Leaky salt: pipe trails record the history of cross-evaporite fluid escape in the northern Levant Basin, Eastern Mediterranean

Hydrocarbon escape systems can be regionally active on multi-million-year timescales. However, reconstructing the timing and evolution of repeated escape events can be challenging because their expression may overlap in time and space. In the northern Levant Basin, eastern Mediterranean, distinct fluid escape episodes from common leakage points formed discrete, cross-evaporite fluid escape pipes, which are preserved in the stratigraphic record due to the coeval Messinian salt tectonics.The pipes consistently originate at the crest of prominent sub-salt anticlines, where thinning and hydrofracturing of overlying salt permitted focused fluid flow. Sequential pipes are arranged in several kilometers-long trails that were progressively deformed due to basinward gravity-gliding of salt and its overburden. The correlation of the oldest pipes within 12 trails suggests that margin-wide fluid escape started in the Late Pliocene/Early Pleistocene, coincident with a major phase of uplift of the Levant margin. We interpret that the consequent transfer of overpressure from the deeper basin areas triggered seal failure and cross-evaporite fluid flow. We infer that other triggers, mainly associated with the Messinian Salinity Crisis and compressive tectonics, played a secondary role in the northern Levant Basin. Further phases of fluid escape are unique to each anticline and, despite a common initial cause, long-term fluid escape proceeded independently according to structure-specific characteristics, such as the local dynamics of fluid migration and anticline geometry.Whereas cross-evaporite fluid escape in the southern Levant Basin is mainly attributed to the Messinian Salinity Crisis and compaction disequilibrium, we argue that these mechanisms do not apply to the northern Levant Basin; here, fluid escape was mainly driven by the tectonic evolution of the margin. Within this context, our study shows that the causes of cross-evaporite fluid escape can vary over time, act in synergy, and have different impacts in different areas of large salt basins.

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Cosmogenic burial dating of in cave-deposited alluvium: unravelling long-term incision rates and complex speleogenesis in multi-level cave systems

10.5194/egusphere-egu2020-19598 ◽

2020 ◽

Author(s):

Gilles Rixhon ◽

Didier L. Bourlès ◽

Régis Braucher ◽

Alexandre Peeters ◽

Alain Demoulin

Keyword(s):

Early Pleistocene ◽

Middle Pleistocene ◽

Fluvial Terrace ◽

Base Level ◽

Cave System ◽

River Incision ◽

Order Of Magnitude ◽

History Of ◽

Multi Level

Multi-level cave systems record the history of regional river incision in abandoned alluvium-filled phreatic passages which, mimicking fluvial terrace sequences, represent former phases of fluvial base-level stability. In this respect, cosmogenic burial dating of in cave-deposited alluvium (usually via the nuclide pair 26Al/10Be) represents a suitable method to quantify the pace of long-term river incision. Here, we present a dataset of fifteen 26Al/10Be burial ages measured in fluvial pebbles washed into a multi-level cave system developed in Devonian limestone of the uplifted Ardenne massif (eastern Belgium). The large and well-documented Chawresse system is located along the lower Ourthe valley (i.e. the main Ardennian tributary of the Meuse river) and spans altogether an elevation difference exceeding 120 m.The depleted 26Al/10Be ratios measured in four individual caves show two main outcomes. Firstly, computed burial ages ranging from ~0.2 to 3.3 Ma allows highlighting an acceleration by almost one order of magnitude of the incision rates during the first half of the Middle Pleistocene (from ~25 to ~160 m/Ma). Secondly, according to the relative elevation above the present-day floodplain of the sampled material in the Manants cave (<35 m), the four internally-consistent Early Pleistocene burial ages highlight an &#8220;anomalous&#8221; old speleogenesis in the framework of a gradual base-level lowering. They instead point to intra-karsting reworking of the sampled material in the topographically complex Manants cave. This in turn suggests an independent, long-lasting speleogenetic evolution of this specific cave, which differs from the per descensum model of speleogenesis generally acknowledged for the regional multi-level cave systems and their abandoned phreatic galleries. In addition to its classical use for inferring long-term incision rates, cosmogenic burial dating can thus contribute to better understand specific and complex speleogenetic evolution.

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Interaction and boundary work: Western merchant colonies in the Levant and the Eastern Churches, 1650–1800

Journal of Modern European History ◽

10.1177/1611894420910899 ◽

2020 ◽

Vol 18 (2) ◽

pp. 156-176

Author(s):

Cornel Zwierlein

Keyword(s):

Nineteenth Century ◽

Early Modern ◽

National Culture ◽

Eastern Mediterranean ◽

Boundary Work ◽

Modern Times ◽

History Of ◽

Early Modern Times ◽

Close Distance

European merchants in their factories (‘nations’) in the Eastern Mediterranean under Ottoman rule were not really colonizers; in early modern times, they were somehow privileged guests. However, they deserve an important part in a long-term history of types of ‘close distance’ and forms of segregational coexistence. Different from recent studies that stress a strong overall interaction, understanding, sharing, and exchange between Europeans and Ottoman subjects, it is proposed to distinguish three levels: (1) The daily commercial interaction of Western Europeans with their Ottoman counterparts; (2) the stronger involvement in some politico-religious struggles (the 1724 schism in the patriarchate of Antioch serves as example): also here, one has still to distinguish between real interest in the religious cause and other activities as credit lending; (3) the care for and maintenance by the Europeans of their own Western national culture abroad: these cultural activities served more to (eventually unconsciously) perform ‘boundary work’ and to close up the ‘nation’. These early modern forms of close distance and segregation were only isomorphic but not homologous with later highly conscious colonial and modern imperial forms of contact between ‘West’ and ‘East’ as in the nineteenth-century European settlements in Istanbul.

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Drainage systems and their relations to the Messinian Salinity Crisis in the Levant Basin

10.5194/egusphere-egu2020-22621 ◽

2020 ◽

Author(s):

Jimmy Moneron ◽

Zohar Gvirtzman

Keyword(s):

Salt Tectonics ◽

Messinian Salinity Crisis ◽

Time Intervals ◽

Drainage Systems ◽

Resolution Imaging ◽

Levant Basin ◽

Channel Patterns ◽

Seismic Reflection Profiles ◽

Short Time ◽

Channel Systems

New high-resolution imaging of recently acquired data in the Levant basin shed light on very dense channel systems. The processes behind their origin, timing and direction - during the different stages of the Messinian Salinity Crisis (MSC) - is still unresolved and partly understood. Discoveries of such drainage systems raise questions on a past topography and mechanisms responsible for the channel morphologies, the understanding of these channel patterns is thus essential for a meaningful assessment of such mechanisms involved in the context of the MSC and its aftermath. Our results show that the drainage direction was undergoing extreme changes during short time intervals in the Levant Basin. Indeed, new maps presented here indicate different past drainage orientations, which is in contrast to the current-day turbidite channels - draining the Sinai-Levant continental margin northward towards the Cyprus Arc. We hypothesize from these results that drainage change, from southwest to north, expresses northward tilting of the basin towards the Cyprus subduction zone, however, when exactly did this tilting occur? Deciphering the timing of such events is important in order to get a better understanding of tectonostratigraphic settings, controlling depocenter locations in the Levant basin in the MSC. We also suggest that the unique pattern of channels over the Intra-Messinian Truncation Surface (IMTS), expresses a complex seafloor relief which was mainly controlled by salt tectonics induced thrusts faults.Keywords: Messinian Salinity Crisis, Channel systems, Evaporites, Seismic Reflection Profiles

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Major erosion at the end of the Messinian Salinity Crisis: evidence from the Levant Basin, Eastern Mediterranean

Basin Research ◽

10.1111/j.1365-2117.2006.00309.x ◽

2007 ◽

Vol 19 (1) ◽

pp. 1-18 ◽

Cited By ~ 70

Author(s):

C. Bertoni ◽

J. A. Cartwright

Keyword(s):

Eastern Mediterranean ◽

Messinian Salinity Crisis ◽

Levant Basin

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Levant Basin as a key for Understanding the Messinian Salinity Crisis: Challenging the Desiccation Paradigm

10.5194/egusphere-egu2020-4040 ◽

2020 ◽

Author(s):

Zohar Gvirtzman ◽

Vinicio Manzi ◽

Ran Calvo ◽

Ittai Gavrieli ◽

Rocco Gennari ◽

...

Keyword(s):

High Resolution ◽

Mediterranean Sea ◽

Water Column ◽

Mediterranean Basin ◽

Eastern Mediterranean ◽

Messinian Salinity Crisis ◽

Seismic Surveys ◽

Salt Rocks ◽

The Mediterranean ◽

Levant Basin

The Messinian salinity crisis (MSC) is an extreme event in Earth history during which a salt giant (>1&#215;106 km3) accumulated on the Mediterranean seafloor within ~640 kyrs. The Messinian salt giant was formed about 6 million years ago when the restriction of water exchanges between the Atlantic Ocean and the Mediterranean Sea turned the Mediterranean into an enormous saline basin. After more than 40 years of research, the timing and the depositional environments of shallow (<200 m) and intermediate (200-1000 m) water-depth Messinian basins are known quite well from onshore outcrops. But what happened in the deepest portions of the Mediterranean Sea is still unclear, because the information about offshore successions is mainly based on geophysical data with no rock samples that can be dated. The Levant Basin is the only deep Mediterranean basin where the entire Messinian section has been penetrated by wells tied to high resolution 3D seismic surveys. Here we present two studies challenging the desiccation paradigm dominating the MSC scientific literature for more than 40 years. The first study focuses on the nearly flat top erosion surface (TES) that truncates a basinward-tilted Messinian evaporitic succession. This truncation is commonly interpreted to be the result of subaerial erosion at the end of the MSC. However, based on high resolution seismic surveys and wireline logs, we show that (1) the TES is actually an intra-Messinian truncation surface (IMTS) located ~100 m below the Messinian-Zanclean boundary; (2) the topmost, post-truncation, Messinian unit is very different from the underlying salt deposits and consists mostly of shale, sand, and anhydrite showing typical 87Sr/86Sr values and fauna assemblages from stage 3; and (3) the flat IMTS is a dissolution surface related to significant dilution and stratification of the water column during the transition from stage 2 to stage 3. We suggest that dissolution occurred upslope where salt rocks at the seabed were exposed to the upper diluted brine, while downslope the salt rocks were preserved because submerged in the deeper halite-saturated layer. The model, which requires a stratified water column, is inconsistent with a complete desiccation of the eastern Mediterranean Sea. The second study focuses on the onset of the Messinian salinity crisis in the deep Eastern Mediterranean basin. Biostratigraphy and astronomical tuning of the Messinian pre-salt succession in the Levant Basin allows for the first time the reconstruction of a detailed chronology of the MSC events in deep setting and their correlation with marginal records that supports the CIESM (2008) 3-stage model. Our main conclusions are (1) MSC events were synchronous across marginal and deep basins, (2) MSC onset in deep basins occurred at 5.97 Ma, (3) only foraminifera-barren, evaporite-free shales accumulated in deep settings between 5.97 and 5.60 Ma, (4) deep evaporites (sulfate and halite) deposition started later, at 5.60 Ma. The wide synchrony of events implies inter-sub-basin connection during the whole salinity crisis and is not compatible with large sea-level fall that would have separated the eastern and western basins producing diachronic processes.

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Aquifer Response to Estuarine Stream Dynamics

Water ◽

10.3390/w11081678 ◽

2019 ◽

Vol 11 (8) ◽

pp. 1678 ◽

Cited By ~ 2

Author(s):

Yehuda Shalem ◽

Yoseph Yechieli ◽

Barak Herut ◽

Yishai Weinstein

Keyword(s):

Eastern Mediterranean ◽

Mediterranean Coast ◽

Low Permeability ◽

High Permeability ◽

Dynamic Changes ◽

Groundwater Levels ◽

Groundwater Dynamics ◽

Large Fluctuations ◽

History Of

While seawater intrusions are widely discussed, the salinization of coastal aquifers via narrow rivers is hardly documented. This study investigates groundwater dynamics in an aquifer next to an estuarine stream on the eastern Mediterranean coast. Groundwater levels and salinization patterns were examined as a response to dynamic changes in estuary water, both in low-and high-permeability aquifer units. In the high-permeability unit, the extent of salinization was relatively constant, reaching a distance of at least 80 m from the river, with no long-term changes in fresh-saline interface depth, indicating that the system is in a quasi-steady state. Groundwater salinity in the low-permeability unit showed frequent and large fluctuations (up to 36 and 22 at 5 and 20 m from the river, respectively). We suggest that the river may have a more immediate impact on a low-permeability than on a high-permeability aquifer. This is dependent on the history of seawater encroachments to the river, which are better preserved in the low-permeability unit, and on the hydrogeology of this unit, where sand lenses can serve as high-permeability conduits. However, this unit can efficiently prevent a large extent of salinization of the regional coastal aquifer by the estuary water.

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Salt tectonics in the Eastern Mediterranean Sea: Where a giant delta meets a salt giant

Geology ◽

10.1130/g47031.1 ◽

2019 ◽

Vol 48 (2) ◽

pp. 134-138 ◽

Cited By ~ 3

Author(s):

Elchanan Zucker ◽

Zohar Gvirtzman ◽

Josh Steinberg ◽

Yehouda Enzel

Keyword(s):

Deep Sea ◽

Nile Delta ◽

Eastern Mediterranean ◽

Elevation Gradient ◽

Salt Tectonics ◽

Deep Basin ◽

Delta Front ◽

Squeeze Out ◽

Levant Basin ◽

Sea Fan

Abstract The circum-Nile deformation belt (CNDB) demonstrates the interaction between a giant delta and a giant salt body. The semi-radial shape of the CNDB is commonly interpreted as the product of salt squeezing out from under the Nile Delta. We demonstrate, however, that this is not the dominant process, because the delta and its deep-sea fan do not reach the deep-basin salt. The distal part of the deep-sea fan overlies the edge of the salt giant, but squeezing this edge (<150 m thickness) should have had only little effect on the regional salt tectonics. Only on the easternmost side of the deep-sea fan, toward the Levant Basin, does the squeeze-out model work. Here, the delta front reaches the thick salt layer and differential loading promotes basinward salt flow, even upslope. On the western side of the delta, downslope gliding of the sediment-salt sequence toward the Herodotus Basin is driven by the elevation gradient toward the deepest part of the basin. Our analysis shows that salt squeezing by differential loading was previously overestimated in the Eastern Mediterranean and raises the need to carefully map the boundary of salt basins prior to any interpretation. This conclusion is especially relevant in young basins where deltas and shelves have not propagated far enough into the basin.

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Greek History

Greece and Rome ◽

10.1017/s0017383517000109 ◽

2017 ◽

Vol 64 (2) ◽

pp. 193-198

Author(s):

Kostas Vlassopoulos

Keyword(s):

Eastern Mediterranean ◽

Late Antique ◽

Greek History ◽

History Of ◽

Late Roman

Three cities dominated the late antique eastern Mediterranean: Constantinople, Alexandria, and Antioch. Constantinople was the late Roman re-foundation of an archaic Greek apoikia, Byzantion; Alexandria and Antioch were cities created by Alexander and his Hellenistic successors. This review includes two important books that examine the long-term history of two of these cities: Byzantion and Antioch. Both books stress the need to situate these cities within the landscapes and territories from which they drew their economic, political, and spiritual sustenance; both also adopt a long-term perspective, covering roughly a millennium each, which makes it possible to trace wider continuities, trends, and changes.

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