmission ◽  
Juvenile Stages ◽  
The Caribbean

AbstractThe PaV1 virus infects spiny lobsters (Panulirus argus) throughout most of the Caribbean, where its prevalence in adult lobsters can reach 17% and where it poses a significant risk of mortality for juveniles. Recent studies indicate that vertical transmission of the virus is unlikely and PaV1 has not been identified in the phyllosoma larval stages. Yet, the pathogen appears subclinically in post-larvae collected near the coast, suggesting that lobster post-larvae may harbour the virus and perhaps have aided in the dispersal of the pathogen. Laboratory and field experiments also confirm the waterborne transmission of the virus to post-larval and early benthic juvenile stages, but its viability in the water column may be limited to a few days. Here, we coupled Lagrangian modelling with a flexible matrix model of waterborne and post-larval-based pathogen dispersal in the Caribbean to investigate how a large area with complex hydrology influences the theoretical spread of disease. Our results indicate that if the virus is waterborne and only viable for a few days, then it is unlikely to impact both the Eastern and Northwestern Caribbean, which are separated by dispersal barriers. However, if PaV1 can be transported between locations by infected post-larvae, then the entire Caribbean becomes linked by pathogen dispersal with higher viral prevalence in the North. We identify possible regions from which pathogens are most likely to spread, and highlight Caribbean locations that function as dispersal “gateways” that could facilitate the rapid spread of pathogens into otherwise isolated areas.

scholarly journals G279.0+1.1: a new extended source of high-energy gamma-rays

2020 ◽  
Vol 492 (4) ◽  
pp. 5980-5986
Author(s):  
M Araya
Keyword(s):  
Spectral Index ◽  
Gamma Rays ◽  
Gamma Ray ◽  
High Energy ◽  
Particle Spectrum ◽  
Large Area ◽  
Extended Source ◽  
The North ◽  
Energy Gamma ◽  
High Energy Emission

ABSTRACT G279.0+1.1 is a supernova remnant (SNR) with poorly known parameters, first detected as a dim radio source and classified as an evolved system. An analysis of data from the Fermi-Large Area Telescope (LAT) revealing for the first time an extended source of gamma-rays in the region is presented. The diameter of the GeV region found is ${\sim} 2{^{\circ}_{.}}8$, larger than the latest estimate of the SNR size from radio data. The gamma-ray emission covers most of the known shell and extends further to the north and east of the bulk of the radio emission. The photon spectrum in the 0.5–500 GeV range can be described by a simple power law, $\frac{\mathrm{ d}N}{\mathrm{ d}E} \propto E^{-\Gamma }$, with a spectral index of Γ = 1.86 ± 0.03stat ± 0.06sys. In the leptonic scenario, a steep particle spectrum is required and a distance lower than the previously estimated value of 3 kpc is favoured. The possibility that the high-energy emission results from electrons that already escaped the SNR is also investigated. A hadronic scenario for the gamma-rays yields a particle spectral index of ∼2.0 and no significant constraints on the distance. The production of gamma-rays in old SNRs is discussed. More observations of this source are encouraged to probe the true extent of the shell and its age.

scholarly journals Holocene climate variability in the North-Western Mediterranean Sea (Gulf of Lions)

2016 ◽  
Vol 12 (1) ◽  
pp. 91-101 ◽  
Author(s):  
B. Jalali ◽  
M.-A. Sicre ◽  
M.-A. Bassetti ◽  
N. Kallel
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Early Holocene ◽  
Inner Shelf ◽  
Catchment Basin ◽  
Rhône River ◽  
Gulf Of Lions ◽  
The North ◽  
Western Mediterranean Sea ◽  
Rhone River

Abstract. Sea surface temperatures (SSTs) and land-derived input time series were generated from the Gulf of Lions inner-shelf sediments (NW Mediterranean Sea) using alkenones and high-molecular-weight odd-carbon numbered n-alkanes (TERR-alkanes), respectively. The SST record depicts three main phases: a warm Early Holocene ( ∼  18 ± 0.4  °C) followed by a cooling of  ∼  3  °C between 7000 and 1000 BP, and rapid warming from  ∼  1850 AD onwards. Several superimposed multi-decadal to centennial-scale cold events of  ∼  1  °C amplitude were also identified. TERR-alkanes were quantified in the same sedimentary horizons to identify periods of high Rhone River discharge and compare them with regional flood reconstructions. Concentrations show a broad increase from the Early Holocene towards the present with a pronounced minimum around 2500 BP and large fluctuations during the Late Holocene. Comparison with Holocene flood activity reconstructions across the Alps region suggests that sediments of the inner shelf originate mainly from the Upper Rhone River catchment basin and that they are primarily delivered during positive North Atlantic Oscillation (NAO).

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