- Jerusalem, Yerushalayim, Israel
Zohar Gvirtzman
G.S.I., Stratigraphy and sub-surface, Department Member
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... Compiled chronostratigraphic charts were published by Bein and Gvirtzman (1977) and by Picard and Hirsch (1987). ... the earliest part of the first transgressive cycle of the Ardon For-mation is missing in the Negev (drilled in... more
... Compiled chronostratigraphic charts were published by Bein and Gvirtzman (1977) and by Picard and Hirsch (1987). ... the earliest part of the first transgressive cycle of the Ardon For-mation is missing in the Negev (drilled in northern Sinai and termed Dika Formation; Buchbinder ...
Research Interests: Geology and Subsidence
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Research Interests: Earth Sciences, Geology, Geochemistry, Paleontology, Brackish Water, and 14 morePaleogeography, Salinity, Messinian Salinity Crisis, Paratethys, Gypsum, Facies, Mediterranean Climate, Evaporite, Marl, Mediterranean Basin, Basin connectivity, Lago-Mare, Salt Giant, and Atlantic-Mediterranean connectivity
At present, salt tectonics in the Levant Basin comprises extension along the continental slope and folding and thrusting in the deep basin. However, here we show that the shape, the age, and the amplitude of deformation in the extensional... more
At present, salt tectonics in the Levant Basin comprises extension along the continental slope and folding and thrusting in the deep basin. However, here we show that the shape, the age, and the amplitude of deformation in the extensional and contractional domains do not fit the paradigm of “updip extension and downdip contraction.” Deep basin shortening is not parallel to continental margin extension; it is younger and stronger. We propose that while extension of the Levant continental slope is an expression of basinward gliding, the deep basin shortening belongs to the circum‐Nile deformation belt (CNDB) propelled by out‐squeezing of salt from under the Nile delta. However, despite the independent driving forces, the two deformation systems seem to affect each other. In the southern part of the basin where the two systems meet, the NW gliding of the continental slope is restrained by the NE motion of the CNDB and vice versa. Interestingly, the beginning of folding along the CNDB (...
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We present a basin-wide correlation of the pre-evaporitic succession across the deep Levant basin, based on integrated bio- and cyclostratigraphy. The onset of Messinian salinity crisis (MSC) can be placed in all studied wells where... more
We present a basin-wide correlation of the pre-evaporitic succession across the deep Levant basin, based on integrated bio- and cyclostratigraphy. The onset of Messinian salinity crisis (MSC) can be placed in all studied wells where foraminifers suddenly disappear and normal marine calcareous nannofossils are replaced by opportunistic assemblages. These changes mark the base of the Foraminifers Barren Interval (FBI), a 10s-of-m-thick (below seismic resolution), evaporite-free, shale unit that records the entire duration of the first stage. Moving towards the basin margin the FBI is progressively truncated on top by the Messinian erosional surface (MES), a regional-scale discontinuity sealed by a thin clastic evaporite units overlain by thick halite deposits. Our results confirm previous hypothesis suggesting that the crisis started in deep- as well as in shallow-water settings at 5.97 Ma and pointing to a synchronous onset of the MSC but diachronous deposition of evaporites. During stage 1 of the crisis, coeval with gypsum deposition in marginal basins, the salinity in deep basins progressively increased (with possible oxygen reduction) hindering the life of marine organisms. Then, at 5.60 Ma, when salinity in deep basins exceeded halite saturation, massive halite precipitation started, and a nearly 2-km-thick salt sequence accumulated in deep basins within a short period of 60 kyr. At that time (stage 2), sedimentation rate jumped by an order of magnitude reaching a few cm/yr. Similar sedimentation rates are inferred for the Realmonte salt mine (Sicily) and observed in the modern Dead Sea and artificial salinas
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Hydrological restriction from the Atlantic Ocean and a negative freshwater balance transformed the Mediterranean Sea into a giant saline basin during the Messinian Salinity Crisis (MSC) (5.97 – 5.33 million years ago). After more than 50... more
Hydrological restriction from the Atlantic Ocean and a negative freshwater balance transformed the Mediterranean Sea into a giant saline basin during the Messinian Salinity Crisis (MSC) (5.97 – 5.33 million years ago). After more than 50 years of research, it is still unclear if the deposition of nearly one million km3 of evaporite salts during this event was accompanied by a major (≥ 1.5 km) drawdown of Mediterranean sea level; and if halite deposition occurred only during this drawdown event, or also in a filled Mediterranean connected to the Atlantic.We present evidence based on the chlorine stable isotope composition of halite for a sea level drawdown of 2 km in the eastern Mediterranean during the final stages of deposition of the Mediterranean halite layer. This is the largest sea level drop ever reported from the geological record and implies a short (~20 kyr), but nearly complete hydrological disconnection of the Mediterranean from the Atlantic. About half of the halite volu...
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Log analysis, seismic interpretation, channel identification and distinction methods, and additional results.
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The question of whether the Mediterranean Sea desiccated during the Messinian salinity crisis (MSC) has been strongly debated for decades. In the Levant Basin, this debate was recently reignited in relation to the latest stage of the... more
The question of whether the Mediterranean Sea desiccated during the Messinian salinity crisis (MSC) has been strongly debated for decades. In the Levant Basin, this debate was recently reignited in relation to the latest stage of the crisis after cessation of salt deposition. The desiccation supporters argue that salt truncation—and its subsequent burial by a latest Messinian, clastic-rich evaporitic unit—occurred subaerially on a desiccated seafloor. However, we show that this latest Messinian unit contains a dense net of channels with meanders, levees, and overspill deposits and is very similar to the turbidite channels observed on the modern seafloor. The aggradation characteristics of these buried channels (levee height, channel depth, and channel-floodplain coupling) indicate a marine rather than fluvial origin. Our conclusion adds to the findings of a previous study that salt truncation occurred in deep waters by dissolution. In a wider perspective, we suggest that the flush o...
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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... more
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 sal...
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We present an interpretation of the two strongest magnetic anomalies produced by Ramon Basalt (Early Cretaceous volcanics within the Hatira Formation) located in the west Ramon area (central Negev, southern Israel): The shape of the... more
We present an interpretation of the two strongest magnetic anomalies produced by Ramon Basalt (Early Cretaceous volcanics within the Hatira Formation) located in the west Ramon area (central Negev, southern Israel): The shape of the anomalies, particularly the WNW location of the low in relation to the high, suggests a WNW magnetization caused by a strong remanent magnetization. This hypothesis was confirmed by a paleomagnetic study that revealed this magnetization in the exposed edge of the southern body. All three basalt flows comprising this body have remarkably strong natural remanent magnetization (NRM) ranging from 8 to 23 Nm, with Konigsberger ratios ranging from 6 to 15. The upper flow has the strongest NRM of the three, with a WNW declination (288°), as expected from the shape of the aeromagnetic anomaly. The unusual intensity and direction of the NRM are uncommon in outcrops of Ramon Basalt and are related to a late overprint. In our model, the effecti ve magnetization of ...
ABSTRACT Seismic tomography has developed into one of the most effective and significant sources of information in modern geophysical research, specifically in understanding subduction zone dynamics. The Western Pacific convergent margin... more
ABSTRACT Seismic tomography has developed into one of the most effective and significant sources of information in modern geophysical research, specifically in understanding subduction zone dynamics. The Western Pacific convergent margin is a well studied area, but as more data is collected and technology improves further detailed observations and theories are being developed. New tomographic images of the Mariana Arc region have enhanced resolution of gradients and strong variations in wave speeds through the use a three-dimensional ray-tracing inversion algorithm. Although the images obtained from the Mariana arc show relatively low amplitudes of heterogeneity due to the limited number of seismic stations in the area, details of the geometry and morphology of the Pacific Plate subducting beneath the Philippine Sea Plate are visualized in three dimensions with unprecedented detail. The slab has an arcuate shape in depth, similar to the surface expression of the trench axis, and plunges steeply into the lower mantle in the northern and central portion. A markedly different geometry exists south of 14°N where the slab continues to have a steep dip, but is only 200 km in length. Between the two distinct morphologies is a seismic velocity anomaly that we interpret as a tear. This near vertical tear in the slab strikes E-W, is 75-200 km in depth, and has an eastern extent of 145.5°E and continues westward to approximately 143.5°E. We propose three models to explain the formation of the tear: rapid rollback of the Challenger Deep slab segment, the junction of the Pacific and Caroline plates, or the subduction of the Caroline Islands Ridge.
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... siliciclastics, offshore Israel, highlighted a new world-class gas province, and has subsequently ... Gvirtzman, Z., Steinberg, J., Bar, O., Buchbinder, B., Zilberman, E., Siman-Tov, R., Calvo, R., Grossowicz, L., Almogi-Labin, A.,... more
... siliciclastics, offshore Israel, highlighted a new world-class gas province, and has subsequently ... Gvirtzman, Z., Steinberg, J., Bar, O., Buchbinder, B., Zilberman, E., Siman-Tov, R., Calvo, R., Grossowicz, L., Almogi-Labin, A., and Rosensaft, M. ABSTRACT 1. INTRODUCTION 1.1. ...
&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;am... more
&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;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.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;Keywords: Messinian Salinity Crisis, Channel systems, Evaporites, Seismic Reflection Profiles&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;
Abstract Numerous normal faults, expressing thin-skinned salt tectonics, are detected along the Levant continental slope, 15–30 km west of the Israeli coast. Previous studies estimated that this faulting initiated during Late Pliocene to... more
Abstract Numerous normal faults, expressing thin-skinned salt tectonics, are detected along the Levant continental slope, 15–30 km west of the Israeli coast. Previous studies estimated that this faulting initiated during Late Pliocene to Early Pleistocene, which leaves an uncertainty of about 50% in the total duration of active faulting. The purpose of this study is to improve the dating of the onset of faulting, and to reconstruct displacement rates with time. This will allow better understanding of salt tectonics as well as better assessment of geohazards. To increase dating resolution, we use 2D and 3D seismic material integrated with well logs and cuttings to combine bio- and seismo-stratigraphic data and to divide the Plio-Quaternary section offshore Israel to 4 depositional units: Pliocene (5.33–2.6 Ma); Gelasian (2.6–1.8 Ma); Calabrian-Ionian (1.8–0.35 Ma); and Ionian-Holocene ( Our analysis shows that during the Pliocene (duration of 2.7 my) faulting activity was minor. In the Gelasian (duration of 0.8 my) faulting activity peaked alongside huge slumping. In the past 1.8 my, faulting and slumping had both decreased, but they are still active today. The observation that the onset of faulting significantly predates the progradation of the shelf edge to its present location indicates that differential loading was probably not the first trigger that initiated salt tectonics offshore Israel. The association of intense faulting and slumping in the Gelasian is interpreted as a result of basinwards tilting due to regional inland uplift and basin subsidence. Yet positive feedback between faulting and slumping cannot be ruled out. The presence of fault scars on the present seafloor, where current sedimentation rate is similar and even faster than the average displacement rate, apparently indicates that faulting is dominated by sudden seismic ruptures rather than by continued creeping. Hence, considering sedimentation rate of about 50 m/my, a 1 m high fault scarp should be roughly younger than about 20 ky.