titoli, abstracts, parole chiave >>>
Processes controlling very low sedimentation rates on the continental slope of the Gonone-Orosei canyon system, NE Sardinia-terrestrial and oceanic significance

Giresse, Pierre and Pascucci, Vincenzo and Lymer, Gaël and Gaullier, Virginie and Thinon, Isabelle (2014) Processes controlling very low sedimentation rates on the continental slope of the Gonone-Orosei canyon system, NE Sardinia-terrestrial and oceanic significance. Geo-Marine Letters, Vol. 34 (6), p. 483-498. ISSN 0276-0460. eISSN 1432-1157. Article.

Full text not available from this repository.

DOI: 10.1007/s00367-014-0379-x

Abstract

The narrow shelf and upper slope immediately above the Gonone canyon head off NE Sardinia represent areas of very low sedimentation rates. Along the sides of the canyon head (1,600 m water depth), the sediment deposits are homogeneous but show alternating light-grey intervals rich in carbonate and dark-grey ones rich in organic matter, possibly related to distal turbidite processes. Deposits older than 50,000 years are already encountered at core depths of 2.50 m, the sedimentation rates varying from 6–21 cm/103 years in the lower parts of two cores and from 1.5–3 cm/103 years in the upper parts. At about 35,000 years BP, both cores show a simultaneous drop in sedimentation rate by a factor of 3, probably in response to local mechanisms of channel avulsion. Lithological, mineralogical and geochemical properties reveal the environmental factors which are responsible for the extremely slow sediment accumulation. The southernmost sector of the coast, and partly also of the shelf, consists of Jurassic limestones which supply only small amounts of fine-grained material transported in suspension. During the last sea-level highstand, the accumulation of the Cedrino River pro-delta remained restricted to the coast, the low siliciclastic sediment yields resulting in poor shelf sediment trapping. The present morphology of the canyon head prevented the occurrence of gravity processes in the deeper part of the canyon system, including the coring sites. Accordingly, deposition was mainly fed by hemipelagic material of planktonic origin, together with only moderate terrigenous inputs. On a wider late Pleistocene timescale, seismic data indicate the occurrence of a coarse-grained, layered turbidite facies, implying a very different architecture of the canyon drainage system probably prior to 60,000 years BP.

Item Type:Article
ID Code:10071
Status:Published
Refereed:Yes
Uncontrolled Keywords:Geology, Gonone canyon, low sedimentation rates, Cedrino River, Sardinia
Subjects:Area 04 - Scienze della terra > GEO/02 Geologia stratigrafica e sedimentologica
Divisions:001 Università di Sassari > 01-a Nuovi Dipartimenti dal 2012 > Architettura, Design e Urbanistica
Publisher:Springer Berlin / Heidelberg
ISSN:0276-0460
eISSN:1432-1157
Deposited On:15 Sep 2014 10:53

I documenti depositati in UnissResearch sono protetti dalle leggi che regolano il diritto d'autore

Repository Staff Only: item control page