scholarly journals Mineralogical and hydrogeological study of "pouhons" in the lower Palaeozoic formations of the Stavelot-Venn Massif, Belgium

2021 ◽  
Vol 24 (3-4) ◽  
pp. 109-124
Author(s):  
Martin DEPRET ◽  
Yannick BRUNI ◽  
Alain DASSARGUES ◽  
Agathe DEFOURNY ◽  
Jean-Marc MARION ◽  
...  
Keyword(s):  
Land Surface ◽  
Iron Hydroxide ◽  
Black Shales ◽  
Surface Circulation ◽  
Hydrogeological Study ◽  
Orange Colour ◽  
Lower Palaeozoic ◽  
Water Springs ◽  
Radon Measurements ◽  
Iron Manganese

Numerous naturally CO2-rich mineral water springs, locally called pouhons, occur in the Stavelot-Venn Massif. These water springs show a particular composition with a high content of iron, manganese and lithium, and are characterised by a red-orange colour resulting from iron hydroxide precipitation near the land surface. Radon measurements have shown that these ferruginous deposits are weakly radioactive. The Upper Cambrian black shales of the La Gleize Formation are also known to display radioactive anomalies. These rocks show enrichment in HFSE (Pb, U, Y, Ce, Zr, Ti, Nb) and are depleted in transition metals (Co, Ni, Cu, Zn). Specific minerals such as florencite-(Ce), monazite-(Ce), xenotime-(Y) and zircon have been identified and are probably at the origin of the radioactive anomalies. Uranium was gradually leached from these minerals, transported in solution, and finally concentrated in ferruginous muds. These muds are mainly composed of goethite (most often amorphous), residual quartz and calcite in some samples. The most probable hypothesis is that uranium is adsorbed in small concentrations on the goethite surface. On the other hand, the Ottré Formation (Ordovician) appears to be the main source of lithium, iron and manganese. Pouhon waters have therefore probably leached rocks of various mineralogy and chemical composition during their sub-surface circulation.

Stratigraphy in an accretionary prism: the Ordovician rocks in North Down, Ireland

1984 ◽  
Vol 74 (4) ◽  
pp. 183-191 ◽  
Author(s):  
Lorraine E. Craig
Keyword(s):  
Oceanic Crust ◽  
Accretionary Prism ◽  
Black Shales ◽  
Ocean Floor ◽  
Middle Ordovician ◽  
Iapetus Ocean ◽  
Lower Palaeozoic

ABSTRACTSediments, mainly sandstones, conglomerates and shales, accumulated in small turbidite fans along the northern arc–trench margin of the Iapetus Ocean from middle Ordovician to Silurian time. These fans, together with the underlying pelagic facies and part of the oceanic crust, were sliced and accreted northward resulting in the Lower Palaeozoic accretionary prism which forms the Scottish Southern Uplands and the Longford-Down inlier in Ireland. North Down is the continuation of the Northern belt of the Southern Uplands of Scotland into Ireland, bounded to the S by the Orlock Bridge fault. Lithological and petrographical comparison with the rest of the Northern belt indicates closer affinities with the Southern Uplands of Scotland than with the western end of the Longford-Down inlier. Major ENE—WSW-trending Caledonian strike faults define five blocks, in which new formations of Caradoc and ? Ashgill age are defined. Pillowed spilitic rock, interpreted as a fragment of the ocean-floor, is only recognised in the Ballygrot block. Pelagic and hemipelagic black shales and cherts are overlain by arenaceous sediments in all blocks.

scholarly journals Shale gas investigations in Denmark: Lower Palaeozoic shales on Bornholm

1969 ◽  
Vol 23 ◽  
pp. 9-12 ◽  
Author(s):  
Niels Hemmingsen Schovsbo ◽  
Arne Thorshøj Nielsen ◽  
Kurt Klitten ◽  
Anders Mathiesen ◽  
Per Rasmussen
Keyword(s):  
Shale Gas ◽  
Black Shales ◽  
Rock Properties ◽  
Groundwater Exploitation ◽  
Lower Silurian ◽  
Gas Source ◽  
Alum Shale ◽  
Lower Palaeozoic ◽  
Global Sea Level ◽  
Deep Exploration

The Cambrian to Lower Silurian succession in Denmark is mostly composed of organic-rich black shales that were deposited in an epicontinental sea during a period of high global sea level (Haq & Schutter 2008). The mid-Cambrian to early Ordovician Alum Shale was intensively studied in the 1980s for its source-rock properties (e.g. Buchardt et al. 1986). Recent attention has focused on its potential as an unconventional shale gas source (Energistyrelsen 2010). On southern Bornholm, many wells have been drilled through the Lower Palaeozoic succession because of its importance for groundwater exploitation. In western Denmark, only the deep exploration wells Slagelse-1 and Terne-1 have penetrated the Alum Shale, and knowledge of the unit west of Bornholm is thus very limited (Fig. 1).

scholarly journals Ordovician turbidites and black shales of Bennett Island (De Long Islands, Russian Arctic), and their significance for Arctic correlations and palaeogeography

2020 ◽  
Vol 157 (8) ◽  
pp. 1207-1237
Author(s):  
Maria K. Danukalova ◽  
Alexander B. Kuzmichev ◽  
Nikolai V. Sennikov ◽  
Tatiana Yu. Tolmacheva
Keyword(s):  
Carbonate Platform ◽  
Black Shales ◽  
The Arctic ◽  
New Siberian Islands ◽  
Faunal Assemblages ◽  
Lower Palaeozoic ◽  
Early Palaeozoic ◽  
First Time ◽  
Remote Part ◽  
Siberian Shelf

AbstractBennett Island stands alone in a remote part of the Arctic and information on its geology is essential to ascertain relations with other terranes in order to restore the early Palaeozoic Arctic palaeogeography. Lower Palaeozoic sedimentary rocks throughout the island were studied thoroughly for the first time. The Ordovician section (> 1.1 km thick) comprises three units: Tremadocian, lowest Floian black shale (130–140 m); Floian, lower Dapingian carbonate turbidite (> 250 m); and Dapingian, lower Darriwilian siliciclastic turbidite (> 730 m). Ordovician deposits conformably overlie Cambrian rocks deposited within the Siberian shelf, as shown earlier. Most of the Ordovician succession was formed in a deep trough that received carbonate debris from a nearby carbonate platform and silicate material from a distant landmass located to the NE (present coordinates). The Bennett Island Ordovician rocks have much in common with those of both the Central and Northern Taimyr belts. It could be tentatively suggested that both belts merged at their eastern continuation in the vicinity of De Long Islands. The whole system probably extends further eastwards. The Ordovician facies patterns and faunal assemblages in the New Siberian Islands are notably similar to those of northwestern Alaska, where the same lateral transition from turbidites to shelf limestones was reported.

scholarly journals The sedimentology of Lower Palaeozoic black shales from the shallow wells Skelbro 1 and Billegrav 1, Bomholm, Denmark

1989 ◽  
Vol 37 ◽  
pp. 151-173
Author(s):  
Gunver Krarup, Pedersen
Keyword(s):  
Gamma Ray ◽  
Average Rate ◽  
Sedimentary Facies ◽  
Black Shales ◽  
Low Energy ◽  
Upper Ordovician ◽  
Middle Cambrian ◽  
Facies Associations ◽  
Shallow Wells ◽  
Lower Palaeozoic

Previous studies of the Lower Palaeozoic shales on Bornholm have mainly been based on the outcrops along the streams. The outcrops provide data on the lateral continuity of the facies while the selection of (2-3 cm wide) cores for the present study focused the attention on the vertical sequence of facies. Cores of high quality were obtained and have been found to provide an excellent basis for a study of structures, sediment composition and diagenesis. In the outcrops of shale fossils are locally present in high numbers and such levels are also recognized in the cores. Seven sedimentary facies, ranging from black mudshale to greyish mudstone and silt-streaked shale, are distinguished in the Middle Cambrian to lowermost Silurian shales. Gamma-ray logs were run in the two wells and a convincing correlation to the cored sequence can be demonstrated. Gamma-ray logs provide thus a good means of correlation to wells where no cores have been cut. The shales are all interpreted as deposited in an epicontinental sea due to their geological setting i.e. the association with shallow water carbonates (Andrarum Limestone and Komstad Limestone) and their stratigraphical position above the shelf to shoreface sandstones of the Lresa formation. Three facies associations are distinguished: The mudshale association comprises black organic-rich shales which represent a low-energy anoxic depositional environment which prevailed in the Middle Cambrian to Lower Ordovician. The mudstone association is typical of the Middle and Upper Ordovician and represents a continuation of low-energy environments though mottling indicates that ventilation improved in certain periods. The siltshale association represents higher energy environments which were dominant in the lowermost Silurian. A well defined Upper Ordovician CU sequence probably reflects the global eustatic fall in sea level caused by the extensive glaciation in Gondwanaland. In the late Silurian the average rate of deposition increased in response to the approaching Caledonian orogeny.

Stratosphere–Troposphere Coupling and Links with Eurasian Land Surface Variability

2007 ◽  
Vol 20 (21) ◽  
pp. 5335-5343 ◽  
Author(s):  
Judah Cohen ◽  
Mathew Barlow ◽  
Paul J. Kushner ◽  
Kazuyuki Saito
Keyword(s):  
Land Surface ◽  
Planetary Wave ◽  
Vertical Component ◽  
Polar Vortex ◽  
Subsequent Development ◽  
Wave Activity ◽  
The Arctic ◽  
Surface Circulation ◽  
The Arctic Oscillation ◽  
Hemisphere Winter

Abstract A diagnostic of Northern Hemisphere winter extratropical stratosphere–troposphere interactions is presented to facilitate the study of stratosphere–troposphere coupling and to examine what might influence these interactions. The diagnostic is a multivariate EOF combining lower-stratospheric planetary wave activity flux in December with sea level pressure in January. This EOF analysis captures a strong linkage between the vertical component of lower-stratospheric wave activity over Eurasia and the subsequent development of hemisphere-wide surface circulation anomalies, which are strongly related to the Arctic Oscillation. Wintertime stratosphere–troposphere events picked out by this diagnostic often have a precursor in autumn: years with large October snow extent over Eurasia feature strong wintertime upward-propagating planetary wave pulses, a weaker wintertime polar vortex, and high geopotential heights in the wintertime polar troposphere. This provides further evidence for predictability of wintertime circulation based on autumnal snow extent over Eurasia. These results also raise the question of how the atmosphere will respond to a modified snow cover in a changing climate.

The precursor environment for vascular plant colonization

1985 ◽  
Vol 309 (1138) ◽  
pp. 143-145 ◽  
Keyword(s):  
Land Surface ◽  
Vascular Plants ◽  
Vascular Plant ◽  
Plant Cover ◽  
Biologically Active ◽  
Plant Colonization ◽  
Physico Chemical ◽  
History Of ◽  
Lower Palaeozoic ◽  
Soil Forming Processes

There is evidence, although inconclusive, that a biologically active soil cover existed long before the late Silurian. The earliest vascular plants may have colonized a land surface containing well-developed soils which were functioning biologically and biochemically in similar ways to modern soils. In any discussion of the late Silurian-early Devonian ‘invasion of the land’, two basic questions arise in relation to the history of the land cover and its soils: (i) Did vascular plants colonize a barren landscape or did biologically functioning soils already exist? (ii) What changes did the vascular plant cover cause to the land surface and its soils? This latter question has been tackled by Retallack (this symposium) and the following is a discussion of some aspects of the former. Many soil-forming processes are purely physical or physico-chemical in origin and examples of such pedogenic modifications of the land surface have now been documented from the Precambrian and lower Palaeozoic (Retallack 1981). However, there is also some evidence that these early soils were biologically active and were associated with microbial communities. Golubic & Campbell (1979) have compared the mid Precambrian microfossil, Eosynechnococcus moorei Hofmann with the extant cyanobacterium Gloeothece coerulea Geitler, which is a subaerial form. They have suggested that prokaryotic communities may have colonized the land surface as long ago as the early Precambrian. Organic-rich palaeosols are known from Blind River Formation of Ontario (Campbell 1979) which is 2.4 Ga old.

The Fine Structure of Glycocalyx in Human Spermatozoa. A High Resolution Cytochemical Study

1973 ◽  
Vol 31 ◽  
pp. 640-641
Author(s):  
P. Hernández-Jáuregui ◽  
A. Sosa ◽  
A. González Angulo
Keyword(s):  
Negative Charge ◽  
Iron Hydroxide ◽  
Human Spermatozoa ◽  
Surface Coat ◽  
Cell Surfaces ◽  
Colloidal Iron ◽  
Cytochemical Study ◽  
Specific Permeability ◽  
Extracellular Glycoprotein ◽  
Mammalian Spermatozoa

Glycocalyx is the name given by Bennett to the extracellular glycoprotein coat present in some cell surfaces. It appears to play an important role in cell properties such as antigenicity, cell adhesivity, specific permeability, and ATP ase activity. In the sperm this coat can be directly related to such important phenomena as capacitation and fertilization. The presence of glycocalyx in invertebrate spermatozoa has already been demonstrated. Recently Yanagimachi et al. has determined the negative charges on sperm surfaces of mammalian spermatozoa including man, using colloidal iron hydroxide. No mention was made however of the outer surface coat as composed of substances other than those confering a negative charge. The purpose of this work was therefore to determine the presence of a glycocalyx in human spermatozoa using alcian blue and lanthanum staining.

Solid Solution Effects and Deformation Micros trueture of Shock-Loaded Iron Manganese Alloys

1970 ◽  
Vol 28 ◽  
pp. 420-421
Author(s):  
A. Christou ◽  
J. V. Foltz ◽  
N. Brown
Keyword(s):  
Solid Solution ◽  
Shock Loading ◽  
High Strain ◽  
Local Stress ◽  
Strain Rates ◽  
Local Stress Concentration ◽  
Bcc Metals ◽  
Manganese Alloys ◽  
Iron Manganese ◽  
Transmission Microscope

In general, all BCC transition metals have been observed to twin under appropriate conditions. At the present time various experimental reports of solid solution effects on BCC metals have been made. Indications are that solid solution effects are important in the formation of twins. The formation of twins in metals and alloys may be explained in terms of dislocation mechanisms. It has been suggested that twins are nucleated by the achievement of local stress-concentration of the order of 15 to 45 times the applied stress. Prietner and Leslie have found that twins in BCC metals are nucleated at intersections of (110) and (112) or (112) and (112) type of planes.In this paper, observations are reported of a transmission microscope study of the iron manganese series under conditions in which twins both were and were not formed. High strain rates produced by shock loading provided the appropriate deformation conditions. The workhardening mechanisms of one alloy (Fe - 7.37 wt% Mn) were studied in detail.

Land surface processes and Sahel climate

2000 ◽  
Vol 38 (1) ◽  
pp. 117-140 ◽  
Author(s):  
Sharon Nicholson
Keyword(s):  
Land Surface ◽  
Surface Processes ◽  
Land Surface Processes
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