SEA-LEVEL CHANGES AND VULNERABILITY OF THE COASTAL ZONE

Author(s):  
NOBUO MIMURA ◽  
HIROMUNE YOKOKI
2017 ◽  
Vol 50 (1) ◽  
pp. 434 ◽  
Author(s):  
A. Karkani ◽  
N. Evelpidou ◽  
H. Maroukian ◽  
S. Kawasaki

Sea level indicators, such as tidal notches and beachrocks, may provide valuable information for the relative sea level changes of an area. Beachrocks in particular have received various arguments concerning their use as reliable sea level indicators and their formation environment. This work focuses on the coasts of East Attica in order to trace the palaeoshorelines of the Upper Holocene through the study of beachrocks. The coastal zone was surveyed in detail by snorkelling and diving, in order to locate, map and sample beachrocks. The samples were studied under a SEM, which showed that the beachrocks are mainly composed of quartz grains, a few calcites and feldspars, while the carbonate cement is characterized with the presence of MgO at percentages between 5 and 7.8%. Based on correlations with published drillings in the study area, the studied beachrocks should not be older than 2000 years BP.


2021 ◽  
Author(s):  
Anna Karkani ◽  
Giannis Saitis ◽  
Konstantinos Tsanakas ◽  
Niki Evelpidou ◽  
Efthimios Karymbalis ◽  
...  

<p>The study of environmental changes in coastal areas provide useful information for past conditions and constitute a powerful tool for accurate palaeogeographic reconstructions. Several coastal landforms are present on the coastal zone, with different response to environmental change. Coastal wetlands and lagoons are particularly sensitive to local paleoenvironmental changes and provide an excellent opportunity to reconstruct the evolution of the coastal zone evolution and the sea level changes. In this context, the aim of this work is to elucidate the coastal evolution of Psatha bay, Alkyonides Gulf, Greece, through coastal drillings and geomorphological sea level markers.</p><p>The study area is located at the eastern end of Corinth Gulf, in the Gulf of Alkyonides. Psatha is bounded by active neotectonic structures, which have been a determining factor in its development. In this work we adopt a multiproxy approach through the study of coastal drillings and beachrocks, and micro-topography constructed after photogrammetric processing of very high resolution and accuracy images acquired by several Unmanned Aerial System flights. We coupled detailed beachrock mapping, microstratigraphic analysis and luminescence dating to study beachrock outcrops found up to 1 m above the present sea-level. For the palaeoenvironmental reconstruction, multiproxy analyses were undertaken, which included sedimentological analysis of the core, paleontological analysis of macrofauna and microfauna and radiocarbon dating. The results of this work will contribute to the better understanding of a coastal site in a tectonically active area and the relative sea level changes.</p>


Terra Nova ◽  
1995 ◽  
Vol 7 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Helena Maria Granja ◽  
G. Soares Carvalho

2020 ◽  
pp. 109-124
Author(s):  
Elie Verleyen ◽  
Dominic A. Hodgson ◽  
Wim Vyverman

2010 ◽  
Vol 58 (spe2) ◽  
pp. 35-44 ◽  
Author(s):  
Jair Weschenfelder ◽  
Iran Carlos Stalliviere Corrêa ◽  
Salvador Aliotta ◽  
Ricardo Baitelli

The geological evolution of the continental shelf and in the coastal zone of southern Brazil during the Quaternary period is addressed in this study. High-resolution seismic records obtained at the Patos Lagoon revealed the presence of channels that deeply dissected the coastal zone before the formation of the modern, low-relief, coastal plain. Two periods of channel incision are inferred, based mainly on seismic records. The paleodrainage paths mapped from the seismic records can be connected with those recognized by previous studies on the adjacent continental shelf and slope. Upstream, the drainage incised mainly into the coastal prism deposited during previous sea-level highstand events. The paleodrainage network, recognized on the coastal plain and continental shelf, represents a river-shelf system, linking the drainage basin to the depositional settings on the marginal basin, bypassing the continental shelf exposed during a forced regression event. The drainage incised into the coastal plain and continental shelf of Rio Grande do Sul played an important role in the basin-margin architecture, facies distribution and accommodation during the Quaternary sea-level fluctuations.


10.1029/ft354 ◽  
1989 ◽  
Author(s):  
John M. Dennison ◽  
Edwin J. Anderson ◽  
Jack D. Beuthin ◽  
Edward Cotter ◽  
Richard J. Diecchio ◽  
...  

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