Journal ArticleDOI
Interaction between the Mid-Atlantic Ridge and the Azores hot spot during the last 85 Myr: Emplacement and rifting of the hot spot-derived plateaus
TLDR
In this paper, multiple and single-beam bathymetric data are compiled over the Azores plateau to produce a 1 km × 1 km grid between latitudes 32°N and 49°N, and longitudes 22°W and 43°W.Abstract:
[1] Multiple- and single-beam bathymetric data are compiled over the Azores plateau to produce a 1 km × 1 km grid between latitudes 32°N and 49°N and longitudes 22°W and 43°W. Mantle Bouguer anomalies are then calculated from this grid and the satellite-derived gravity. These grids provide new insights on the temporal and spatial variations of melt supply to the ridge axis. The elevated seafloor of the Azores plateau is interpreted as resulting from the interaction of a mantle plume with the Mid-Atlantic Ridge (MAR). The presence of a large region of elevated seafloor associated with a thick crust between the Great Meteor Seamounts and the Azores platform on the Africa plate, and less developed conjugate structures on the North America plate, favors genetic relations between these hot spot-derived structures. This suggests that a ridge-hot spot interaction has occurred in this region since 85 Ma. This interaction migrated northward along the ridge axis as a result of the SSE absolute motion of the Africa plate, following a direction grossly parallel to the orientation of the MAR. Kinematic reconstructions from chron 13 (∼35 Ma) to the present allow a proposal that the formation of the Azores plateau began around 20 Ma and ended around 7 Ma. A sharp bathymetric step is associated with the beginning of important melt supply around 20 Ma. The excess of melt production is controlled by the interaction of the ridge and hot spot melting zones. The geometry and distribution of the smaller-scale features on the plateau record episodic variations of the hot spot melt production. The periodicity of these variations is about 3–5 Myr. Following the rapid decrease of widespread volcanism, the plateau was subsequently rifted from north to south by the Mid-Atlantic Ridge since 7 Ma. This rifting begins when the MAR melting zone is progressively shifted away from the 200-km plume thermal anomaly. These results bear important consequences on the motion of the Africa plate relative to the Azores hot spot. They also provide an explanation to the asymmetric geochemical signature of the Azores hot spot along the Mid-Atlantic Ridge.read more
Citations
More filters
Journal ArticleDOI
Petrogenesis of the Peralkaline Ignimbrites of Terceira, Azores
TL;DR: In this paper, a model for the magmatic plumbing system from which the ignimbrite-forming trachytes of Terceira were produced by evaluating various petrogenetic processes and constraining pre-eruptive magma storage conditions was developed.
Journal ArticleDOI
Chapter 2 The structure of the Azores Triple Junction: implications for São Miguel Island
TL;DR: In this paper, it is shown that only two main rift systems can be found on the plateau, the older one matching the Princess Alice Basin, and the newer one matching Terceira Rift; the shift between the two probably occurs close to c. 3 Ma.
Journal ArticleDOI
Northward drift of the Azores plume in the Earth's mantle.
TL;DR: Using for the first time a 3D-spherical mantle convection where plumes, ridges and plates interact in a fully dynamic way, plume-derived basalts from the Mid-Atlantic ridge are used to confirm that the upper-mantle thermal anomaly associated with the Azores plume is asymmetric, spreading over ~2,000 km southwards and ~600km northwards.
Journal ArticleDOI
Building of the Amsterdam‐Saint Paul plateau: A 10 Myr history of a ridge‐hot spot interaction and variations in the strength of the hot spot source
Marcia Maia,Marcia Maia,Ivo Pessanha,Ivo Pessanha,Ivo Pessanha,Esther Courrèges,Esther Courrèges,Martin Patriat,Pascal Gente,Pascal Gente,Christophe Hémond,Christophe Hémond,Myriam Janin,Myriam Janin,Myriam Janin,Kevin T. M. Johnson,Walter R. Roest,Jean-Yves Royer,Jean-Yves Royer,J. Vatteville +19 more
TL;DR: In this paper, a joint analysis of gravity-derived crust thickness and bathymetry reveals that the Amsterdam-Saint Paul plateau started to form at ~10 Ma by an increase of the crustal production at the ridge axis, due to the nearby hot spot.
Journal ArticleDOI
Relationships between tectonics and magmatism in a transtensive/transform setting: An example from Faial Island (Azores, Portugal)
Daniele Trippanera,Massimiliano Porreca,Joel Ruch,Adriano Pimentel,Valerio Acocella,Joana Pacheco,Maria Cristina Salvatore +6 more
TL;DR: In this article, the relationship between tectonics and hotspot-related magmatism in transform/transtensive settings is investigated in the Azores archipelago.
References
More filters
Journal ArticleDOI
Free software helps map and display data
Paul Wessel,Walter H. F. Smith +1 more
TL;DR: The Generic Mapping Tools (GMT) is introduced, which is a free, public domain software package that can be used to manipulate columns of tabular data, time series, and gridded data sets and to display these data in a variety of forms ranging from simple x-y plots to maps and color, perspective, and shaded-relief illustrations.
Journal ArticleDOI
Revised calibration of the geomagnetic polarity timescale for the Late Cretaceous and Cenozoic
Steven C. Cande,Dennis V. Kent +1 more
TL;DR: An adjusted geomagnetic reversal chronology for the Late Cretaceous and Cenozoic is presented that is consistent with astrochronology in the Pleistocene and Pliocene and with a new timescale for the Mesozoic.
Journal ArticleDOI
Current plate motions
TL;DR: A global plate motion model, named NUVEL-1, which describes current plate motions between 12 rigid plates is described, with special attention given to the method, data, and assumptions used as discussed by the authors.
Current plate motions
TL;DR: In this paper, a new global model (NUVEL-1) was proposed to describe the geologically current motion between 12 assumed-rigid plates by inverting plate motion data.
Journal ArticleDOI
An analysis of the variation of ocean floor bathymetry and heat flow with age
Barry Parsons,John G. Sclater +1 more
TL;DR: In this paper, a simple cooling model and the plate model were proposed to account for the variation in depth and heat flow with increasing age of the ocean floor. But the results were limited to the North Pacific and North Atlantic basins.
Related Papers (5)
The Terceira Rift as hyper-slow, hotspot-dominated oblique spreading axis: A comparison with other slow-spreading plate boundaries
Peter R. Vogt,W.Y Jung +1 more