Morphology and evolution of a modern mixed (turbidite-contourite) depositional system associated with deeply-incised submarine canyons in the Patagonian Continental Margin

IF 2.6 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Marine Geology Pub Date : 2025-02-01 DOI:10.1016/j.margeo.2025.107476

José I. Isola , Fermín I. Palma , Sebastían Y. Principi , Graziella Bozzano , Ornella Silvestri , Juan P. Ormazabal , Alejandro A. Tassone

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引用次数: 0

Abstract

This study integrates a novel multi-beam bathymetry and high-resolution sub-bottom seismic database with previous works, to investigate a Late Quaternary Mixed (turbidite-contourite) Depositional System (MDS) related to a major submarine canyon system located on the Patagonian Continental Margin (PCM) between water depths of 1500 and 4000 m.

The studied MDS exhibits unique and unusual features, including the along-slope deviation of three submarine canyons, large-mounded drifts (>100 ms TWT) forming downstream of canyons, and small patchy drifts (a few tens ms TWT) accumulating in canyon-free slope areas. The genesis of these features is explained by a temporal substitution from contourite to mixed settings and different styles of interaction between along-slope and across-slope processes.

The along-slope deviation of the canyons is associated with the temporal substitution of contourite processes dominated period to the establishment of a MDS, marked by increased down-slope activity inferred to have occurred after the Mid-Pleistocene Transition (MPT). The fossil mounded morphologies developed during the dominant contourite period (pre MPT) acted as barriers to the subsequent submarine canyons formed during the increased down-slope activity period (post MPT), causing them to deviate by 90° along the slope.

After the MPT, spatial intercalation and interactions between along and across slope processes produced patchy and mounded drifts. The patchy drifts are associated with unconfined settings and are interpreted as the outcome of turbidites redistributed by bottom currents. Synchronous interactions between along-slope and across-slope processes appear to have played a crucial role in the formation of large, mounded drifts near submarine canyons.

This study highlights the temporal and spatial complexity of MDSs and provides new insights into their development within submarine canyon systems. Additionally, this work addresses the role that the stratification of deep-water masses could have played in the distribution of sediments along the PCM during the Late Quaternary.

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来源期刊

Marine Geology 地学-地球科学综合

CiteScore

6.10

自引率

6.90%

发文量

175

审稿时长

21.9 weeks

期刊介绍： Marine Geology is the premier international journal on marine geological processes in the broadest sense. We seek papers that are comprehensive, interdisciplinary and synthetic that will be lasting contributions to the field. Although most papers are based on regional studies, they must demonstrate new findings of international significance. We accept papers on subjects as diverse as seafloor hydrothermal systems, beach dynamics, early diagenesis, microbiological studies in sediments, palaeoclimate studies and geophysical studies of the seabed. We encourage papers that address emerging new fields, for example the influence of anthropogenic processes on coastal/marine geology and coastal/marine geoarchaeology. We insist that the papers are concerned with the marine realm and that they deal with geology: with rocks, sediments, and physical and chemical processes affecting them. Papers should address scientific hypotheses: highly descriptive data compilations or papers that deal only with marine management and risk assessment should be submitted to other journals. Papers on laboratory or modelling studies must demonstrate direct relevance to marine processes or deposits. The primary criteria for acceptance of papers is that the science is of high quality, novel, significant, and of broad international interest.