scholarly journals The Influence of Channel Planform and Slope Topography on Turbidity Current Overbank Processes: The Example of the Acquarone Fan (Southeastern Tyrrhenian Sea)

2022 ◽  
Vol 9 ◽  
Author(s):  
Elena Scacchia ◽  
Roberto Tinterri ◽  
Fabiano Gamberi
Keyword(s):  
Tectonic Setting ◽  
Vertical Stratification ◽  
Tyrrhenian Sea ◽  
Seafloor Topography ◽  
Sediment Distribution ◽  
Jump Size ◽  
Depositional Processes ◽  
Levee System ◽  
The Right ◽  
Channel Planform

Overbank deposits provide a potentially valuable record of flows that have passed through a submarine channel. The architecture of overbank deposits has generally assumed to relate to autogenic processes related to channel construction. In previous models, which are largely based on passive margins, the distribution and geometry of these deposits is relatively simple, and hence generally predictable. Here, we show how the interaction of different flow types with the complex morphology on a highly-tectonically modified margin can profoundly affect overbank depositional processes, and hence also the resultant deposit geometry and architecture. Our case study is the Acquarone Fan, located in the intraslope Gioia Basin in the south-eastern Tyrrhenian Sea, whose topography is mainly controlled by the presence of the Acquarone structural ridge, which results in the confinement of the left south-west side of the channel-levee system. The research is carried out through analysis of multibeam bathymetric and high-resolution Chirp sub-bottom profiler data. Seven depositional units (Units I-VII) record the recent depositional history of the fan; their thickness has been mapped and their parent flow-types have been interpreted through their seismic response. According to unit thickness maps, two main patterns of deposition are recognized in the overbank area. Their depocenters coincide with different extensive sediment wave fields developed in specific tracts of the right levee and in the frontal splay area. We show that the location of the depocenters varies in time according to the prevalent flow-type and by its interaction with the surrounding seafloor topography and channel planform. We interpret that the lateral confinement of the channel by the structural high generates episodic rebound of the overspilling flow and the inversion of the channel asymmetry. The vertical stratification of the flow strongly influences the overbank deposition where the channel planform has a non-linear shape such as bends and knick-points. In particular, the vertical stratification influences the hydraulic jump size that conditions the amount of overspill and thus the location of overbank depocenters. This study highlights that variations in the sediment distribution and composition on the overbank can be related to the way different flows interact with tectonic setting.

scholarly journals MORFOLOGÍA Y SEDIMENTOS DE LA PLAYA Y PLATAFORMA DE LA BAHÍA SAN LUCAS, BAJA CALIFORNIA SUR, MÉXICO

2009 ◽  
Vol 24 (1) ◽  
pp. 1
Author(s):  
J. O. Navarro Lozano ◽  
E. H. Nava Sánchez ◽  
L. Godinez-Orta ◽  
J. Murillo-Jimenez
Keyword(s):  
Baja California ◽  
Submarine Canyon ◽  
High Energy ◽  
Baja California Sur ◽  
Seafloor Topography ◽  
Sediment Distribution ◽  
Wave Refraction ◽  
Portion Control ◽  
The Pacific ◽  
El Sistema

Bahía San Lucas está localizada en la punta sur de la Península de Baja California, por lo que recibe el oleaje de alta energía del Océano Pacífico. El análisis morfológico y sedimentológico del litoral y del fondo marino de la Bahía San Lucas, a partir del levantamiento batimétrico y del análisis de los parámetros texturales del sedimento permitió conocer la relación que existe entre las geoformas y el comportamiento sedimentológico. La morfología y orientación de las puntas que protegen a la bahía, así como la presencia temporal del abanico-delta El Salto en la porción central de la misma, condicionan los procesos de refracción y difracción del olaje. Así, el litoral de la bahía se puede dividir en dos zonas, en donde los procesos energéticos del oleaje y agente transportante son diferentes entre ellas y determinan la morfología y distribución de sedimentos en el sistema playero. El relieve del fondo marino de la bahía está dominado por la presencia del cañón submarino San Lucas, cuya cabecera se proxima hasta el pie de la playa, en la zona más interna de la bahía. Dicho cañón condiciona el desarrollo de la plataforma, la cual es de sólo 1.5 km de ancho, con profundidad máxima de 50 m. La poca profundidad de la plataforma, que permite que el oleaje interactúe con el fondo, así como la presencia del cañón submarino, condicionan la distribución de sedimentos del fondo marino de la bahía. Morphology and sediments of the beach and shelf of the Bahía San Lucas, Baja California Sur, México Bahía San Lucas is located at the southern tip of the Baja California peninsula, thus it receives high energy waves from the Pacific Ocean. The morphology of the coastline and marine bottom of the bay was interpreted based on a bathymetric survey and beach profiles, while the characteristics of the sediments were obtained through a textural analysis. Both, morphology and sedimentology allowed us to know the relationship between landforms and the sedimentological behavior. The geometry and orientation of the limiting points of the bay and the temporary presence of the fan-delta El Salto in the central portion, control the processes of wave refraction and diffraction. Thus, the coastline of the bay can be divided into two areas, where the wave energy processes and the transporting agent are different from each other and determine the morphology and sediment distribution of the beach. Seafloor topography of the bay is dominated by the presence of the San Lucas submarine canyon, whose head is just at the foot of he beach, in the innermost area of the bay. This canyon controls the development of the peninsular shelf, which is only 1.5 km wide with a maximum depth of 50m. This shallow depth of the shelf, which allows the waves interact with seabed, and the presence of the submarine canyon are the responsible for the distribution of sediments in the seabed of the bay.

scholarly journals A new depositional model for the Tuaheni Landslide Complex, Hikurangi Margin, New Zealand

2020 ◽  
Vol 500 (1) ◽  
pp. 551-566 ◽  
Author(s):  
Benjamin Couvin ◽  
Aggeliki Georgiopoulou ◽  
Joshu J. Mountjoy ◽  
Lawrence Amy ◽  
Gareth J. Crutchley ◽  
...  
Keyword(s):  
Seismic Data ◽  
Lateral Spreading ◽  
3D Seismic ◽  
Depositional Processes ◽  
Attribute Analysis ◽  
Internal Structures ◽  
Show Evidence ◽  
Levee System ◽  
Central Ridge ◽  
International Ocean Discovery Program

AbstractThe Tuaheni Landslide Complex (TLC) is characterized by areas of compression upslope and extension downslope. It has been thought to consist of a stack of two genetically linked landslide units identified from seismic data. We used 3D seismic reflection, bathymetry data and International Ocean Discovery Program Core U1517C (Expedition 372) to understand the internal structures, deformation mechanisms and depositional processes of the TLC deposits. Units II and III of U1517C correspond to the two chaotic units in 3D seismic data. In the core, Unit II shows deformation, whereas Unit III appears more like an in situ sequence. Variance attribute analysis showed that Unit II is split into lobes around a coherent stratified central ridge and is bounded by scarps. By contrast, we found that Unit III is continuous beneath the central ridge and has an upslope geometry, which we interpreted as a channel–levee system. Both units show evidence of lateral spreading due to the presence of the Tuaheni Canyon removing support from the toe. Our results suggest that Units II and III are not genetically linked, are separated substantially in time and had different emplacement mechanisms, but they fail under similar circumstances.

scholarly journals Geologic and geomorphologic study of the Terra Murata and Centane-Panoramica Sites (Island of Procida, Naples Bay, Southern Tyrrhenian Sea) aimed at solving some applied geological and geotechnical problems

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Gemma Aiello
Keyword(s):  
Middle Ages ◽  
Tectonic Setting ◽  
Geological Survey ◽  
Tyrrhenian Sea ◽  
Pyroclastic Deposits ◽  
Coastal Cliff ◽  
Coastal Cliffs ◽  
Naples Bay ◽  
Strong Control ◽  
Geotechnical Problems

A geologic and geomorphologic study aimed at solving some geological and geotechnical problems, regarding the massive seepage of meteoric waters in the coastal cliffs of the Island of Procida (Naples Bay, Southern Italy) composed of both tuffs and loose pyroclastic deposits, has been carried out in the geosites of Terra Murata (Middle Ages village and coastal cliff towards the Corricella Bay) and Centane-Panoramica (coastal cliff facing on the Tyrrhenian Sea).A detailed geologic and geomorphologic survey has allowed to suggest solutions to the applied geological and geotechnical problems related to the occurrence of massive seepages of waters at the physical interface between pyroclastic rocks and loose pyroclastic deposits, characterized by different density, permeability and porosity and also controlled by a dense network of fractures, involving the pyroclastic deposits cropping out in the selected areas.Field sampling and geotechnical laboratory analyses have been carried out to calculate the values of main geotechnical parameters of the yellow tuffs cropping out at the Terra Murata Promontory. At the same time, a detailed monitoring of the seepages of waters has been carried out through a detailed geological survey of the tuff outcrops of the promontory. The obtained results have suggested a strong control from both the geomorphologic instability of the coastal cliff and tectonic setting. At the Centane-Panoramica geosite, the geological survey, coupled with geotechnical analyses and standard penetrometric tests, has accordingly evidenced that the geomorphologic instability was mainly concentrated in the sectors of the tuff coastal cliffs facing seawards towards the Tyrrhenian Sea.

Sediment distribution and depositional processes along the fluvial to marine transition zone of the Mekong River delta, Vietnam

Sedimentology ◽  
2018 ◽  
Vol 66 (1) ◽  
pp. 146-164 ◽  
Author(s):  
Marcello Gugliotta ◽  
Yoshiki Saito ◽  
Van Lap Nguyen ◽  
Thi Kim Oanh Ta ◽  
Toru Tamura
Keyword(s):  
Transition Zone ◽  
River Delta ◽  
Mekong River ◽  
Sediment Distribution ◽  
Mekong River Delta ◽  
Depositional Processes

Geochemistry Features and the Tectonic Setting of Intrusive Rocks in Halegati, Xinjiang

2014 ◽  
Vol 962-965 ◽  
pp. 286-291
Author(s):  
Xin Li Wang ◽  
Wen Tian Mi ◽  
Yi Wei Peng ◽  
Hu Gao ◽  
Li Qiang Zhang ◽  
...  
Keyword(s):  
Close Association ◽  
Tectonic Setting ◽  
High Field Strength ◽  
Low Magnesium ◽  
Metallogenic Belt ◽  
High K ◽  
Ree Distribution ◽  
Intrusive Rocks ◽  
Type Granite ◽  
The Right

Halegati Fe-Cu deposit of skarn was located in the Boluokenu metallogenic belt. With the research of the geochemistry characteristic of granodiorites, the results showed that the rocks belonged to I type granite with the features of siliceous, metaluminous, low magnesium , high-k and alkalic. The intrusive rocks had a close association with the mineralization, which had the features of enrichment of large-ion lithophile elements (K, Rb, Ba, Th) and relative depleted in high-field strength elements (Nb, Ta, P, Ti).The intrusive rocks in Halegati had the characteristic of strongly differentiation between LREE and HREE and negative Eu anomalies obviously. The REE distribution curves had the right types. The intrusive rocks were formed in the environment of volcanic arc, which produced in the tectonic setting of supra subduction zone.

The Bridge on the Strait of Messina: “Lowering” the Right of Innocent Passage?

2001 ◽  
Vol 50 (2) ◽  
pp. 411-419 ◽  
Author(s):  
Fabio Spadi
Keyword(s):  
Mediterranean Sea ◽  
Tyrrhenian Sea ◽  
Ionian Sea ◽  
The West ◽  
Minimum Depth ◽  
The Mediterranean ◽  
The Right

The Strait of Messina is a body of water in the Mediterranean Sea separating the island of Sicily to the west from mainland Italy to the east, linking the Lower Tyrrhenian Sea with the Ionian Sea. The strait is around 30 miles long and its width ranges from 13/4 miles (between Faro Point and the Rock of Scylla) to 10 miles (between Cape Alì and Cape Pellaro). At its northern end it reaches, at one point, a minimum depth of 70 metres.1

scholarly journals Channel Planform Dynamics along Distributary Channels: Case Study of the River Nun a Major Distributary of the River Niger

2019 ◽  
pp. 1-11
Author(s):  
Tombra S. Akana ◽  
O. C. Adeigbe
Keyword(s):  
Gis And Remote Sensing ◽  
Migration Rates ◽  
Erosion Rates ◽  
Sensing Applications ◽  
Accretion Rates ◽  
Remote Sensing Applications ◽  
The Right ◽  
River Niger ◽  
Channel Planform

Channel planform dynamics were analyzed for the River Nun; a major distributary of the River Niger from 1985 to 2015 using GIS and Remote sensing applications. Satellite imagery of the area from 1985, 1995, 2005, and 2015 were analyzed by means of GIS and used to determine the planform characteristics and changes in width, sinuosity, and shoreline migration rates. The channel planform dynamics were determined by comparing sequential changes in the position of the shorelines in these years. Sinuosity adjustments during the study were small and range between 1.74–1.76. The initial sinuosity (1.74 in 1985) increased to 1.75 in 1995 and then increased to 1.76 in 2015. Channel expansion is observed to be the dominant planform process, owing to periodic floods within the study area. The river’s channel width barely expanded from 1985 to 1995 (by 0.1 %). However, there is a constant increase in expansion within the study years that by 2005-2015 expansion had increased to 9%. The bank erosion was prevalent. Mean erosion rates ranged from 0.7 m/year in 20 years (1985-2005) to 2m/year in 30 years (1985-2015). In the 1st 10 years (1985-1995) less than 0.1 m of deposition was observed. The mean erosion rates ranged from 1.3 to 1.6 m/year on the left side and 2.8 to 3.8 m/year on the right side of the channel. Mean accretion rates of 1.2 m/year on the left side and 1.8 m/year on the right side were observed. The channel is observed to move generally towards the east (right).

scholarly journals Seismic stratigraphy of the broad, low-gradient continental shelf of the Palaeo-Agulhas Plain, South Africa

2019 ◽  
Author(s):  
Hayley C Cawthra ◽  
Peter Frenzel ◽  
Annette Hahn ◽  
John Compton ◽  
Lukas Gander ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Sea Level ◽  
Tectonic Setting ◽  
Sea Level Change ◽  
Equal Proportion ◽  
Depositional Sequence ◽  
Level Change ◽  
Depositional Processes ◽  
Shelf Sediment ◽  
Stratigraphic Model

The continental shelf of the Palaeo-Agulhas Plain (PAP) is scattered with Pleistocene deposits with subdued topography. Their exaggerated lateral extension is the expression of a flat underlying substrate and availability of accommodation space, depositional processes and response to glacio-eustatic sea-level change have influenced deposition and distribution of these units. We present new results for the upper ~30 m (up to ~200 ka) of the stratigraphic record in this area and show that this shelf offers the opportunity to examine the response of a stable tectonic setting to the effects of sea-level change. This paper presents the results of extensive sub-bottom profiling surveys and chronostratigraphic investigations from marine sediment vibracores. Radiocarbon and Optically stimulated Luminescence dates are integrated into a seismic stratigraphic model composed of twenty Quaternary units, where two depositional sequences are bounded by shelf-wide unconformities. The upper sequence was cored where Pleistocene deposits were observed to be close to the seafloor and are draped in a thin veneer of marine shelf sediment and allow us to describe the environments of deposition of the PAP. The most pervasive stratigraphic pattern in these shelf deposits is made up of the depositional sequence remnant of the Falling Stage Systems Tract (FSST) forced regression from Marine Isotope Stage 5e–2. The other dominant stratigraphic group is the Transgressive Systems Tract (TST) associated with the Postglacial Marine Transgression. Surprisingly, the TST makes up an almost equal proportion of deposits in both sequences in the sedimentological record as the FSST, despite the shorter temporal span of the TST. The sub-bottom profiles were acquired on regional surveys extending from the Breede River in the west to Plettenberg Bay in the east, and to a maximum depth of 110 m below Mean Sea Level, with the exception of one ~200 m deep shelf-edge profile.

scholarly journals Improved Stock Unearthing Method (ISUM) as a tool to determine the value of alternative topographic factors in estimating inter-row soil mobilisation in citrus orchards

2020 ◽  
Vol 10 ◽  
Author(s):  
Jesús Rodrigo-Comino ◽  
Alexandre Marco da Silva ◽  
Ehsan Moradi ◽  
Enric Terol ◽  
Artemi Cerdà
Keyword(s):  
Rill Erosion ◽  
Sediment Distribution ◽  
Mean Values ◽  
Tillage Practices ◽  
Natural Rainfall ◽  
Local Soil ◽  
Citrus Orchards ◽  
The Difference ◽  
The Moment ◽  
The Right

The Improved Stock Unearthing Method (ISUM) was initially designed to assess soil mobilisation rates in vineyards; however, other grafted crops such as citrus orchards could also be successfully used. The results obtained from ISUM have been used for several goals, but have not yet been applied for computing the LS factor (length and slope) as a part of the Universal Soil Loss Equation (USLE), which could give useful information to improve soil management system plans. This investigation was conducted in an 8-year old clementine field located in Canals (Valencia, Spain) and values of the LS factor were calculated by means of two pre-established algorithms, which allowed us to calculate a Transect Length Index (TLI). Our results demonstrated that the micro-topographical changes can show frequent irregularities. For the values of the Transect Length Index (TLI), the mean values were 1.02% for the left side and 1.04% for the right one. The difference among the areas predicted at the moment of furrow construction and the moment of data survey permitted us to estimate a total volume of 56.9 m<sup>3</sup> of soil mobilized in 19 years. Taking into account the studied area (360 m<sup>2</sup>), the volume of mobilised soil, and the bulk density for the local soil (1.3 g cm<sup>-3</sup>), we estimated a total soil mobilisation of 8.3 mm yr<sup>-1</sup> or 10.4 kg m<sup>-2</sup> yr<sup>-1</sup>. We did not observe any evidence or indicator of rill and inter-rill erosion by natural rainfall events, suggesting that the runoff homogenizes the sediment distribution during heavy rains (corroborated by the TLI data) or tillage practices. The data created following the ISUM was suitable to be used to calculate the LS-factor values. The amount of soil mobilised as predicted by USLE was always lower than the ones predicted by ISUM.

scholarly journals Geologic and geomorphologic study of the Terra Murata and Centane-Panoramica sites (Island of Procida, Naples Bay, Southern Tyrrhenian sea) aimed at solving some applied geological and geotechnical problems

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Gemma Aiello
Keyword(s):  
Middle Ages ◽  
Tectonic Setting ◽  
Geological Survey ◽  
Tyrrhenian Sea ◽  
Pyroclastic Deposits ◽  
Coastal Cliff ◽  
Coastal Cliffs ◽  
Naples Bay ◽  
Strong Control ◽  
Geotechnical Problems

A geologic and geomorphologic study aimed at solving some geological and geotechnical problems, regarding the massive seepage of meteoric waters in the coastal cliffs of the Island of Procida (Naples Bay, southern Italy), composed of both tuffs and loose pyroclastic deposits, has been carried out in the geosites of Terra Murata (Middle Ages village and coastal cliff towards the Corricella Bay) and Centane-Panoramica (coastal cliff facing on the Tyrrhenian sea). A detailed geologic and geomorphologic survey has allowed to suggest solutions to the applied geological and geotechnical problems related to the occurrence of massive seepages of waters at the physical interface between pyroclastic rocks and loose pyroclastic deposits, characterized by different density, permeability and porosity and also controlled by a dense network of fractures, involving the pyroclastic deposits cropping out in the selected areas. Field sampling and geotechnical laboratory analyses have been carried out to calculate the values of main geotechnical parameters of the yellow tuffs cropping out at the Terra Murata promontory. At the same time, a detailed monitoring of the seepages of waters has been carried out through a detailed geological survey of the tuff outcrops of the promontory. The obtained results have suggested a strong control from both the geomorphologic instability of the coastal cliff and tectonic setting. At the Centane-Panoramica geosite the geological survey, coupled with geotechnical analyses and standard penetrometric tests, has accordingly evidenced that the geomorphologic instability was mainly concentrated in the sectors of the tuff coastal cliffs facing seawards towards the Tyrrhenian sea. 

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