Living Bulimina marginata in the SW Atlantic continental margin: Effect of the Subtropical Shelf Front and South Atlantic Central Water

2014 ◽  
Vol 89 ◽  
pp. 88-92 ◽  
Author(s):  
Patrícia P.B. Eichler ◽  
Felipe M. Pimenta ◽  
Beatriz B. Eichler ◽  
Helenice Vital
Keyword(s):  
Continental Margin ◽  
South Atlantic ◽  
South Atlantic Central Water ◽  
Sw Atlantic

Anorogenic magmatism and the Grenvillian Orogeny

1989 ◽  
Vol 26 (3) ◽  
pp. 479-489 ◽  
Author(s):  
Brian F. Windley
Keyword(s):  
United States ◽  
South America ◽  
Continental Margin ◽  
South Atlantic ◽  
Island Arc ◽  
The South ◽  
The West ◽  
Continental Block ◽  
Grenvillian Orogeny ◽  
Alkaline Complexes

The Grenvillian Orogeny was preceded by extensive anorogenic volcanism and plutonism in the period 1500–1300 Ma in the form of rhyolites, epizonal granites, anorthosites, gabbros, alkaline complexes, and basic dykes. An analogue for the mid-Proterozoic anorogenic complexes is provided by the 2000 km by 200 km belt of anorogenic complexes in the Hoggar, Niger, and Nigeria, which contain anorthosites, gabbros, and peralkaline granites and were generated in a Cambrian to Jurassic rift that farther south led to the formation of the South Atlantic. An analogue for the 1 × 106 km2 area of 1500–1350 Ma rhyolites (and associated epizonal granites) that underlie the mid-continental United States is provided by the 1.7 × 106 km2 area of Jurassic Tobifera rhyolites in Argentina, which were extruded on the stretched continental margin of South America immediately preceding the opening of the South Atlantic. The mid-Proterozoic complexes were intruded close to the continental margin of the Grenvillian ocean and were commonly superimposed by the craton-directed thrusts that characterized the final stages of the Grenvillian Orogeny. The bulk of the Keweenawan rift and associated anorogenic magmatism formed about 1100 Ma at the same time as the Ottawan Orogeny in Ontario, which probably resulted from the collision of the island arc of the Central Metasedimentary Belt attached to the continental block in the east with the continental block to the west. The most appropriate modern equivalent would be the Rhine Graben, which formed at the same time as the main Alpine compression.

Compiled potential field data and seismic surveys across the Eastern Brazilian continental margin integrated with new magnetometric profiles and stratigraphic configuration for Trindade Island, South Atlantic, Brazil

2018 ◽  
Vol 61 (14) ◽  
pp. 1728-1744 ◽  
Author(s):  
Anderson Costa Santos ◽  
Webster Ueipass Mohriak ◽  
Mauro Cesar Geraldes ◽  
Werlem Holanda Santos ◽  
Cosme Ferreira Ponte-Neto ◽  
...  
Keyword(s):  
Continental Margin ◽  
Potential Field ◽  
Field Data ◽  
South Atlantic ◽  
Potential Field Data ◽  
Seismic Surveys ◽  
Trindade Island

Segmentation and volcano-tectonic characteristics along the SW African continental margin, South Atlantic, as derived from multichannel seismic and potential field data

2014 ◽  
Vol 50 ◽  
pp. 22-39 ◽  
Author(s):  
Hannes Koopmann ◽  
Dieter Franke ◽  
Bernd Schreckenberger ◽  
Henning Schulz ◽  
Alexander Hartwig ◽  
...  
Keyword(s):  
Continental Margin ◽  
Potential Field ◽  
Field Data ◽  
South Atlantic ◽  
Potential Field Data

The structure of the lower crust at the Argentine continental margin, South Atlantic at 44°S

2008 ◽  
Vol 454 (1-4) ◽  
pp. 14-22 ◽  
Author(s):  
Michael Schnabel ◽  
Dieter Franke ◽  
Martin Engels ◽  
Karl Hinz ◽  
Sönke Neben ◽  
...  
Keyword(s):  
Continental Margin ◽  
Lower Crust ◽  
South Atlantic

scholarly journals Relationship between spatial distribution of chaetognaths and hydrographic conditions around seamounts and islands of the tropical southwestern Atlantic

2014 ◽  
Vol 86 (3) ◽  
pp. 1151-1165 ◽  
Author(s):  
CHRISTIANE S. DE SOUZA ◽  
JOANA A.G. LUZ ◽  
PAULO O. MAFALDA JUNIOR
Keyword(s):  
Spatial Distribution ◽  
Water Column ◽  
Water Mass ◽  
South Atlantic ◽  
Northeastern Brazil ◽  
Southwestern Atlantic ◽  
The South ◽  
Water Column Stability ◽  
South Atlantic Central Water ◽  
Hydrographic Conditions

Relationship between spatial distribution of chaetognaths and hydrographic conditions around seamounts and islands off Northeastern Brazil were analyzed from 133 oceanographic stations during the months of January – April of 1997 and April – July of 1998. Oblique zooplankton tows, using 50 cm diameter Bongo nets with 500µm mesh with a flowmeter to determine the filtered volume, were carried out to a maximum of 200m depth. The Superficial Equatorial Water, which had a salinity > 36 PSU and temperature > 20°C, occupied the top 80 to 200m depth. Below this water mass was the South Atlantic Central Water with salinity ranging from 34.5 to 36 PSU and temperature from 6 to 20°C. The community of chaetognaths showed six species: Pterosagitta draco, Flaccisagitta enflata, Flaccisagitta hexaptera, Pseudosagitta lyra, Serratosagitta serratodentata, and Sagitta helenae. Of these species, F. enflata was the most abundant (32.05% in 1997 and 42.18% in 1998) and the most frequent (87.88% in 1997 and 95% in 1998) during both periods. A mesopelagic specie was identified (P. lyra). This specie was more abundant in 1997 (3.42%), when the upwelling was more intense. P. lyra occurred in 22% of the samples during 1997. The abundance of F. enflata, an epiplanktonic species, increased, associated with greater water-column stability.

scholarly journals Electrical resistivity image of the South Atlantic continental margin derived from onshore and offshore magnetotelluric data

2016 ◽  
Vol 43 (1) ◽  
pp. 154-160 ◽  
Author(s):  
G. Kapinos ◽  
U. Weckmann ◽  
M. Jegen‐Kulcsar ◽  
N. Meqbel ◽  
A. Neska ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Continental Margin ◽  
South Atlantic ◽  
The South ◽  
Magnetotelluric Data ◽  
Resistivity Image

scholarly journals Characteristics of Water Masses in the Atlantic Ocean based on GLODAPv2 data

2019 ◽  
Author(s):  
Mian Liu ◽  
Toste Tanhua
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
Deep Water ◽  
Bottom Water ◽  
South Atlantic ◽  
Weddell Sea ◽  
Water Masses ◽  
Intermediate Water ◽  
South Atlantic Central Water ◽  
The North

Abstract. The characteristics of the main water masses in the Atlantic Ocean are investigated and defined as Source Water Types (SWTs) from their formation area by six key properties based on the GLODAPv2 observational data. These include both conservative (potential temperature and salinity) and non-conservative (oxygen, silicate, phosphate and nitrate) variables. For this we divided the Atlantic Ocean into four vertical layers by distinct potential densities in the shallow and intermediate water column, and additionally by concentration of silicate in the deep waters. The SWTs in the upper/central water layer originates from subduction during winter and are defined as central waters, formed in four distinct areas; East North Atlantic Central water (ENACW), West North Atlantic Central Water (WNACW), East South Atlantic Central Water (ESACW) and West South Atlantic Central Water (WSACW). Below the upper/central layer the intermediate layer consist of three main SWTs; Antarctic Intermediate Water (AAIW), Subarctic Intermediate Water (SAIW) and Mediterranean Overflow Water (MOW). The North Atlantic Deep Water (NADW) is the dominating SWT in the deep and overflow layer, and is divided into upper and lower NADW based on the different origins and properties. The origin of both the upper and lower NADW is the Labrador Sea Water (LSW), the Iceland–Scotland Overflow Water (ISOW) and Denmark Strait Overflow Water (DSOW). Antarctic Bottom Water (AABW) is the only natural SWT in the bottom layer and this SWT is redefined as North East Atlantic Bottom Water (NEABW) in the north of equator due to the change of key properties, especial silicate. Similar with NADW, two additional SWTS, Circumpolar Deep Water (CDW) and Weddell Sea Bottom Water (WSBW), are defined in the Weddell Sea in order to understand the origin of AABW. The definition of water masses in biogeochemical space is useful for, in particular, chemical and biological oceanography to understand the origin and mixing history of water samples.

scholarly journals Methane emissions from the upwelling area off Mauritania (NW Africa)

2008 ◽  
Vol 5 (4) ◽  
pp. 1119-1125 ◽  
Author(s):  
A. Kock ◽  
S. Gebhardt ◽  
H. W. Bange
Keyword(s):  
Surface Layer ◽  
Coastal Upwelling ◽  
Hot Spot ◽  
Methane Emissions ◽  
South Atlantic ◽  
Minor Importance ◽  
Ch4 Emissions ◽  
Surface Ocean ◽  
South Atlantic Central Water ◽  
Upwelling Area

Abstract. Coastal upwelling regions have been identified as sites of enhanced CH4 emissions to the atmosphere. The coastal upwelling area off Mauritania (NW Africa) is one of the most biologically productive regions of the world's ocean but its CH4 emissions have not been quantified so far. More than 1000 measurements of atmospheric and dissolved CH4 in the surface layer in the upwelling area off Mauritania were performed as part of the German SOPRAN (Surface Ocean Processes in the Anthropocene) study during two cruises in March/April 2005 (P320/1) and February 2007 (P348). During P348 enhanced CH4 saturations of up to 200% were found close to the coast and were associated with upwelling of South Atlantic Central Water. An area-weighted, seasonally adjusted estimate yielded overall annual CH4 emissions in the range from 1.6 to 2.9 Gg CH4. Thus the upwelling area off Mauritania represents a regional hot spot of CH4 emissions but seems to be of minor importance for the global oceanic CH4 emissions.

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