Aragonite Crystal Fans In Neoproterozoic Cap Carbonates: A Case Study From Brazil and Implications For the Post-Snowball Earth Coastal Environment

2015 ◽  
Vol 85 (3) ◽  
pp. 285-300 ◽  
Author(s):  
L. C. Vieira ◽  
A. Nedelec ◽  
S. Fabre ◽  
R. I. F. Trindade ◽  
R. P. de Almeida
Keyword(s):  
Coastal Environment ◽  
Snowball Earth ◽  
Aragonite Crystal ◽  
Cap Carbonates

scholarly journals A geochemical modelling study of the evolution of the chemical composition of seawater linked to a "snowball" glaciation

2008 ◽  
Vol 5 (1) ◽  
pp. 253-267 ◽  
Author(s):  
G. Le Hir ◽  
Y. Goddéris ◽  
Y. Donnadieu ◽  
G. Ramstein
Keyword(s):  
Environmental Changes ◽  
Snowball Earth ◽  
Large Shift ◽  
Environmental Perturbations ◽  
Seawater Ph ◽  
Oceanic Surface ◽  
Cap Carbonates ◽  
Evolution Of Life ◽  
Global Cycles ◽  
Modelling Study

Abstract. The Snowball Earth theory initially proposed by Kirschvink (1992) to explain the Neoproterozoic glacial episodes, suggested that the Earth was fully ice-covered at 720 Ma (Sturtian episode) and 640 Ma (Marinoan episode). This succession of extreme climatic crises induced environmental perturbations which are considered as a strong selective pressure on the evolution of life (Hoffman et al., 1998). Using a numerical model of carbon-alkalinity global cycles, we quantify environmental stresses caused by a global glaciation. According to our results, we suggest that during global glaciations, the ocean becomes acidic (pH~6), and undersaturated with respect to carbonate minerals. Moreover the quick transition from ice-house to greenhouse conditions implies an abrupt and large shift of the oceanic surface temperature which causes an extended hypoxia. The intense continental weathering, in the aftermath of the glaciation, deeply affects the seawater composition inducing rapid changes in terms of pH and alkalinity. We also propose a new timing for post glacial perturbations and for the cap carbonates deposition, ~2 Myr instead of 200 kyr as suggested in a previous modelling study. In terms of Precambrian life sustainability, seawater pH modifications appear drastic all along the glaciation, but we suggest that the buffering action of the oceanic crust dissolution avoids a total collapse of biological productivity. But short-lived and large post-glacial perturbations are more critical and may have played the role of an environmental filter proposed in the classic snowball Earth theory. Although the link between environmental changes and life sustainability cannot be modelled accurately, we suggest that only a permissive life (Knoll, 2003) may explain the relative continuity in microfossils diversity observed before, during and after Neoproterozoic glaciation events.

scholarly journals MAPPING BATHYMETRY BY LANDSAT DATA IN SHALLOW COASTAL ENVIRONMENT (CASE STUDY: THE SOUTHEAST OF THE CASPIAN SEA)

2019 ◽  
Vol XLII-4/W18 ◽  
pp. 83-87
Author(s):  
L. Amini ◽  
A. A. Kakroodi
Keyword(s):  
High Accuracy ◽  
Coastal Environment ◽  
Landsat 8 ◽  
Landsat Data ◽  
Effective Solution ◽  
The Caspian Sea ◽  
Highly Correlated ◽  
Shallow Coastal Environment ◽  
Reflectance Data

Abstract. Compared to traditional methods, remote sensing (RS) technique is an efficient, fast, low-priced and effective solution in bathymetry. In this study, a linear equation was applied between field and reflectance data to achieve bathymetry map. Landsat-8 is characterized by additional visible band compared with previous Landsat bands on coastal zone application, therefore, we apply two regions of spectrum to compare the accuracy of bathymetry, Bands 1, 3, 4 and bands 2, 3 and 4 respectively. Furthermore, Logarithmic transformation also applied on both spectral regions to have bathymetry map. The coefficient obtained from reflectance and filed data was applied on Tm bands to retrieve the bathymetry of Gomishan lagoon in 2000. The results show that the second spectral region, Bands 2, 3 and 4, is highly correlated with filed data and more accurate (R2 = 0.94, RMSE = 0.35). Moreover, there is a relatively high accuracy between the retrieval of Gomishan bathymetry and the report of recent studies.

scholarly journals DEVELOPMENT AND COASTAL ENVIRONMENT CHANGE, WILL HAVE A MEETING POINT? CASE STUDY OF COASTAL ZONE OF WEST JAVA PROVINCE, INDONESIA

2020 ◽  
Vol 31 (3) ◽  
pp. 1034-1042
Author(s):  
Achmad RIZAL ◽  
◽  
Izza M. APRILIANI ◽  
Rega PERMANA ◽  
Isni NURRUHWATI ◽  
...  
Keyword(s):  
Coastal Zone ◽  
Coastal Environment ◽  
Environment Change ◽  
West Java ◽  
Meeting Point

Sources and Distribution of Fecal Coliforms in the Coastal Environment: A Case Study from Chilika Lagoon, Odisha, India

2021 ◽  
pp. 23-44
Author(s):  
Madhusmita Mohapatra ◽  
Stiti Prangya Dash ◽  
Pratiksha Behera ◽  
Sudhakar Panda ◽  
Gurdeep Rastogi
Keyword(s):  
Coastal Environment ◽  
Fecal Coliforms ◽  
Chilika Lagoon

Assessment of the Desirability of Tourism Destinations Based on Perceptual Analysis of the Quality of Environment Case Study: The Coastal Areas of Ramsar

2012 ◽  
Vol 178-181 ◽  
pp. 914-921
Author(s):  
Sajad Alipour Eshliki ◽  
Ramin Norouzian
Keyword(s):  
Social Security ◽  
Field Study ◽  
Significant Relationship ◽  
Coastal Environment ◽  
Coastal Areas ◽  
Quality Factors ◽  
Perceptual Analysis ◽  
Tourism Destinations

Planning for tourism destinations in order to develop collect useful policies with the aim of qualitative improvement of them has a lot of importance.Tourism destinations should have qualities to provide the conditions for attracting the tourists and accommodating them. Different aspects were considered for improving the quality of tourism destinations that one of the most important ones is the quality of tourism environment. This study evaluated the qualitative indicators of the coastal environment of Ramsar city in a field study through questionnaire tool. To this end, 304 questionnaires were distributed among coastal tourists of Ramsar city, and they were analysed after collecting data. The results of the analysis indicated that the qualitative indicators of coastal environment of Ramsar can be recognized in a specified factors. These factors are; 1. Cleanness, the quality of environment sight and social security 2.Tourism facilities 3. Recreational space and activities for families 4.Access and traffic 5.Welfare services and hospitality. There was also significant relationship between quality factors and satisfaction with tourism environment and probability of returning to the tourism destination.

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