Evolution of the Levant alongside Africa-Arabia breakup
Our research highlights the importance of a ~15 myr period during the early stage of Africa-Arabia breakup when the Red Sea began opening, the Tethys Ocean was closing, and a huge land mass now composing the Middle East region was uplifted and exposed. We show that at that time, prior to the localization of deformation along the DST, the Levant (passive) continental margin was tectonically reactivated. In a series of recent studies we have documented and analyzed the Late Tertiary history of the Levant region in several aspects:
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First, we show that approximately 35 my ago a significant change has occurred in the paleogeography, nature of sedimentation, vertical motions, faulting; and magmatism;
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We describe the paleogeography in terms of inland uplift and shoreline retreat;
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We document the rapid filling of the Levant basin concurrent with inland uplift and discuss possible sediment sources;
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We document an Oligocene to Early Miocene transpressional deformation along the continental margin and interpret it in terms of an incipient plate boundary that developed at the early stage of Africa-Arabia breakoff and then failed;
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We document a Late Miocene to Early Pliocene extensional deformation along the central coastal plain, which previously was identified only in Northern Israel;
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We analyze the opposing vertical motions of the inland and offshore regions by distinguishing between tectonic forces and isostatic response to sedimentary loading;
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We present a set of structural and isopach maps that illustrate basin architecture down to the unconformity surface at the base of the Saqiye Group (nearly base Oligocene).
Reactivation of the Levant passive margin during the late Tertiary and formation of the Jaffa Basin offshore central Israel
Reexamination of the stratigraphic record in the continental margin of Israel indicates that approximately 35 my ago sedimentation rates increased after prolonged gradual decay; the shelf-slope facies transition zone was revived; faulting and magmatism resumed and the Judea Hills began rising. The combination of these processes along with the Africa-Arabia breakup eventually led to the recognition that the overall picture at that time should be understood in terms of plate boundaries.
Gvirtzman, Z., Zilberman, E., Folkman, Y., 2008.
Reactivation of the Levant passive margin during the late Tertiary and formation of the Jaffa Basin offshore central Israel,
Journal of the Geological Society, 165, 563-578, doi:10.1144/0016-
76492006-200
Retreating Late Tertiary Shorelines in Israel: Implications for the Exposure of north Arabia and Levant During Neo-Tethys Closure
We examine the trends of Late Tertiary shorelines from central Israel northwards and document the gradual change in shoreline direction. We discuss the regional gradual land exposure and suggest that northern Israel was exposed much later than central and southern Israel and that a major phase of regional uplift occurred in the Early Miocene.
Gvirtzman, Z., Steinberg, J., Siman-Tov, R., Zilberman, E., Bar, O., Calvo, R., Grossowicz, L., Almogi-Labin, A., and Rosensaft, M., 2011, Retreating Late Tertiary Shorelines in Israel: Implications for the Exposure of north Arabia and Levant During Neo-Tethys Closure, Lithosphere, vol. 3., 95-109, DOI: 10.1130/L124.1.
The origin and nature of the rapid late Tertiary filling of the Levant Basin
We present two fundamental observations. Firstly, that more than half of the Levant Basin sedimentary column accumulated within a mere ~15% of the basin's life span, that is a ~6 km thick section within 37 million years (post Mid Eocene). Secondly, that this young section first accumulated in the deep basin and only then did large amounts of sediments amass along the eastern Levant continental margin. Our analysis suggests that Africa was the dominant sediment source, though turbidity currents probably entered the basin both from south and from east.
Steinberg, J., Gvirtzman, Z., Folkman, Y., and Garfunkel, Z., 2011, The origin and nature of the rapid late Tertiary filling of the Levant Basin, Geology, vol. 39, 355-458, DOI: 10.1130/G31615.1.
Inland Jump of the Arabian Northwest Plate Boundary from the Levant Continental Margin to the Dead Sea Transform
While the breakup of Arabia and Africa began in the Early Oligocene, the northwestern boundary of the Arabian Plate along the Dead Sea Transform (DST) formed 10-15 my later (Early-Mid Miocene). Here we describe an abandoned segment of the Arabian northwestern plate boundary that extended at that time from the northern tip of the Suez Rift northeastwards, along the Levant margin. We propose that during the early stage of continental breakup a left-lateral strike-slip motion of ~10 km took place along this embryonic plate boundary.
Gvirtzman, Z. and Steinberg, J., 2012, Inland jump of the Arabian northwest plate boundary from the Levant continental margin to the Dead Sea Transform, Tectonics, vol. 31, TC4003, doi:10.1029/2011TC002994.
Late Miocene to Early Pliocene extension
Using old seismic data from the coastal plain of central Israel we documented a Late Miocene to Early Pliocene phase of deformation, previously described only in northern Israel. This deformation phase includes a 70 km long, N-S, normal fault with a vertical throw of 200-400 meters (Steinberg et al., 2008), and an E-W normal fault, known as the Or Akiva fault, with a vertical throw exceeding 1000m south of Mt. Carmel (Steinberg et al., 2010). The existence of these faults shows that the Late Miocene- Early Pliocene extension that was previously described in the Galilee, affected a region larger than previously estimated.
Steinberg, J., Gvirtzman, Z., Gvirtzman, H., Ben Gai, Y., 2008, Late Tertiary faulting along the coastal plain of Israel. Tectonics, 27, doi:10.1029/2007TC002151
Steinberg, J., Gvirtzman, Z., Folkman, Y., 2010. New age constraints on the evolution of the Mt. Carmel structure and its implications on a Late Miocene extensional phase of the Levant continental margin.
Journal of the Geological Society, vol. 167, 203-216, doi: 10.1144/0016-76492009-089.
Late Tertiary subsidence of the Levant continental margin: Distinction between sedimentary load and tectonics
Since the Middle Eocene, the northwest Arabian Platform has been emerging from water and rising above sea level, whereas the adjacent Levant Basin has been subsiding and accumulating a thick sedimentary section. We suggest that the enhanced subsidence of the basin and its continental margin, reflect an isostatic response to sedimentary filling of a pre-existing deep-water basin with no involvement of a downward tectonic force. On the contrary, we argue that the regional tectonic force was upward counteracting sedimentary loading. The regional implication of this understanding is that the cause for uplifting and exposure of the Arabian platform in the Late Tertiary extended far westward beyond the inland region, where this process was accompanied by magmatism and heating.
Bar, O., Gvirtzman, Z., Feinstein, S., Zilberman, E., 2013, Accelerated Subsidence and Sedimentation in the Levant Basin during the Late Tertiary and Concurrent Uplift of the Arabian Platform: Tectonic versus Counteracting Sedimentary Loading Effects, Tectonics, vol. 32 (3), 334-350, DOI: 10.1002/tect.20026
The uplift history of the Arabian Plateau as inferred from geomorphologic analysis of its northwestern edge
The Arabian Plateau (AP) is an Oligocene sub-horizontal regional planation surface, extending throughout the western half of the Arabian Peninsula. Its present elevation of about 1 km required a prominent uplift since the Late Eocene. In order to reconstruct the uplift history, we documented abundant abrasive and fluvial terraces that were left along and across the raised Judea Mountains (JM), which comprised the NW edge of the AP. Using the ages of those terraces and the differences in height between them, we found that the JM was uplifted in three major phases: a few hundred meters during the Late Eocene–Early Oligocene, ~500 m during the Early Miocene–early Middle Miocene, and ~350mduring the Late Pliocene. The two earliest uplift phases predate the formation of the Dead-Sea Transform (DST), which today separates the JM from the AP, meaning that these two phases affected the continuous rigid lithosphere extending southeastwards to the AP interiors.
Moreover, restoration of the paleogeography predating the lateral offset along the DST eliminates the main height differences across it and suggests that the DST does not play a major role in the vertical position of its bordering plates, but rather forms a relatively narrow deformation stripwithin the AP. Those two early phases of uplift can be corroborated by previous thermochronology studies, which exhibit similar ages around the Red Sea but may reflect the uplift age of the entire region. The present sub-horizontalmorphology of the AP is in contrast to the presumed original northeastward drainage andmay suggest a subsequent long-wavemoderate tilting to theSW. Three possible mechanisms were suggested for the uplift of the AP: a long wavelength flexure of the Arabian plate during early stages of the uplift, and lithospheric thinning or dynamic topography during later stages of the uplift.