scholarly journals STRUCTURAL ANALYSIS OF MANGROVE COMMUNITIES ON THE CENTRAL QUEENSLAND COASTLINE

1970 ◽  
Vol 18 ◽  
pp. 101-118
Author(s):  
P. Saenger ◽  
J. Robson
Keyword(s):  
Structural Analysis ◽  
Tidal Range ◽  
Annual Rainfall ◽  
Areal Extent ◽  
The South ◽  
Initial Investigation ◽  
The North ◽  
Mangrove Communities

The mangrove communities of the Central Queensland coastline are structurally and floristically intermediate between the relatively simple, temperate mangrove communities to the south, and the more complex and luxuriant communities to the north. Climatically the central Queensland coastline is subtropical with a low (1011 mm) annual rainfall, falling mainly in the summer months; evaporation rates are high, particularly in winter. As a result of a four-metre tidal range and a gentlysloping depositional coastline, the areal extent of mangroves is large and most topographic and physiognomic types are represented. Twelve species of mangroves occur in the study area and although zonation is recognizable, the zones are neither constant nor discrete. In the Port Curtis area, three large plots (500 m2 have been established in which all mangroves have been numbered and tagged since January 1975. The results of the initial investigation of the plots are presented together with some of the changes noted on re-examination after 12 months.

Climatology and Trends of Climate Extremes of Temperature and Precipitation in Belo Monte Hydropower Plant – Eastern Amazon, Brazil

2021 ◽  
Author(s):  
Wanderson Luiz-Silva ◽  
Pedro Regoto ◽  
Camila Ferreira de Vasconcellos ◽  
Felipe Bevilaqua Foldes Guimarães ◽  
Katia Cristina Garcia
Keyword(s):  
Climate Change ◽  
Climate Extremes ◽  
Annual Rainfall ◽  
The South ◽  
North Central ◽  
Adaptation Capacity ◽  
The North ◽  
South Central ◽  
Daily Data ◽  
Belo Monte

<p>This research aims to support studies related to the adaptation capacity of the Amazon region to climate change. The Belo Monte Hydroelectric Power Plant (HPP) is in the Xingu River basin, in eastern Amazonia. Deforestation coupled with changes in water bodies that occurred in the drainage area of Belo Monte HPP over the past few decades can significantly influence the hydroclimatic features and, consequently, ecosystems and energy generation in the region. In this context, we analyze the climatology and trends of climate extremes in this area. The climate information comes from daily data in grid points of 0.25° x 0.25° for the period 1980-2013, available in http://careyking.com/data-downloads/. A set of 17 climate extremes indices based on daily data of maximum temperature (TX), minimum temperature (TN), and precipitation (PRCP) was calculated through the RClimDex software, recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI). The Mann-Kendall and the Sen’s Curvature tests are used to assess the statistical significance and the magnitude of the trends, respectively. The drainage area of the Belo Monte HPP is dominated by two climatic types: an equatorial climate in the north-central portion of the basin, with high temperatures and little variation throughout the year (22°C to 32°C), in addition to more frequent precipitation; and a tropical climate in the south-central sector, which experiences slightly more pronounced temperature variations throughout the year (20°C to 33°C) and presents a more defined wet and dry periods. The south-central portion of the basin exhibits the highest temperature extremes, with the highest TX and the lowest TN of the year occurring in this area, both due to the predominant days of clear skies in the austral winter, as to the advance of intense masses of polar air at this period. The diurnal temperature range is lower in the north-central sector when compared to that in the south-central region since the first has greater cloud cover and a higher frequency of precipitation. The largest annual rainfall volumes are concentrated at the north and west sides (more than 1,800 mm) and the precipitation extremes are heterogeneous across the basin. The maximum number of consecutive dry days increases from the north (10 to 20 days) to the south (90 to 100 days). The annual frequency of warm days and nights is increasing significantly in a large part of the basin with a magnitude ranging predominantly from +7 to +19 days/decade. The annual rainfall shows a predominant elevation sign of up to +200 mm/decade only in the northern part of the basin, while the remainder shows a reduction of up to -100 mm/decade. The duration of drought periods increases in the south-central sector of the basin, reaching up to +13 days/decade in some areas. The results of this study will be used in the future as an important input, together with exposure, sensibility, and local adaptation capacity, to design adaptation strategies that are more consistent with local reality and to the needs of local communities.</p>

scholarly journals Numerical modelling of the Caspian Sea tides

Ocean Science ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 209-219
Author(s):  
Igor P. Medvedev ◽  
Evgueni A. Kulikov ◽  
Isaac V. Fine
Keyword(s):  
Caspian Sea ◽  
Ocean Model ◽  
Tidal Range ◽  
The South ◽  
Tidal Dynamics ◽  
The Caspian Sea ◽  
Sea Levels ◽  
The North ◽  
Anticlockwise Rotation ◽  
Diurnal Tides

Abstract. The Caspian Sea is the largest enclosed basin on Earth and a unique subject for the analysis of tidal dynamics. Tides in the basin are produced directly by the tide-generating forces. Using the Princeton Ocean Model (POM), we examine details of the spatial and temporal features of the tidal dynamics in the Caspian Sea. We present tidal charts of the amplitudes and phase lags of the major tidal constituents, together with maps of the form factor, tidal range, and tidal current speed. Semi-diurnal tides in the Caspian Sea are determined by a Taylor amphidromic system with anticlockwise rotation. The largest M2 amplitude is 6 cm and is located in Türkmen Aylagy (called Turkmen Bay hereafter). For the diurnal constituents, the Absheron Peninsula separates two individual amphidromes with anticlockwise rotation in the north and in the south. The maximum K1 amplitudes (up to 0.7–0.8 cm) are located in (1) the south-eastern part of the basin, (2) Türkmenbaşy Gulf, (3) Mangyshlak Bay; and (4) Kizlyar Bay. As a result, the semi-diurnal tides prevail over diurnal tides in the Caspian Sea. The maximum tidal range, of up to 21 cm, has been found in Turkmen Bay. The strongest tidal currents have been located in the straits to the north and south of Ogurja Ada, where speeds reach 22 and 19 cm s−1, respectively. Numerical simulations of the tides using different mean sea levels (within a range of 5 m) indicate that spatial features of the Caspian Sea tides are strongly sensitive to changes in mean sea level.

scholarly journals From meteorological to hydrological drought using standardised indicators

2016 ◽  
Vol 20 (6) ◽  
pp. 2483-2505 ◽  
Author(s):  
Lucy J. Barker ◽  
Jamie Hannaford ◽  
Andrew Chiverton ◽  
Cecilia Svensson
Keyword(s):  
Time Series ◽  
Hydrological Drought ◽  
Annual Rainfall ◽  
Strongly Correlated ◽  
Propagation Characteristics ◽  
The South ◽  
Drought Characteristics ◽  
The North ◽  
The Uk ◽  
Hydrological Droughts

Abstract. Drought monitoring and early warning (M & EW) systems are a crucial component of drought preparedness. M & EW systems typically make use of drought indicators such as the Standardised Precipitation Index (SPI), but such indicators are not widely used in the UK. More generally, such tools have not been well developed for hydrological (i.e. streamflow) drought. To fill these research gaps, this paper characterises meteorological and hydrological droughts, and the propagation from one to the other, using the SPI and the related Standardised Streamflow Index (SSI), with the objective of improving understanding of the drought hazard in the UK. SPI and SSI time series were calculated for 121 near-natural catchments in the UK for accumulation periods of 1–24 months. From these time series, drought events were identified and for each event, the duration and severity were calculated. The relationship between meteorological and hydrological drought was examined by cross-correlating the 1-month SSI with various SPI accumulation periods. Finally, the influence of climate and catchment properties on the hydrological drought characteristics and propagation was investigated. Results showed that at short accumulation periods meteorological drought characteristics showed little spatial variability, whilst hydrological drought characteristics showed fewer but longer and more severe droughts in the south and east than in the north and west of the UK. Propagation characteristics showed a similar spatial pattern with catchments underlain by productive aquifers, mostly in the south and east, having longer SPI accumulation periods strongly correlated with the 1-month SSI. For catchments in the north and west of the UK, which typically have little catchment storage, standard-period average annual rainfall was strongly correlated with hydrological drought and propagation characteristics. However, in the south and east, catchment properties describing storage (such as base flow index, the percentage of highly productive fractured rock and typical soil wetness) were more influential on hydrological drought characteristics. This knowledge forms a basis for more informed application of standardised indicators in the UK in the future, which could aid in the development of improved M & EW systems. Given the lack of studies applying standardised indicators to hydrological droughts, and the diversity of catchment types encompassed here, the findings could prove valuable for enhancing the hydrological aspects of drought M & EW systems in both the UK and elsewhere.

scholarly journals Chemical data on some rock-forming minerals from high-grade gneisses, amphibolites and anorthosites from the Fiskenæsset area

1971 ◽  
Vol 35 ◽  
pp. 22-23
Author(s):  
T Frisch
Keyword(s):  
Rock Type ◽  
Amphibolite Facies ◽  
Chemical Data ◽  
High Grade ◽  
Boundary Zone ◽  
Areal Extent ◽  
Common Occurrence ◽  
The South ◽  
The West ◽  
The North

The area mapped by the writer is situated to the west of Fiskenæsset and lies in the boundary zone between granulite and amphibolite facies rocks (see Kalsbeek, this report). In the north a creamy- to pink-weathering gneiss, commonly containing hypersthene and biotite is the chief rock type. In the south small-folded, pale-grey weathering biotite-hornblende gneisses are predominant. Amphibolite is of common occurrence in layers, pods and agmatite. The areal extent of the anorthosite-pyribolite complex as previously outlined by reconnaissance mapping (Ghisler & Windley, 1967) was confirmed in general but modified in detail. Additional occurrences of rocks belonging to the complex were found.

scholarly journals Bioclimatic Impact on the Carob Seeds Morphological Diversity in Morocco

2021 ◽  
Vol 18 (1) ◽  
pp. 207-217
Author(s):  
Foughali Boubkar ◽  
Fghire Rachid ◽  
Anaya Fatima ◽  
Issa Ali Oudou ◽  
Tahrouch Saadia ◽  
...  
Keyword(s):  
Morphological Diversity ◽  
Annual Rainfall ◽  
Shape Parameters ◽  
The South ◽  
Rainfall Gradient ◽  
Dry Land ◽  
The North ◽  
Carob Tree ◽  
Length Width ◽  
Ceratonia Siliqua L

The carob tree, Ceratonia siliqua L., a typical thermophilic sclerophyllous species, is a multipurpose tree (agronomic, silvicultural and pastoral) with aromatic and medicinal properties. Due to its geographical distribution, it occupies different countries of the Mediterranean. In Morocco, this species spreads over the different bioclimatic from the arid in the south to the humid in the north. The present work, study the morphological diversity of the seeds of five carob tree ecotypes distributed along a rainfall gradient (from the arid in the south to the humid one towards the north of the country). The shape parameters studied are the length, width, thickness, weight, volume and density of the seeds.The results obtained show that the carob tree ecotypes are characterized by significant differences in the different morphological parameters of the seeds among the five ecotypes studied. Indeed, dry land seeds are generally reduced in length, volume and weight, while those in humid regions are larger in weight and size. Those of the dry sowing areas have moderate parameters. The variance analysis shows that the origin of the ecotypes hada significant effect on the various shape parameters. Moreover, the multiple comparison of averages revealed different distinct groups. ACP analysis revealed that seed weight and volume is strongly correlated with the first component (the bioclimatic origin and the annual rainfall of the site of origin). While the second component corresponds to the parameters of length, width and thickness of the seeds. As for the factor 3, it corresponds to the density of the seeds which is not dependent on the other variables.In terms of conclusion, it is deduced that in Morocco, the carob tree seeds are characterized by a large morphological diversity which varies according to the rainfall gradient.

Déformation coaxiale en bordure de la discontinuité structurale de Lyndhurst, sous-province de l'Abitibi

1992 ◽  
Vol 29 (4) ◽  
pp. 783-792 ◽  
Author(s):  
Jean-Yves Labbé ◽  
Real Daigneault ◽  
Pierre A. Cousineau
Keyword(s):  
Structural Analysis ◽  
Deformation Zone ◽  
Thrust Fault ◽  
The South ◽  
Mesoscopic Scale ◽  
The North ◽  
The Poor ◽  
Crenulation Cleavage ◽  
Deformation Regime ◽  
East West

The Lyndhurst discontinuity is a major east–west structure located some 40 km north of Rouyn–Noranda. It separates the rhyolitic and sedimentary units of the Hunter Mine Group to the north from the basalts of the Kinojévis Group to the south. Evidence of deformation is observed only in the rhyolites and sediments along the south edge of the Hunter Mine Group. The deformation zone is approximately 1 km wide and is continuous for about 30 km. The Kinojévis Group rocks are not deformed. Deformed rhyolites show a strong sericite and chlorite alteration of hydrothermal origin. The competency of the rhyolites is significantly reduced by the presence of these phyllosilicates, which results in the deformation being preferentially localized in the more altered rocks. Competency contrasts observed on a mesoscopic scale are also valid on the microscopic and megascopic scales. The structural analysis of the deformation zone reveals different arrays that characterize three distinct sectors. These arrays reflect competency contrasts of the lithology and a crenulation cleavage. The stretching lineation is generally steeply plunging. Although the deformation seems significant in a zone contiguous to the Lyndhurst discontinuity, the poor development of the stretching lineation, the preservation of the original crystalline shapes of phenocrysts in the rhyolites, and the constant symmetry of the pressure shadows suggest a global coaxial deformation. This deformation regime is difficult to reconcile with a compressive fault such as a thrust fault.

Study on Salinity Stratification and Distribution in Lingding Yang Estuary

2008 ◽  
Author(s):  
Mingyuan Yang ◽  
Wei Zhang
Keyword(s):  
Fresh Water ◽  
Salt Water ◽  
Flood Tide ◽  
Tidal Range ◽  
Observation Data ◽  
The South ◽  
Wet Season ◽  
Mean Velocity ◽  
Temporal And Spatial Distribution ◽  
The North

Ling Ding Yang (LDY) estuary is one of the main parts of the whole Zhujiang estuary, which lies in the south sea, China. It is about 60km wide from Hong Kong in the east to Macao in the west and the water areas are approximately 2110 km2. The mixing process of salt water and fresh water in the estuary is influenced by many factors, such as the estuarine geometry, tidal range and ravine flows, etc. In this paper, based on the data from the tidal gauge stations and synchronously surveyed data during July 2003, a study on the temporal and spatial distribution characteristics of salinity was made. According to the observation data, in wet season, the fresh water and salt water mixes with the N parameter between 0.21 and 1.63. The distribution of salinity concentration in the east part of LDY is due to coriolis’ force. The salinity concentration decreases from the sea to the estuary, and there exists apparent division point, Nei Lingding Island. To the south of Nei Lingding Island, it is almost partially mixed, and to the north of Nei Lingding Island, it belongs to highly stratification. At the same time, the stratification parameter and the vertical mean velocity in wet season are compared. The N parameter changes with the velocity of tide flow in a tidal cycle. The value of N in a flood tide is usually larger than that is in an ebb tide. That is to say, the mix intensity is much bigger in the flood tide.

scholarly journals The Geometry and Structural Analysis of the Gold Deposits of Chirano Mine

2016 ◽  
Vol 16 (2) ◽  
pp. 10-19
Author(s):  
K. Ackon-Wood ◽  
J. S. Y. Kuma ◽  
J. A. Yendaw
Keyword(s):  
Structural Analysis ◽  
Gold Deposit ◽  
Shear Zone ◽  
Gold Deposits ◽  
Drill Core ◽  
The South ◽  
Complex Interplay ◽  
The North ◽  
Structural Deformations

The Chirano Mine gold deposit is a typical example of a structurally controlled deposit developed along the Kumasi Basin and the Sefwi Belt margin structure. The area has undergone various regimes of structural deformations. Consequently, all the Chirano deposits are intimately associated with shears and faults along a single continuous structural corridor known as the Chirano Shear Zone (CSZ). The CSZ geometry has been categorised into three major zones namely: (i) Laminated veins in shears, (ii) Breccia and (iii) Ductile to brittle ductile zones. The shear veins trend NE-SW and N-S, are laminated and occur in the sheared fabric close to the footwall. Penetrative foliated zones varying from a few centimeters to several meters constitute the ductile to brittle-ductile structures. Gold grades are much higher within this zone. Analysis of cataclasis intensity recorded in drill core confirms a semi brittle form of deformation within the mineralised domain. The CSZ has different orientations in dip and strike from the south of the mining lease to the north. The subtle changes in orientation are deposit dependent. The structure has a sinuous shape and tends to pinch and swell. The current geometry and the distribution of stratigraphy and orebodies at Chirano is a manifestation of the complex interplay of magmatic and hydrothermal events in the area.  Keywords: Ductile, Brittle-Ductile, Breccia, Chirano Shear Zone, Chirano Lode Horizon

The ‘Historiated’ Neolithic Stele of Saint-Samson-sur-Rance (Côtes-d'Armor, France)

2017 ◽  
Vol 28 (2) ◽  
pp. 259-281 ◽  
Author(s):  
Serge Cassen ◽  
Valentin Grimaud ◽  
Laurent Lescop ◽  
Hervé Paitier ◽  
Carlos Rodríguez-Rellán ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Structured Light ◽  
Tidal Wave ◽  
Wild Animals ◽  
The South ◽  
The North ◽  
Structured Light Scanner ◽  
Human Figure ◽  
3D Methods ◽  
The Relationship

The stone of Saint-Samson is a Neolithic stele of 70 tons and 10 m of probable length. Its intriguing leaning position and its very regular morphology have aroused curiosity since medieval times. Three of its four faces—oriented towards the cardinal points—display engravings that were discovered in the 1970s. Now, a new recording protocol has combined 2D techniques for emphasizing the contrast of the engravings (oblique rotating lights) and 3D methods for restoring the volumes of the support (photogrammetry, structured-light scanner). The results obtained have made it possible to implement the first structural analysis of the stone. The north and west faces show an opposition between domestic (cattle, goats) and wild animals (suidae, cervidae, birds, cetaceans), depicted confronted and with their horns or tusks clearly visible. The south face was reserved for the human figure and for iconic artefacts (polished axe, throwing stick, ring disk, steering oar). The four faces have in common the presence of boats. The relationship linking the monument to waterways and the sea is approached by analysing both local legends and the phenomenon of the tidal wave.

scholarly journals Late Triassic successive amalgamation between the South China and North China blocks: Insights from structural analysis and magnetic fabrics study of the Bikou Terrane and its adjacent area, northwestern Yangtze block, central China

2021 ◽  
Author(s):  
Zhenhua Xue ◽  
Wei Lin ◽  
Yang Chu ◽  
Wei Wei ◽  
Zhentian Feng ◽  
...  
Keyword(s):  
Structural Analysis ◽  
South China ◽  
North China ◽  
Late Triassic ◽  
Yangtze Block ◽  
The South ◽  
Structural Geometry ◽  
The North ◽  
Magnetic Fabrics ◽  
Multi Phase

The Bikou Terrane, located at the conjunction of the Longmenshan fold-thrust belt and the west Qinling orogenic belt in centeral China, was involved in the Late Triassic collision between the South China and North China blocks. The Bikou Terrane has preserved crucial information on structural geometry and kinematics of Triassic tectonics, and is therefore of great importance for reconstructing the Paleo-Tethyan evolutionary history. However, multi-phase tectonic events of the Bikou Terrane are unsettled. This work presents detailed structural analysis based on both the field and laboratory works, which reveals three phases of deformation events in Bikou and its adjacent areas, including top-to-the-SW shearing related to SW-ward thrusting (DI) mainly to the north of the Bikou Terrane, top-to-the-NNW shearing related to NNW-ward thrusting (DII) in the Bikou Terrane, and strike-slip faulting (DIII) locally developed in the northern Bikou Terrane. Anisotropy of magnetic susceptibility (AMS) study and related structural analysis not only support the multiphase deformation but also reveal a gradual transition from the DII-related magnetic fabrics to the DIII-related magnetic fabrics in the Bikou Terrane. Integrating published geochronological data, it is constrained that DI occurred at ca. 237−225 Ma, DII occurred at ca. 224−219 Ma, and DIII possibly occurred during the Early Cretaceous. Based on regional tectonics, the DI event corresponds to the collision between the South Qinling block and the Bikou Terrane, and the DII event reflects the intracontinental amalgamation between the Bikou Terrane and the Yangtze block, which indicates a Late Triassic successive amalgamation from the North China block to the South China block. Intracontinental adjustment represented by the strike-slip (DIII event) occurred after the final amalgamation between the North China and South China blocks. By applying AMS on deciphering structural geometry and multi-phase deformation, our study suggests that AMS is a useful tool for structural analysis.

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