Carbonaceous sediments in the North and South Atlantic: The role of salinity in stable stratification of early Cretaceous basins

1979 ◽  
pp. 375-401 ◽  
Author(s):  
Michael A. Arthur ◽  
James H. Natland
Keyword(s):  
Early Cretaceous ◽  
Stable Stratification ◽  
South Atlantic ◽  
The North ◽  
North And South

Observed seasonal regimes of North-South Atlantic Ocean interbasin exchange

2019 ◽  
Author(s):  
Hamed D. Ibrahim
Keyword(s):  
North Atlantic ◽  
Climate Models ◽  
South Atlantic ◽  
Meridional Overturning Circulation ◽  
Volume Flux ◽  
The South ◽  
The North ◽  
Basin Scale ◽  
Interbasin Exchange ◽  
North And South

North and South Atlantic lateral volume exchange is a key component of the Atlantic Meridional Overturning Circulation (AMOC) embedded in Earth’s climate. Northward AMOC heat transport within this exchange mitigates the large heat loss to the atmosphere in the northern North Atlantic. Because of inadequate climate data, observational basin-scale studies of net interbasin exchange between the North and South Atlantic have been limited. Here ten independent climate datasets, five satellite-derived and five analyses, are synthesized to show that North and South Atlantic climatological net lateral volume exchange is partitioned into two seasonal regimes. From late-May to late-November, net lateral volume flux is from the North to the South Atlantic; whereas from late-November to late-May, net lateral volume flux is from the South to the North Atlantic. This climatological characterization offers a framework for assessing seasonal variations in these basins and provides a constraint for climate models that simulate AMOC dynamics.

The Role of Oceanic Heat Advection in the Evolution of Tropical North and South Atlantic SST Anomalies*

2006 ◽  
Vol 19 (23) ◽  
pp. 6122-6138 ◽  
Author(s):  
Gregory R. Foltz ◽  
Michael J. McPhaden
Keyword(s):  
Surface Flux ◽  
South Atlantic ◽  
Shortwave Radiation ◽  
Heat Advection ◽  
Horizontal Advection ◽  
Latent Heat Loss ◽  
North And South ◽  
Sst Gradient ◽  
Sst Anomalies

Abstract The role of horizontal oceanic heat advection in the generation of tropical North and South Atlantic sea surface temperature (SST) anomalies is investigated through an analysis of the oceanic mixed layer heat balance. It is found that SST anomalies poleward of 10° are driven primarily by a combination of wind-induced latent heat loss and shortwave radiation. Away from the eastern boundary, horizontal advection damps surface flux–forced SST anomalies due to a combination of mean meridional Ekman currents acting on anomalous meridional SST gradients, and anomalous meridional currents acting on the mean meridional SST gradient. Horizontal advection is likely to have the most significant effect on the interhemispheric SST gradient mode through its impact in the 10°–20° latitude bands of each hemisphere, where the variability in advection is strongest and its negative correlation with the surface heat flux is highest. In addition to the damping effect of horizontal advection in these latitude bands, evidence for coupled wind–SST feedbacks is found, with anomalous equatorward (poleward) SST gradients contributing to enhanced (reduced) westward surface winds and an equatorward propagation of SST anomalies.

scholarly journals Anthropocene and “Development”: Intertwined Trajectories Since the Beginning of The Great Acceleration

2020 ◽  
Vol 24 (5) ◽  
pp. 400-413
Author(s):  
Marina Dantas de Figueiredo ◽  
Fábio Freitas Schilling Marquesan ◽  
José Miguel Imas
Keyword(s):  
Developmental Model ◽  
Environmental Crisis ◽  
Environmental Consequences ◽  
The North ◽  
Development Policies ◽  
Global North ◽  
Definition Of ◽  
Great Acceleration ◽  
North And South

ABSTRACT Objectives: We aim to propose the thesis that the trajectories of the Anthropocene and the current mainstream understandings of development are intertwined from the beginning. It means that the Anthropocene and the “development” are coetaneous: the implementation of development policies for the so-considered underdeveloped regions started to happen at the same time of what is known as The Great Acceleration of production, consumption and environmental degradation in a global level. Method: In this conceptual paper, we adopt a decolonial critique as an analytical lens and argue that different geopolitical positions may be necessary for approaching the issue of the Anthropocene from epistemological reflections that can include the cultural and political context of the production and reproduction of local knowledge. Results: Our theoretical argumentation sheds light on the role of Global North and South relations in shaping the environmental crisis. Latin America (LA) exemplifies the modus operandi of the intertwinement of the practical effects of development policies and the environmental consequences underlying the Anthropocene, in which natural resources are over-explored to satisfy export-oriented trade, from the South toward the North. LA is not only a propitious context to show the validity of our thesis, but also the source of alternatives to such developmental model. Conclusion: The emphasis on development as a cause of the Anthropocene supports The Great Acceleration thesis. The proposition of the name Developmentocene comes from the thesis that development and Anthropocene are coetaneous, the intertwinement of both resulting in the very definition of the new epoch.

Control of Precambrian-to-Paleozoic orogenic trends on along-strike variations in Early Cretaceous continental rifts of the South Atlantic Ocean

2019 ◽  
Vol 7 (4) ◽  
pp. SH45-SH69 ◽  
Author(s):  
Kyle Reuber ◽  
Paul Mann
Keyword(s):  
Early Cretaceous ◽  
South Atlantic ◽  
Orogenic Belt ◽  
Deep Penetration ◽  
The South ◽  
The North ◽  
Continental Rifts ◽  
Rift Zones ◽  
Seismic Reflection Profiles ◽  
Orogenic Belts

The Early Cretaceous (135–130 Ma) continental rupture of Western Gondwana to form the South American and African plates closely paralleled the elongate trends of Precambrian and Paleozoic orogenic belts. These orogenic belts were produced as a result of the Neoproterozoic convergent and strike-slip assembly of Gondwana that redeformed during later, Paleozoic orogenic events. Continued continental rifting led to the formation of conjugate, South Atlantic volcanic passive margins whose widths vary from 55 to 180 km. Along-strike variations in crustal stretching, as measured from deep-penetration seismic reflection profiles, correlate with parallel and oblique orientations of rifts relative to the trend of the orogenic, basement fabric. Where orogenic fabric trends parallel to the north–south South Atlantic rift direction such as in the Dom Feliciano orogenic belt of Uruguay and Brazil and the Kaoko Uruguay/Brazil and Kaoko orogenic belt of Namibia, we observe narrow (55–90 km) rift zones with modest continental beta factors of 2.5–3.5 because smaller amounts of rifting were needed to stretch the weaker and parallel, orogenic, basement fabric. Where the basement fabric trends near-orthogonally to the north–south South Atlantic rift direction such as in the Salado suture of Southern Uruguay and the Damara Belt of Namibia, we observe wider (185–220 km) rift zones with higher beta factors of 4.3–5 because greater amounts of stretching were needed to rupture the orthogonal, orogenic, basement fabric. The rift-oblique Gariep Belt intersects the South Atlantic continental rupture at an intermediate angle (30°) and exhibits a predicted intermediate beta factor of 4.0. A compilation of published beta factors from 36 other rifted margins worldwide supports the same basement-trend-degree of stretching relationship that we have developed — with rift-parallel margins having lower beta factors in a range of 1.3–3.5 and rift-orthogonal or oblique margins having higher beta factors in a range of 4–8.

scholarly journals Monitoring the Influence of the Mesoscale Ocean Dynamics on Phytoplanktonic Plumes around the Marquesas Islands Using Multi-Satellite Missions

2020 ◽  
Vol 12 (16) ◽  
pp. 2520 ◽  
Author(s):  
Angelina Cassianides ◽  
Elodie Martinez ◽  
Christophe Maes ◽  
Xavier Carton ◽  
Thomas Gorgues
Keyword(s):  
Finite Size ◽  
Ocean Dynamics ◽  
Dynamic Activity ◽  
Marquesas Islands ◽  
The North ◽  
Run Off ◽  
Dynamical Regimes ◽  
North And South

The Marquesas islands are a place of strong phytoplanktonic enhancement, whose original mechanisms have not been explained yet. Several mechanisms such as current−bathymetry interactions or island run-off can fertilize waters in the immediate vicinity or downstream of the islands, allowing phytoplankton enhancement. Here, we took the opportunity of an oceanographic cruise carried out at the end of 2018, to combine in situ and satellite observations to investigate two phytoplanktonic blooms occurring north and south of the archipelago. First, Lagrangian diagnostics show that both chlorophyll-a concentrations (Chl) plumes are advected from the islands. Second, the use of Finite-size Lyaponov Exponent and frontogenesis diagnostics reveal how the Chl plumes are shaped by the passage of a mesoscale cyclonic eddy in the south and by a converging front and finer-scale dynamic activity in the north. Our results based on these observations provide clues to the hypothesis of a fertilization from the islands themselves allowing phytoplankton to thrive. They also highlight the role of advection to disperse and shape the Chl plumes in two regions with contrasting dynamical regimes.

scholarly journals Migration of exotic species of ammonites during highstands of sea level

1992 ◽  
Vol 6 ◽  
pp. 324-324
Author(s):  
Keith Young
Keyword(s):  
North America ◽  
South America ◽  
Exotic Species ◽  
Sea Level ◽  
South Atlantic ◽  
Horn Of Africa ◽  
Mozambique Channel ◽  
The North ◽  
North And South ◽  
Early Late

In northeastern Chihuahua and Trans-Pecos Texas, in the early Late Albian zone of Hysteroceras varicosum occurs the Boeseites romeri (Haas) fauna with B. romeri (Hass), B. perarmata (Hass), B. aff. barbouri (Haas), B. cf. howelli (Haas), B.proteus (Haas), Prohysteroceras cf. P. hanhaense Haas, Elobiceras sp., and Dipoloceras (?) sp. B. perarmata has also been collected at Cerro Mercado, near Monclova, Coahuila. Haas originally described this fauna from Angola. Now, from rocks in the same zone in the Sierra Mojada, Coahuila, Mexico, there is a form related to if not identical with Hysteroceras famelicum Van Hoepen, also originally described from Angola and also from the zone of Hysteroceras varicosum.These fossils are known only from southern North America and Angola; they have not been described from the European Tethys. In 1984 I suggested that during the highstand of sea level of the early Late Albian (Hysteroceras varicosum zone) these ammonites migrated from Angola to Mexico and Trans-Pecos Texas via an epeiric seaway extending across the sag between South America and Africa proposed by Kennedy and Cooper. This would be twelve to fifteen million years prior to an oceanic connection between the North and South Atlantic.I would now ask, can similar epeiric seas and highstands of sea level explain the migration of successive European, Tethyan, Jurassic ammonite faunas down the Mozambique Channel and around the horn of Africa into the Neuquen Basin of Argentina before Africa and Antarctica separated, as proposed by Spath.

Similarity in microbial amino acid uptake in surface waters of the North and South Atlantic (sub-)tropical gyres

2011 ◽  
Vol 91 (4) ◽  
pp. 437-446 ◽  
Author(s):  
Polly G. Hill ◽  
Isabelle Mary ◽  
Duncan A. Purdie ◽  
Mikhail V. Zubkov
Keyword(s):  
Amino Acid ◽  
Surface Waters ◽  
Amino Acid Uptake ◽  
South Atlantic ◽  
Acid Uptake ◽  
The North ◽  
North And South

scholarly journals Urban Regeneration Projects Bound to Water, along and towards the Tagus Estuary (Portugal)

2019 ◽  
Vol 11 (23) ◽  
pp. 6578
Author(s):  
Caterina Anastasia
Keyword(s):  
Public Space ◽  
Urban Regeneration ◽  
Tagus Estuary ◽  
Open Spaces ◽  
The North ◽  
Surrounding Areas ◽  
The City ◽  
North And South ◽  
Hydrographic Network

Water is becoming a support for landscape and urban projects in a densely urbanised area settled along the Tagus Estuary, dubbed the City of the Tagus Estuary (CTE). Analysing two recent projects along and towards the Tagus Estuary hydrographic network, this article highlights how the most evident limit (the water) can function as the strongest binder, natural link, and shared public space of the CTE. Located, respectively, on the north and south banks of the estuary, the analysed projects become a way to think about urban strategies and promotions that use water as a way to build (re-build or reformulate) the image of the Lisbon Metropolitan Area. Today, open spaces bound to waterlines support an appealing and winning urban regeneration formula. Our goal is to understand what kind of role water is called to play with regard to the CTE. We ask: is the water called to play merely the role of building a new image of the city as a ground for investors? Is water the way to build a green and habitable CTE? This article concludes that the analysed projects contribute (as expected) to the promotion of the surrounding areas and propose appropriate solutions while occasionally overcoming the current local urban planning.

Link between the North and South Atlantic during the Heinrich events of the last glacial period

1999 ◽  
Vol 15 (12) ◽  
pp. 909-919 ◽  
Author(s):  
L. Vidal ◽  
R.R. Schneider ◽  
O. Marchal ◽  
T. Bickert ◽  
T.F. Stocker ◽  
...  
Keyword(s):  
South Atlantic ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Last Glacial ◽  
Heinrich Events ◽  
The North ◽  
North And South ◽  
The Last Glacial
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