Geodynamic reconstructions of the South America-Antarctica plate system

Details

Serval ID
serval:BIB_18006840F814
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Geodynamic reconstructions of the South America-Antarctica plate system
Journal
Journal of Geodynamics
Author(s)
Vérard C., Flores K.E., Stampfli G.M.
ISSN-L
0264-3707
Publication state
Published
Issued date
2012
Peer-reviewed
Oui
Volume
53
Pages
43-60
Language
english
Abstract
The South America-Antarctica plate system shows many oceanic
accretionary systems and subduction zones that initiated and then
stopped. To better apprehend the evolution of the system, geodynamic
reconstructions (global) have been created from Jurassic (165 Ma) to
present, following the techniques used at the University of Lausanne.
However, additional synthetic magnetic anomalies were used to refine the
geodynamics between 33 Ma and present.
The reconstructions show the break up of Gondwana with oceanisation
between South America (SAM) and Antarctica (ANT), together with the
break off of `Andean' geodynamical units (GDUs). We propose that
oceanisation occurs also east and south of the Scotian GDUs. Andean GDUs
collide with other GDUs crossing the Pacific. The west coast of SAM and
ANT undergo a subsequent collision with all those GDUs between 103 Ma
and 84 Ma, and the Antarctic Peninsula also collides with Tierra del
Fuego. The SAM-ANT plate boundary experienced a series of extension and
shortening with large strike-slip component, culminating with
intra-oceanic subduction leading to the presence of the `V-' and
anomalies in the Weddell Sea. From 84 Ma, a transpressive collision
takes place in the Scotia region, with active margin to the east. As
subduction propagates northwards into an old and dense oceanic crust,
slab roll-back initiates, giving rise to the western Scotia Sea and the
Powell Basin opening. The Drake Passage opens. As the Scotian GDUs
migrate eastwards, there is enough space for them to spread and allow a
north-south divergence with a spreading axis acting simultaneously with
the western Scotia ridge. Discovery Bank stops the migration of South
Orkney and `collides with' the SAM-ANT spreading axis, while the
northern Scotian GDUs are blocked against the Falkland Plateau and the
North-East Georgia Rise. The western and central Scotia and the Powell
Basin spreading axes must cease, and the ridge jumps to create the South
Sandwich Islands Sea. The Tierra del Fuego-Patagonia region has always
experienced mid-oceanic ridge subduction since 84 Ma. Slab window
location is also presented (57-0 Ma), because of its important
implication for heat flux and magmatism. (C) 2011 Elsevier Ltd. All
rights reserved.
Create date
20/10/2012 18:10
Last modification date
20/08/2019 12:48
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