scholarly journals Evolution of the Crustal and upper Mantle seismic structure from 0 – 27 Ma in the equatorial Atlantic Ocean at 2º 43´S

2021 ◽  
Author(s):  
Venkata A. Vaddineni ◽  
Satish C. Singh ◽  
Ingo Grevemeyer ◽  
Pranav Audhkhasi ◽  
Cord Papenberg
Keyword(s):  
Atlantic Ocean ◽  
Upper Mantle ◽  
Seismic Structure ◽  
Equatorial Atlantic ◽  
Equatorial Atlantic Ocean

scholarly journals Seismic structure of the St. Paul Fracture Zone and Late Cretaceous to Mid Eocene oceanic crust in the equatorial Atlantic Ocean near 18°W

2021 ◽  
Author(s):  
Kevin Growe ◽  
Ingo Grevemeyer ◽  
Satish Chandra Singh ◽  
Milena Marjanovic ◽  
Emma PM Gregory ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Oceanic Crust ◽  
Late Cretaceous ◽  
Fracture Zone ◽  
Seismic Structure ◽  
Equatorial Atlantic ◽  
Equatorial Atlantic Ocean

scholarly journals Seismic structure of the St. Paul Fracture Zone and Late Cretaceous to Mid Eocene oceanic crust in the equatorial Atlantic Ocean near 18°W

2021 ◽  
Author(s):  
Kevin Growe ◽  
Ingo Grevemeyer ◽  
Satish Chandra Singh ◽  
Milena Marjanovic ◽  
Emma PM Gregory ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Oceanic Crust ◽  
Late Cretaceous ◽  
Fracture Zone ◽  
Seismic Structure ◽  
Equatorial Atlantic ◽  
Equatorial Atlantic Ocean

scholarly journals Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean

2008 ◽  
Vol 26 (1) ◽  
pp. 69-86 ◽  
Author(s):  
Susanna Eleonora Sichel ◽  
Sonia Esperança ◽  
Akihisa Motoki ◽  
Marcia Maia ◽  
Mary F. Horan ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Upper Mantle ◽  
Equatorial Atlantic ◽  
Geochemical Evidence ◽  
Equatorial Atlantic Ocean

scholarly journals Uppermost Mantle Velocity beneath the Mid-Atlantic Ridge and Transform Faults in the Equatorial Atlantic Ocean

2020 ◽  
Author(s):  
Guilherme W. S. de Melo ◽  
Ross Parnell-Turner ◽  
Robert P. Dziak ◽  
Deborah K. Smith ◽  
Marcia Maia ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Upper Mantle ◽  
Equatorial Atlantic ◽  
Uppermost Mantle ◽  
Transform Faults ◽  
Equatorial Atlantic Ocean ◽  
Mid Atlantic Ridge ◽  
Mantle Velocity ◽  
Ray Paths

ABSTRACT Seismic rays traveling just below the Moho provide insights into the thermal and compositional properties of the upper mantle and can be detected as Pn phases from regional earthquakes. Such phases are routinely identified in the continents, but in the oceans, detection of Pn phases is limited by a lack of long-term instrument deployments. We present estimates of upper-mantle velocity in the equatorial Atlantic Ocean from Pn arrivals beneath, and flanking, the Mid-Atlantic Ridge and across several transform faults. We analyzed waveforms from 50 earthquakes with magnitude Mw>3.5, recorded over 12 months in 2012–2013 by five autonomous hydrophones and a broadband seismograph located on the St. Peter and St. Paul archipelago. The resulting catalog of 152 ray paths allows us to resolve spatial variations in upper-mantle velocities, which are consistent with estimates from nearby wide-angle seismic experiments. We find relatively high velocities near the St. Paul transform system (∼8.4  km s−1), compared with lower ridge-parallel velocities (∼7.7  km s−1). Hence, this method is able to resolve ridge-transform scale velocity variations. Ray paths in the lithosphere younger than 10 Ma have mean velocities of 7.9±0.5  km s−1, which is slightly lower than those sampled in the lithosphere older than 20 Ma (8.1  km±0.3  s−1). There is no apparent systematic relationship between velocity and ray azimuth, which could be due to a thickened lithosphere or complex mantle upwelling, although uncertainties in our velocity estimates may obscure such patterns. We also do not find any correlation between Pn velocity and shear-wave speeds from the global SL2013sv model at depths <150  km. Our results demonstrate that data from long-term deployments of autonomous hydrophones can be used to obtain rare and insightful estimates of uppermost mantle velocities over hundreds of kilometers in otherwise inaccessible parts of the deep oceans.

scholarly journals Seismic structure of the St. Paul Fracture Zone and Late Cretaceous to Mid Eocene oceanic crust in the equatorial Atlantic Ocean near 18°W

2021 ◽  
Author(s):  
Kevin Growe ◽  
Ingo Grevemeyer ◽  
Satish Chandra Singh ◽  
Milena Marjanovic ◽  
Emma PM Gregory ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Oceanic Crust ◽  
Late Cretaceous ◽  
Fracture Zone ◽  
Seismic Structure ◽  
Equatorial Atlantic ◽  
Equatorial Atlantic Ocean

Pesticides in the lower atmosphere of the northern equatorial Atlantic Ocean

1972 ◽  
Vol 6 (4) ◽  
pp. 283-284
Author(s):  
C.P Lloyd-Jones ◽  
D.P Seba ◽  
J.M Prospero
Keyword(s):  
Atlantic Ocean ◽  
Lower Atmosphere ◽  
Equatorial Atlantic ◽  
Equatorial Atlantic Ocean
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