Fontan A.

No Thumbnail Available
Last Name
Fontan
First Name
A.
ORCID

Filters

2012 - 2013 2
2
2
Reset filters

Settings

Search Results

Now showing 1 - 2 of 2
  • Preprint
    The morpho-tectonic setting of the Southeast margin of Iberia and the adjacent oceanic Algero-Balearic Basin
    ( 2013-04) Acosta, Juan ; Fontan, A. ; Munoz, Araceli ; Munoz-Martin, A. ; Rivera, J. ; Uchupi, Elazar
    Multi-beam bathymetry and high-resolution low-penetration seismic reflection profiles of the offshore extensions of the Bétic Internal Zone off Sierra de Cartagena-La Unión margin along its south side and the Mar Menor margin along its east side, the Mazarrón Escarpment forming its southern boundary and the adjacent oceanic Algero-Balearic basin have provided images of the neo-tectonic structures of the region equal to those provided by subaerial photography. For the first time we mapped with unprecedented detail the Mazarrón Escarpment and the Southeast margin of Iberia. The first-order structures of the region are due to the consequence of the collision of the African and Eurasian plates during the Alpine orogeny in late Oligocene-Middle Miocene, the westward migration of the Alborán plate in the Middle Miocene and the desiccation of the Mediterranean in the Messinian (Late Miocene) that led to the deposition of evaporites in the Algero-Balearic basin and erosion of the Mazarrón Escarpment, the Sierra de Cartagena-La Unión shelf, the Mar Menor margin and the adjacent coast. Our data images second order tectonic features (neo-tectonic features) superimposed on the larger structures. These include the deformation of the strata in the Algero-Balearic basin by the gliding of the Plio-Quaternary sediments on Messinian halite on the margins of the basin and sediment loading in its center, the Late Miocene-Quaternary deformation of the area north of the Mazarrón Escarpment resulting from the continuous oblique convergence of the African and Eurasian plates in a NNW-SSE direction, the Miocene to Pleistocene volcanic edifices and pinnacles (dikes), the pockmarks formed by the extrusion of gas/water via faults and the massive gravitational failure of the Mazarrón Escarpment triggered by this plate convergence. The data also show in detail features formed on the Mazarrón Escarpment during the Messinian, Pliocene and Pleistocene regressions and those on the shelf formed during the Pleistocene glacially induced regressions/transgression and sediment drifts generated by modern currents.
  • Preprint
    Sediment drifts and cold-water coral reefs in the Patagonian upper and middle continental slope
    ( 2012-05) Munoz, Araceli ; Cristobo, J. ; Rios, P. ; Druet, M. ; Polonio, V. ; Uchupi, Elazar ; Acosta, Juan ; Iglesias, S. ; Portela, J. ; del Rio, J. L. ; Parra, S. ; Sacau, M. ; Vilela, R. ; Patrocinio, T. ; Almon, B. ; Elvira, E. ; Jimenez, P. ; Fontan, A. ; Alcala, C. ; Lopez, V.
    The north flowing Falkland / Malvinas Current has generated sediment drifts at a depth of 1200-1600 m in the Patagonian middle continental slope out of early Holocene hemipelagics, late Pleistocene ice rafted clastics, and Neogene fluvial sediments. Possibly there may be two generations of drifts, Pleistocene on the outer middle slope and Holocene on the inner shelf. The ice rafted debris originated in Antarctica, at a distance of 2000 to 4000 km south of Patagonia. Scattered over the upper and middle slopes, at depths ranging from 300 to 1400 m, are cold-water coral reefs of less than a meter to about ten of meters in relief. It is inferred that most of cold-water coral structures flourish as a consequence of the Falkland /Malvinas Current that concentrates the food supply at the reef sites. Growth of cold-water coral reefs, documented by digital submarine photographs on the upper slope, at a depth of 300/400 m, may be promoted by upwelling of nutrient-rich waters and associated plankton blooms created by the intrusion of Falkland /Malvinas Current onto the outer shelf.