The University of Southampton
University of Southampton Institutional Repository

Facies architecture of individual basin-plain turbidites: Comparison with existing models and implications for flow processes

Facies architecture of individual basin-plain turbidites: Comparison with existing models and implications for flow processes
Facies architecture of individual basin-plain turbidites: Comparison with existing models and implications for flow processes
Current understanding of submarine sediment density flows is based heavily on their deposits, because such flows are notoriously difficult to monitor directly. However, it is rarely possible to trace the facies architecture of individual deposits over significant distances. Instead, bed-scale facies models that infer the architecture of ‘typical’ deposits encapsulate current understanding of depositional processes and flow evolution. In this study, the distribution of facies in 12 individual beds has been documented along downstream transects over distances in excess of 100 km. These deposits were emplaced in relatively flat basin-plain settings in the Miocene Marnoso Arenacea Formation, north-east Italy and the late Quaternary Agadir Basin, offshore Morocco. Statistical analysis shows that the most common series of vertical facies transitions broadly resembles established facies models. However, mapping of individual beds shows that they commonly deviate from generalized models in several important ways that include: (i) the abundance of parallel laminated sand, suggesting deposition of this facies from both high-density and low-density turbidity current; (ii) three distinctly different types of grain-size break, suggesting waxing flow, erosional hiatuses and bypass of silty sediment; (iii) the presence of mud-rich debrites demonstrating hybrid flow deposition; and (iv) dune-scale cross-lamination in fine-medium grained sandstones. Submarine sediment density flows in basin-plain settings flow over relatively simple topography. Yet, their deposits record complex flow events, involving transformation between different flow types, rather than the simple waning surges often associated with the distal parts of turbidite systems.
Marnoso Arenacea Formation, Agadir Basin, turbidity current, debris flow, sedimentary structures
0037-0746
1850-1887
Sumner, Esther J.
dbba4b92-89cc-45d9-888e-d0e87e5c10ac
Talling, Peter J.
1cbac5ec-a9f8-4868-94fe-6203f30b47cf
Amy, Lawrence A.
857f581c-1529-424c-a948-91ab2fd476eb
Wynn, Russell B.
72ccd765-9240-45f8-9951-4552b497475a
Stevenson, Christopher J.
4dd8706f-1d26-437c-95d0-6e131a5ec078
Frenz, Michael
8c9cae60-8127-447e-91fb-94a442444f75
Sumner, Esther J.
dbba4b92-89cc-45d9-888e-d0e87e5c10ac
Talling, Peter J.
1cbac5ec-a9f8-4868-94fe-6203f30b47cf
Amy, Lawrence A.
857f581c-1529-424c-a948-91ab2fd476eb
Wynn, Russell B.
72ccd765-9240-45f8-9951-4552b497475a
Stevenson, Christopher J.
4dd8706f-1d26-437c-95d0-6e131a5ec078
Frenz, Michael
8c9cae60-8127-447e-91fb-94a442444f75

Sumner, Esther J., Talling, Peter J., Amy, Lawrence A., Wynn, Russell B., Stevenson, Christopher J. and Frenz, Michael (2012) Facies architecture of individual basin-plain turbidites: Comparison with existing models and implications for flow processes. Sedimentology, 59 (6), 1850-1887. (doi:10.1111/j.1365-3091.2012.01329.x).

Record type: Article

Abstract

Current understanding of submarine sediment density flows is based heavily on their deposits, because such flows are notoriously difficult to monitor directly. However, it is rarely possible to trace the facies architecture of individual deposits over significant distances. Instead, bed-scale facies models that infer the architecture of ‘typical’ deposits encapsulate current understanding of depositional processes and flow evolution. In this study, the distribution of facies in 12 individual beds has been documented along downstream transects over distances in excess of 100 km. These deposits were emplaced in relatively flat basin-plain settings in the Miocene Marnoso Arenacea Formation, north-east Italy and the late Quaternary Agadir Basin, offshore Morocco. Statistical analysis shows that the most common series of vertical facies transitions broadly resembles established facies models. However, mapping of individual beds shows that they commonly deviate from generalized models in several important ways that include: (i) the abundance of parallel laminated sand, suggesting deposition of this facies from both high-density and low-density turbidity current; (ii) three distinctly different types of grain-size break, suggesting waxing flow, erosional hiatuses and bypass of silty sediment; (iii) the presence of mud-rich debrites demonstrating hybrid flow deposition; and (iv) dune-scale cross-lamination in fine-medium grained sandstones. Submarine sediment density flows in basin-plain settings flow over relatively simple topography. Yet, their deposits record complex flow events, involving transformation between different flow types, rather than the simple waning surges often associated with the distal parts of turbidite systems.

Text
abstract - Version of Record
Restricted to Repository staff only
Request a copy

More information

Published date: October 2012
Keywords: Marnoso Arenacea Formation, Agadir Basin, turbidity current, debris flow, sedimentary structures
Organisations: Geology & Geophysics, Marine Geoscience

Identifiers

Local EPrints ID: 340160
URI: http://eprints.soton.ac.uk/id/eprint/340160
ISSN: 0037-0746
PURE UUID: fb792811-3c90-4f9b-bd88-81092f2ac7c4

Catalogue record

Date deposited: 13 Jun 2012 13:05
Last modified: 14 Mar 2024 11:19

Export record

Altmetrics

Contributors

Author: Peter J. Talling
Author: Lawrence A. Amy
Author: Russell B. Wynn
Author: Christopher J. Stevenson
Author: Michael Frenz

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×