scholarly journals Central Santa Catarina coastal dunefields chronology and their relation to relative sea level and climatic changes

2015 ◽  
Vol 45 (suppl 1) ◽  
pp. 79-95 ◽  
Author(s):  
Vinícius Ribau Mendes ◽  
Paulo César Fonseca Giannini ◽  
Carlos Conforti Ferreira Guedes ◽  
Regina DeWitt ◽  
Helena Asmar de Abreu Andrade
Keyword(s):  
Sea Level ◽  
Age Distribution ◽  
Coastal Dunes ◽  
Level Variation ◽  
Santa Catarina ◽  
Relative Sea Level ◽  
The Past ◽  
Sea Level Variation ◽  
Climatic Control

ABSTRACTDuring the past decades, there have been contrarian explanations for the formation and stabilization of coastal dunefields: while many authors believe the dunes formation would be enhanced by falling sea level, others argue that a rising or stable sea level context would be favorable. For Brazilian coastal dunefields, the second hypothesis seems to be more consistent with the luminescence ages found so far; however, most of these data were obtained without using the SAR protocol. Another point of concern is the role of climate change in the aeolian system, which is still not very clear. The aim of this paper is to try to clarify these two questions. To this end, five coastal dunefields were selected in central Santa Catarina coast. The remote sensing and dating results allowed the discrimination and mapping of at least four aeolian generations. Their age distribution in relation to the global curve of relative sea level variation during the Late Pleistocene allows us to suggest that the formation of Aeolian dunefields in the coastal context is supported by stable relative sea level. However, relative sea level is not the only determinant for the formation and preservation of the aeolian coastal dunes. Evidences of climatic control indicate that the initiation of dunefields would be favored by periods of less humidity while their stabilization would occur preferably during the periods of rain intensification, connected to monsoon activity.

scholarly journals Internal Variability Role on Estimating Sea Level Acceleration in Fremantle Tide Gauge Station

2021 ◽  
Vol 9 ◽  
Author(s):  
Armin Agha Karimi
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Low Frequency ◽  
Internal Variability ◽  
Climate Indices ◽  
Level Variation ◽  
Sea Level Variation ◽  
Gauge Station ◽  
Trajectory Models

Low frequency internal signals bring challenges to signify the role of anthropogenic factors in sea level rise and to attain a certain accuracy in trend and acceleration estimations. Due to both spatially and temporally poor coverage of the relevant data sets, identification of internal variability patterns is not straightforward. In this study, the identification and the role of low frequency internal variability (decadal and multidecadal) in sea level change of Fremantle tide gauge station is analyzed using two climate indices, Pacific Decadal Oscillation (PDO) and Tripole Interdecadal Pacific Oscillation (TPI). It is shown that the multidecadal sea level variability is anticorrelated with corresponding components of climate indices in the Pacific Ocean, with correlation coefficients of −0.9 and −0.76 for TPI and PDO, respectively. The correlations are comparatively low on decadal time scale, −0.5 for both indices. This shows that internal variability on decadal and multidecadal scales affects the sea level variation in Fremantle unequally and thus, separate terms are required in trajectory models. To estimate trend and acceleration in Fremantle, three trajectory models are tested. The first model is a simple second-degree polynomial comprising trend and acceleration terms. Low passed PDO, representing decadal and interdecadal variabilities in Pacific Ocean, added to the first model to form the second model. For the third model, decomposed signals of decadal and multidecadal variability of TPI are added to the first model. In overall, TPI represents the low frequency internal variability slightly better than PDO for sea level variation in Fremantle. Although the estimated trends do not change significantly, the estimated accelerations varies for the three models. The accelerations estimated from the first and second models are statistically insignificant, 0.006 ± 0.012 mm yr−2 and 0.01 ± 0.01 mm yr−2, respectively, while this figure for the third model is 0.018 ± 0.011 mm yr−2. The outcome exemplifies the importance of modelling low frequency internal variability in acceleration estimations for sea level rise in regional scale.

High-frequency relative sea level variation cycles recorded in sedimentary discontinuities

2005 ◽  
Vol 176 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Youri Hamon ◽  
Gilles Merzeraud ◽  
Pierre-Jean Combes
Keyword(s):  
Sea Level ◽  
High Frequency ◽  
Level Variation ◽  
Relative Sea Level ◽  
Mud Mounds ◽  
Synsedimentary Tectonics ◽  
Sea Level Variation ◽  
Southwestern Margin ◽  
Regressive Phase ◽  
Flooding Period

Abstract In the Lodève region (“Caussenard High” southwestern margin of the South-East Basin), upper Hettangian to Lotharingian carbonate series shows more than twenty sedimentary discontinuities of various types. Some of these discontinuities are polyphase surfaces, which record high-frequency sea-level variation cycles. One of these discontinuities has been studied in detail, in order to understand its origin (processes, chronology of formation). Several stages of formation have been recognized. A transgressive erosion occurred first. Next, development of Skolithos and Diplocraterion burrows, associated with iron mineralizations, could be indicative of a condensation phase corresponding to the subsequent maximum-flooding period. The burrows sparitic fills may characterize the highstand period following the maximum-flooding period. Next, alteration and corrosion observed on the surface and in the burrows may indicate an emersion related to a regressive phase and the subsequent lowstand period. Finally, micro mud-mounds (formed by pelecypods and corals trapping fine lime sediment) may indicate a new condensation phase, associated with the transgression and the following maximum-flooding period. Thus, this discontinuity records one and a half relative sea level variation cycle. Counting sequences observed in the deposits and in the discontinuities leads to an estimate of 100,000 years duration for these cycles. That could correspond to the eccentricity variation cycles. Moreover, the local synsedimentary tectonics may have influenced the formation of this type of discontinuity, by forming shallow restricted environments favourable to their development. Recognition and understanding of these particular discontinuities are essential because they may be laterally correlated with other surfaces in continental settings (paleokarst) or with classical sequences in marine environments.

scholarly journals Dynamic Sea Level Variation from GNSS: 2020 Shumagin Earthquake Tsunami Resonance and Hurricane Laura

2020 ◽  
Author(s):  
Kristine M. Larson ◽  
Thorne Lay ◽  
Yoshiki Yamazaki ◽  
Kwok Fai Cheung ◽  
Lingling Ye ◽  
...  
Keyword(s):  
Sea Level ◽  
Level Variation ◽  
Sea Level Variation ◽  
Dynamic Sea Level

scholarly journals ESTIMATION OF LONG-TERM SEA LEVEL VARIATION TAKING INTO CONSIDERATION GROUND DEFORMATION BY GNSS SURVEY

2018 ◽  
Vol 74 (2) ◽  
pp. I_145-I_150
Author(s):  
Ryoji NAITO ◽  
Kazunori SAMESHIMA ◽  
Yasunori KONDOU ◽  
Naokazu ITO ◽  
Koji KAWAGUCHI
Keyword(s):  
Sea Level ◽  
Ground Deformation ◽  
Level Variation ◽  
Sea Level Variation
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