Dipartimento di
Scienze della Terra e Geoambientali

moretti

Ruolo: Professore Associato
SSD: GEO 02 Geologia stratigrafica e sedimentologia

Studio: 2° Piano
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Tel.: +39 080 5442563
Fax: +39 080 5442625

SHORT COURSE

The significance of soft-sediment deformation structures

The Geological Society of Italy, the GEOSED section (Italian Association for Sedimentary Geology), the Ph.D. in Geoscience and the Department of Earth and Geoenvironmental Sciences (Bari University) organize a short course on soft-sediment deformation structures (see the brochure).

This course is intended for Ph.D. and post-doctoral students and researchers in Sedimentary Geology. The total duration is 2 days: one day of lessons (about 8 hours) followed by one day in the field visiting well-exposed examples of soft-sediment deformation structures (a total of 2 CFU).

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SSDS in the Pleistocene lacustrine deposits of the Neuquén Basin (northern Patagonia - Moretti and Ronchi, 2011)

 


 CLASS - LESSONS

The soft-sediment deformation structures are the unique record of sedimentary and tectonic processes occurring in the little-known time interval between the latest sedimentation phases and the diagenesis.

Soft-sediment deformation structures are widespread in sedimentary successions of all ages and most depositional settings. They develop at or close to the sediment surface, during or shortly after sediment accumulation and before signicant burial has taken place. As such, they have the potential to contribute to the understanding of depositional palaeoenvironments. Progress has been made recently in developing methodologies to understand the processes that trigger the instabilities leading to soft-sediment deformation. In particular, it is possible in many cases to distinguish structures that have been generated by triggers of external origin (exogenic triggers such as earthquakes) from those of "internal" origin (endogenic triggers such as rapid sedimentation or flood-related turbulence). The focus of this course will be to develop understanding of the palaeoenvironmental signicance of soft-sediment deformation structures. All aspects of the palaeoenvironment will be considered, including the physical environment, tectonic setting, palaeoclimate and depositional processes. The aim is to further develop the understanding of soft-sediment deformation structures beyond their description and classication, with an emphasis on their context and signicance. We will treat all aspects of soft-sediment deformation that contribute to understanding the environmental context and signicance, including theoretical approaches, experimental investigations, methodologies for analysing soft-sediment deformation, process studies and field-based case studies from bed to basin scale.

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MAIN TOPICS

- Deformation mechanisms in soft-sediments. Liquefaction and fluidization.

- Classifications of soft-sediment deformation structures.

Trigger mechanisms with field examples:

1) overloading;

2) storm wave-induced deformation;

3) seismically-induced soft-sediment deformation;

4) tectonic deformation of soft-sediments;

5) karstic deformation of soft-sediments;

6) other trigger mechanisms.

- Procedures to establish the trigger mechanism for soft-sediment deformation.

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FIELD TRIP

Different outcrops of well-exposed examples of SSDS are located in the Apulia region covering a large range of mechanisms of deformation, morphologies, trigger mechanisms, facies and age of the deposits involved in the deformation. 3 main localities have been visited during the 2015 Short Course (1 - Monopoli - BA, 2 - Santa Cesarea and 3 - Porto Selvaggio - LE).

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STOP 1. Deformation in soft-sediment induced by sinkhole collapses in shallow marine deposits.

Large-scale soft-sediment deformation features exposed in sea cliffs in the Cala Corvino area, a few kilometres N of Monopoli on the Adriatic coast of southern Italy show no evidence for the development of liquefaction or fluidization. Deformation involves the lower part of the Calcarenite di Gravina Formation (late Pliocene–early Pleistocene), that is locally about 15 m thick. Its base is transgressive on Cretaceous limestones and crops out at sea-level. Moretti et al al. (2011) documented that the soft-sediment deformation structures at Cala Corvino formed in association with sinkhole activity in the underlying Cretaceous bedrock. Facies analysis of the Calcarenite di Gravina Formation at Cala Corvino shows that this deformation occurred when the water–sediment interface was below wavebase, and there is no evidence of subaerial exposure.

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More details about this stop can be found at the following link: ScienceDirect.com/Monopoli

 

STOP 2. Slump and slide features in Pleistocene slope deposits.

In the south-eastern sector of the Salento coastal area, the Calcarenite di Gravina Fm. crops out inside some indentations of the rocky slope (along main fault zones) showing very unusual sedimentological features. In fact, the Calcarenite di Gravina Fm. occurs in small isolated bodies with a variable thickness (up to several tens of metres) being deposited along and at the base of a steep slope system. The occurrence of large-scale scar surfaces, slump and slide bodies, debris-flow deposits is well documented along the good coastal exposures of Santa Cesarea, Porto Miggiano and Castro localities.

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More details about this stop can be found at the following link:AIQUA.Salento

STOP 3. Slump sheets in intraplatform carbonate deposits.

Two soft-sediment deformation horizons (slump sheets) separated by undeformed limestones occur in well laminated carbonate deposits formed in a localised and short-lived intraplatform basin during the late Cretaceous. The folds of the slump sheets show well-exposed cylindrical features and record a rapid, localised and tectonically-induced palaeoenvironmental change in the interior of the Apulian Platform.

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More details about this stop can be found at the following link: ScienceDirect.com.PortoSelvaggio

 


2015 FIELD TRIP PHOTOS

 

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STOP 1. Cala Corvino. Unusual soft-sediment deformation structures in the lower part of the Calcarenite di Gravina.

 

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STOP 1. Cala Corvino. Load-structure in the lower part of the Calcarenite di Gravina.

 


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STOP 2. Santa Cesarea. A scar surface.

 

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STOP 2. Santa Cesarea. The slump sheet of Torre Miggiano.

 


 

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STOP 3. Porto Selvaggio. Cylindrical fold in the lower slump sheet.

 

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STOP 3. Porto Selvaggio. Detail of the lower slump sheet. Note the presence of imbricated thrust structures.

 


ACKNOWLEDGEMENTS

I thank Stefania Lisco, Demetrio Meloni, Luca Smeraglia, Irene CornacchiaDanica Jablonská e Marco Petruzzelli (from the left to the right in the figure below) for the photos, the organization support and the scientific curiosity.

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