Tectonophysique comparee des chaines telliennes et rifaines

1952 ◽  
Vol S6-II (7-9) ◽  
pp. 619-639
Author(s):  
Louis Glangeaud
Keyword(s):  
Fourth Order ◽  
Coastal Region ◽  
Second Order ◽  
North African ◽  
The South ◽  
Structural Interpretation ◽  
The North ◽  
The Alps

Abstract Correlates the structure and evolution of the Atlas ranges of the Tell and Rif regions and presents a general structural interpretation of the north African coastal region. The Miocene thrusts in the south are local regional adjustments (of the fourth order) to second-order processes occurring farther to the north--compression of the Alps in upper Nummulitic time (Tertiary).

scholarly journals A Study of the Surface Air Temperature Variations in Nigeria

2017 ◽  
Vol 11 (1) ◽  
pp. 54-70 ◽  
Author(s):  
Najib Yusuf ◽  
Daniel Okoh ◽  
Ibrahim Musa ◽  
Samson Adedoja ◽  
Rabia Said
Keyword(s):  
Air Temperature ◽  
Cloud Cover ◽  
Coastal Region ◽  
Surface Air Temperature ◽  
The South ◽  
Climate Type ◽  
Temperature Variations ◽  
North Central ◽  
North East ◽  
The North

Background: Simultaneous measurements of air temperature were carried out using automatic weather stations at 14 tropical locations in Nigeria. Diurnal variations were derived from the 5-minute update cycle initial data for the years ranging between 2007 and 2013. The temperature trends in Nigeria revealed a continuous variability that is seasonally dependent within any particular year considered. Method: The analysis was carried out using available data from the network and the results are presented with a focus to characterize the temperature variations at different locations in the country using the mean, maximum and minimum temperatures from the north which is arid in nature to the south, which is a tropical monsoon climate type and a coastal region. Result: In overall, temperature variations in Nigeria were observed to have higher values in the far north, attributed to the influence of Sahara Desert, which has less cloud cover and therefore is more transparent to solar irradiance and lowers values in the south, where there are more cloud cover and abundant vegetation. Conclusion: Measured maximum and minimum temperatures in Nigeria are respectively 43.1°C at Yola (north-east part of Nigeria) and 10.2°C for Jos (north-central part of Nigeria). The least temperature variations were recorded for stations in the southern part of the country, while the largest variations were recorded in the north-central region of the country.

Geodynamics of the France Southeast Basin

2010 ◽  
Vol 181 (6) ◽  
pp. 477-501 ◽  
Author(s):  
Xavier Le Pichon ◽  
Claude Rangin ◽  
Youri Hamon ◽  
Nicolas Loget ◽  
Jin Ying Lin ◽  
...  
Keyword(s):  
Seismic Activity ◽  
Sedimentary Cover ◽  
Central Basin ◽  
The South ◽  
Western Basin ◽  
Active Deformation ◽  
The North ◽  
The Alps ◽  
Sediment Cover ◽  
Surrounding Areas

AbstractWe investigate the geodynamics of the Southeast Basin with the help of maps of the basement and of major sedimentary horizons based on available seismic reflection profiles and drill holes. We also present a study of the seismicity along the Middle Durance fault. The present seismic activity of the SE Basin cannot be attributed to the Africa/Eurasia shortening since spatial geodesy demonstrates that there is no significant motion of Corsica-Sardinia with respect to Eurasia and since gravitational collapse of the Alps has characterized the last few millions years. Our study demonstrates that the basement of this 140 by 200 km Triassic basin has been essentially undeformed since its formation, most probably because of the hardening of the cooling lithosphere after its 50% thinning during the Triassic distension. The regional geodynamics are thus dominated by the interaction of this rigid unit with the surrounding zones of active deformation. The 12 km thick Mesozoic sediment cover includes at its base an up to 4 km thick mostly evaporitic Triassic layer that is hot and consequently highly fluid. The sedimentary cover is thus decoupled from the basement. As a result, the sedimentary cover does not have enough strength to produce reliefs exceeding about 500 to 750 m. That the deformation and seismicity affecting the basin are the results of cover tectonics is confirmed by the fact that seismic activity in the basin only affects the sedimentary cover. Based on our mapping of the structure of the basin, we propose a simple mechanism accounting for the Neogene deformation of the sedimentary cover. The formation of the higher Alps has first resulted to the north in the shortening of the Diois-Baronnies sedimentary cover that elevated the top of Jurassic horizons by about 4 km with respect to surrounding areas to the south and west. There was thus passage from a brittle-ductile basement decollement within the higher Alps to an evaporitic decollement within the Diois-Baronnies. This shortening and consequent elevation finally induced the southward motion of the basin cover south of the Lure mountain during and after the Middle Miocene. This southward motion was absorbed by the formation of the Luberon and Trévaresse mountains to the south. To the east of the Durance fault, there is no large sediment cover. The seismicity there, is related to the absorption of the Alps collapse within the basement itself. To the west of the Salon-Cavaillon fault, on the other hand, gravity induces a NNE motion of the sedimentary cover with extension to the south and shortening to the north near Mont Ventoux. When considering the seismicity of this area, it is thus important to distinguish between the western Basin panel, west of the Salon-Cavaillon fault affected by very slow NNE gliding of the sedimentary cover, with extension to the south and shortening to the north; the central Basin panel west of the Durance fault with S gliding of the sedimentary cover and increasing shortening to the south; and finally the basement panel east of the Durance fault with intrabasement absorption of the Alps collapse through strike-slip and thrust faults.

The arc of the Western Alps : understanding its kinematics and formation mechanisms based on new structural and paleomagnetic datas, and thermo-mechanical modelling.

2021 ◽  
Author(s):  
Quentin Brunsmann ◽  
Claudio Rosenberg ◽  
Nicolas Bellahsen ◽  
Laetitia Le Pourhiet
Keyword(s):  
Western Alps ◽  
Strike Slip ◽  
Rheological Parameters ◽  
The South ◽  
Adriatic Plate ◽  
The North ◽  
Field Evidence ◽  
Internal Zone ◽  
The Alps ◽  
East West

<p>The Alps have an overall East-West orientation, which changes radically in their western termination, where they rotate southward into a N-S strike, and then eastward into an E-W strike, forming the arc of the Western Alps. This arc is commonly inferred to have formed during collision, due to indentation of the Adriatic plate into the European continental margin. Several models attempted to provide a kinematic explanation for the formation of this arched, lateral end of the Alps. Indeed, the radial nature of the transport directions observed along the arc of the Western Alps cannot be explained by a classic convergence model.<br>For more than 50 years the formation of this arc was been associated to westward-directed indentation of Adria, accommodated along East-West oriented strike-slip faults, a sinistral one in the South of the arc and a dextral one in the North. The dextral one correspond to the Insubric Fault. The sinistral strike-slip zone, inferred to be localized along the «Stura corridor» (Piedmont, Italy) would correspond to a displacement of 100 to 150 km according to palaeogeographical, and geometric analyses. However, field evidence is scarce and barely documented in the literature.<br>Vertical axis rotations of the Adriatic indenter also inferred to be syn-collisional could have influenced the acquisition of the morphology of the arc. Paleomagnetic analyses carried out in the Internal Zone and in the Po plain suggest a southward increading amount of counter-clockwise rotation of the Adriatic plate and the Internal Zone, varying from 20°-25° in the North to nearly 120° in the South.<br>Dextral shear zones possibly accommodating this rotation in some conceptual models is observed in several places below the Penninic Front and affect the Argentera massif to the south. However, the measured displacement quantities do not appear to be equivalent to those induced by such rotations.<br>The present study aims to constrain the kinematic evolution of the arc of the Western Alps through a multidisciplinary approach. The first aspect of this project is the structural analysis of the area (Stura corridor) inferred to accommodate large sinistral displacements allowing for the westward indentation of the Adriatic indenter. We discuss the general lack of field evidence supporting sinistral strike-slip movements, in contrast to large-scale compilation of structures suggesting the possible occurrence of such displacement. The second part consists of a palaeomagnetic study, in which new data are integred with a compilation of already existing data. This compilation shows that several parts of the arc in the External Zone did not suffer any Cenozoic rotations, hence suggesting that a proto-arc already axisted at the onset collision, as suggested by independent evidence of some paleogeographic reconstruction. Finally, 2D and 3D thermo-mechanical modeling in using the pTatin3D code is used to test which structural (geometrical), and rheological parameters affected the first-order morphology of the Western Alpin arc and its kinematics. The synthesis of these different approaches allows us to propose a new model explaining the kinematics and the mechanisms of formation of the Western Alps arc.</p>

scholarly journals Other Zebras

Oryx ◽  
1951 ◽  
Vol 1 (4) ◽  
pp. 191-191
Author(s):  
T. J. Steyn
Keyword(s):  
West Africa ◽  
Coastal Region ◽  
The South ◽  
The North ◽  
South West ◽  
South West Africa

Although scattered and greatly reduced in numbers, Hartmann's Zebras (form(s) of Mountain Zebra) still seem to occur over practically the whole mountainous coastal region of South-West Africa, west of the Namib, from the Orange River in the south to beyond the Cunene in the north.

Mālvan—Further Light on the Southern Extension of the Indus Civilization

1970 ◽  
Vol 102 (1) ◽  
pp. 20-28 ◽  
Author(s):  
F. R. Allchin ◽  
J. P. Joshi
Keyword(s):  
Coastal Region ◽  
Single Site ◽  
Archaeological Survey ◽  
The South ◽  
Indus Civilization ◽  
The Past ◽  
The North ◽  
Principal Directions ◽  
Three Stages ◽  
The Ganges

In 1947 partition left India without a single site attributable to the Indus civilization. During the past two decades there has been a considerable extension of our knowledge, due mainly to the explorations and excavations of the Archaeological Survey of India. It now appears as though the Harappan culture spread into India in two principal directions: north-eastwards into the eastern Panjāb and across the Indo-Gangetic divide into the plains that lie between the Ganges and Jamunā rivers; and south-eastwards into Kacch and Kāṭhiāwār, and thence perhaps inland towards southern Rājāsthān and into the coastal region of Gujarāt. In the north the principal sites are at Rūpar in the Panjāb, Alamgīrpur in U.P., and Kālibangan in north Rājāsthān. In the south the principal excavated site is at Lothal on the Gulf of Cambay. In particular the extensive excavations at Kālibangan and Lothal have provided a mass of solid data relating to the Harappan settlements and series of well stratified radio-carbon dates. In 1957 S. R. Rao explored southern Gujarāt and in the light of his discoveries at a number of sites there he proposed a sequence of three stages of “Harappan” and “late Harappan” cultures. These he showed might be related to the sequence revealed by his excavations at Lothal and Rangpur in Saurāṣṭra. Rao's exploration suggested a number of interesting questions.

The Oppidum of Manching

Antiquity ◽  
1960 ◽  
Vol 34 (135) ◽  
pp. 191-200 ◽  
Author(s):  
Werner Krämer
Keyword(s):  
Central Europe ◽  
The South ◽  
The North ◽  
Literary Sources ◽  
History Of ◽  
The Alps ◽  
Area North ◽  
Cultural Connections ◽  
The City ◽  
Bear Witness

Only a few decades after the conquest of Gaul by Caesar the power of the free Celtic tribes in central Europe collapsed as a consequence of their finding themselves placed, during the course of the 1st century B.C., in an insecure position between the Romans and the Germans pressing down from the North. The victorious Alpine campaign of Drusus and Tiberius in 15 B.C. sealed the fate of, among others, the Vindelicians who occupied the south German area north of the Alps as far as the Danube. Here, still today, mighty hillforts bear witness to the power of those nameless Celtic chieftains who caused them to be erected. Contemporary literary sources tell all too little about the history of this area and about the cultural connections of its inhabitants before the Roman occupation. Therefore modern research relied upon Caesar’s description of the Gallic tribes in drawing parallels between the large late La Tène hillforts in central Europe and the city-like tribal centres of the Gauls in France, which Caesar called ‘oppida’ or even ‘urbes’.

scholarly journals Notes on some animal parasites in British Guiana

1916 ◽  
Vol 7 (2) ◽  
pp. 179-190 ◽  
Author(s):  
G. E. Bodkin ◽  
L. D. Cleare
Keyword(s):  
Sea Level ◽  
Sand Dunes ◽  
Coastal Region ◽  
The South ◽  
British Guiana ◽  
North East ◽  
The North ◽  
South West ◽  
Western Side ◽  
River Valleys

British Guiana lies between the latitudes 0·41′ N. (source of the Essequebo River) and 8° 33′ 22″ N. (Punta Playa), has a depth from north to south of about 500 miles, a seaboard of about 270 miles trending in a south-easterly direction, and occupies in the north-east of South America an area approximately equal in extent to Great Britain. It is bounded on the north by the Atlantic Ocean, on the east by Surinam or Dutch Guiana, on the south and south-west by Brazil, and on the west by Venezuela.The Colony may be divided broadly into three belts. The northern one consists of a low-lying flat and swampy belt of marine alluvium—the coastal region. This rises gradually from the seaboard and extends inland for a distance varying from 5 to 49 miles. It is succeeded by a broader and slightly elevated tract of country of sandy and clayey soils. This belt is generally undulating, and is traversed in places by sand-dunes rising from 50 to 180 ft. above sea-level. The more elevated portion of the Colony lies to the southward of the above-mentioned regions. It rises gradually to the south-west, between the river valleys, which are in many parts swampy, and contains three principal mountain ranges, several irregularly distributed smaller ranges, and in the southern and eastern parts numerous isolated hills and mountains. The eastern portion is almost entirely forest-clad, but on the south-western side there is an extensive area of flat grass-clad savannah land elevated about 300 feet above sea-level.

Diradamenti di cedui castanili invecchiati - risultati di due parcelle sperimentali (1975–1997) a Novaggio, Ticino | Study of the Problem of Thinning Ageing Chestnut Coppice Forest over 25-Years-Old: Findings from Two Study Areas near Novaggio, in the Canton of Ticino (1975–1997)

2000 ◽  
Vol 151 (2) ◽  
pp. 43-56 ◽  
Author(s):  
Ernst Ott ◽  
Fabrizio Conceprio ◽  
Andrea Pedrini
Keyword(s):  
Practical Experience ◽  
The Other ◽  
Pedunculate Oak ◽  
The South ◽  
Central Plateau ◽  
The North ◽  
The Alps ◽  
Chestnut Coppice ◽  
Scientific Results ◽  
Coppice Forest

A study was undertaken to determine the extent to which practical and scientific results of a study in the Swiss Central plateau can be applied to the chestnut coppice to the south of the Alps in Switzerland. The Central plateau study was carried out using selective thinning in former coppice with standards and seedling forests. The neglect of the chestnut coppices which occurred during the early 1970s made this a topical issue at the time. With this in mind, our experiment was primarily aimed at answering the following question: Can selective thinning contribute to the long-term transformation of these chestnut coppices, and eventually bring about natural regeneration through seedlings? Particular interest was paid to the effect it has on improving timber production,timber quality, vitality, and species mixture. Two stands were selected for the study: these were sufficiently large to produce valid results, and had as homogeneous a structure as possible. One was a typical stand of chestnut coppice forest; the other contained chestnut coppice but also had a high proportion of Turkey oak and pedunculate oak. Two sub-plots of 50 ares were marked out on each stand; selective thinning was carried out on one sub-plot, the other was left untouched. In 1975, the condition of the four sub-plots was surveyed in great detail. All trees with a DBH of over 8 cm were permanently numbered, measured with calipers, and classified on the basis of the IUFRO system. The trees selected for culling in the two relevant sub-plots were then marked. In 1976, these trees were felled as planned. A second survey was conducted in 1980 and a final one carried out in 1996/97. Our findings largely match and confirm the practical experience gained over the last 20 years when thinning ageing chestnut coppice on dry sites, including those with an intermixture of Turkey and pedunculate oak. Coppice forests over the age of 25 were unable to replenish the loss of timber reserves by thinning. Both their growth and ability to react diminish greatly with age. As strongly light-demanding trees, the chestnuts and oaks in the saw-timber stage are unable to sufficiently regenerate their crowns once these are reduced by too great an extent through pressure from competing trees. Altogether, these findings match our practical observations and experiences. Thinning techniques used on sites to the north of the Alps cannot be applied to the chestnut coppice forests in dry sites to the south. We can conclude that the technique used in this study will not significantly improve the condition of chestnut coppice forests in dry sites to the south of the Alps.

scholarly journals The Occurrence of Palæoliths in North-East Lancashire

1915 ◽  
Vol 2 (1) ◽  
pp. 61-71
Author(s):  
T. E. Nuttall
Keyword(s):  
Great Britain ◽  
Ice Sheet ◽  
Ice Age ◽  
Interglacial Period ◽  
The South ◽  
North East ◽  
The North ◽  
Southern Margin ◽  
Imaginary Line ◽  
The Alps

For many years it was postulated that an ice sheet had covered the north and west of Great Britain during the period when Palæolithic man lived and made his flint implements in the south and east of England. It was taught that the southern margin of this ice sheet corresponded in the main with an imaginary line stretching from about the mouth of the Severn to the Wash, or, as others claimed, from the mouth of the Severn to the mouth of the Thames. These views were held to be supported by the fact that very few palæoliths had been found north of the above-mentioned line. As years passed, however, new facts testifying to the lengthy duration of the Palæolithic period slowly accumulated, and knowledge respecting the great Ice Age gradually increased. True, many and divergent views have been advanced respecting the several phases of the Ice Age as these concern Lancashire and the north of England generally. Some glacialists hold that the Ice Age there, as also in the Alps, was broken up into several complete cycles consisting of a number of glaciations with a corresponding number of interglacial periods. Others believe that there was only one interglacial period in the north of England.

Apercu morphotectonique et paleogeographique du domaine calabro-lucanien (Italie meridionale)

1961 ◽  
Vol S7-III (6) ◽  
pp. 610-618 ◽  
Author(s):  
Claude Grandjacquet
Keyword(s):  
North Africa ◽  
Structural Features ◽  
Western Mediterranean ◽  
Tectonic Deformation ◽  
North African ◽  
The South ◽  
African Region ◽  
Structural Pattern ◽  
The North ◽  
Upper Oligocene

Abstract In the region lying between Salerno and the Ofanto river on the north and Cetraro and the gulf of Tarento on the south and southeast, the south end of the Apennines merges into the structural pattern of the western Mediterranean region (southwestern Italy-Sicily-North Africa). After a cycle of sedimentation, tectonic deformation, and erosion extending from Triassic to upper Oligocene, a second cycle began in the late Oligocene and earliest Miocene. Mosaic faulting, in general based upon major structural features of the earlier cycle, occurred throughout the entire southern Italy-North African region. The age of the quartzite flysch remains unknown but is probably Jurassic-Cretaceous.

Sign in / Sign up

Export Citation Format

Share Document