Geological record of tsunami inundations in Pantano Morghella (south-eastern Sicily) both from near and far-field sources

Abstract. Analysis of tsunami deposits from the Pantano Morghella area provided geological evidence for two inundations occurred along the south-eastern Ionian coast of Sicily. Pantano Morghella is a large pond characterised by a fine-grained sedimentation indicating a low-energy depositional environment. Two anomalous yellow sandy layers found at different depths indicate the occurrence of high-energy marine inundations. We studied sedimentological and paleontological features of the anomalous deposits as well as their spatial distribution observing the following properties: different facies with respect to the local stratigraphic sequence; erosive bases, rip-up clasts and broken elements testifying violent deposition mechanisms; macro and micro fauna of marine environment; relatively constant thickness throughout most of the depositional zone with thinning at the distal end; large sand sheets that extend inland. These observations, jointly with their infrequency in the sedimentary record and the age indicating a fast deposition, provided strong evidence for tsunami inundations. Correlations between anomalous layers and historical tsunamis are supported by radiocarbon and OSL dating results. The younger deposit is likely due to the 1908 near-source tsunami, whereas the flooding of the oldest event is most likely associated with a far and large source, the Crete 365 AD earthquake.

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On the origin of multiple tsunami inundation of the archaeological site of Ognina (Sicily): Numerical models and field geological data

10.5194/egusphere-egu21-8591 ◽

2021 ◽

Author(s):

Giovanni Scardino ◽

Angela Rizzo ◽

Vincenzo De Santis ◽

Despo Kyriakoudi ◽

Alessio Rovere ◽

...

Keyword(s):

Sea Level ◽

Tsunami Wave ◽

Numerical Models ◽

Narrow Channel ◽

High Energy ◽

Central Mediterranean ◽

Geological Evidence ◽

Tsunami Modelling ◽

South Eastern ◽

The Past

South-eastern Sicily is among the most seismically active areas of the central Mediterranean. As such, it is marked by a high level of crustal seismicity producing major earthquakes (up to Mw &#8764;7), and consequent several earthquake-generated tsunami, which have affected the Ionian coast of South-eastern Sicily in historical times. These tsunami events left geomorphic imprints such as large boulders or high-energy deposits along the Sicily coasts. In Ognina, a small town located 20 km south of Siracusa, high-energy deposits were correlated with three tsunami events that struck this coast on 21 July 365 Common Era (CE), 4 February 1169 CE, and 11 January 1693 CE. The deposits are detected in the inner part of a narrow channel, that is thought to have funnelled the tsunami flow energy. In this work, numerical models have been performed to simulate the tsunami impacts, considering the most probable tsunamogenic sources described in literature and integrating them with the past sea-level positions. To this end, we used Delft Dashboard, Delft 3d-FLOW and XBeach. A reconstruction of the past topography of Ognina coast was performed through geological and historical information, in order to model the tsunami wave propagation in the ancient landscape. Geological evidence with model results, under different scenarios, allow us to benchmark fault location and displacement scenarios. Modelling results indicate that the 1693 tsunami event was stronger than others impacting the Ognina area, determining significant inland flooding in the narrow channel. Moreover, simulations show that the most probable tsunamogenic sources of 1693 and 1169 tsunami events could be attributed to Western Fault dislocations occurred off-shore of Ognina area, rather than the other tsunamogenic sources described in literature, located off-shore of Catania and Siracusa. Modelling of 365 AD event shows a long period for the tsunami wave that determined the sedimentation on the lower units in the outcrop. For each of the three tsunami events, models of high-energy deposition match with position and thickness of high-energy layers detected in the field. The results of this study show how a combined approach between geological evidence and tsunami modelling could be a suitable tool for the attribution of tsunami deposits connected to specific tsunamogenic sources.&#160;Keyword: tsunami; earthquake; faults; flooding; sea-level

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Sedimentary Cyclicity in the Upper Paleocene- Eocene Successions of the Haymana Basin (Ankara, Turkey): Responses of Fossils to Cyclicity

10.5194/egusphere-egu2020-8 ◽

2020 ◽

Author(s):

Nilya Bengül

Keyword(s):

Depositional Environment ◽

Middle Eocene ◽

Planktonic Foraminifera ◽

High Energy ◽

Central Anatolia ◽

Accretionary Wedge ◽

Depositional Model ◽

Stratigraphic Sequence ◽

Large Benthic Foraminifera ◽

Upper Paleocene

The Haymana Basin in central Anatolia (Turkey) formed during the closure of the Neo-Tethys on Late Cretaceous to Middle Eocene as a forearc accretionary wedge. Late Paleocene to Middle Eocene aged units in this basin are exposed near &#199;ayraz Village, Haymana. The &#199;ayraz Formation is the youngest unit of the Haymana Basin, and it is represented by packages of nummulitic banks, and the intercalation of calcareous mudstones. The aim of this study is to investigate the sedimentary cyclicity and depositional sequences in the Upper Paleocene- Eocene successions of the Haymana Basin. To be able to achieve this objective, a stratigraphic section has been measured through this succession. In this study, detailed microfacies analyses of the shallow-water carbonate successions indicate a ramp type depositional model of the carbonate rocks. The facies composed of Alveolina sp., Orbitolites sp., and&#160; Miliolids that indicate low energy depositional environment . After that depositional environment to&#160; the shoal; the facies composed of Nummulites spp., Assilina spp. occur and increase their abundance towards high-energy environments. Absence of the Alveolina sp., Orbitolites sp., and Miliolids. occur in accordance with that. The facies composed of Nummulites spp., Assilina spp. become associated with Discocyclina sp. towards to open sea on the ramp, and the shallow open marine part is represented by the shale with the association of planktonic foraminifera. Lateral relationships of the facies from proximal (inner ramp) to the distal (mid ramp) part of the ramp are investigated by using the knowledge of paleoecology preferences of the fossils, lithologic data of the rocks and biological aspects of the fossils.&#160; The fossil associations and their indicator environments can be used in vertical changes of the facies as in the lateral relationships of the facies. It has potential to derive cyclic relationships of the stratigraphic sequence. Therefore, based on the detailed microfacies analysis and change in the distribution of the fossil associations in the stacking pattern of the sequence, a composite depositional model has been suggested. At this part of the research newly acquired question is that the driven factor of these cyclic relationships of the sequence, whether it occurred by the control of the eustatic sea- level or the interplay between tectonics and the eustacy as the dominating factor in the sequence formation.&#160;Keywords: Large Benthic Foraminifera, Nummulites spp., Assilina spp., Haymana Basin, &#199;ayraz Formation

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Stromatoporoid Beds and Flat-Pebble Conglomerates Interpreted as Tsunami Deposits in the Upper Silurian of Podolia, Ukraine

Acta Geologica Polonica ◽

10.2478/agp-2014-0014 ◽

2014 ◽

Vol 64 (3) ◽

pp. 261-280 ◽

Cited By ~ 4

Author(s):

Piotr Łuczyński ◽

Stanisław skompski ◽

Wojciech Kozłowski

Keyword(s):

Large Scale ◽

Energy Levels ◽

High Energy ◽

Tsunami Deposits ◽

Growth Environment ◽

Tsunami Waves ◽

Fine Grained ◽

Storm Wave ◽

Very High Energy ◽

Upper Silurian

Abstract Tsunami deposits are currently a subject of intensive studies. Tsunamis must have occurred in the geological past in the same frequency as nowadays, yet their identified depositional record is surprisingly scarce. Here we describe a hitherto unrecognized example of probable palaeotsunamites. The Upper Silurian (Pridoli) carbonate succession of Podolia (southwestern Ukraine) contains variously devel-oped event beds forming intercalations within peritidal deposits (shallow water limestones, nodular marls and dolomites). The event beds are represented by stromatoporoid and fine-grained bioclastic limestones, in some places accompanied by flat-pebble conglomerates. The interval with event beds can be traced along the Zbruch River in separate outcrops over a distance of more than 20 km along a transect oblique to the palaeoshoreline. The stro-matoporoid beds have erosional bottom surfaces and are composed of overturned and often fragmented massive skele-tons. The material has been transported landward from their offshore habitats and deposited in lagoonal settings. The flat-pebble conglomerates are composed of sub-angular micritic clasts that are lithologically identical to the sediments forming the underlying beds. Large-scale landward transport of the biogenic material has to be attributed to phenomena with very high energy levels, such as tropical hurricanes or tsunamis. This paper presents a tsunamigenic interpretation. Morphome-tric features of redeposited stromatoporoids point to a calm original growth environment at depths well below storm wave base. Tsunami waves are the most probable factor that could cause their redeposition from such a setting. The vastness of the area covered by parabiostromal stromatoporoid beds resembles the distribution of modern tsunami deposits in offshore settings. The stromatoporoid beds with unsorted stromatoporoids of various dimensions evenly distributed throughout the thickness of the beds and with clast-supported textures most probably represent deposition by traction. In some sections, the stromatoporoids are restricted to the lowermost parts of the beds, which pass upwards into bioclastic limestones. In this case, the finer material was deposited from suspension. The coexistence of stromatoporoid beds and flat-pebble conglomerates also allows presenting a tsunami interpretation of the latter. The propagating tsunami waves, led to erosion of partly lithified thin-layered mudstones, their fragmentation into flat clasts and redeposition as flat-pebble conglomerates.

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Overpressure Identification Using The Eaton Method on The Gumai Formation of Geragai Graben, Jambi Sub Basin

Proc. Indon. Petrol. Assoc., Digital Technical Conference, 2020 ◽

10.29118/ipa20-sg-180 ◽

2020 ◽

Author(s):

A. O. Marnila

Keyword(s):

Pressure Data ◽

Stratigraphic Sequence ◽

Fine Grained ◽

Marine Sedimentation ◽

Plot Analysis ◽

Significant Reversal ◽

Porosity And Permeability ◽

Upper Level ◽

Type Data ◽

Fine Grained Sand

Geragai graben is located in the South Sumatera Basin. It was formed by mega sequence tectonic process with various stratigraphic sequence from land and marine sedimentation. One of the overpressure indication zones in the Geragai graben is in the Gumai Formation, where the sedimentation is dominated by fine grained sand and shale with low porosity and permeability. The aim of the study is to localize the overpressure zone and to analyze the overpressure mechanism on the Gumai Formation. The Eaton method was used to determine pore pressure value using wireline log data, pressure data (RFT/FIT), and well report. The significant reversal of sonic and porosity log is indicating an overpressure presence. The cross-plot analysis of velocity vs density and fluid type data from well reports were used to analyze the causes of overpressure in the Gumai Formation. The overpressure in Gumai Formation of Geragai graben is divided into two zones, they are in the upper level and lower level of the Gumai Formation. Low overpressure have occurred in the Upper Gumai Formation and mild overpressure on the Lower Gumai Formation. Based on the analyzed data, it could be predicted, that the overpressure mechanism in the Upper Gumai Formation might have been caused by a hydrocarbon buoyancy, whereas in the Lower Gumai Formation, might have been caused by disequilibrium compaction as a result of massive shale sequence.

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A PRELIMINARY REPORT ON MODEL STUDIES OF MAGNETIC ANOMALIES OF THREE‐DIMENSIONAL BODIES

Geophysics ◽

10.1190/1.1438277 ◽

1956 ◽

Vol 21 (3) ◽

pp. 794-814 ◽

Cited By ~ 10

Author(s):

Isidore Zietz ◽

Roland G. Henderson

Keyword(s):

Magnetic Fields ◽

Rapid Method ◽

Preliminary Report ◽

Three Dimensional ◽

Magnetic Anomalies ◽

Constant Thickness ◽

Laboratory Methods ◽

Model Experiments ◽

Model Studies ◽

Different Depths

Model experiments were made to devise a rapid method for calculating magnetic anomalies of three‐dimensional structures. The magnetic fields of the models were determined using the equipment at the Naval Ordnance Laboratory, White Oaks, Md. An irregularly shaped mass was approximated by an array of prismatic rectangular slabs of constant thickness and varying horizontal dimensions. Contoured maps are being prepared for these magnetic models at different depths and for several magnetic inclinations. The fields of these three‐dimensional structures are obtained by super‐imposing the appropriate contoured maps and adding numerically the effects at each point. The equipment and laboratory methods are described. Theoretical and practical examples are given.

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Ostracods as Tsunami Tracers in Holocene Sequences

Quaternary Research ◽

10.1016/j.yqres.2009.08.005 ◽

2010 ◽

Vol 73 (1) ◽

pp. 130-135 ◽

Cited By ~ 25

Author(s):

Francisco Ruiz ◽

Manuel Abad ◽

Luís Miguel Cáceres ◽

Joaquín Rodríguez Vidal ◽

María Isabel Carretero ◽

...

Keyword(s):

Population Structure ◽

Species Diversity ◽

Indian Ocean ◽

High Energy ◽

Indian Ocean Tsunami ◽

Tsunami Deposits ◽

Shallow Marine ◽

Juvenile Stages ◽

Marine Areas ◽

Age Population Structure

This review analyses the ostracod record in Holocene tsunami deposits, using an overview of the 2004 Indian Ocean tsunami impact on its recent populations and the associated tsunamigenic deposits, together with results from numerous investigations of other Holocene sequences. Different features such as the variability of the local assemblages, population density, species diversity, age population structure (e.g., percentages of adults and juvenile stages) or taphonomical signatures suggest that these microorganisms may be included amongst the most promising tracers of these high-energy events in marshes, lakes, lagoons or shallow marine areas.

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The Making of Catalogues of Very-High-Energy γ-ray Sources

Universe ◽

10.3390/universe7110421 ◽

2021 ◽

Vol 7 (11) ◽

pp. 421

Author(s):

Mathieu de Naurois

Keyword(s):

Galactic Plane ◽

Population Studies ◽

High Energy ◽

Cherenkov Telescopes ◽

Background Rejection ◽

Fine Grained ◽

Very High Energy ◽

Advanced Analysis ◽

Γ Ray ◽

Very High

Thirty years after the discovery of the first very-high-energy γ-ray source by the Whipple telescope, the field experienced a revolution mainly driven by the third generation of imaging atmospheric Cherenkov telescopes (IACTs). The combined use of large mirrors and the invention of the imaging technique at the Whipple telescope, stereoscopic observations, developed by the HEGRA array and the fine-grained camera, pioneered by the CAT telescope, led to a jump by a factor of more than ten in sensitivity. The advent of advanced analysis techniques led to a vast improvement in background rejection, as well as in angular and energy resolutions. Recent instruments already have to deal with a very large amount of data (petabytes), containing a large number of sources often very extended (at least within the Galactic plane) and overlapping each other, and the situation will become even more dramatic with future instruments. The first large catalogues of sources have emerged during the last decade, which required numerous, dedicated observations and developments, but also made the first population studies possible. This paper is an attempt to summarize the evolution of the field towards the building up of the source catalogues, to describe the first population studies already made possible, and to give some perspectives in the context of the upcoming, new generation of instruments.

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Stratigraphic Sequence and Depositional Environment of Unconsolidated Deposits in the West Seacoast

Journal of the Korean Geotechnical Society ◽

10.7843/kgs.2012.28.10.55 ◽

2012 ◽

Vol 28 (10) ◽

pp. 55-68 ◽

Cited By ~ 1

Author(s):

Yong-Mok Lee ◽

Eun-Kyeong Choi ◽

Sung-Wook Kim ◽

Kyu-Hwan Lee ◽

Yeo-Jin Yoon ◽

...

Keyword(s):

Depositional Environment ◽

The West ◽

Stratigraphic Sequence

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The Witwatersrand pyrites and metamorphism

Mineralogical Magazine ◽

10.1180/minmag.1983.047.345.08 ◽

1983 ◽

Vol 47 (345) ◽

pp. 473-479 ◽

Cited By ~ 17

Author(s):

D. K. Hallbauer ◽

K. von Gehlen

Keyword(s):

Trace Element ◽

Fluid Inclusions ◽

Depositional Environment ◽

Volcanic Rocks ◽

Source Rocks ◽

Fine Grained ◽

Mineral Inclusions ◽

Ore Minerals ◽

Hand Specimen

AbstractEvidence obtained from morphological and extensive trace element studies, and from the examination of mineral and fluid inclusions in Witwatersrand pyrites, shows three major types of pyrite: (i) detrital pyrite (rounded pyrite crystals transported into the depositional environment); (ii) synsedimentary pyrite (round and rounded aggregates of fine-grained pyrite formed within the depositional environmen); and (iii) authigenic pyrite (newly crystallized and/or recrystallized pyrite formed after deposition). The detrital grains contain mineral inclusions such as biotite, feldspar, apatite, zircon, sphene, and various ore minerals, and fluid inclusions with daughter minerals. Most of the inclusions are incompatible with an origin by sulphidization. Recrystallized authigenic pyrite occurs in large quantities but only in horizons or localities which have been subjected to higher temperatures during the intrusion or extrusion of younger volcanic rocks. Important additional findings are the often substantial amounts of pyrite and small amounts of particles of gold found in Archaean granites (Hallbauer, 1982) as possible source rocks for the Witwatersrand detritus. Large differences in Ag and Hg content between homogeneous single gold grains within a hand specimen indicate a lack of metamorphic homogenization. The influence of metamorphism on the Witwatersrand pyrites can therefore be described as only slight and generally negligible.

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