Morphology and sedimentary filling of an ancient estuarine valley in an urban environment (Gijón, NW Spain)

Author(s):  
Luis Pando ◽  
Germán Flor-Blanco ◽  
Jorge Rey Díaz de Rada ◽  
Adrián García-Rodríguez

<p>The city of Gijón is located on the Cantabrian Coast (NW, Spain), and its subsurface is formed mainly by sand linked to an old estuarine mouth barrier (beach and dunes), sand bay and marshes. Under these sediments, there is a layer of clays related to the weathering of a Jurassic rock basement. This research addresses the setting of the estuary sediments in both the submerged area, located north of the city, and under the built-up area.</p><p>The seafloor morphology was investigated by means of a bathymetric survey with multi-beam echo sounder. A geophysical survey using high-resolution reflection seismic profiles allowed studying the thickness of the unconsolidated deposits that fill the bay of Gijón. Likewise, the distribution of coastal sediments under the city was reviewed from boreholes collected within a GIS-based geotechnical database.</p><p>The bathymetric reconstruction led to the identification of a paleo-valley supposedly excavated by the main river of the city, with N-S orientation that evolves to NNE-SSW towards the north. It shows a sandy bottom with a very low slope, a length of about 4 km and a width that ranges between 400 and 800 m. In this channel, the unconsolidated deposits reach a maximum thickness of around 15 m while at S, in the urban subsurface, the thickness exceeds 20 m locally. With these data, it was also possible to investigate the geometry of the bedrock under the sedimentary filling.</p>

2012 ◽  
Vol 4 (1) ◽  
pp. 241-278 ◽  
Author(s):  
E. Lundberg ◽  
C. Juhlin ◽  
A. Nasuti

Abstract. The Møre-Trøndelag Fault Complex (MTFC) is one of the most prominent fault zones of Norway, both onshore and offshore. In spite of its importance, very little is known of the deeper structure of the individual fault segments comprising the fault complex. Most seismic lines have been recorded offshore or focused on deeper structures. This paper presents results from two reflection seismic profiles, located on each side of the Tingvollfjord, acquired over the Tjellefonna fault in the south-eastern part of the MTFC. Possible kilometer scale vertical offsets reflecting, large scale north-west dipping normal faulting separating the high topography to the south-east from lower topography to the north-west have been proposed for the Tjellefonna fault. In this study, however, the Tjellefonna fault is interpreted to dip approximately 50–60° towards the south-east to depths of at least 1.4 km. Travel-time modeling of reflections associated with the fault was used to establish the geometry of the fault structure at depth and detailed analysis of first P-wave arrivals in shot-gathers together with resistivity profiles were used to define the near surface geometry of the fault zone. A continuation of the structure on the north-eastern side of the Tingvollfjord is suggested by correlation of an in strike direction P-S converted reflection (generated by a fracture zone) seen on the reflection data from that side of the Tingvollfjord. The reflection seismic data correlate well with resistivity profiles and recently published near surface geophysical data. A highly reflective package forming a gentle antiform structure was also identified on both seismic profiles. The structure may be an important boundary within the gneissic basement rocks of the Western Gneiss Region. The Fold Hinge Line is parallel with the Tjellefonna fault trace while the topographic lineament diverges, following secondary fracture zones towards north-east.


1994 ◽  
Vol 41 ◽  
pp. 162-180
Author(s):  
L O. Baldreel ◽  
M.S. Andersen

The Faeroe-Rockall Plateau is located in the NE Atlantic Ocean between Iceland and Scotland and is characterized by a late Paleocene-early Eocene basalt cover, which was extruded in association with the incipient opening of the NE Atlantic. The Faeroe-Rockall Plateau is separated from the NW European continental shelf by the Rockall Trough and the Faeroe­Shetland Channel, whose nature and age is still debated. Reflector configuration within the basalt allows volcanic seismic facies inteipretation to be carried out. The thickness of the basalt cover is estimated from reflection seismic data. Subbasalt geological structures are identified below subaerially extruded basalt on recently acquired as well as reprocessed seismic profiles. Overlying the basalt are early Eocene and younger Sediments. The distribution of these sedi- . ments is largely controlled by 1) the topography after the cessation of the volcanism, 2) the post volcanic subsidence of the area which is estimated from the depth to the breakpoints located on prim¥)' volcanic escaipments, 3) the Eocene-Miocene compressional tectonics which formed ridge& and minor basins, and 4) bottom currents of Norwegian Sea Deep Water (NSDW) which in the Neogene flowed into the North Atlantic south of the Greenland-Iceland-Faeroe-Scotland Ridg,e. A considerable part of the NSDW flows east and south of th


Antiquity ◽  
1976 ◽  
Vol 50 (200) ◽  
pp. 216-222
Author(s):  
Beatrice De Cardi

Ras a1 Khaimah is the most northerly of the seven states comprising the United Arab Emirates and its Ruler, H. H. Sheikh Saqr bin Mohammad al-Qasimi, is keenly interested in the history of the state and its people. Survey carried out there jointly with Dr D. B. Doe in 1968 had focused attention on the site of JuIfar which lies just north of the present town of Ras a1 Khaimah (de Cardi, 1971, 230-2). Julfar was in existence in Abbasid times and its importance as an entrep6t during the sixteenth and seventeenth centuries-the Portuguese Period-is reflected by the quantity and variety of imported wares to be found among the ruins of the city. Most of the sites discovered during the survey dated from that period but a group of cairns near Ghalilah and some long gabled graves in the Shimal area to the north-east of the date-groves behind Ras a1 Khaimah (map, FIG. I) clearly represented a more distant past.


Author(s):  
Sergey B. Kuklev ◽  
Vladimir A. Silkin ◽  
Valeriy K. Chasovnikov ◽  
Andrey G. Zatsepin ◽  
Larisa A. Pautova ◽  
...  

On June 7, 2018, a sub-mesoscale anticyclonic eddy induced by the wind (north-east) was registered on the shelf in the area of the city of Gelendzhik. With the help of field multidisciplinary expedition ship surveys, it was shown that this eddy exists in the layer above the seasonal thermocline. At the periphery of the eddy weak variability of hydrochemical parameters and quantitative indicators of phytoplankton were recorded. The result of the formation of such eddy structure was a shift in the structure of phytoplankton – the annual observed coccolithophores bloom was not registered.


2020 ◽  
Vol 8 (2) ◽  
pp. 13
Author(s):  
Ankita Pandey

Guwahati derives its name from the Assamese word “Guwa” means areca nut and “Haat” means market. However, the modern Guwahati had been known as the ancient Pragjyotishpura and was the capital of Assam under the Kamrupa kingdom. A beautiful city Guwahati is situated on the south bank of the river Bramhaputra. Moreover, It is known as the largest city in the Indian state of Assam and also the largest metropolis in North East India. It has also its importance as the gateway to the North- East India. Assamese and English are the spoken languages in Guwahati.  In 1667, the Mogul forces were defeated in the battle by the Ahom forces commanded by Lachut Barphukan. Thus, in a sense Guwahati became the bone of contention among the Ahoms, Kochas and the Moguls during the medieval period.  Guwahati the administrative headquarters of Lower Assam with a viceroy or Barbhukan was made by the Ahom king.  Since 1972 it has been the capital of Assam. The present paper will discuss the changes happened in Guwahati over the period of late 1970s till the present time. It will focus on the behavior of people, transformed temples, Panbazar of the city, river bank of Bramhaputra, old Fancy Bazaar, chaotic ways, festivals and seasons including a fifth man made season etc. It will also deal how over the years a city endowed with nature’s gifts and scenic views, has been changing as “a dirty city”. Furthermore, it will also present the insurgencies that have barged into the city. The occurrence of changes will be discussed through the perspective and point of view of Srutimala Duara as presented in her book Mindprints of Guwahati.


Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 170
Author(s):  
Gladys N. Benitez ◽  
Glenn D. Aguilar ◽  
Dan Blanchon

The spatial distribution of corticolous lichens on the iconic New Zealand pōhutukawa (Metrosideros excelsa) tree was investigated from a survey of urban parks and forests across the city of Auckland in the North Island of New Zealand. Lichens were identified from ten randomly selected trees at 20 sampling sites, with 10 sites classified as coastal and another 10 as inland sites. Lichen data were correlated with distance from sea, distance from major roads, distance from native forests, mean tree DBH (diameter at breast height) and the seven-year average of measured NO2 over the area. A total of 33 lichen species were found with coastal sites harboring significantly higher average lichen species per tree as well as higher site species richness. We found mild hotspots in two sites for average lichen species per tree and another two separate sites for species richness, with all hotspots at the coast. A positive correlation between lichen species richness and DBH was found. Sites in coastal locations were more similar to each other in terms of lichen community composition than they were to adjacent inland sites and some species were only found at coastal sites. The average number of lichen species per tree was negatively correlated with distance from the coast, suggesting that the characteristic lichen flora found on pōhutukawa may be reliant on coastal microclimates. There were no correlations with distance from major roads, and a slight positive correlation between NO2 levels and average lichen species per tree.


2021 ◽  
Vol 13 (2) ◽  
pp. 826
Author(s):  
Meiling Zhou ◽  
Xiuli Feng ◽  
Kaikai Liu ◽  
Chi Zhang ◽  
Lijian Xie ◽  
...  

Influenced by climate change, extreme weather events occur frequently, and bring huge impacts to urban areas, including urban waterlogging. Conducting risk assessments of urban waterlogging is a critical step to diagnose problems, improve infrastructure and achieve sustainable development facing extreme weathers. This study takes Ningbo, a typical coastal city in the Yangtze River Delta, as an example to conduct a risk assessment of urban waterlogging with high-resolution remote sensing images and high-precision digital elevation models to further analyze the spatial distribution characteristics of waterlogging risk. Results indicate that waterlogging risk in the city proper of Ningbo is mainly low risk, accounting for 36.9%. The higher-risk and medium-risk areas have the same proportions, accounting for 18.7%. They are followed by the lower-risk and high-risk areas, accounting for 15.5% and 9.6%, respectively. In terms of space, waterlogging risk in the city proper of Ningbo is high in the south and low in the north. The high-risk area is mainly located to the west of Jiangdong district and the middle of Haishu district. The low-risk area is mainly distributed in the north of Jiangbei district. These results are consistent with the historical situation of waterlogging in Ningbo, which prove the effectiveness of the risk assessment model and provide an important reference for the government to prevent and mitigate waterlogging. The optimized risk assessment model is also of importance for waterlogging risk assessments in coastal cities. Based on this model, the waterlogging risk of coastal cities can be quickly assessed, combining with local characteristics, which will help improve the city’s capability of responding to waterlogging disasters and reduce socio-economic loss.


1988 ◽  
Vol 19 (2) ◽  
pp. 266-291 ◽  
Author(s):  
James L. Cobban

By the beginning of the twentieth century, Semarang was a major port city and administrative centre on Java. Attainment of this position was due partly to the expansion of its hinterland during the nineteenth century. This expansion was closely related to developments in the means of transportation and the consequent ability of plantation owners to bring the products of their plantations to the port for shipment to foreign markets. By the end of the century virtually the whole economic life of central Java focused upon Semarang. The city also exercised administrative functions in the Dutch colonial administration and generally had been responsible for Dutch interests in the middle and eastern parts of the island. The importance of Semarang as an administrative centre increased after 1906. In that year the government incorporated the city as an urban municipality (stadsgemeente). In 1914 it had consular representation from the United States, Belgium, Denmark, France, Great Britain, Italy, Norway, Germany, and Thailand. Subsequently, in 1926 it became the capital of the Province of Central Java under the terms of an administrative reform fostered by the colonial government at Batavia. Status as an urban municipality meant that local officials sitting on a city council would govern the domestic affairs of the city. The members of the city council at first were appointed from Batavia, subsequently some of them were elected by residents of the city. By the beginning of the twentieth century Semarang had enhanced its position as a major port on the north coast of the island of Java. It was one of the foremost cities of the Dutch East Indies, along with Batavia and Surabaya, a leading port and a centre of administration and trade. This article outlines the growth of the port of Semarang during the nineteenth century and discusses some of the conflict related to this growth over living conditions in parts of the city during the twentieth century, a conflict which smouldered for several decades among the government, members of the city council, and the non-European residents of the city, one which remained unresolved at the end of the colonial era.


Antiquity ◽  
1936 ◽  
Vol 10 (37) ◽  
pp. 77-85
Author(s):  
S. R. K. Glanville

Aconcession to excavate the site of Tell el Amarna was given to the Egypt Exploration Society in 1920, and with the exception of two seasons the Society has sent an expedition there every year since that date. Beginning with the central town site, at the point where the Deutsche Orient-Gesellschaft had left it before the war, the work of the first two seasons was confined to the southern half of the city, although it included several important outlying buildings of a nondomestic character and the ‘Eastern Village’ of workmen’s houses. The discovery of the North Palace in 1923 turned the attention of the excavators to the distant end of the site, leading them to the building of a new house from which to work and to the discovery of other official buildings at the extreme north of the bay, and a group of houses connected with them. These last have not yet been completely excavated.


Archaeologia ◽  
1860 ◽  
Vol 38 (1) ◽  
pp. 135-148
Author(s):  
Weston Styleman Walford

The Deed exhibited this evening by Mr. Joseph Jackson Howard has appeared to me sufficiently interesting to justify a few remarks on its contents. It bears date the 7th of August 1456 (34 Hen. VI.). By it Richard Acreman granted to John Oudene, master of the fraternity or guild of St. George of the Men of the Mystery of Armourers of the city of London, to John Ruttour and William Terry, the wardens, and to the brothers and sisters of the same guild the advowson of or right of presenting a chaplain to the chantry which Joan, formerly the wife of Nicholas de Wokyndon, Knight, founded at the altar of St. Thomas the Martyr in the new work of the cathedral church of St. Paul, London, viz. on the north side of the same church; which altar was, at the time of this grant, placed in the chapel then commonly called the chapel of St. George within the said church, in which chapel the said guild was then lately founded and established by King Henry VI.: this advowson the said Richard Acreman had of the grant of Thomas Coburley and Thomas Burghille, who had it (inter alia) of the gift of Richard Bastard of Bedford and Isabella his wife, who was kinswoman and heiress of the said Nicholas de Wokyndon. The deed was witnessed by William Marwe, the Mayor of the city of London, and John Yonge and Thomas Ouldegreve, the Sheriffs.


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