Permian and Quaternary playas, a discussion based on climatic, tectonic and palaeogeographic settings

Las playas representan ambientes evaporíticos que están controlados básicamente por la evaporación, evapotranspiración y la elevación. Están bien representados en la actualidad en la Tierra y también lo estuvieron en Pangea, durante el Pérmico, aunque su distribución geográfica era diferente. La primera intención del presente trabajo está en la clarificación del relativamente confuso término de playa o alkali flat, incluyendo los aspectos geomorfológicos y geológicos basándonos en la experiencia llevada a cabo en Túnez, Tíbet y Omán. Seguidamente discutimos la relación entre playas, clima y tectónica, con sus implicaciones paleogeográficas, utilizando comparaciones entre los cinturones tectónicos actuales (Alpes, Himalaya, etc.) y el cinturón de los Apalaches-Varisco- Urales-Mongol, cuyo desarrollo se prolongó hasta el final del Pérmico en sus segmentos más jóvenes. Se sacan a la luz algunos problemas tectónicos tales como la barrera climática producida por el propio orógeno y la importancia de la fracturación de tipo desgarre a gran escala

Analyse des images satellitales radar RSO-ERS et optique ETM+ de Landsat 7 comme outils de prospection minière : application aux localités de Tiébissou et de Tienko en Côte d’Ivoire (Afrique de l’Ouest)

L’approche géologique par l’imagerie satellitale ETM+ de LANDSAT 7 et RSO d’ERS, à haute résolution, donne des résultats nouveaux qui  améliorent les cartes géologiques préexistantes. Ainsi, dans la localité deTiébissou (Centre de la Côte d’Ivoire), le contour du granite de Grogro intrusif est précisé comme celui du granite à biotite. Au sein de l’unité métavolcano-sédimentaire, des aires granitiques sont signalées. Quatreprincipales familles de fractures sont détectées. Il s’agit, des zones de fractures de Molonou, de Komorossou et d’Ando Zumé de direction NO-SE (N130° à N150°) ; des fractures de Sakiaré, de Propronou et de Bofia de direction E-O (N080° à N100°) ; des fractures de Grogro, de Niamienkro, d’Akrétia et de Tiébissou de direction NS à NNE-SSO (N170° à N020°) et enfin des zones de fractures de Ngangro et de Suibonou de direction NE-SO (N040° à N060°). Certaines de ces zones de fractures ont pu être  identifiées sur le terrain. Ce sont par exemple, les zones de fractures de Propronou et de Bofia de direction E-O ; des zones de fractures de  Molonou d’orientation NE-SO. Trois directions majeures des filons de quartz apparaissent (N090° à N110°, N060° et N140°). Dans la localité de Tienko, située dans l’extrême Nord de la Côte d’Ivoire, aux confins de la Côte d’Ivoire et du Mali, la forme de la granodiorite de Kimbirila est précisée pour la première fois. Elle a un caractère intrusif car le massif a une forme ± arrondie en carte. Le tracé des zones de failles connues comme celles du Sassandra et du Banifing est précisé. La zone de failles de Konéla, cartographiée également pour la première fois, de direction NO-SE se surimpose à des anomalies géochimiques aurifères mises en évidence par une compagnie minière de la place. Ces exemples montrent que l’analyse des images satellitales est un outil¸ au même titre que par exemple, la géophysique de prospection minière. Les spatio-cartes géologiques obtenues peuvent permettre de mieux planifier les travaux miniers sur le terrain.Mots-clés : images satellitales, Radar RSO-ERS, ETM+ - LANDSAT 7,  prospection minière, Tiébissou, Tienko, Côte d’Ivoire, Afrique de l’Ouest

Lyapunov exponents of the Brownian motion on a Kähler manifold

If E is a flat bundle of rank r over a Kähler manifold X, we define the Lyapunov spectrum of E: a set of r numbers controlling the growth of flat sections of E, along Brownian trajectories. We show how to compute these numbers, by using harmonic measures on the foliated space P(E). Then, in the case where X is compact, we prove a general inequality relating the Lyapunov exponents and the degrees of holomorphic subbundles of E and we discuss the equality case

ignition: A Research and Design Center for DaimlerChrysler in Detroit, MI

This Project was founded through the study and understanding of the parallel circumstances facing the automotive industry and architectural profession. Both fields are organized and structured in similar manners, and both share similar problems. Primary among them is the recent need to shift design focuses from viewing sustainable practices as necessary, a move unpopular among many designers and consumers because of the perception that with sustainable design comes a boring, unappealing design. This project will attempt to offer an architectural solution that through program (a design and research center for sustainable vehicles) and design, will challenge these stereotypes and blend the two fields together

Performance of Mouse Lines Divergently Selected for Heat Loss When Exposed to Different Environmental Temperatures. I. Reproductive Performance, Pup Survival, and Metabolic Hormones

Mouse populations differing in metabolic rate have been developed through selection for high (MH) and low (ML) heat loss, along with the unselected controls (MC). Objectives of the study were to compare the MH, ML, and MC lines for reproductive performance, pup survival, and metabolic hormones when reared at 12, 22, and 31°C, and to search for line × environment interactions. Conception and litter size were recorded on the parent generation mice introduced to the environments at 11 wk of age and bred after a 3-wk acclimatization period. Survival of pups (pre-weaning to 3 wk; post-weaning from 3 to 9 wk of age) was measured with continuous exposure in the designated environment from birth to the time of measurement. Corticosterone, triiodothyronine (T3), and thyroxine (T4) serum concentrations were measured on the parent generation after producing litters and on the pup generation at 9 wk. No line × environment interaction was detected for conception rate, preweaning mortality, postweaning survival, pup weaning weight, or body temperature. There were no differences in conception rate among lines and environments. Environments affected survival of pups, but there were no line differences. Rectal body temperatures were greater for MH than ML mice, and MC mice were intermediate; body temperature of mice did not differ among the environments. Lines differed significantly in litter size only in the 22°C environment. No significant line differences were found for serum corticosterone or serum T3 or T4. Line × environment interaction was detected only for litter size and for serum corticosterone concentration in dams. Contrary to the other two lines, ML dam performance relative to MH and MC was not affected negatively by either of the thermal environments. Results from this study do not raise concern that selection to decrease maintenance requirements will produce livestock with any greater liability to cope and perform under an array of environmental temperatures

Les mines d’or ptolémaïques. Résultats des prospections dans le district minier de Samut (désert Oriental)

International audienceAbundant in the Eastern Desert, gold is mined as soon as the early days of the Egyptian kingdom. But in the Ptolemaic Period the State initiates for the first time a systematic and intensive exploitation of the Egyptian gold-bearing veins, to consolidate its power and pursue an ambitious foreign policy. However, if the constant use of gold in Egyptian art has produced a numerous ancient and modern literature, the history of its extraction, production and circulation is less known. In order to study the golden age of the Eastern Desert gold mining, the French mission began its work by exploring the mining district of Samut, located south of the road leading from Edfu to Marsa Allam.This article presents the results of the first mission, carried out in January 2013. The survey has yielded important results: it showed that the area of Samut was organized as a real mine district, coherent and ordered, centred on a large vein in the mountains (North Samut) and a fort in the plain (Bi’r Samut). All technical steps of ore extraction and treatment, until its transformation into gold, have also been located in the area. Ceramics collected on the surface showed, finally, that the vein was used from the beginning of the Ptolemaic Period (late fourth century BC).Abondant dans le désert Oriental, l’or est exploité dès les premiers temps de la royauté égyptienne, mais c’est surtout à l’époque ptolémaïque que le pouvoir engage une exploitation systématique et intensive des filons aurifères égyptiens, pour asseoir sa puissance et mener une politique étrangère ambitieuse. Toutefois, si l’usage constant de l’or dans l’art égyptien a engendré une littérature antique et moderne abondante, l’histoire de son extraction, de sa production et de sa circulation est moins bien connue. Désireuse de se pencher sur l’âge d’or de l’exploitation des mines du désert Oriental, la mission française a débuté ses travaux par l’exploration du district minier de Samut, situé au sud de la route reliant Edfou à Marsa Allam.Le présent article expose les résultats de la première mission, effectuée en janvier 2013. La prospection a donné des résultats importants : elle a démontré que la zone de Samut était organisée comme un véritable district minier, cohérent et hiérarchisé, centré autour d’un grand filon dans les montagnes (Samut Nord) et d’un fortin dans la plaine (Bi’r Samut). Toutes les étapes techniques de l’extraction du minerai et de son traitement, jusqu’à sa transformation en or, ont, en outre, été localisées dans la zone. La céramique ramassée en surface a démontré, enfin, que le filon était exploité dès les débuts de l’époque ptolémaïque (fin du ive s. av. J.-C.).Abundant in the Eastern Desert, gold is mined as soon as the early days of the Egyptian kingdom. But in the Ptolemaic Period the State initiates for the first time a systematic and intensive exploitation of the Egyptian gold-bearing veins, to consolidate its power and pursue an ambitious foreign policy. However, if the constant use of gold in Egyptian art has produced a numerous ancient and modern literature, the history of its extraction, production and circulation is less known. In order to study the golden age of the Eastern Desert gold mining, the French mission began its work by exploring the mining district of Samut, located south of the road leading from Edfu to Marsa Allam.This article presents the results of the first mission, carried out in January 2013. The survey has yielded important results: it showed that the area of Samut was organized as a real mine district, coherent and ordered, centred on a large vein in the mountains (North Samut) and a fort in the plain (Bi’r Samut). All technical steps of ore extraction and treatment, until its transformation into gold, have also been located in the area. Ceramics collected on the surface showed, finally, that the vein was used from the beginning of the Ptolemaic Period (late fourth century BC).Keywords: oldmine – Ptolemaic Period – Samut (Eastern Desert) – survey – mine district

Les mines d’or ptolémaïques. Résultats des prospections dans le district minier de Samut (désert Oriental)

International audienceAbundant in the Eastern Desert, gold is mined as soon as the early days of the Egyptian kingdom. But in the Ptolemaic Period the State initiates for the first time a systematic and intensive exploitation of the Egyptian gold-bearing veins, to consolidate its power and pursue an ambitious foreign policy. However, if the constant use of gold in Egyptian art has produced a numerous ancient and modern literature, the history of its extraction, production and circulation is less known. In order to study the golden age of the Eastern Desert gold mining, the French mission began its work by exploring the mining district of Samut, located south of the road leading from Edfu to Marsa Allam.This article presents the results of the first mission, carried out in January 2013. The survey has yielded important results: it showed that the area of Samut was organized as a real mine district, coherent and ordered, centred on a large vein in the mountains (North Samut) and a fort in the plain (Bi’r Samut). All technical steps of ore extraction and treatment, until its transformation into gold, have also been located in the area. Ceramics collected on the surface showed, finally, that the vein was used from the beginning of the Ptolemaic Period (late fourth century BC).Abondant dans le désert Oriental, l’or est exploité dès les premiers temps de la royauté égyptienne, mais c’est surtout à l’époque ptolémaïque que le pouvoir engage une exploitation systématique et intensive des filons aurifères égyptiens, pour asseoir sa puissance et mener une politique étrangère ambitieuse. Toutefois, si l’usage constant de l’or dans l’art égyptien a engendré une littérature antique et moderne abondante, l’histoire de son extraction, de sa production et de sa circulation est moins bien connue. Désireuse de se pencher sur l’âge d’or de l’exploitation des mines du désert Oriental, la mission française a débuté ses travaux par l’exploration du district minier de Samut, situé au sud de la route reliant Edfou à Marsa Allam.Le présent article expose les résultats de la première mission, effectuée en janvier 2013. La prospection a donné des résultats importants : elle a démontré que la zone de Samut était organisée comme un véritable district minier, cohérent et hiérarchisé, centré autour d’un grand filon dans les montagnes (Samut Nord) et d’un fortin dans la plaine (Bi’r Samut). Toutes les étapes techniques de l’extraction du minerai et de son traitement, jusqu’à sa transformation en or, ont, en outre, été localisées dans la zone. La céramique ramassée en surface a démontré, enfin, que le filon était exploité dès les débuts de l’époque ptolémaïque (fin du ive s. av. J.-C.).Abundant in the Eastern Desert, gold is mined as soon as the early days of the Egyptian kingdom. But in the Ptolemaic Period the State initiates for the first time a systematic and intensive exploitation of the Egyptian gold-bearing veins, to consolidate its power and pursue an ambitious foreign policy. However, if the constant use of gold in Egyptian art has produced a numerous ancient and modern literature, the history of its extraction, production and circulation is less known. In order to study the golden age of the Eastern Desert gold mining, the French mission began its work by exploring the mining district of Samut, located south of the road leading from Edfu to Marsa Allam.This article presents the results of the first mission, carried out in January 2013. The survey has yielded important results: it showed that the area of Samut was organized as a real mine district, coherent and ordered, centred on a large vein in the mountains (North Samut) and a fort in the plain (Bi’r Samut). All technical steps of ore extraction and treatment, until its transformation into gold, have also been located in the area. Ceramics collected on the surface showed, finally, that the vein was used from the beginning of the Ptolemaic Period (late fourth century BC).Keywords: oldmine – Ptolemaic Period – Samut (Eastern Desert) – survey – mine district

Book reviews

Volume: 21Start Page: 153End Page: 15