Geologic and geophysical study of the Scotia Arc: The Southern ridge of the Scotia area

In English:

The objectives of this campaign were:

-Transition among different plates and sub-plates; Shetland, Drake, Scotia
and Antarctic and their joint points.

-Study of the link between the Bransfield spreading centre of and the South
Shetlands subduction zone.

-Detailed morphostructural analysis of a shear plate boundary and
one of the biggest intracrest depressions (Hesp?rides Deep), by
means of the multibeam probe.

-Establishment of geomagnetic guidelines in the Bransfield
spreading zone in the shear's plate boundaries.

-Study of the formation of regional infilling and discontinuities
in the basins adjacent to the ridge.

-Application of the studied models in the international working
plans on oceanic ridges (Interidge project).

Data obtained:

-More than 1500 km of multichannel seismics
-3500 km of multibeam probes
-3500 km of hydrographic sounding
-3500 km of geomagnetic data

It was recognised with 100% insoundification an intracrest depression of the
South Scotia Ridge, it was called Hesperides Deep in honours of the RV
Hesperides in its first Antarctic campaign.

-Study of the Bransfield Strait, a semi-graben with recent activity
and neovolcanic crests indicative of an initial process of
sea-floor spreading.

-The South Scotia ridge was recognised, being established its
morphoestructure.

-Establishment of the seismotectonic character of the Scotia Plate
and the Powell Basin.

-It was showed the origin of the pull-apart basin of the Hesperides
Deep and the important compression-subduction component of the Scotia
Plate over the ridge.

En Espa&#241ol:

Los objetivos de la campa&#241a fueron:

-Transici&#243n entre diferentes placas y sub-placas; Shetland,
Drake, Scotia y Ant&#225rtica y sus puntos de uni&#243n.

-Estudio del enlace entre el centro de expansi&#243n de Bransfield y
la zona de subduccI&#243n de las Shetlands del sur.

-An&#225lisis morfoestructural detallado de un borde de placas
cizallante y de una de las grandes depresiones intracrestas (fosa
Hesp&#233rides), mediante la utilizaci&#243n de las sondas multihaz.

-Establecimiento de pautas geomagn&#233ticas en la zona de
expansi&#243n de Bransfield y en los bordes de placas cizallantes.

-Estudio de la formaci&#243n de rellenos y discontinuidades
regionales en las cuencas adyacentes a la dorsal.

-Aplicaci&#243n de los modelos estudiados dentro de los planes de trabajo
internacionales en dorsales Oce&#225nicas (proyecto InterRidge).

Datos Obtenidos
- M&#225s de 1.500 km de s&#237smica multicanal
- 3.500 km de sondas multihaz
- 3.500 km de sondador Hidrogr&#225fico
- 3.500 km de datos geomagn&#233ticos

Se reconoci&#243 con insonificaci&#243n al 100% una depresi&#243n
intracresta, de lA Dorsal Sur de Scotia , denomin&#225ndola FOSA
HESPERIDES en honor del B/O hesperides en su primera campa&#241a
Ant&#225rtica.

-Estudio del Estrecho de Bransfield , un Semi-Graben con actividad reciente
y crestas neovolc&#225nicas indicativas de un proceso inicial de Sea-floor
spreading.

-Se reconoci&#243 La Dorsal sur de Scotia, estableciendose su
Morfoestructura

-Establecimiento del caracter sismotect&#243nico de la Placa Scotia y Cuenca
de Powell.

-Se puso de manifiesto el origen de cuenca Pull-apart de la Fosa
Hesperides y de la importante componente de
compresi&#243n-Subducci&#243n de la placa Scotia bajo la Dorsal.