Review of Clastic Rift Plays along the Rift Borders of the Central South Atlantic Margins

2015 ◽  
pp. 836-855
Author(s):  
Ian Davison
Keyword(s):  
South Atlantic ◽  
Central South

Fireworms (Amphinomidae: Annelida) from Ascension and Saint Helena Island, Central South Atlantic Ocean

2015 ◽  
Vol 8 ◽  
Author(s):  
Beatriz Yáñez-Rivera ◽  
Judith Brown
Keyword(s):  
Atlantic Ocean ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
Genetic Connectivity ◽  
The West ◽  
Hermodice Carunculata ◽  
The Family ◽  
Volcanic Islands ◽  
Central South

Ascension and Saint Helena Islands are isolated volcanic islands in the South Atlantic Ocean. Records of annelids from the family Amphinomidae, commonly known as fireworms, are rare. Fireworm species recorded in both localities includeEurythoe complanataandHermodice carunculata,which are broadly distributed throughout the Atlantic Ocean. Here we present the characterization of both species from a recent expedition to Ascension and Saint Helena. Morphologically, specimens fromH. carunculatacorrespond to the West Atlantic population, whileE. complanataspecimens were clearly identified based on chaetal type. A genetic analysis, including material from Ascension and Saint Helena Islands, will be necessary to elucidate the genetic connectivity across the Atlantic Ocean.

scholarly journals The Sinking of Another Tristan da Cunha Moss Endemic and Its Phytogeographical Consequences

2020 ◽  
Vol 89 (3) ◽  
Author(s):  
Ryszard Ochyra ◽  
Vítězslav Plášek
Keyword(s):  
Atlantic Ocean ◽  
Southern Hemisphere ◽  
Endemic Species ◽  
Distribution Patterns ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
Original Material ◽  
The Third ◽  
Tristan Da Cunha ◽  
Central South

<p>The original material of <em>Isopterygium tristaniense </em>Dixon, an endemic species of the Tristan da Cunha archipelago in the central South Atlantic Ocean, is taxonomically evaluated and some details of its morphology are illustrated. The species is found to be conspecific with the Holarctic <em>Pseudotaxiphyllum elegans </em>(Brid.) Z.Iwats. and it is the third record of the species in the Southern Hemisphere. The global distribution of this species is reviewed and the distribution patterns of the South Atlantic mosses are briefly discussed.</p>

scholarly journals South Atlantic island record reveals a South Atlantic response to the 8.2 kyr event

2007 ◽  
Vol 3 (3) ◽  
pp. 729-753 ◽  
Author(s):  
K. Ljung ◽  
S. Björck ◽  
H. Renssen ◽  
D. Hammarlund
Keyword(s):  
North Atlantic ◽  
Energy Transport ◽  
Climate Model ◽  
South Atlantic ◽  
Laurentide Ice Sheet ◽  
Climate Fluctuations ◽  
The North ◽  
Central South ◽  
Atlantic Island ◽  
8.2 Kyr Event

Abstract. One of the most distinct climate fluctuations during the Holocene is the short and rapid event centred around 8200 years ago, the 8.2 kyr event, which was most likely triggered by glacial melt-water forcing from the receding Laurentide ice-sheet. Evidence for this cooling has primarily been reported from sites around the North Atlantic, but an increasing number of observations imply a more wide-spread occurrence. Palaeoclimate archives from the Southern Hemisphere have hitherto failed to uncover a distinct climatic anomaly associated with the 8.2 kyr event. Here we present a lake sediment record from Nightingale Island in the central South Atlantic showing enhanced precipitation between 8275 and 8025 cal. yrs BP, most likely as a consequence of increased sea surface temperature (SST). We show that this is consistent with climate model projections of a warming of the South Atlantic in response to reduced north-ward energy transport during the 8.2 kyr event.

The summer foraging ranges of adult spectacled petrels Procellaria conspicillata

2013 ◽  
Vol 26 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Tim A. Reid ◽  
Robert A. Ronconi ◽  
Richard J. Cuthbert ◽  
Peter G. Ryan
Keyword(s):  
South America ◽  
South Atlantic ◽  
Breeding Birds ◽  
Shelf Break ◽  
Fishing Activity ◽  
Breeding Grounds ◽  
Satellite Transmitters ◽  
Longline Fisheries ◽  
Central South ◽  
Foraging Ranges

AbstractSatellite transmitters were attached to eight adult spectacled petrels Procellaria conspicillata Gould captured during the early incubation period at their breeding grounds on Inaccessible Island, one of the Tristan da Cunha Islands in the central South Atlantic Ocean. Data on their at-sea distribution was obtained for up to six months. All birds remained within the South Atlantic from 24–44°S, with most between 25 and 40°S. Breeding birds mainly foraged in oceanic waters, but failed breeders or non-breeders concentrated their foraging activity over the Rio Grande Rise and the Walvis Ridge and along the shelf break off the east coast of South America. Little foraging occurred along the Benguela shelf break off southern Africa. Non-breeders favoured relatively warm water with low chlorophyll concentrations, reducing the risk of bycatch in fisheries. Tracked birds spent 16% of their time in areas with high levels of tuna longline fishing activity, with overlap greater for non-breeding birds (22%) than breeding birds (3%). Birds in this study foraged in shallower waters along the continental shelf edge off South America than spectacled petrels tracked in this area in winter, potentially increasing their risk of exposure to demersal longline fisheries in this area in summer.

scholarly journals St. Helena: An Important Reproductive Habitat for Whale Sharks (Rhincodon typus) in the Central South Atlantic

2020 ◽  
Vol 7 ◽  
Author(s):  
Cameron T. Perry ◽  
Elizabeth Clingham ◽  
D. Harry Webb ◽  
Rafael de la Parra ◽  
Simon J. Pierce ◽  
...  
Keyword(s):  
South Atlantic ◽  
Rhincodon Typus ◽  
Whale Sharks ◽  
St Helena ◽  
Central South

Synrift subsidence and magmatism of the Central South Atlantic passive margins based on long term 2-D thermo-mechanical modelling

2020 ◽  
Author(s):  
Thomas Theunissen ◽  
Ritske Huismans ◽  
Frank Despinois ◽  
Jean-Claude Ringenbach ◽  
François Sapin
Keyword(s):  
Sedimentary Basin ◽  
Thickness Distribution ◽  
Water Environment ◽  
South Atlantic ◽  
Passive Margin ◽  
Basin Evolution ◽  
Margin Width ◽  
Structural Style ◽  
Mechanical Modelling ◽  
Central South

&lt;p&gt;Here we use observations from the central South Atlantic conjugate margins to constrain the structural style of rifting and its relation with sedimentary basin evolution during the syn and early post-rift. Three synthetics transects from North (Gabon-Brazil) to South (Angola-Brazil) are used to constrain fault distribution, margin width, crustal thickness, distribution of magmatism, syn-rift sedimentary section thickness and paleo-environment from the start of rifting in the Berriasian (145 Ma) until the early post rift in the Aptian (113 Ma). This integrated study aims to understand variations in along strike structural style, magmatic output, and sedimentary basin evolution to assess the contribution of mantle processes on topography using forward 2-D thermo-mechanical modelling. We design a model setup that reproduces South Atlantic central segment main characteristics before rifting. We then explore scenarios of lithospheric thinning where strain weakening mechanisms, degree of depletion of lithopsheric mantle and crustal rheology are the main variables. The model accounts for decompression melting with feedbacks on temperature, viscosity and density of the mantle. The subsidence in the thermo-mechanical models is calibrated with a reference ridge elevation, where a 6 km thick oceanic crust is predicted, and explained by the different contributions on buoyancy of rifted passive margin during rifting. We discuss conditions to get magma-poor margins with/without exhumed mantle at the seafloor and conditions to reach a small topographic gradient and shallow water environment between the proximal and distal domains over more than 200 km of the wide margin during most of the syn-rift.&lt;/p&gt;

The origin of finches on Tristan da Cunha and Gough Island, central South Atlantic ocean

2013 ◽  
Vol 69 (1) ◽  
pp. 299-305 ◽  
Author(s):  
Peter G. Ryan ◽  
Luke B. Klicka ◽  
Keith F. Barker ◽  
Kevin J. Burns
Keyword(s):  
Atlantic Ocean ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
Tristan Da Cunha ◽  
Gough Island ◽  
Central South
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