Vulnerability assessment of coastal areas to sea level rise from the physical and socioeconomic parameters: case of the Gulf Coast of Bejaia,Algeria

The study area (the Gulf of Bejaia) is a coastal zone of about 70 km long in the eastern-central part of the Algerian coast. The coastline characterized by sandy beaches, hotels and tourist facilities, airport, port, villages and towns has known during these last decades several threats like storms, floods and erosion. The present work concerns the mapping of the physical and socioeconomic vulnerability of the Gulf Coast of Bejaia to sea level rise, using Coastal Vulnerability Index (CVI) and geospatial tools. The Physical CVI (CVI_Phys) is calculated from seven physical variables: geomorphology, coastal slope, coastal regional elevation, sea level rise rate, shoreline erosion/accretion rates, tidal range and significant wave height. On the other hand, the parameters population, cultural heritage, roads, railways, land use and conservation designation constitute, for their part, the socioeconomic CVI (CVI_eco). The values obtained from the calculation of CVI_Phys vary between 3.53 and 81.83. These results revealed that 22.42 km of the studied coastline has a low physical vulnerability, 21.68 km a high vulnerability and 15.83 km a very high vulnerability, indicating that the most part of the coastline (53.59%) is vulnerable to sea level rise. According to the obtained values of CVI_eco, the most vulnerable areas of high and very high risk represent 31.81 km of the total coastline. They were found along the western (Bejaia and Tichy) and eastern (Aokas, Souk El Tenine and Melbou) coast, while the least vulnerable stretches, covering 38.19 km of the total length of the coast, occupy the rest of the area. This study highlighted areas that will be most affected by future sea level rise (SLR) and storm events. It revealed that several development projects of Bejaia Gulf Coast, including tourist expansion areas, are planned in sites identified as very vulnerable. The results obtained from this assessment could guide local planners and decision-makers in developing coastal management plans in the most vulnerable areas.     

Reflection–refraction seismics in the Gulf of Corinth: hints at deep structure and control of the deep marine basin

The Gulf of Corinth is a natural laboratory for the study of seismicity and crustal deformation during continental extension. Seismic profiling along its axis provides a 24-fold normal-incidence seismic reflection profile and wide-angle reflection–refraction profiles recorded by sea-bottom seismometers (OBS) and land seismometers. At wide-angle incidence, the land receivers document the Moho at 40-km depth under the western end of the Gulf north of Aigion, rising to 32-km depth under the northern coast in the east of the Gulf. Both refraction and normal-incidence reflection sections image the basement under the deep marine basin that has formed by recent extension. The depth to the base of the sedimentary basin beneath the Gulf, constrained by both methods, is no more than 2.7 km, with 1 km of water underlain by no more than 1.7 km of sediment, less than what was expected from past modeling of uplift of the south coast in the East of the Gulf. Unlike the flat sea-bottom, the basement and sedimentary interfaces show topography along this axial line. Several deeps are identified as depocenters, which suggest that this axial line is not a strike line to the basin. It appears instead to be controlled by several faults, oblique to the S60°E overall trend of the south coast of the Gulf, their more easterly strikes being consistent with the instantaneous direction of extension measured by earthquake slip vectors and by GPS.     

Late Cretaceous stratigraphy,sediments and structure: Gems of the Dorset and East Devon Coast World Heritage Site (Jurassic Coast), England

Extraordinary, long-distance litho-marker beds such as the Lewes and Shoreham Tubular Flints and associated marl seams and fossils, recognised in cliff exposures and cliff-fall boulders, are keys to unlocking the stratigraphy and tectonic structures in the Late Cretaceous of the Dorset and East Devon Coast World Heritage Site (Jurassic Coast). Durdle Cove is a special gem exposing the Lewes and Seaford Chalk stratigraphy where new marker beds are identified and sediments and tectonic structures provide clues to timing of movements that produced a Late Cretaceous pericline which grew into a Miocene monocline along the line of the underlying Purbeck Reverse Fault. During ‘inversion’ along this fault some Late Cretaceous Chalk formations were in part or completely ‘lost’ (e.g. Middle Turonian New Pit Chalk Formation) and others were condensed (e.g. Late Santonian and Early Campanian Newhaven Chalk Formation). Excavation of the A354 road cutting at the Lower Bincombe Farm, has greatly added to the stratigraphical records of Late Cretaceous fossils in South Dorset, especially Coniacian and Early Campanian inoceramid bivalves and the various stratigraphically specific forms of the Late Santonian to Early Campanian echinoid fossil Echinocorys scutata spp. not recorded before in this coastline. The very large bivalve fossil Platyceramus sp. provides clues to chalk sea-floor environments.     

An Upper Cretaceous (middle Campanian) marine chondrichthyan and osteichthyan fauna from the Rattlesnake Mountain sandstone member of the Aguja Formation in West Texas

A thin phosphate-granule conglomerate within the Upper Cretaceous (middle Campanian) Rattlesnake Mountain sandstone member of the Aguja Formation preserves a diverse chondrichthyan and osteichthyan fauna. This highly fossiliferous deposit (the ‘Ten Bits Microsite’) yielded about 5000 teeth, spines, and denticles in a small amount of matrix (c. 150 kg). About 30 identifiable species of sharks, rays, and bony fishes are recognized. Two of the three most abundant chondrichthyan species at Ten Bits (Scapanorhynchus texanus and Ischyrhiza mira) are also the most common species in other middle to late Campanian marine vertebrate faunas along the Gulf and Atlantic Coastal Plain. The myliobatiform rays Brachyrhizodus and Rhombodus that occur at Ten Bits also appear to be characteristic of the Gulf and Atlantic Coast, as are lamniform sharks such as Cretalamna and Serratolamna. These taxa are entirely absent or extremely rare in Western Interior Campanian faunas. In contrast, some small orectolobiform sharks (Cantioscyllium, Chiloscyllium, Columbusia) and small rays (Protoplatyrhina) found at Ten Bits are common in shallow water faunas of the Western Interior and Texas Coastal Plain, but rarely reported from the eastern Gulf or Atlantic Coast. The common Western Interior ray Myledaphus bipartitus does not occur at Ten Bits or in any Gulf or Atlantic Coast fauna. Ptychotrygon agujaensis is abundantly represented in the Ten Bits fauna, but unknown in correlative marine faunas. Although Ptychotrygon occurs in all Western Interior, Gulf and Atlantic Coastal Plain faunas, it is represented elsewhere by apparently endemic species at each collection site. The differences between Western Interior, Gulf, and Atlantic Coastal Plain faunas probably reflect latitudinal variation in water temperature or salinity, or different oceanic water circulation patterns between the Western Interior Seaway and the Gulf or Atlantic Coast that restricted the distributions of some marine fish species. The Ten Bits fauna shares typical species with both Western Interior and Gulf and Atlantic Coast faunas, reflecting its position at the border between these provinces; however, the dominant taxa found at Ten Bits are the same as those found on the Gulf and Atlantic Coast, and indicate that western Texas was more closely allied biogeographically with that province than with the Western Interior of North America. One species tentatively identified in the Ten Bits fauna on the basis of a single tooth, Igdabatis cf. I. indicus, is otherwise known only from southern Europe and Asia, although a similar large myliobatid ray also occurs rarely in Texas Coastal Plain faunas. These occurrences indicate that western Texas may have been near the northern limit of the range for some tropical Tethyan marine vertebrate species.     

Hydroperiod and its influence on nekton use of the salt marsh: A pulsing ecosystem

The salt marsh surface is not a homogeneous environment. Rather, it contains a mix of different microhabitats, which vary in elevation, microtopography, and location within the estuarine system. These attributes act in concert with astronomical tides and meteorological and climatological events and result in pulses of tidal flooding. Marsh hydroperiod, the pattern of flooding events, not only controls nekton access to marsh surface habitats directly but may also mediate habitat exploitation through its influence on other factors, such as prey abundance or vegetation stem density. The relative importance of factors affecting marsh hydroperiod differ between the southeast Atlantic and northern Gulf of Mexico coasts. Astronomical tidal forcing is the primary determinant of hydroperiod in Atlantic Coast marshes, whereas predictable tides are often overridden by meteorological events in Gulf Coast marshes. In addition, other factors influencing coastal water levels have a proportionately greater effect on the Gulf Coast. The relatively unpredictable timing of marsh flooding along the Gulf Coast does not seem to limit habitat utilization. Some of the highest densities of nekton reported from salt marshes are from Gulf Coast marshes that are undergoing gradual submergence and fragmentation caused by an accelerated rise in relative sea level. Additional studies of habitat utilization are needed, especially on the Pacific and Atlantic coasts. Investigations should include regional comparisons of similar microhabitats using identical quantitative sampling methods. Controlled field experiments are also needed to elucidate the mechanisms that affect the habitat function of salt marshes.     

Galveston Bay: Temporal changes in the concentrations of trace organic contaminants in national status and trends oysters (1986–1994)

The temporal distributions for six classes of trace organic contaminants (chlordanes, DDTs, dieldrin, PAHs, PCBs, and butyltins) in oysters from six Galveston Bay sites from National Oceanic and Atmospheric Administration’s National Status and Trends (NS&T) Mussel Watch Program are compared with other NS&T sites from the Gulf of Mexico as well as all NS&T sites of the United States (East Coast, West Coast, and Gulf of Mexico). Decreases in the median for the Gulf-wide concentration of chlordanes, dieldrin, and butyltins occurred during 1986–1994. The Gulfwide median concentrations of DDTs, PAHs, and PCBs exhibited a strong cyclic distribution with time. For Galveston Bay oysters, “high” concentration is defined as the concentration greater than the median plus one standard deviation for all Gulf of Mexico sites. The percentage of sites having high concentrations during 1986–1994 for Galveston Bay oysters are 49% for dieldrin, 45% for butyltins, 40% for chlordanes, 38% for PCBs, 30% for PAHs, and 21% for DDTs. For PCBs, 43% of Galveston Bay oyster samples analyzed over the first 9 yr have concentrations high enough for potential biological effects to be observed in oysters. The percentages in other agents were chlordanes (22%), butyltins (22%), dieldrin (5%), and PAHs (4%). National Academy of Science-proposed regulatory limits for oysters were exceeded in only 2% of Galveston Bay samples for DDTs and 1% for PCBs. All other contaminants were below proposed NAS limits.     

Evaluation of ecotourism potential in the northern coastline of the Persian Gulf

This research has identified areas located in the northern coastline of the Persian Gulf in the south of Iran, as strategic and ecological sites, based on tourism potential assessing criteria. To this end coastal limits were identified by satellite imagery in terms of shorelines and the maximum extent of water approach into the land and taking into consideration the characteristics of the nearby coastal villages. The studied region was then compared to similar international criteria and experiences. The original criteria were then divided into three main and four sub criteria. The Kangan region was found to have a potential for tourism industry according to the mentioned criteria. Naiband Gulf with a score of 20 was ranked first followed by Asalouyeh with a score of 18 and finally Taheri and Kangan Ports with scores of 16 and 15, respectively. With a high tourism industry potential in the studied region the necessity of ecotourism quality enhancement and environmental management planning for the northern shoreline of the Persian Gulf becomes of vital importance.     

Geological evolution of the Afro-Arabian dome

The Afro-Arabian dome includes the elevated continental regions enclosing the Red Sea, Gulf of Aden, and the Ethiopian rift system, and extends northwards as far as Jordan. It is more than an order of magnitude larger than other African uplifts. Both the structures and the igneous rocks of the dome appear to be products of the superimposition of two, perhaps three, semi-independent generating systems, initiated at different times but all still active. A strain pattern dominated by NW-trending basins and rifts first became established early in the Cretaceous. By the end of the Oligocene, much of the extensional strain had been taken up along the Red Sea and Gulf of Aden axes, which subsequently developed into an ocean. Palaeogene “trap” volcanism of mildly alkaline to transitional character was related to this horizontal extension rather than to doming. Further west, the East Sahara swell has a history of intermittent alkaline volcanicity which began in the Mesozoic and was independent of magmatism in the Afro-Arabian dome. Volcanicity specifically related to doming began in the Miocene along a N-S zone of uplift extending from Ethiopia to Syria. This elongated swell forms the northern termination of the East African system of domes and rifts, characterized by episodic vertical uplift but very little extension. Superimposition of epeirogenic uplift upon structures formed by horizontal extension took place in the Neogene. Volcanicity related to vertical tectonics is mildly alkaline in character, whereas transitional and tholeiitic magmas are found along the spreading axes.     

Hydrologic hydrochemical characterization of texas frio formation used for deep-well injection of chemical wastes

Hydrologic hydrochemical investigations were conducted to determine the long-term fate of hazardous chemical waste disposed in the Texas Gulf Coast Tertiary formations by deep-well injection. The study focused on the hydrostatic section of the Frio Formation because it is the host of a very large volume of injected waste and because large data bases of formation pressures and water chemistry are available.Three hydrologic regimes exist within the Frio Formation: a shallow fresh to moderately saline water section in the upper 3,000–4,000 ft (914–1,219 m); an underlying 4,000- to 5,000-ft-thick (1,219- to 1,524-m) section with moderate to high salinities: and a deeper overpressured section with moderate to high salinities. The upper two sections are normally pressured and reflect either freshwater or brine hydrostatic pressure gradients. Geopressured conditions are encountered as shallow as 6,000 ft (1,829 m). The complexity of the hydrologic environment is enhanced due to extensive depressurization in the 4,000- to 8,000-ft-depth (1,219- to 2,438-m) interval, which presumably results from the estimated production of over 10 billion barrels (208 × 10⁶ m³) of oil equivalent and associated brines from the Frio in the past 50 yr. Because of the higher fluid density and general depressurization in the brine hydrostatic section, upward migration of these brines to shallow fresh groundwaters should not occur. Depressured oil and gas fields, however, may become sinks for the injected chemical wastes.Water samples appear to be in approximate oxygen isotopic equilibrium with the rock matrix, suggesting that active recharge of the Frio by continental waters is not occurring. In the northern Texas Gulf Coast region salt dome dissolution is a prime process controlling water chemistry. In the central and southern Frio Formation, brines from the deeper geopressured section may be leaking into the hydrostatic section. The lack of organic acids and the alteration of Frio oils from samples collected from depths shallower than approximately 7,000 ft (2,133 m) suggest microbial degradation of organic material. This has useful implications for degradation of injected chemical wastes and needs to be investigated further.     

基于多源遥感数据的辽东湾北部海岸线变化监测与分析

应用遥感技术,从海岸线长度和曲度两个方面分析辽东湾北部海岸线变化,研究区域海岸线变化规律和趋势.选用美国陆地卫星（Landsat）的MSS、TM、ETM+系列数据,法国SPOT/4-5系列数据和国产陆地卫星ZY-1 02C数据等多源遥感数据,通过人工目视解译和计算机信息自动提取结合的方法,监测了自1973~2012年辽东湾北部海岸线变化情况.研究表明,辽东湾北部海岸线长度和曲度均呈增加趋势,尤其是1997年以后,为快速增加时期,其中中段岸线增速最快,西段岸线次之,东段岸线居尾.人为因素是辽东湾北部海岸线变化主要驱动力.     

福建泉州湾全新世海滩岩特征及物源环境分析

泉州湾处于我国东南沿海构造活动带,具有发生地震的地质环境和同震海岸崩塌、海湾下沉的构造地貌条件。通过对泉州湾海滩岩产状、14 C测年、古生物化石及岩石学特征的研究分析,认为其物源为海岸崩塌的志留纪花岗岩和潮滩、河口堆积的陆源碎屑。搬运方向自南向北偏东,形成于泉州湾北部潮间带接近高潮位,在温暖和高蒸发的气候条件下有淡水参与,由钙质胶结发生的快速成岩作用。海滩岩形成的地质时代为全新世晚期,是突发性海洋强动力事件的记录,可能与距今2 000a在泉州湾以南发生的古地震造成深沪湾岩岸大规模崩塌和海湾快速下沉引发的海啸有关。     

Assessment of the sensitivity of the southern coast of the Gulf of Corinth (Peloponnese, Greece) to sea-level rise

The eustatic sea-level rise due to global warming is predicted to reach approximately 18?C59 cm by the year 2100, which necessitates the identification and protection of sensitive sections of coastline. In this study, the classification of the southern coast of the Gulf of Corinth according to the sensitivity to the anticipated future sealevel rise is attempted by applying the Coastal Sensitivity Index (CSI), with variable ranges specifically modified for the coastal environment of Greece, utilizing GIS technology. The studied coastline has a length of 148 km and is oriented along the WNW-ESE direction. CSI calculation involves the relation of the following physical variables, associated with the sensitivity to long-term sea-level rise, in a quantifiable manner: geomorphology, coastal slope, relative sea-level rise rate, shoreline erosion or accretion rate, mean tidal range and mean wave height. For each variable, a relative risk value is assigned according to the potential magnitude of its contribution to physical changes on the coast as the sea-level rises. Every section of the coastline is assigned a risk ranking based on each variable, and the CSI is calculated as the square root of the product of the ranked variables divided by the total number of variables. Subsequently, a CSI map is produced for the studied coastline. This map showed that an extensive length of the coast (57.0 km, corresponding to 38.7% of the entire coastline) is characterized as highly and very highly sensitive primarily due to the low topography, the presence of erosionsusceptible geological formations and landforms and fast relative sea-level rise rates. Areas of high and very high CSI values host socio-economically important land uses and activities.     

Evidence of regional subsidence and associated interior wetland loss induced by hydrocarbon production, Gulf Coast region, USA

Analysis of remote images, elevation surveys, stratigraphic cross-sections, and hydrocarbon production data demonstrates that extensive areas of wetland loss in the northern Gulf Coast region of the United States were associated with large-volume fluid production from mature petroleum fields. Interior wetland losses at many sites in coastal Louisiana and Texas are attributed largely to accelerated land subsidence and fault reactivation induced by decreased reservoir pressures as a result of rapid or prolonged extraction of gas, oil, and associated brines. Evidence that moderately-deep hydrocarbon production has induced land-surface subsidence and reactivated faults that intersect the surface include: (1) close temporal and spatial correlation of fluid production with surficial changes including rapid subsidence of wetland sediments near producing fields, (2) measurable offsets of shallow strata across the zones of wetland loss, (3) large reductions in subsurface pressures where subsidence rates are high, (4) coincidence of orientation and direction of displacement between surface fault traces and faults that bound the reservoirs, and (5) accelerated subsidence rates near producing fields compared to subsidence rates in surrounding areas or compared to geological rates of subsidence. Based on historical trends, subsidence rates in the Gulf Coast region near producing fields most likely will decrease in the future because most petroleum fields are nearly depleted. Alternatively, continued extraction of conventional energy resources as well as potential production of alternative energy resources (geopressured-geothermal fluids) in the Gulf Coast region could increase subsidence and land losses and also contribute to inundation of areas of higher elevation.     

Coastal environmental injustice in Ghana: the activities of coastal sediment miners in the Elmina,Cape Coast and Moree area

Human impact has increased stunningly during the last century with coastal problems being one manifestation of environmental injustice with ecological, economic, and social dimensions on coastal resources. The study sought to assess the residents’ perception of coastline changes in the milieu of the rampant sand mining activities along the Elmina, Cape Coast and Moree coastline of Ghana. The study employed the purposive sampling technique: 100 respondents were engaged from the selected study areas through simple random sampling method. Interviews, Focus group discussions, observations and questionnaire were the main instruments used. The study revealed that beach sand mining is widespread across the Elmina-Cape Coast-Moree coastline and takes place in several forms, with the magnitude of sand taken from the beach being dependent on the transportation medium and the purpose to which sand is to be put. It is considered that the 1995 National Environmental Policy has become outdated and the sections dedicated to the coastal zone are irrelevant due to new research data and trends in administration. The time is right for a concerted national policy dedicated to only the coastal zone that takes into consideration the multiplicity of use of the zone and adopts an integrated management approach.     

Reply to the Discussion by Rose of Phelps et al. (2014) ‘Oceanographic and eustatic control of carbonate platform evolution and sequence stratigraphy on the Cretaceous (Valanginian–Campanian) passive margin,northern Gulf of Mexico’, Sedimentology, 61, 461–496

Discussion points raised by Rose ( 2016 ) concentrate on late Albian stratigraphic relationships between formations of the East Texas Basin and the San Marcos Arch of the Comanche Platform in the northern Gulf of Mexico. Criticisms of Phelps et al. (2014) regarding stratigraphic nomenclature, palaeogeography and regional lithostratigraphic correlations generally focus on interpretive aspects of the study or do not account for the full scope of published information. Revisions to the top Aptian–Albian Supersequence boundary by Rose are incompatible with the relative location of a subaerial unconformity, as well as deepening lithofacies trends and retrogradational stratigraphic patterns below the interpreted boundary. Rose's placement of the top Aptian–Albian Supersequence boundary precisely at the Albian–Cenomanian stage boundary also implies ca 1·4 Ma of diachroneity in second order sea‐level patterns between the northern Gulf of Mexico and other documented global sedimentary basins.     

Specific features of the geochemistry of Eocene-Miocene rocks in the Perovskii Gulf,northern Aral region

The major and trace element distribution was studied in the Eocene-Miocene stratotype section of the northern Aral region, northern coast of the Perovskii Gulf. The geochemical specific of ore-bearing rocks is shown. Qualitative trends in the distribution of element in genetically diverse rocks are established.     

Neogene sedimentary evolution of Baja California in relation to regional tectonics

During the Neogene, the tectonic and sedimentary evolution of the Baja California Peninsula followed four stages: (1) during the early Miocene (22 Ma), the initiation of transform motion between Pacific and North American plates, caused a rapid subsidence in the Continental Borderland Province and in some adjacent areas.This subsidence coincided in time with with a global rise in sea level. At this time, the eastern and southern parts of the peninsula did not show any evidence of subsidence. (2) During the middle Miocene (12 Ma), normal and strike slip faulting migrated eastward, causing subsidence in the northern part of the Gulf of California, where the oldest Tertiary marine sedimentary rocks were deposited. The areas in central Baja California Sur and the central part of the Gulf itself received abundant volcanic deposits related to continental extension. (3) During the late Miocene (8 Ma), the western margin of the Peninsula changed to a slightly compressive regime, while the northern part of the Gulf contained a marine basin with upper bathyal environments. The central area of the Gulf continued receiving abundant volcanic deposits, while the Los Cabos block received marine sedimentation, correlatable with sedimentary units reported from the continental margins in Nayarit, Jalisco and Michoacán. (4) Beginning in the early Pliocene (5 Ma), the present configuration of the Gulf of California developed through right-lateral strike slip and extension in the Gulf itself. Since Pliocene times, the Gulf presents widespread marine sedimentation with deep basins reaching lower bathyal depths.     

The internal grabens of the Levant Rifts and their geodynamic significance

The Levant Rift system is a linear assemblage of rifts and their mountainous flanks that comprise three structural distinct sections. The southern Jordan Rift is built of series of secondary axial grabens that diminish in length northwards and are separated from each other by poorly rifted threshold zones. The central section of the rift system is the Lebanese Baqa’a embedded between mountainous flanks, and a splay of faults that scatter to the north-northeast; the northern section comprises the SW-trending Karasu–Hatay Rifts from which the Ghab graben branches southwards. It is suggested that the rifting of the Jordan Rift is the northern extension of the Red Sea continental break-up, while the Karasu–Tatay section correlates geodynamically with the migration of Anatolia westwards. The Baqa’a, its mountainous flanks and the fault splay mark the termination of the crustal break-up from the south, but rejuvenation of some faults indicate the effects of the Anatolian migration.     

CO<Subscript>2</Subscript> source-sink matching in the lower 48 United States,with examples from the Texas Gulf Coast and Permian Basin

Documenting geographic distribution and spatial linkages between CO₂ sources and potential sinks in areas with significant levels of CO₂ emissions is important when considering carbon-management strategies such as geologic sequestration or enhanced oil recovery (EOR). For example, the US Gulf Coast overlies a thick succession (>6,000 m [>20,000 ft]) of highly porous and permeable sandstone formations separated by thick, regionally extensive shale aquitards. The Gulf Coast and Permian Basin also have a large potential for EOR, in which CO₂ injected into suitable oil reservoirs could be followed by long-term storage of CO₂ in nonproductive formations below reservoir intervals. For example, >6 billion barrels (Bbbl) of oil from 182 large reservoirs is technically recoverable in the Permian Basin as a result of miscible-CO₂ flooding_. The Gulf Coast also contains an additional 4.5 Bbbl of oil that could be produced by using miscible CO₂. Although the CO₂ pipeline infrastructure is well-developed in the Permian Basin, east Texas and the Texas Gulf Coast may have a greater long-term potential for deep, permanent storage of CO₂ because of thick brine-bearing formations near both major subsurface and point sources of CO₂.