Partitioning of deformation within a subduction channel during exhumation of high-pressure rocks: a case study from the Western Alps

The metamorphic belt of the Western Alps was subjected to widespread extensional tectonism at the end of the Eocene (ca. 45-35 Ma). Extension was accommodated by hinterland-directed movements along gently inclined extensional shear zones, which facilitated rapid exhumation of high-pressure and ultra-high-pressure rocks. This deformation resulted in a normal metamorphic sequence. Extension in the inner parts of the Western Alps was coeval with shortening at the front of the belt (foreland-directed thrusts), which took place during decompression, and emplaced higher grade metamorphic units over lower grade metamorphic rocks, thus forming an inverse metamorphic sequence. Two mechanisms for this extensional episode are discussed: (1) collapse of an overthickened lithosphere, and (2) internal readjustments within the orogenic wedge due to subduction channel dynamics. We favour the latter mechanism because it can account for the development of the observed inverse and normal metamorphic sequences along foreland-directed thrusts and hinterland-directed detachments, respectively. This hypothesis is supported by published structural, metamorphic and geochronological data from four geological transects through the Western Alps. This study also emphasizes the importance of post-shearing deformation (e.g. horizontal buckling versus vertical flattening), which can modify the distribution of hinterland- and foreland-directed shear zones in orogenic belts. (c) 2006 Elsevier Ltd. All rights reserved.

RELIGIÃO E SERTÃO: A VIDA, A PALAVRA E O SAGRADO COMO VEREDAS DE LEITURA TEOLÓGICOLITERÁRIA PARA A OBRA DE JOÃO GUIMARÃES ROSA

A presente tese, de título: Religião e Sertão, é uma tentativa de ler, a partir do viés do diálogo entre religião, teologia e literatura, e do método da correspondência de Antonio Carlos de Melo Magalhães, a obra do literato mineiro João Guimarães Rosa. Para tanto, a tese segue por meio de três grandes correspondências encontradas não só na obra rosiana como também, de forma comum e constante, em quase todas as pesquisas que seguem a interface teologia e literatura: palavra, vida e sagrado. Vida como processo de existência a travessia do homem humana, palavra como meio de manifestação dessa existência e sagrado como forma de explicação para essa existência. Desse modo, os quatro capítulos da tese seguem essas correspondências: o primeiro, com uma discussão sobre o próprio diálogo: religião, teologia e literatura, seguido dos outros três, como veredas de leitura: vida, palavra e sagrado.(AU)

Town and Countryside in early modern Hungary The Case of Sopron, c. 1500-1800

The town of Sopron (Ödenburg) is situated near the western border of Hungary at the junction of major routes of commerce, no further than 70 km from Vienna. As early as in 1291 the town had become a chartered town or free royal town, which meant the most fully-fledged municipial autonomy in this period. The town was subordinated only to the king and could represent itself in parliament from 1445. The surrounding seigniorial towns and villages often lodged an appeal with the Town Court due to its wide legal autonomy. The inhabitants of seigniorial towns and the villagers could have been under the necessity of going to the town, and the legal proceedings they experienced in Sopron may have meant a model pattern for them. The seigniorial town (oppidum) is a settlement under the landlord's authority, with limited legal privileges, concentrated mostly on agricultural production and on the exchange of products of its immediate hinterland. Sopron as a county town was gradually becoming significant during the early modern period. The county (megye) was not only the unit of administration in Hungary, but that of the autonomy of nobility, too. The importance of Sopron as a county town attracted many noblemen dwelling in Sopron county to the town. The county was one of the most densely populated in the 15-18th c., at the beginning of the 18th c., for example, the density was 32 person/km2 and it rose more than 40 p/km2 by the end of the century. The population of Sopron was approximately 3500-3700 in the middle of the 15th c., and due to the decline during the later decades some 3000 persons lived in the town in the early 16th c. According to the first national census the population of Sopron was 12600 in 1784-87. These data place Sopron at the high level of Hungarian urban hierarchy in this period. This paper will explore two significant aspects of the relation between the town and its countryside: the problems of mutual economic dependence and the role of Sopron as a centre of culture.

Dialogização de vozes: o fio construtor do estilo de José Bezerra Gomes no romance A porta e o vento

This research aims to investigate the process of stylistic construction in novelistic prose of Northeastern Brazilian writter José Bezerra Gomes, taking as a corpus his novel called A porta e o vento. The theoretical foundations supporting this study are related to the ideas disseminated by a group of linguistic researchers known as Bakhtin Circle, especially the notions of dialogic language, literary word, concrete utterance, social voices, and sociological style/stylistic. Concerning to methodological guidance, this work is characterized by adopting the interpretive paradigm of socio-historical background, still situated in the great field of Applied Linguistics, an undisciplinary area of research and frontier whose primary focus is concrete and situated language. The analysis allowed me to hear several social voices embodied therein, realizing a variety of dialogs, numerous worldviews in constant struggle, that due to the management and the finish given by the author, eventually create a tone, a unique composition compared to other discourses and current styles in his midst. Ideological clashes are evident: the voice of tradition versus particular character Santos’ voice regarding the institution of marriage; confrontation between antagonistic hinterland pictures - a living hinterland (rich and diverse) as opposed to the stereotypical notion of hinterland (poor and sterile); and the door and the wind as a metaphor of a fighting arena and a hint of poeticization of the language of prose. The main feature of Bezerra’s style in A porta e o vento is related to the aforesaid modes dialogization voices present in the novel. Therefore, one can found veiled polemic, dialogical replicas and veiled dialogues, which are categories already discussed in Bakhtin's theory, but also other new modes dialogization, grounded in the dynamics of living and concrete language

Guimarães Rosa: travessia

This study develops a reading of five tales of Guimarães Rosa: “A hora e vez de Augusto Matraga”, “Campo Geral”, “A Benfazeja”, “Esses Lopes” and “Meu tio o Iauaretê”, included, respectively, in Sagarana, Corpo de Baile, Primeiras Estórias, Tutaméia and Estas Estórias. Then, undertakes a brief course in order to observe in the creative genesis of the author a manichean theme, whose view of the world, with poetic intensity, opposes the good and the evil. This research thus has drawn upon the Mythical Symbolism, in Literary Criticism and aspects of Metaphisics, in addition to analyzing classic literary essays in approaching of histories masterpiece structure. It has also demonstrate that in the rosiano hinterland the contradictory contributes to the speculation about the human man, in the continuous learning of his passing

Areia sob os pés da alma: uma leitura da vida e obra de Oswaldo Lamartine de Faria

This study followed the development of Oswaldo Lamartine de Faria as an intellectual, with the aim of establishing the emergence of that de Faria’s work under the umbrella of the sertão (hinterland) in Northeast Brazil. It accompanied the emergence of the researcher, his discovery of his mission to study the sertão in Seridó and the vital importance of his relationship with Luís da Câmara Cascudo, since despite being a natural born observer, Oswaldo Lamartine embarked on a career as a researcher after encouragement by Cascudo. The first chapter of this study, denominated The Gates of Time, portrays the country during the drought of 1919, the year Lamartine was born. It describes his childhood and first encounters with Câmara Cascudo; his urban exile in Rio de Janeiro; the books written by the young Oswaldo, those that came later, and his definitive return to the state of Rio Grande do Norte. The following two chapters, Sand beneath the Feet of the Soul and Images of a Nobleman from the Sertão, summarize Lamartine’s books and describe his entry into the canon of the state’s culture, with particular prominence given to his interview for the documentary “Oswaldo Lamartine: prince of the sertão”, highlighting his attempt (through his writing) to preserve his own existence. In the second section, Verses, Bold, Between the Lines features analyses of texts dedicated to Oswaldo Lamartine, such as those written by de Zila Mamede, Maria Lúcia Dal Farra and Paulo de Tarso Correia de Melo. The next chapter, entitled Warm and Vivid Ashes, highlights Lamartine’s correspondence with Luís da Câmara Cascudo and the incredible friendship between the two researchers. Cascudo’s letters are analyzed through the book De Cascudo para Oswaldo (From Cascudo to Oswaldo) and and are a powerful testimony of Oswaldo Lamartine’s permanent connection to Rio Grande do Norte. In conclusion, the final chapter entitled Combine, Tattoo, Imprint analyzes the writer’s five-book collection entitled Sertões do Seridó (Hinterlands of Seridó). In reading each of these, it becomes clear that observing reality was vital to the writer’s work. This is one of the first studies to be conducted about Oswaldo Lamartine at the Federal University of Rio Grande do Norte and its main theoretical references were the reflections of authors Jacques Le Goff (2003), Lejeune (1994; 2008), Maurice Blanchot (1987; 2005), Alfredo Bosi (1987) and Gaston Bachelard (n.d.).

Stable-isotope ratios and accumulation rates of four firn cores from the Dronning Maud Land, Antarctica

Four firn cores were retrieved in 2007 at two ridges in the area of the Ekström Ice Shelf, Dronning Maud Land, coastal East Antarctica, in order to investigate the recent regional climate variability and the potential for future extraction of an intermediate-depth core. Stable water-isotope analysis, tritium content and electrical conductivity were used to date the cores. For the period 1981-2006 a strong and significant correlation between the stable-isotope composition of firn cores in the hinterland and mean monthly air temperatures at Neumayer station was (r=0.54-0.71). No atmospheric warming or cooling trend is inferred from our stable-isotope data for the period 1962-2006. The stable-isotope record of the ice/firn cores could expand well beyond the meteorological record of the region. No significant temporal variation of accumulation rates was detected. However, decreasing accumulation rates were found from coast to hinterland, as well as from east (Halvfarryggen) to west (Søråsen). The deuterium excess (d) exhibits similar differences (higher d at Søråsen, lower d at Halvfarryggen), with a weak negative temporal trend on Halvfarryggen (0.04 per mil/a), probably implying increasing oceanic input. We conclude that Halvfarryggen acts as a natural barrier for moisture-carrying air masses circulating in the region from east to west.

Last glacial maximum sediment record of the southern Weddell Sea shelf

Abstract: The history of grounded ice-sheet extent on the southern Weddell Sea shelf during the Last Glacial Maximum (LGM) and the timing of post-LGM ice-sheet retreat are poorly constrained. Several glaciological models reconstructed widespread grounding and major thickening of the Antarctic Ice Sheet in the Weddell Sea sector at the LGM. In contrast, recently published onshore data and modelling results concluded only very limited LGM-thickening of glaciers and ice streams feeding into the modern Filchner and Ronne ice shelves. These studies concluded that during the LGM ice shelves rather than grounded ice covered the Filchner and Ronne troughs, two deep palaeo-ice stream troughs eroded into the southern Weddell Sea shelf. Here we review previously published and unpublished marine geophysical and geological data from the southern Weddell Sea shelf. The stratigraphy and geometry of reflectors in acoustic sub-bottom profiles are similar to those from other West Antarctic palaeo-ice stream troughs, where grounded ice had advanced to the shelf break at the LGM. Numerous cores from the southern Weddell Sea shelf recovered sequences with properties typical for subglacially deposited tills or subglacially compacted sediments. These data sets give evidence that grounded ice had advanced across the shelf during the past, thereby grounding in even the deepest parts of the Filchner and Ronne troughs. Radiocarbon dates from glaciomarine sediments overlying the subglacial deposits are limited, but indicate that the ice grounding occurred at the LGM and that ice retreat started before ~15.1 corrected 14C kyrs before present (BP) on the outer shelf and before ~7.7 corrected 14C kyrs BP on the inner shelf, which is broadly synchronous with ice retreat in other Antarctic sectors. The apparent mismatch between the ice-sheet reconstructions from marine and terrestrial data can be attributed to ice streams with very low surface profiles (similar to those of "ice plains") that had advanced through Filchner Trough and Ronne Trough at the LGM. Considering the global sea-level lowstand of ~130 metres below present, a low surface slope of the expanded LGM-ice sheet in the southern Weddell Sea can reconcile grounding-line advance to the shelf break with limited thickening of glaciers and ice streams in the hinterland. This scenario implies that ice-sheet growth in the Weddell Sea sector during the LGM and ice-sheet drawdown throughout the last deglaciation could only have made minor contributions to the major global sea-level fluctuations during these times.

Mineralogy and petrology of Black Sea Basin sediments

The origin and modes of transportation and deposition of inorganic sedimentary material of the Black Sea were studied in approximately 60 piston, gravity, and Kasten cores. The investigation showed that the sediment derived from the north and northwest (especially from the Danube) has a low calcite-dolomite ratio and a high quartz-feldspar ratio. Rock fragments are generally not abundant; garnet is the principal heavy mineral and illite is the predominant clay mineral. This sedimentary material differs markedly from that carried by Anatolian rivers, which is characterized by a high calcite-dolomite ratio and a low quartz-feldspar ratio. Rock fragments are abundant; pyroxene is the principal heavy mineral and montmorillonite is the predominant clay mineral. In generel, the clay fraction is large in all sediments (27.6-86.9 percent), and the lateral distributian indicates an increase in clay consent from the coasts toward two centers in the western and eastern Black Sea basin. Illite is the most common clay mineral in the Black Sea sediments. The lateral changes in composition of the clay mineral can easily be traced to the petrologic character of northern (rich in illite) and southern (rich in montmorillonite) source areas. In almost all cores, a rhythmic change of the montmorillonite-illite ratio with depth was observed. These changes may be related to the changing influence of the two provinces during the Holocene and late Pleistocene. Higher montmorillonite content seems to indicate climctic changes, probably stages of glaciation end permafrost in the northern area, at which time the illite supply was diminished to a large extent. The composition of the sand fraction is relatad to the different petrologic and morphologic characteristics of two major source provimces: (1) a northern province (rich in quartz, feldspars, and garnet) characterized by a low elevation, comprising the Danube basin area and the rivers draining the Russian platform; and (2) a southern province (rich in pyroxene and volcanic and metamorphic rocks) in the mountainous region of Anatolia and the Caucasus, characterized by small but extremely erosive rivers. The textural properties (graded bedding) of the deep-sea send layers clearly suggest deposition from turbidity currents. The carbonate content of the contemporary sediments ranges from 5 to 65 percent. It increases from the coast to a maximum in two centers in the western and eastern basin. This pattern reflects the distribution of the <2-µm fraction. The contemporary mud sedimentation is governed by two important factors: (1) the deposition of terrigenous allochthonous material of low carbonate content originating from the surrounding hinterland (northern and southern source areas), and (2) the autochthonous production of large quantities of biogenic calcite by coccolithophores during the last period of about 3,000-4,000 years.

Clay mineral analysis of sediments from the Amundsen Sea

The Amundsen Sea embayment is a probable site for the initiation of a future collapse of the West Antarctic Ice Sheet. This paper contributes to a better understanding of the transport pathways of subglacial sediments into this embayment at present and during the last glacial period. It discusses the clay mineral composition of sediment samples taken from the seafloor surface and marine cores in order to decipher spatial and temporal changes in the sediment provenance. The most striking feature in the presentday clay mineral distribution is the high concentration of kaolinite, which is mainly supplied by the Thwaites Glacier system and indicates the presence of hitherto unknown kaolinite-bearing sedimentary strata in the hinterland, probably in the Byrd Subglacial Basin. The main illite input is via the Pine Island Glacier. Smectite originates from the erosion of volcanic rocks in Ellsworth Land and western Marie Byrd Land. The clay mineral assemblages in diamictons deposited during the last glacial period are distinctly different from those in corresponding surface sediments. This relationship indicates that glacial sediment sources were different from modern ones, which could reflect changes in the catchment areas of the glaciers and ice streams.

Microbialites and lipid biomarker from coral reefs off the volcanic islands Tahiti and Vanuatu and from the nonvolcanic sites Belize and the Maldives

The occurrence of microbialites in post-glacial coral reefs has been interpreted to reflect an ecosystem response to environmental change. The greater thickness of microbialites in reefs with a volcanic hinterland compared to thinner microbial crusts in reefs with a non-volcanic hinterland led to the suggestion that fertilization of the reefal environment by chemical weathering of volcanic rocks stimulated primary productivity and microbialite formation. Using a molecular and isotopic approach on reef-microbialites from Tahiti (Pacific Ocean), it was recently shown that sulfate-reducing bacteria favored the formation of microbial carbonates. To test if similar mechanisms induced microbialite formation in other reefs as well, the Tahitian microbialites are compared with similar microbialites from coral reefs off Vanuatu (Pacific Ocean), Belize (Caribbean Sea, Atlantic Ocean), and the Maldives (Indian Ocean) in this study. The selected study sites cover a wide range of geological settings, reflecting variable input and composition of detritus. The new lipid biomarker data and stable sulfur isotope results confirm that sulfate-reducing bacteria played an intrinsic role in the precipitation of microbial carbonate at all study sites, irrespective of the geological setting. Abundant biomarkers indicative of sulfate reducers include a variety of terminally-branched and mid chain-branched fatty acids as well as mono-O-alkyl glycerol ethers. Isotope evidence for bacterial sulfate reduction is represented by low d34S values of pyrite (-43 to -42 per mill) enclosed in the microbialites and, compared to seawater sulfate, slightly elevated d34S and d18O values of carbonate-associated sulfate (21.9 to 22.2 per mill and 11.3 to 12.4 per mill, respectively). Microbialite formation took place in anoxic micro-environments, which presumably developed through the fertilization of the reef environment and the resultant accumulation of organic matter including bacterial extracellular polymeric substances (EPS), coral mucus, and marine snow in cavities within the coral framework. ToF-SIMS analysis reveals that the dark layers of laminated microbialites are enriched in carbohydrates, which are common constituents of EPS and coral mucus. These results support the hypothesis that bacterial degradation of EPS and coral mucus within microbial mats favored carbonate precipitation. Because reefal microbialites formed by similar processes in very different geological settings, this comparative study suggests that a volcanic hinterland is not required for microbialite growth. Yet, detrital input derived from the weathering of volcanic rocks appears to be a natural fertilizer, being conductive for the growth of microbial mats, which fosters the development of particularly abundant and thick microbial crusts.

AMS radiocarbon dates on ten monospecific samples of planktonic foraminifer Globigerinoides ruber of sediment core GeoB8509-2 (Table 1)

Aeolian and fluvial sediment transport to the Atlantic Ocean offshore Mauritania were reconstructed based on grain-size distributions of the carbonate-free silt fraction of three marine sediment records of Cap Timiris Canyon to monitor the climatic evolution of present-day arid north-western Africa. During the late Pleistocene, predominantly coarse-grained particles, which are interpreted as windborne dust, characterise glacial dry climate conditions with a low sea level and extended sand seas that reach onto the exposed continental shelf off Mauritania. Subsequent particle fining and the abrupt decrease in terrigenous supply are attributed to humid climate conditions and dune stabilisation on the adjacent African continent with the onset of the Holocene humid period. Indications for an ancient drainage system, which was discharging fluvial mud offshore via Cap Timiris Canyon, are provided by the finest end member for early to mid Holocene times. However, in comparison to the Senegal and Niger River further south, the river system connecting Cap Timiris Canyon with the Mauritanian hinterland was starved during the late Holocene and is non-discharging under present-day arid climate conditions.

(Table 1) Results of pore water analyses, including boron content and boron isotope ratios

Drilling a transect of holes across the Costa Rica forearc during ODP Leg 170 demonstrated the margin wedge to be of continental, non accretionary origin, which is intersected by permeable thrust faults. Pore waters from four drillholes, two of which penetrated the décollement zone and reached the underthrust lower plate sedimentary sequence of the Cocos Plate, were examined for boron contents and boron isotopic signatures. The combined results show dilution of the uppermost sedimentary cover of the forearc, with boron contents lower than half of the present-day seawater values. Pore fluid "refreshening" suggests that gas hydrate water has been mixed with the sediment interstitial water, without profoundly affecting the d11B values. Fault-related flux of a deeply generated fluid is inferred from high B concentration in the interval beneath the décollement, being released from the underthrust sequence with incipient burial. First-order fluid budget calculations over a cross-section across the Costa Rica forearc indicate that no significant fluid transfer from the lower to the upper plate is inferred from boron fluid profiles, at least within the frontal 40 km studied. Expulsed lower plate pore water, which is estimated to be 0.26-0.44 km3 per km trench, is conducted efficiently along and just beneath the décollement zone, indicating effective shear-enhanced compaction. In the upper plate forearc wedge, dewatering occurs as diffuse transport as well as channelled flow. A volume of approximately 2 km3 per km trench is expulsed due to compaction and, to a lesser extent, lateral shortening. Pore water chemistry is influenced by gas hydrate instability, so that it remains unknown whether deep processes like mineral dehydration or hydrocarbon formation may play a considerable role towards the hinterland.

Structural evolution of the Lesser Himalayan fold-thrust belt of west central Nepal

The Lesser Himalayan fold-thrust belt on the south flank of the Jajarkot klippe in west central Nepal was mapped in detail between the Main Central thrust in the north and the Main Boundary thrust in the south. South of the Jajarkot klippe, the fold-thrust belt involves sandstone, shale and carbonate rocks that are unmetamorphosed in the foreland and increase in metamorphic grade with higher structural position to sub-greenschist facies towards the hinterland. The exposed stratigraphy is correlative with the Proterozoic Ranimata, Sangram, Galyang, Syangia Formations and Lakharpata Group of Western Nepal and overlain by the Paleozoic Tansen and Kali Gandaki Groups. Based on field mapping and cross-section construction, three distinct thrust sheets were identified separated by top-to-the-south thrust faults. From the foreland (south) to the hinterland (north), the first thrust sheet in the immediate hanging wall of the Main Boundary thrust defines an open syncline. The second thrust sheet contains a very broad synformal duplex, which is structurally stacked against the third thrust sheet containing a homoclinal panel of the oldest exposed Proterozoic stratigraphy. Outcrop scale folds throughout the study area are predominantly south vergent, open, and asymmetric reflecting the larger regional scale folding style, which corroborate the top-to-the-south deformation style seen in the faults of the region. Field techniques were complemented with microstructural and quartz crystallographic c-axis preferred orientation analyses using a petrographic microscope and a fabric analyzer, respectively. Microstructural analysis identified abundant strain-induced recrystallization textures and occasional occurrences of top-to-the-south shear-sense indicators primarily in the hinterland rocks in the immediate footwall of the Main Central Thrust. Top-to-the-south shearing is also supported by quartz crystallographic c-axis preferred orientations. Quartz recrystallization textures indicate an increase in deformation temperature towards the Main Central thrust. A line balance estimate indicates that approximately 15 km of crustal shortening was accommodated by folding and faulting in the fold-thrust belt south of the Jajarkot klippe. Additionally, estimations of shortening velocity suggest that the shortening velocity operating in this section of the fold-thrust belt between 23 to 14 Ma was slower than what is currently observed as a result of the ongoing deformation of the Sub-Himalayan fold-thrust belt.

Floristic And Ethnobotanical Studies Of Medicinal Plants Of The City Of El -Jadida (MOROCCO)

Abstract: BRIGUICHE. H, ZIDANE. L. Floristic And Ethnobotanical Studies Of Medicinal Plants Of The City Of El -Jadida (MOROCCO). In the framework of the ethnobotanical studies on medicinal plants undertaken by the Laboratory of Biodiversity and Natural Resources of the Faculty of Sciences of Kenitra (Morocco), we are interested in the area of El Jadida which presents a rather important floristic richness thanks to changes in its ecological conditions By using 204 questionnaire, the ethnobotanical surveys were conducted in the field during the years 2012-2013. The location of the different sampling sites was determined by the stratified sampling method. The analysis of the results obtained from the questionnaires and forms using statistical processing allowed us to identify 70 plant species distributed in 69 genera and 37 families. These results also show that most of these species are mainly used in the care of the digestive system and respiratory system. The seed is the most used part in local traditional medicines and the decoction is the most frequent mode with a rate of 31%. The species Origanum compactum is the most used by the population of the city of El Jadida 47 quotes.