SEA-LEVEL HISTORY AND QUATERNARY EVOLUTION OF RIVER MOUTH-ASSOCIATED BEACH-RIDGE PLAINS ALONG THE EAST-SOUTHEAST BRAZILIAN COAST: A SUMMARY

1987 ◽  
pp. 115-127 ◽  
Author(s):  
JOSE M. L. DOMINGUEZ ◽  
LOUIS MARTIN ◽  
ABILIO C. S. P. BITTENCOURT
Keyword(s):  
Sea Level ◽  
River Mouth ◽  
Brazilian Coast ◽  
Beach Ridge

scholarly journals Late Holocene differential subsidence and relative sea level rise in the Tabasco Delta, Mexico

2020 ◽  
Vol 382 ◽  
pp. 149-153
Author(s):  
Kees Nooren ◽  
Kim M. Cohen ◽  
Jaap H. Nienhuis ◽  
Wim Z. Hoek
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Late Holocene ◽  
Gulf Coast ◽  
Time Windows ◽  
River Mouth ◽  
Beach Ridge ◽  
Relative Sea Level ◽  
Southern Mexico ◽  
Relative Sea Level Rise

Abstract. Coastal subsidence owing to compaction of Holocene strata and deeper-rooted components affects large delta plains such as the Tabasco delta in southern Mexico (Gulf coast). For this system, GNSS3-PPP ground-truthed LiDAR imagery of high-resolution dated beach-ridge series reveals considerable differential subsidence on either side of the present Usumacinta-Grijalva River mouth. Collected field-data allows for quantification of differential subsidence over several time windows and reconstruction of relative sea-level rise back to 5000 years ago. Observed differential subsidence of 1–1.5 m is regarded to be syn-sedimentary delta-subsurface compaction of buried strata in response to the accumulating overburden of the prograding beach-ridge complex.

scholarly journals Sea-level proxies in Holocene raised beach ridge deposits (Greenland) revealed by ground-penetrating radar

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Lars Nielsen ◽  
Mette Bendixen ◽  
Aart Kroon ◽  
Mikkel Ulfeldt Hede ◽  
Lars B. Clemmensen ◽  
...  
Keyword(s):  
Sea Level ◽  
Ground Penetrating Radar ◽  
Beach Ridge ◽  
Ground Penetrating

scholarly journals Sea-level fluctuations and coastal evolution in the state of Rio de Janeiro, southeastern Brazil

2014 ◽  
Vol 86 (2) ◽  
pp. 671-683 ◽  
Author(s):  
JOÃO WAGNER A. CASTRO ◽  
KENITIRO SUGUIO ◽  
JOSÉ C.S. SEOANE ◽  
ALINE M. DA CUNHA ◽  
FABIO F. DIAS
Keyword(s):  
Sea Level ◽  
Rio De Janeiro ◽  
Atlantic Coast ◽  
Southeastern Brazil ◽  
Brazilian Coast ◽  
14C Dating ◽  
Relative Sea Level ◽  
Coastal Evolution ◽  
The Holocene ◽  
First Time

The present paper aims to investigate the relative sea-level and the coastal evolution during the Holocene in the Rio de Janeiro coastline, based on geological and biological indicators. Using topographic survey, excavation and coring, and 14C dating of these coastal deposits and beachrocks outcrops, we have reconstructed a sea-level curve for the Holocene. For the first time on the Brazilian coast it was identified a negative record of relative sea-level during Late Pleistocene and Early Holocene transition. After the transition, a relatively rapid increase of sea-level began. At approximately at 8500 cal yr BP, the sea-level was 0.5 m below the current level, was overtaken for the first time in the Holocene, at approximately 7500 cal yr BP. The maximum level of +2.5 m was reached between 4770 and 4490 cal yr BP. At the point of maximum transgression, the sea-level began a general behavior of lowering until the present. These results confirm other data already obtained elsewhere along the Atlantic coast of South America. The results of this study are consistent with previous researches and they help to refine the Holocene sea-level record along the Brazilian coast.

scholarly journals Flowing into the unknown: inferred paleodrainages for studying the ichthyofauna of Brazilian coastal rivers

2018 ◽  
Vol 16 (3) ◽  
Author(s):  
Andréa T. Thomaz ◽  
L. Lacey Knowles
Keyword(s):  
Information System ◽  
Continental Shelf ◽  
Sea Level ◽  
Brazilian Coast ◽  
Strongly Correlated ◽  
Bathymetric Data ◽  
Biological Studies ◽  
Coastal Rivers ◽  
Coastal Basins ◽  
Geologic Data

ABSTRACT The eastern coastal basins of Brazil are a series of small and isolated rivers that drain directly into the Atlantic Ocean. During the Pleistocene, sea-level retreat caused by glaciations exposed the continental shelf, resulting in enlarged paleodrainages that connected rivers that are isolated today. Using Geographic Information System (GIS), we infer the distribution of these paleodrainages, and their properties for the east Brazilian coast. Specifically, using elevation/bathymetric data for the largest sea-level retreats during the Pleistocene, the paleodrainages, their area and the number of contemporary basins connected by each palaeodrainage, was inferred. For the 145 inferred paleodrainages, total paleodrainage area is strongly correlated with the contemporary area encompassed by each paleodrainage, as well as with the number of contemporary basins encompassed by a paleodrainage. Differences in the continental shelf exposure along the coast affected the degree of past connectivity among contemporary rivers. With our results freely available, we discuss how paleodrainages have tremendous utility in biological studies, especially in regions with limited geologic data. With respect to the diverse ichthyofauna of the Brazilian coast, and its high endemism, we highlight how the inferred paleodrainages provide a backdrop to test hypotheses about the effect of past riverine connectivity on diversity patterns.

scholarly journals Long-term challenge to mangrove in the National park Xuanthuy – data released from shallow subsidence monitoring

2018 ◽  
Vol 34 (3) ◽  
Author(s):  
Le Xuan Thuyen
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
National Park ◽  
Low Cost ◽  
River Mouth ◽  
Biosphere Reserve ◽  
The United States ◽  
Red River ◽  
United States Geological Survey ◽  
The Core

A small mangrove colony growing for several decades on a mud flat on the left side of Balat River mouth has become today a large and healthy forest, containing a high ecosystem service value in the core of the Red River biosphere reserve. As a pioneer ecosystem located at land– water interface in the tropic, there exist always risks to mangroves, especially due to climate change and sea level rise. Sea level rise is a worldwide process, but subsidence is a local problem that can exacerbate these geo-hazards. A monitoring of shallow subsidence has been carried out by using SET-MH technique (developed by the United States Geological Survey) to track the both accretion and land sinking in the core zone of the National Park. The measurement shows the average sedimentation rate of 2.9 cm / yr and the sinking rate of 3.4 cm / yr, since Dec. 30th 2012. This is the first ground-based observation of shallow subsidence under mangroves in the Tonkin Gulf. As a simple and low cost method, so further expansion of this monitoring could provide more useful information to help identify the generally sinking trend of coastal areas in the Red River Delta and also to protect its own biosphere reserve.

Isostasy amplifies relative sea-level change on continental-scale deltas

2021 ◽  
Author(s):  
Sara Morón ◽  
Mike Blum ◽  
Tristan Salles ◽  
Bruce Frederick ◽  
Rebecca Farrington ◽  
...  
Keyword(s):  
Sea Level ◽  
Drainage Basin ◽  
Sediment Accumulation ◽  
River Mouth ◽  
Feedback Mechanism ◽  
Landscape Dynamics ◽  
Passive Margin ◽  
Sea Level Changes ◽  
Isostatic Compensation ◽  
Continental Scale

<p>The nature and contribution of flexural isostatic compensation to subsidence and uplift of passive margin deltas remains poorly understood. We performed a series of simulations to investigate flexural isostatic responses to high frequency fluctuations in water and sediment load associated with climatically-driven sea-level changes. We use a parallel basin and landscape dynamics model, BADLANDS, (an acronym for BAsin anD LANdscape DynamicS) that combines erosion, sedimentation, and diffusion with flexure, where the isostatic compensation of the load is computed by flexural compensation. We model a large drainage basin that discharges to a continental margin to generate a deltaic depocenter, then prescribe synthetic and climatic-driven sea-level curves of different frequencies to assess flexural response. Results show that flexural isostatic adjustments are bidirectional over 100-1000 kyr time-scales and mirror the magnitude, frequency, and direction of sea-level fluctuations, and that isostatic adjustments play an important role in driving along-strike and cross-shelf river-mouth migration and sediment accumulation. Our findings demonstrate that climate-forced sea-level changes set up a feedback mechanism that results in self-sustaining creation of accommodation into which sediment is deposited and plays a major role in delta morphology and stratigraphic architecture.</p>

Sedimentary responses to the Pleistocene climatic variations recorded in the South China Sea

2007 ◽  
Vol 68 (1) ◽  
pp. 162-172 ◽  
Author(s):  
Sébastien Boulay ◽  
Christophe Colin ◽  
Alain Trentesaux ◽  
Stéphane Clain ◽  
Zhifei Liu ◽  
...  
Keyword(s):  
Grain Size ◽  
South China Sea ◽  
Sea Level ◽  
South China ◽  
East Asian Monsoon ◽  
River Mouth ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Sea Level Variations

AbstractGrain-size analyses, coupled with end-member modelling, have been performed on the terrigenous fraction of two Leg 184 Ocean Drilling Program sites (1144 and 1146) from the South China Sea. The grain-size distributions over the last 1.8 Ma enable a new interpretation of their connections to sea-level variations and East Asian monsoon strength. Previous investigations in this area have associated grain-size variability with enhanced eolian input during glacial stages. End-member modelling downgrades the importance of this eolian contribution and indicates that the sediments can be described as a mixture of three end-members: fluvial mud inputs, shelf reworking and river mouth migration. Grain-size variations in the Pleistocene section of the cores indicate a multiple-stage evolution: (i) from 1.8 to 1.25 Ma, the downcore grain-size variations are low but show a correspondence between monsoon rainfall intensity and the fine grain-sized fluvial inputs; no link with sea-level variations is noticeable; (ii) from 1.25 to 0.9 Ma, there is an increase (decrease) in the intermediate (fine) end-member (∼ 100 kyr cycle) that is associated with the onset of a stronger summer monsoon and modest shelf reworking; (iii) from 0.9 to 0 Ma the grain-size record is dominated by global sea-level variations; each glacial stage is associated with extensive shelf reworking and conveyance of coarse particles to the basin.

scholarly journals Relative sea-level records preserved in Holocene beach-ridge strandplains – An example from tropical northeastern Australia

2019 ◽  
Vol 411 ◽  
pp. 107-118 ◽  
Author(s):  
Brendan P. Brooke ◽  
Zhi Huang ◽  
William A. Nicholas ◽  
Thomas S.N. Oliver ◽  
Toru Tamura ◽  
...  
Keyword(s):  
Sea Level ◽  
Beach Ridge ◽  
Relative Sea Level

Geomorphic diversity and complexity of the inner shelf, Canadian Arctic Archipelago, based on LiDAR and multibeam sonar surveys

2020 ◽  
Vol 57 (1) ◽  
pp. 123-132
Author(s):  
John Shaw ◽  
D. Patrick Potter ◽  
Yongsheng Wu
Keyword(s):  
Sea Level ◽  
Gas Hydrate ◽  
Canadian Arctic ◽  
Slight Modification ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Beach Ridge ◽  
Terrestrial Lidar ◽  
Sea Levels ◽  
Glacial Landforms

Data from two surveys by multi-beam sonar and two by marine/terrestrial LiDAR are used to evaluate the geomorphology of the seafloor in littoral areas of the Canadian Arctic Channels, near King William Island, Nunavut. Submarine terrains show well-preserved glacial landforms (drumlins, mega-scale glacial lineations, iceberg-turbated terrain, recessional moraines, and glaciofluvial landforms) with only slight modification by modern processes (wave action and sea-ice activity). At Gjoa Haven the seafloor is imprinted by fields of pits 2 m wide and 0.15 m deep. They may result from gas hydrate dissolution triggered by falling relative sea levels. The Arctic Archipelago displays what might be termed inverted terrains: marine terrains, chiefly beach ridge complexes, exist above modern sea level and well-preserved glacial terrains are present below modern sea level. This is the inverse of the submerging regimes of Atlantic Canada, where glacial terrains exist on land, but below sea level they have been effaced and modified by marine processes down to the lowstand depth.

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