Origin and evolution of smectites in Recent marine sediments of the NE Atlantic

Clay Minerals ◽  
1985 ◽  
Vol 20 (3) ◽  
pp. 335-346 ◽  
Author(s):  
M. Parra ◽  
P. Delmont ◽  
A. Ferragne ◽  
C. Latouche ◽  
J. C. Pons ◽  
...  
Keyword(s):  
Comparative Study ◽  
Marine Environment ◽  
Marine Sediments ◽  
Sedimentary Environment ◽  
Sedimentary Basins ◽  
Soil Environment ◽  
Ne Atlantic ◽  
Origin And Evolution ◽  
Hydrothermal Origin

AbstractPresent-day marine sediments around the emerged basaltic areas of Iceland and the Faeroe Islands are characterized by the abundance and predominance of smectites. Smectites increase regularly and systematically near volcanic areas. Their origin from (i) meteoric/deuteric weathering, (ii) hydrothermal products, (iii) neoformation in the marine environment or (iv) transformation during their transport to or stay in oceanic regions is considered in a comparative study of three types of environments on or near the Faeroe Islands. These are (1) a basaltic environment where phyllite minerals of deuteric and hydrothermal origin are abundant; (2) a soil environment formed on basaltic flows; (3) a marine sedimentary environment within adjacent sedimentary basins. This investigation clearly shows the link between hydrothermal and deuteric saponite-celadonite in basalt, Fe,Mg-smectite in Faeroe soils and Fe-smectite in marine sediments.

F-specific bacteriophage as an indicator of human viruses in natural waters and sewage effluents in Northern New Zealand

1995 ◽  
Vol 31 (5-6) ◽  
pp. 231-234 ◽  
Author(s):  
Gillian D. Lewis
Keyword(s):  
New Zealand ◽  
Comparative Study ◽  
Marine Environment ◽  
Natural Waters ◽  
Sewage Effluents ◽  
Pathogenic Viruses ◽  
Human Viruses ◽  
Specific Bacteriophage ◽  
Beach Water

To assess the F-specific bacteriophage as an indicator of pathogenic viruses, a comparative study has been made of the occurrence of F-phage and human enteroviruses in sewage wastes and the marine environment. Although F-phage seemed in several respects to match pathogen behaviour, its low abundance in bathing beach water, uncertainty as to its source and other detection irregularities make its use as an indicator problematical.

scholarly journals Late Quaternary paleoenvironment of the Ross Sea continental shelf, Antarctica

1998 ◽  
Vol 27 ◽  
pp. 275-280 ◽  
Author(s):  
Akira Nishimura ◽  
Toru Nakasone ◽  
Chikara Hiramatsu ◽  
Manabu Tanahashi
Keyword(s):  
Organic Carbon ◽  
Marine Environment ◽  
Environmental Changes ◽  
Ross Sea ◽  
Late Quaternary ◽  
Sedimentary Environment ◽  
Sediment Cores ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Accelerator Mass Spectrometer

Based on sedimenlological and micropaleontological work on three sediment cores collected at about 167° Ε in the western Ross Sea, Antarctica, and accelerator mass spectrometer l4C ages of organic carbon, we have reconstructed environmental changes in the area during the late Quaternary. Since 38 ka BP at latest, this area was a marine environment with low productivity. A grounded ice sheet advanced and loaded the sediments before about 30-25 ka BP. After 25 ka BP, the southernmost site (76°46'S) was covered by floating ice (shelf ice), preventing deposition of coarse terrigenous materials and maintaining a supply of diatom tests and organic carbon until 20 ka BP. The northernmost site (74°33'S) was in a marine environment with a moderate productivity influenced by shelf ice/ice sheet after about 20 ka BP. Since about 10 ka BP, a sedimentary environment similar to the present-day one has prevailed over this area.

A new sedimentary cover model for the southern area of the East European Platform and the Pre-Caucasus based on decompensation gravity anomalies data

2021 ◽  
Author(s):  
Mikhail Kaban ◽  
Alexei Gvishiani ◽  
Roman Sidorov ◽  
Alexei Oshchenko ◽  
Roman Krasnoperov
Keyword(s):  
East European Platform ◽  
Sedimentary Cover ◽  
Gravity Anomalies ◽  
Sedimentary Basins ◽  
The Caucasus ◽  
Near Surface ◽  
New Model ◽  
Origin And Evolution ◽  
East European ◽  
Bouguer Anomalies

<p><span>A new model has been developed for the density and thickness of the sedimentary cover in a vast region at the junction of the southern part of the East European Platform, the Pre-Caucasus and some structures adjacent to the south, including the Caucasus. Structure and density of sedimentary basins was studied by employing the approach based on decompensation of gravity anomalies. Decompensative correction for gravity anomalies reduces the effect of deep masses providing compensation of near-surface density anomalies, in contrast to the conventional isostatic or Bouguer anomalies. . The new model of sediments, which implies their thickness and density, gives a more detailed description of the sedimentary thickness and density and reveals new features which were not or differently imaged by previous studies. It helps in better understanding of the origin and evolution of the basins and provides a background for further detailed geological and geophysical studies of the region.</span></p>

scholarly journals AROMATIC STEROIDS BIOMARKERS APPLIED TO HIGH RESOLUTION STRATIGRAPHY: IRATI FORMATION, SOUTHERN OF PARANÁ BASIN, BRAZIL

2018 ◽  
Vol 2 (4) ◽  
pp. 174-182 ◽  
Author(s):  
Lina Liliana Osorio ◽  
Darlly Erika Silva dos Reis ◽  
René Rodrigues
Keyword(s):  
High Resolution ◽  
Sedimentary Environment ◽  
Water System ◽  
Sedimentary Basins ◽  
Lower Permian ◽  
Irati Formation ◽  
Organic Matter Type ◽  
Living Organisms ◽  
Rock Eval ◽  
Geochemical Studies

The use of aromatic steroids in geochemical studies is almost absent in Brazilian sedimentary basins. For this reason, it is intended to test the application of these compounds in high-resolution stratigraphy in the relatively well known Lower Permian Irati Formation. The Irati Formation is about 40 meters thick. It is thermally immature, and comprise two lithological distinct members: the lower siliciclastic Taquaral Member and the upper calcareous-siliciclastic Assistência Member. Based on the whole rock data, mostly TOC, total sulfur, Rock-Eval pyrolysis and alkanes biomarkers, was possible to split the Irati Formation into seven chemostratigraphic units, named from A to C in the Taquaral Member and from D to G in the Assistência Member. Each of these units represents: distinct inputs of land derived organic matter type (chemostratigraphic units C and F) and/or; the response of living organisms to salinity changing of the water system (chemostratigraphic unit D) and; anoxia (chemostratigraphic unit E) during sedimentation. The methodology applied in this work can be used in other sedimentary basins but considering the lithology and sedimentary environment particularities.

scholarly journals Wireless Channel Models for Over-the-Sea Communication: A Comparative Study

2019 ◽  
Vol 9 (3) ◽  
pp. 443 ◽  
Author(s):  
Arafat Habib ◽  
Sangman Moh
Keyword(s):  
Wave Propagation ◽  
Comparative Study ◽  
Radio Wave ◽  
Marine Environment ◽  
Channel Model ◽  
Channel Modeling ◽  
Wireless Channel ◽  
Radio Wave Propagation ◽  
Channel Models ◽  
The Impact

Over the past few years, the modeling of wireless channels for radio wave propagation over the sea surface has drawn the attention of many researchers. Channel models are designed and implemented for different frequencies and communication scenarios. There are models that emphasize the influence of the height of the evaporation duct in the marine environment, as well as models that deal with different frequencies (2.5, 5, and 10 GHz, etc.) or the impact of various parameters, such as antenna height. Despite the increasing literature on channel modeling for the over-the-sea marine environment, there is no comprehensive study that focuses on key concepts that need to be considered when developing a new channel model, characteristics of channel models, and comparative analysis of existing works along with their possible improvements and future applications. In this paper, channel models are discussed in relation to their operational principles and key features, and they are compared with each other in terms of major characteristics and pros and cons. Some important insights on the design and implementation of a channel model, possible applications and improvements, and challenging issues and research directions are also discussed. The main goal of this paper is to present a comparative study of over-the-sea channel models for radio wave propagation, so that it can help engineers and researchers in this field to choose or design the appropriate channel models based on their applications, classification, features, advantages, and limitations.

scholarly journals Jupiter and the other Giants: A Comparative Study

2010 ◽  
Vol 6 (S269) ◽  
pp. 155-164
Author(s):  
Thérèse Encrenaz
Keyword(s):  
Comparative Study ◽  
Ring System ◽  
Atmospheric Dynamics ◽  
Giant Planets ◽  
The Other ◽  
The Sun ◽  
Origin And Evolution ◽  
Open Questions ◽  
Internal Structures ◽  
Pioneer 10

AbstractThe four giant planets - Jupiter, Saturn, Uranus and Neptune - have common properties which make them very different from the terrestrial planets: located at large distances from the Sun, they have big sizes and masses but low densities; they all have a ring system and a large number of satellites. These common properties can be understood in the light of their formation scenario, based upon the accretion of protosolar gas on an initial icy core. Giant planets have been explored by space missions (Pioneer 10 and 11, Voyager 1 and 2, Galileo and Cassini) but also by Earth-orbiting satellites and ground-based telescopes. There are still open questions related to the origin and evolution of the giant planets, in particular their moderate migration, the origin of the cold planetesimals which formed Jupiter, the origin of the atmospheric dynamics in Jupiter and Saturn, and the differences in the internal structures of Uranus and Neptune.

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