Description of two new fossil echinoids (Echinodermata: Echinoidea) from the Early Hauterivian (Early Cretaceous) of the Paris Basin (France)

Zootaxa ◽  
2012 ◽  
Vol 3512 (1) ◽  
pp. 75 ◽  
Author(s):  
THOMAS SAUCÈDE ◽  
JEAN-CHRISTOPHE DUDICOURT ◽  
PHILIPPE COURVILLE

Two new echinoid genera and species, Salvaster roberti gen. et sp. nov. and Pygolampas edita gen. et sp. nov. are de-scribed. They were collected in the Calcaires à Spatangues Formation (CSF) that consists of limestone and clay sedimentsdeposited in the southeast of the Paris Basin (France) during the Early Hauterivian (Early Cretaceous). The CSF is datedfrom the Acanthodiscus radiatus chronozone, a time-interval of overall high sea level in Western Europe, but it yields arich shallow-water fossil fauna mostly represented by benthic invertebrates. Of the 54 echinoid species ever described inthe CSF, 26 species are recognized here. They are distributed into 16 different families, among which regular (13 species)and irregular (13 species) echinoids are represented in equal proportion. This work confirms the high level of echinoid diversity in the CSF for that time-period.

2006 ◽  
Vol 9 (1) ◽  
pp. 7-30 ◽  
Author(s):  
Pierre Pétrequin ◽  
Michel Errera ◽  
Anne-Marie Pétrequin ◽  
Pierre Allard

Two groups of quarries (Mont Viso and Mont Beigua, Italy) were the source of the Alpine axeheads that circulated throughout western Europe during the Neolithic. The quarries on Mont Viso (Oncino: Porco, Bulè and Milanese), discovered in 2003, have been radiocarbon-dated, and this has revealed that the exploitation of jadeites, omphacitites and eclogites at high altitude (2000–2400 m above sea level) seems to have reached its apogee in the centuries around 5000 BC. The products, in the form of small axe- and adze-heads, were distributed beyond the Alps from the beginning of the fifth millennium, a few being found as far away as the Paris Basin, 550 km from their source as the crow flies. However, it was not until the mid-fifth millennium BC that long axeheads from Mont Viso appeared in the hoards and monumental tombs of the Morbihan, 800 km from the quarries. Production continued until the beginning of the third millennium BC, but at this time the distribution of the products was less extensive, and the process of distribution operated in a different way: tools made from jadeite and eclogite are still found in the French Jura, but the extraction sites at the south-east foot of Mont Viso no longer seem to have been used. The variability in the geographical extent of the distribution at different times seems to be related to the social context of exploitation of the high-altitude quarries, which were only ever accessible for a few months each year.


2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Nela Nedeva ◽  
◽  
◽  

The present article showcases the research done by the author on the drawing teachers of the Gabrovo State Boys’ High School during the 19-th and 20-th century. The study focuses on the teachers who have received academic education in Russia and Western Europe. The point of the article is to show the high level of teaching and erudition of the pedagogical staff during the examined time period. As proof the author has indicated information about their students who have left permanent traces in the history of painting even outside the borders of their country.


1992 ◽  
Vol 6 ◽  
pp. 278-278 ◽  
Author(s):  
S.W. Starratt

Taxonomic databases are important tools in the study of faunal diversity and evolution. The usefulness of the inferences drawn from these databases is diminished when the role of environment is not considered. Analysis of the foraminiferal database at the genus and family levels is used to demonstrate the effect of water depth on presumed changes in taxonomic diversity and evolutionary turnover rates.This paleoenvironmental effect is particularly noticeable when foraminiferal faunas of the late Paleozoic and the Mesozoic and Cenozoic intervals are compared. The late Paleozoic fauna is dominated by the Fusulinina and shallow-water (0–200 m) Textularuna. Standing diversity fluctuates greatly, and evolutionary turnover is high. This reflects short-term fluctuations in sea level which led to the rapid formation and destruction of narrow ecological niches. Evolutionary turnover appears to be related to reef growth during this time. This trend may also reflect an increased number of k-selected specialists which serve as proxy indicators for a slow-circulating oligotrophic ocean system. Shallow-water taxa may also be predisposed to extinction due to their reliance on symbiotic algae. The extinction event at the end of the Permian resulted in the loss of almost 70% of the standing generic diversity. This included the complete loss of the Fusulinina as well as a number of shallow-water textularids. Cohort survivorship curves are steep and taxon ages short during this time.The diversity increase over the past 245 million years has largely been due to the addition of deep-water (200-10,000 m) taxa. This was particularly true during the Late Cretaceous and early Eocene, and may reflect the relatively high eustatic sea level during those intervals. The relationship between reef development and evolutionary turnover rates is less clear during this time interval. Although the extinction event that marked the end of the Cretaceous resulted in a greater loss in absolute taxonomic diversity than occurred at the end of the Permian, the relative loss in generic diversity was only about 21% due to the large number of deep-water taxa. When the entire fauna is considered, cohort survivorship curves are less steep and taxon ages are longer than in the late Paleozoic, but when only the shallow-water taxa are considered, the results are similar to those for the late Paleozoic.


2006 ◽  
Vol 177 (3) ◽  
pp. 155-175 ◽  
Author(s):  
Médard Thiry ◽  
Florence Quesnel ◽  
Johan Yans ◽  
Robert Wyns ◽  
Anne Vergari ◽  
...  

Abstract During the early Cretaceous, successive tectonic phases and several sea level falls resulted in the emersion of the main part of western Europe and the development of thick “lateritic” weathering. This long period of continental evolution ended with the Upper Cretaceous transgressions. During this period, the exposed lands displayed a mosaic of diverse morphologies and weathered landscapes. Bauxites are the most spectacular paleoweathering features, known for long in southern France. Recently, new residual outcrops have been identified, trapped in the karstic depressions of the Grands Causses. Other bauxitic formations, containing gibbsite, have also been recognised, occurring with the Clay-with-Jurassic-cherts in the southeastern border of the Paris Basin. These bauxitic formations overlay Jurassic limestone and are buried beneath Upper Cretaceous marine deposits. The recognition of bauxites up north into the southern Paris Basin significantly widens the extension of the Lower Cretaceous bauxitic paleolandscapes. On the Hercynian basements thick kaolinitic weathering mantles occur. They have been classically ascribed to the Tertiary. The first datings of these in situ paleosoils, by means of paleomagnetism and/or radiogenic isotopes, record especially early Cretaceous ages. This is the case for the “Siderolithic” formations on the edges of the French Massif Central, but also for the kaolinitic profiles in the Belgian Ardennes. In the Flanders, the Brabant basement is deeply kaolinised beneath the Upper Cretaceous cover. These paleosoils show polygenetic evolutions. The relief of these basement paleolandscapes may have been significant. There where probably high scarps (often of tectonic origin) reaching 200 m in elevation or beyond, as well as wide surfaces with inselbergs, as in the present day landscapes of tropical Africa and South America. On the Jurassic limestone platforms occur diverse kaolinitic and ferruginous weathering products. Around the Paris Basin they show various facies, ranging from kaolinitic saprolites to ferricretes. Due to the lack of sedimentary cover, the age of these ferruginous and kaolinitic weathering products has been debated for long, most often allocated to the Siderolithic sensu lato (Eocene-Oligocene). Recent datings by paleomagnetism have enabled to date them (Borne de Fer in eastern Paris Basin) back also to the early Cretaceous (130 ± 10 Ma). These wide limestone plateaus show karstified paleolandforms, such as vast closed and flat depressions broken by conical buttes, but also deep sinkholes in the higher areas of the plateaus and piedmonts. The depth of the karst hollows may be indicative of the range of relative paleoelevations. Dissolution holes display seldom contemporaneous karst fillings, thus implying that the karstland had not a thick weathering cover or that this cover had been stripped off before or by the late Cretaceous transgression. Nevertheless, some areas, especially above chert-bearing Jurassic limestone or marl, show weathering products trapped in the karst features or as a thick weathering mantle. In the Paris Basin, the Wealden gutter looked like a wide floodplain in which fluvio-deltaic sands and clays were deposited and on which paleosoils developed during times of non-deposition. The edges of the gutter were shaped as piedmonts linked up with the upstream basement areas. The rivers flowing down to the plain deposited lobes of coarse fluvial sands and conglomerates. The intensity of the weathering, the thickness of the profiles and their maturation are directly dependent on the duration of the emersion and the topographic location relative to the gutter. Near the axis of the gutter, where emersion was of limited duration, the paleoweathering features are restricted to rubefaction and argillization of the Lower Cretaceous marine formations. On the other hand, on the borders of the basin and on the Hercynian basement, where emersion was of longer duration, the weathering profiles are thicker and more intensively developed. The inventory of the Lower Cretaceous paleoweathering features shows the complexity of the continental history of this period. Moreover, the preserved weathering products are only a part of this long lasting period, all the aspects relative to erosion phases are still more difficult to prove and to quantify. In this domain, apatite fission tracks thermochronology (AFTT) can be helpful to estimate the order of magnitude of denudation. Residual testimonies and subsequent transgressions may enable to estimate relative elevations, but in return, we presently have no reliable tool to estimate absolute paleoelevations. In the work presented here, the inventory enabled to draw a continental paleogeographic map showing the nature of the weathering mantles and the paleolandscape features, just as paleoenvironments and paleobathymetry presently appear on marine paleogeographic maps. For the future, the challenge is to make progress in dating the paleoweathering profiles and especially in the resolution of these datings, in order to correlate precisely the continental records with the different events which trigger them (eustatism, climate, regional and global geodynamics). The final goal will be to build up a stratigraphic scale of the “continental geodynamic and climatic events” in parallel with “sequential stratigraphy” in the marine realm.


1987 ◽  
Vol 19 (9) ◽  
pp. 155-174
Author(s):  
Henk L. F. Saeijs

The Delta Project is in its final stage. In 1974 it was subjected to political reconsideration, but it is scheduled now for completion in 1987. The final touches are being put to the storm-surge barrier and two compartment dams that divide the Oosterschelde into three areas: one tidal, one with reduced tide, and one a freshwater lake. Compartmentalization will result in 13% of channels, 45% of intertidal flats and 59% of salt marshes being lost. There is a net gain of 7% of shallow-water areas. Human interventions with large scale impacts are not new in the Oosterschelde but the large scale and short time in which these interventions are taking place are, as is the creation of a controlled tidal system. This article focusses on the area with reduced tide and compares resent day and expected characteristics. In this reduced tidal part salt marshes will extend by 30–70%; intertidal flats will erode to a lower level and at their edges, and the area of shallow water will increase by 47%. Biomass production on the intertidal flats will decrease, with consequences for crustaceans, fishes and birds. The maximum number of waders counted on one day and the number of ‘bird-days' will decrease drastically, with negative effects for the wader populations of western Europe. The net area with a hard substratum in the reduced tidal part has more than doubled. Channels will become shallower. Detritus import will not change significantly. Stratification and oxygen depletion will be rare and local. The operation of the storm-surge barrier and the closure strategy chosen are very important for the ecosystem. Two optional closure strategies can be followed without any additional environmental consequences. It was essential to determine a clearly defined plan of action for the whole area, and to make land-use choices from the outset. How this was done is briefly described.


2017 ◽  
Vol 920 (2) ◽  
pp. 57-60
Author(s):  
F.E. Guliyeva

The study of results of relevant works on remote sensing of forests has shown that the known methods of remote estimation of forest cuts and growth don’t allow to calculate the objective average value of forests cut volume during the fixed time period. The existing mathematical estimates are not monotonous and make it possible to estimate primitively the scale of cutting by computing the ratio of data in two fixed time points. In the article the extreme properties of the considered estimates for deforestation and reforestation models are researched. The extreme features of integrated averaged values of given estimates upon limitations applied on variables, characterizing the deforestation and reforestation processes are studied. The integrated parameter, making it possible to calculate the averaged value of estimates of forest cutting, computed for all fixed time period with a fixed step is suggested. It is shown mathematically that the given estimate has a monotonous feature in regard of value of given time interval and make it possible to evaluate objectively the scales of forest cutting.


Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 480
Author(s):  
Shengbin Li ◽  
Yonghua Cao ◽  
Zeyou Song ◽  
Dan Xiao

The Shuikoushan deposit is an economic ‘skarn-type’ polymetallic Pb-Zn deposit in South China. The deposit is located at the southern margin of the Hengyang basin in the northern part of the Nanling Range. Recently, economic Fe-Cu mineralization that occurs spatially connected to skarns along the contact zone between the granodiorite and limestones was discovered in the lower part of this deposit. Detailed zircon U-Pb geochronological data indicate that the granodiorite was emplaced at 153.7 ± 0.58 Ma (Mean Square of Weighted Deviates (MSWD) = 2.4). However, the pyrite Re-Os isochron age reveals that Fe-Cu mineralization formed at 140 ± 11 Ma (MSWD) = 8.1), which post-dates the emplacement of the granodiorite, as well as the previously determined timing of Pb-Zn mineralization (157.8 ± 1.4 Ma) in this deposit. Considering that Fe-Cu mineralization was connected with the contact zone and also faults, and that sulfide minerals commonly occur together with quartz and calcite veins that crosscut skarns, we interpret this mineralization type as being related to injection of post-magmatic hydrothermal fluids. The timing of Fe-Cu mineralization (140 ± 11 Ma) is inconsistent with a long-held viewpoint that the time interval of 145 to 130 Ma (e.g., Early Cretaceous) in the Nanling Range is a period of magmatic quiescence with insignificant mineralization, the age of 140 Ma may represent a new mineralization event in the Nanling Range.


2016 ◽  
Vol 86 (3) ◽  
pp. 359-372 ◽  
Author(s):  
Pierluigi Pieruccini ◽  
Claudio Di Celma ◽  
Federico Di Rita ◽  
Donatella Magri ◽  
Giorgio Carnevale ◽  
...  

AbstractA 25 m-thick outcrop section exposed at Torre Mucchia, on the sea-cliff north of Ortona, eastern central Italy, comprises a rare Middle Pleistocene succession of shallow-water and paralic sediments along the western Adriatic Sea. An integrated study of the section, including facies and microfacies analyses, and characterization of paleobiological associations (mollusks, fishes, ostracods, foraminifers and pollen), enable a detailed reconstruction of the paleoenvironmental and paleoclimatic conditions during deposition. The shallow-water deposits include a transgressive, deepening- and fining-upward shoreface to offshore-transition facies succession overlain by a regressive shoreface-foreshore sandstone body with an erosive base and a rooted and pedogenically altered horizon at the top that imply deposition during sea-level fall. This forced regressive unit is overlain by paralic strata forming a transgressive succession comprising palustrine carbonates and back-barrier lagoonal mudstones. The palustrine carbonates exhibit some of the typical features encountered in palustrine limestones deposited within seasonal freshwater wetlands (marl prairies). Following the sea-level rising trend, the freshwater marshes were abruptly replaced by a barrier-lagoon system that allowed deposition of the overlying mud-rich unit. Within these deposits, the faunal assemblages are consistent with a low-energy brackish environment characterized by a relatively high degree of confinement. The pollen record documents the development of open forest vegetation dominated by Pinus and accompanied by a number of mesophilous and thermophilous tree taxa, whose composition supports a tentative correlation with Marine Oxygen Isotope Stage 17. The new pollen record from Torre Mucchia improves our understanding of the vegetation development in the Italian Peninsula during the Middle Pleistocene and sheds new light on the role played by the most marked glacial periods in determining the history of tree taxa.


1997 ◽  
Vol 38 (6) ◽  
pp. 1087-1093 ◽  
Author(s):  
R. Rossi Norrlund ◽  
D. Holback ◽  
L. Johansson ◽  
S.-O. Hietala ◽  
K. Riklund Åhlström

Purpose: Placental alkaline phosphatase (PLAP) is a membrane-bound oncofetal antigen that can be used for radioimmunotargeting. Preinjection of nonlabeled monoclonal anti-PLAP antibody (H7) and postinjection of monoclonal anti-idiotypic anti-PLAP antibody (αPH7) were used in order to improve the localization efficacy of 125I-labeled H7 Material and Methods: A human cervix adenocarcinoma cell line (HeLa Hep 2) was inoculated subcutaneously in 24 nude mice. Repeated quantitative radioimmunoscintigraphic recordings were performed on 27 occasions in each of the 24 mice during the observation period which lasted for nearly 3 months. the tumor and nontumor doses were calculated according to the Medical International Radiation Dose Committee formula on the basis of the scintigraphic data Results: All tumors were clearly visualized as early as one day after injection of 125I-labeled H7. the remaining radioactivity was exclusively located in the tumors at days 30–81. as much as 12–16% of the injected dose/g accumulated in the tumors during the first 2 days after injection, and remained stable at this high level for approximately 10 days in all investigated groups. Radioactivity in the whole body was rapidly eliminated during the same time period. the highest tumor/nontumor dose ratio was obtained after a single injection of 125I-labeled H7 Conclusion: Neither a preinjection of nonlabeled H7 nor a postinjection of αPH7 nor a combination of both strategies resulted in improved tumor/nontumor dose ratios compared to a single injection of labeled H7. the monoclonal antibody H7 has a rapid and high uptake, combined with a prolonged retention time in the tumors. the kinetic properties of H7 are different from antibodies targeting intracellular tumor antigens


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