3. The Geological Relations of South Georgia

1914 ◽  
Vol 1 (2) ◽  
pp. 61-64
Author(s):  
J. W. Gregory

The special interest of the island of South Georgia depends on the evidence it promises as to the geological history of that part of the Southern Ocean which lies south of the South Atlantic. According to the well-known views of Professor Suess, South Georgia is on a continuation of the mountain line of the Andes, which at the southern end of South America bends eastward along the northern margin of Drake's Sea and continues 30° to the east, where it turns southward; it completes a great horseshoe-shaped course by passing through South Georgia and returning westward through the South Orkneys to Grahamland.

1916 ◽  
Vol 50 (4) ◽  
pp. 817-824 ◽  
Author(s):  
J. W. Gregory

The special interest of South Georgia depends on its evidence regarding the geology of the part of the Southern Ocean which lies south of the South Atlantic. According to Professor Suess, the island is an extension of the Andes, which, at the southern end of South America, turn eastward, and by a great horse-shoe-shaped curve pass through South Georgia to the South Orkneys and Graham Land.The geology of South Georgia is but little known. Thürach † described the island as consisting of metamorphic rocks, ranging from granular gneiss to clay-slate, and of diabase tuff.


Zootaxa ◽  
2017 ◽  
Vol 4329 (3) ◽  
pp. 256
Author(s):  
FRANCISCO PROVENZANO R. ◽  
NADIA MILANI ◽  
CARLOS ARDILA R.

As a part of an assessment of loricariid catfishes inhabiting the Andes of Colombia, specimens belonging to an interesting new species were identified. The new species is described herein, and it is tentatively included in the genus Cordylancistrus. The new species can be easily distinguished among its congeners by the presence of a unique diagnostic character: a fleshy keel or excrescence, black or dark brown, over the posterior tip of supraoccipital. Specimens of the new species were captured in rivers of the Sierra Nevada de Santa Marta and the Sierra de Perijá that drain to the Magdalena River Basin and Caribbean Sea. The occurrence of one species of Cordylancistrus in the Sierra Nevada de Santa Marta could have interesting biogeographic implications for hypotheses related to the geological history of northwestern corner of South America or to the dispersal or vicariance models used to explain biogeographical patterns of related species in Colombia. 


Author(s):  
Luiz Felipe de Alencastro

Scholarly studies of the colonization of the Americas—especially of Latin America—have tended to minimize the role played by Africans and the African slave trade, treating the history of conquest and colonialism as a story of inevitable European domination of the hemisphere. However, from the sixteenth through the eighteenth century, colonialism in the Americas depended upon the exportation of slaves from Africa, a massive undertaking that was supported not only by Iberian Royal families but also by convoluted ideological and theological justifications elaborated by legal and religious scholars. During this period, Portugal dominated the slave trade, raiding its colonies in Southern Africa to supply its plantations (many run by Jesuits) in South America. In this sense, the story of the South Atlantic is a story of encounters and exchanges between Africa and the Americas.


1989 ◽  
Vol 26 (3) ◽  
pp. 479-489 ◽  
Author(s):  
Brian F. Windley

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.


PMLA ◽  
1976 ◽  
Vol 91 (4) ◽  
pp. 535-536
Author(s):  
Edward W. Bratton

The 1976 convention of the South Atlantic Modern Language Association will be held at the new Peachtree Center Plaza Hotel in Atlanta, Georgia, on Thursday, Friday, and Saturday, 4-6 November. Chairmen of several of the eighty special interest and affiliated meetings comprising the convention have designated Bicentennial themes for their programs in keeping with the nation's celebration of her 200th birthday. Convention preregistration and special housing rates on rooms blocked for SAMLA use are restricted to members of the Association, but persons interested in joining SAMLA and receiving full convention information can do so by forwarding annual dues of $7.00 (graduate students, $2.00; joint husband-wife, $9.00) by no later than 1 October to: SAMLA, Box 8410, U. T. Station, Knoxville, Tennessee 37916.


2008 ◽  
Vol 26 (11) ◽  
pp. 3457-3476 ◽  
Author(s):  
A. S. Taschetto ◽  
I. Wainer

Abstract. The Community Climate Model (CCM3) from the National Center for Atmospheric Research (NCAR) is used to investigate the effect of the South Atlantic sea surface temperature (SST) anomalies on interannual to decadal variability of South American precipitation. Two ensembles composed of multidecadal simulations forced with monthly SST data from the Hadley Centre for the period 1949 to 2001 are analysed. A statistical treatment based on signal-to-noise ratio and Empirical Orthogonal Functions (EOF) is applied to the ensembles in order to reduce the internal variability among the integrations. The ensemble treatment shows a spatial and temporal dependence of reproducibility. High degree of reproducibility is found in the tropics while the extratropics is apparently less reproducible. Austral autumn (MAM) and spring (SON) precipitation appears to be more reproducible over the South America-South Atlantic region than the summer (DJF) and winter (JJA) rainfall. While the Inter-tropical Convergence Zone (ITCZ) region is dominated by external variance, the South Atlantic Convergence Zone (SACZ) over South America is predominantly determined by internal variance, which makes it a difficult phenomenon to predict. Alternatively, the SACZ over western South Atlantic appears to be more sensitive to the subtropical SST anomalies than over the continent. An attempt is made to separate the atmospheric response forced by the South Atlantic SST anomalies from that associated with the El Niño – Southern Oscillation (ENSO). Results show that both the South Atlantic and Pacific SSTs modulate the intensity and position of the SACZ during DJF. Particularly, the subtropical South Atlantic SSTs are more important than ENSO in determining the position of the SACZ over the southeast Brazilian coast during DJF. On the other hand, the ENSO signal seems to influence the intensity of the SACZ not only in DJF but especially its oceanic branch during MAM. Both local and remote influences, however, are confounded by the large internal variance in the region. During MAM and JJA, the South Atlantic SST anomalies affect the magnitude and the meridional displacement of the ITCZ. In JJA, the ENSO has relatively little influence on the interannual variability of the simulated rainfall. During SON, however, the ENSO seems to counteract the effect of the subtropical South Atlantic SST variations on convection over South America.


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