SEDIMENTOLOGY AND STRATIGRAPHY OF TURBIDITE SYSTEMS WITH CONTRASTING ARCHITECTURES: EXAMPLES FROM THE TERTIARY PIEDMONT BASIN (NW ITALY) AND THE TAZA-GUERCIF BASIN (NE MOROCCO)
Tesi di Dottorato
Data di Pubblicazione:
2022
Citazione:
SEDIMENTOLOGY AND STRATIGRAPHY OF TURBIDITE SYSTEMS WITH CONTRASTING ARCHITECTURES: EXAMPLES FROM THE TERTIARY PIEDMONT BASIN (NW ITALY) AND THE TAZA-GUERCIF BASIN (NE MOROCCO) / S. Reguzzi ; tutor: M. Marini ; co-tutor: F. B. Felletti, M. Rossi ; coordinatore: F. Camara Artigas, M. I. Spalla. Dipartimento di Scienze della Terra Ardito Desio, 2022 May 06. 34. ciclo, Anno Accademico 2021.
Abstract:
Architectures of submarine fans and turbidite systems are endowed by a high grade of complexity, inherited by the large variability of depositional flows characterising them. This complexity is reflected upon the superimposition of depositional elements (e.g., channels, levées, splays, etc.) giving rise to contrasting sedimentary facies and geometries at different scales. Thus, the understanding and prediction of their heterogeneity over space is essential to obtain reliable depositional models, which can be applied in the field of natural resources exploration.
Despite heterogeneities of facies and architectures in turbidite deposits are largely studied, several questions regarding evolutionary controls still remain open due to the intricate interplay between autocyclic and allocyclic factors and the lack of roboust chronostratigraphic (i.e., time-related) constraints to be applied to turbidite systems evolution.
This doctoral work focuses on two turbidite units, different for facies, architectures, age, and depositional setting. The work pursues the goal of complementing sedimentological data (collected with cm-scale resolution) with bio-chronostratigraphic data (both novel and collected from the literature) in order to provide a trustworthy estimation of the geological time in turbidite systems depositional models.
In the first two chapters an overview on sediment gravity flows and their evolutionary models is provided, emphasising classical facies and depositional geometries.
In chapter three, the sedimentary architecture and the controls on the evolution of a channel-levée complex from the Tachrift Turbidite System (Upper Miocene, Melloulou Fm., TazaGuercif Basin, NE Morocco) is addressed. The studied complex is spectacularly well exposed and then suitable for detailed sedimentological logging with cm-scale resolution.
Results show a tripartite stratigraphic organisation of the complex, including: (i) a lowermost mud-prone interval with relatively small (a few hundred of metres across and metre-thick) and vertically stacked channels fills, (ii) a middle interval (ca. 4 m-thick and >1 km-wide) made of dominantly amalgamated sandstones with eastward-directed lateral accretion packages (LAPs), and (iii) an uppermost interval made of vertically aggraded channel fills with variously directed LAPs and well-developed levées. This organisation suggests that, after a relatively short phase of inception (lowermost interval), the channel underwent a prolonged lateral migration, prior to become aggradational (uppermost interval). Proportions of turbidite vs. hemipelagic deposits suggest that the migrational and aggradational phases straddle a lapse of reduced turbidite input to the studied section of the slope. It is suggested that the observed architectural style turnaround reflects the feedback of channel morphodynamics, sediment input, and along-dip channel depth profile.
In chapter four, the Rupelian Monastero Fm. turbidite system (Tertiary Piedmont Basin, NW Italy) is addressed. This 1100 m-thick turbidite system was deposited adjacent to a coeval and heteropic fan delta system (i.e., the Savignone Conglomerates), upon a south-eastward dipping clastic ramp, and consists of an apparently monotonous succession of thin-bedded sandstone-mudstone couplets intercalated by erosive-based amalgamated bedsets made of sandstones and conglomerates. The unit was studied along the best exposed and most continuous section (Val di Grue-San Gaudenzio section) by cm-scale resolution sedimentological logging. Thesedimentological data were subsequently complemented with bio-magnetostratigraphic data (novel and from the literature) to refine the depositional model. In addition, seismic lines interpretation (in professional partnership with E
Tipologia IRIS:
Tesi di dottorato
Keywords:
Turbidite Channels; Hypepycnal flows; Taza-Guercif Basin; Tachrift Turbidite System; Tertiary Piedmont Basin; Monastero Formation
Elenco autori:
S. Reguzzi
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