Upper slope contourite deposits off Capo Vaticano (southern Italy, Mediterranean Sea): sedimentological features and short-term bottom current variability related to the modified Levantine Intermediate Water.
Articolo
Data di Pubblicazione:
2021
Abstract:
The upper continental slope offshore Capo Vaticano (southern Tyrrhenian Sea) is characterized by a contourite
depositional system with well-developed elongated sediment drifts. This system is related to a northward paleobottom current, similar to the present-day modified-Levantine Intermediate Water (modified-LIW) flowing from
the Messina Strait. In this work, we show results from an integrated analysis of descriptive oceanography, highresolution seismic profiles and core data (i.e., grain size, foraminiferal assemblages, tephrostratigraphy and AMS
radiocarbon dating) collected from the crest and moat sectors of drift deposits. The studied succession formed
since the mid Holocene, under the action of the modified-LIW and the stratigraphic architecture indicates an
upslope migration of the moat and rather stable position of the crest sector. Grain-size features recorded from
two sediment cores indicate the occurrence of a succession of complete bi-gradational sand-rich contourite sequences. Sandy facies were observed both as lag deposits formed in active moat channel and as coarser intervals
of bi-gradational sequences forming drift deposits close to its crest. Their occurrence would highlight that upper
slope environments impacted by intermediate water masses and proximal to sandy sources may represent
favorable settings for accumulation of sandy sediment. The moat sector is characterized by a more complex
stratigraphic record, where either moat sedimentation or lateral deposition of finer sediment occur, suggesting
that further investigation is required to better understand this complex element of contourite systems. Based on
available age information, some of the bi-gradational sequences probably formed during the Dark Age Cold
Period, providing example of a small-scale cyclicity of contourite deposition, likely related to short-term
(possibly multicentennial scale) fluctuations of the paleo modified-LIW. According to age constraints and
analysis of foraminiferal assemblages, these fluctuations were likely governed by climate variations, with a
weaker activity during warmer periods and faster currents during colder events.
Tipologia CRIS:
01.01 Articolo in rivista
Keywords:
Sandy contourites Bi-gradational sequences Holocene Moat m-Levantine Intermediate Water
Elenco autori:
Giaccio, Biagio; Bosman, Alessandro; Mancini, Marco; Martorelli, Eleonora; Conte, AIDA MARIA
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