Mesozoic and Cenozoic deformation inferred from seismic stratigraphy in the southwestern intracontinental Palmyride fold-thrust belt, Syria

This paper was published in the Geological Society of America Bulletin. The Geological Society of America retains the copyright to this paper. Geological Society of America, P.O. Box 9140 , Boulder, CO 80301-9140 USA See also: http://www.geosociety.org/; http://atlas.geo.cornell.edu/syria/chaimov_gsa_bull_1992.htmlThe Palmyride fold belt in central Syria is an intracontinental northeast-trending, 400 by 100 km transpressive belt embedded in the northern Arabian platform. During the Late Paleozoic and most of the Mesozoic the region of the present-day mountains was a rift-like trough that collected over 5 km of sediments, for a total Phanerozoic thickness of over 10 km. The southwestern sector of the fold belt is bounded in the north by the Jhar fault and in the south by the south-vergent frontal thrust faults of the Palmyrides, with the broad Al-Daww depression in between. Structural features that characterize the southern and southwestern region of the Palmyrides include a short wavelength, typically 5-10 km, fold style controlled by a regional low-angle decollement within Triassic beds, and small inverted Jurassic and Early Cretaceous normal faults. Small intermontane basins (about 10 X 30 km) whose strata can be used to document the history of Palmyride deformation flank growth fault-bend folds and are mainly a product of Cenozoic shortening in the belt. These structures are elucidated by about 2000 km of newly available seismic reflection data in the Palmyrides. Synthetic seismic traces generated solely from forward modeling of outcrop information constrain seismic stratigraphic picks in two small basins about 100 km northeast of Damascus. There, minor Late Cretaceous uplift caused local onlap, marking the first inversion phase of the Palmyride trough. Tectonic quiescence throughout the Paleogene, interrupted only in the Middle Eocene by minor tectonism, resulted in monotonous deposition of about 2500 m of mostly limestone. Marked onlap and probable downlap of Lower Miocene strata onto an Oligocene angular unconformity indicate accelerated tectonism by Late Oligocene to Early Miocene time. This marks the beginning of the major phase of inversion and uplift of the Palmyrides. Recent seismicity indicates that transpression continues today. Despite its relative remoteness from convergent plate boundaries (the nearest, the Bitlis suture in southern Turkey, is about 300 km distant), the Late Cretaceous, Middle Eocene, and Neogene phases of deformation in the intraplate setting of the Palmyrides have a direct temporal relationship with major regional tectonism that occurred along the surrounding Arabian plate boundaries. The Palmyride trough was inverted in Late Cretaceous time and, subsequently, developed into a transpressive zone throughout Neogene and Quaternary times. Thus, the initiation of inversion in the Palmyrides, an integral part of the Syrian Arc, which extends from central Syria southward to central Sinai, apparently predates development of the Red Sea/Dead Sea plate boundary. In contrast, the intense Neogene through Quaternary deformational episode is clearly related to development of the Red Sea/Dead Sea fault system and to convergence along the northern boundary of the Arabian plate in southern Turkey

Tectonic and geologic evolution of Syria

Publisher's version archived with permission from publisher.Using extensive surface and subsurface data, we have synthesized the Phanerozoic tectonic and geologic evolution of Syria that has important implications for eastern Mediterranean tectonic studies and the strategies for hydrocarbon exploration. Syrian tectonic deformation is focused in four major zones that have been repeatedly reactivated throughout the Phanerozoic in response to movement on nearby plate boundaries. They are the Palmyride Mountains, the Euphrates Fault System, the Abd el Aziz-Sinjar uplifts, and the Dead Sea Fault System. The Palmyrides include the SW Palmyride fold and thrust belt and two inverted sub-basins that are now the Bilas and Bishri blocks. The Euphrates Fault System and Abd el Aziz-Sinjar grabens in eastern Syria are large extensional features with a more recent history of Neogene compression and partial inversion. The Dead Sea transform plate boundary cuts through western Syria and has associated pull-apart basins. The geological history of Syria has been reconstructed by combining the interpreted geologic history of these zones with tectonic and lithostratigraphic analyses from the remainder of the country. Specific deformation episodes were penecontemporaneous with regional-scale plate-tectonic events. Following a relatively quiescent early Paleozoic shelf environment, the NE-trending Palmyride/Sinjar Trough formed across central Syria in response to regional compression followed by Permian-Triassic opening of the Neo-Tethys Ocean and the eastern Mediterranean. This continued with carbonate deposition in the Mesozoic. Late Cretaceous tectonism was dominated by extension in the Euphrates Fault System and Abd el Aziz-Sinjar Graben in eastern Syria associated with the closing of the Neo-Tethys. Repeated collisions along the northern Arabian margin from the Late Cretaceous to the Late Miocene caused platform-wide compression. This led to the structural inversion and horizontal shortening of the Palmyride Trough and Abd el Aziz-Sinjar Graben

Upper crustal velocity structure and basement morphology beneath the intracontinental Palmyride fold-thrust belt and north Arabian platform in Syria

An edited version of this paper was published in Geophysical Journal International by Blackwell Publishing. Copyright 1993, Blackwell Publishing. See also: http://www.blackwellpublishing.com/journal.asp?ref=0956-540X&site=1; http://atlas.geo.cornell.edu/syria/seber_gji_1993.htmThe intracontinental Palmyride fold-thrust belt, which is the site of an inverted Mesozoic rift, is sandwiched between two crustal blocks, the Aleppo plateau in the north and the Rutbah uplift in the south. The 400 x 100 km belt merges with the Dead Sea fault system in the southwest and gradually ends near the Euphrates depression in the northeast. Very dense (i.e., 100 m geophone spacing), reversed and multifold seismic refraction profiling was carried out to map approximately the upper 15 km of the crust in the early 1970s. These refraction data are utilized to model sedimentary rock thickness, seismic velocity, and basement morphology. Extensive data coverage also enables identification of the major faults of the region. A 2-D ray tracing technique is used in the modeling. Interpretation of these data indicates that five distinct velocity layers characterize the upper crust of the northern Arabian platform in Syria. The P-wave velocities within these layers are (in km s-1): 2.0-2.8, 4.0-4.4, 5.2-5.3 , 5.5-5.7, corresponding to sedimentary rocks from Quaternary to late Precambrian in age, and 5.9-6.0, corresponding to metamorphic basement. A comparison of the velocity models with the available drill hole information and seismic reflection profiles shows strong velocity variations in a given geologic formation, depending on the depth and location of the formation. The depth to metamorphic basement beneath the Palmyride fold belt clearly shows a deep trough, filled with Phanerozoic sedimentary rocks. These rocks decrease in thickness from about 11 km in the southwest to about 9 km in the central segment of the belt. The basement depth is about 6 km in the Aleppo plateau and not less than 8 km in the Rutbah uplift. Deeper basement in the Rutbah uplift is probably the result of a Precambrian rifting episode, clearly identified to the south in Jordan and Saudi Arabia. Cenozoic crustal shortening of about 20-25% across the southwestern segment of the Palmyride belt has not been sufficient to substantially reduce the size of the basement trough beneath this mountain belt. Finally, northeast decreasing basement depth in the Palmyrides supports the idea that the Palmyride Mesozoic rifting was developed as an aulacogen of the rifted Levantine margin along the eastern Mediterranean

Seismic fabric and 3-D upper crustal structure of the southwestern intracontinental Palmyride fold belt, Syria

Copyright 1993, AAPG. Reprinted by permission of the AAPG whose permission is required for further use. See also: http://aapgbull.geoscienceworld.org/; http://atlas.geo.cornell.edu/syria/chaimov_aapg_bull_1993.htmlThe Palmyride fold belt, a 400 X 100 km transpressive belt in central Syria that is the northeastern arm of the Syrian Arc, which includes the Negev fold belt in the Sinai, is the result of Late Mesozoic and Cenozoic inversion of a Late Paleozoic and Mesozoic, NE-trending, linear intracontinental basin located within the northern Arabian platform. The southwestern Palmyrides, near the Dead Sea transform fault system and the Anti-Lebanon mountains, are characterized by short wavelength (5-10 km) en echelon folds separated by small intermontane basins that developed mainly in Neogene to Recent times. A new three-dimensional data cube, 60 X 70 km, generated on a Landmark Graphics (TM) workstation and based on approximately 700 km of two-dimensional seismic reflection profiles, elucidates the structure of the upper 10 km of the crust in the southwestern Palmyrides. Visualization of the subsurface structure, which is represented by a prominent Upper Cretaceous reflection surface in the data cube, is augmented by the topography and Bouguer gravity of the same region. Preexisting discontinuities, probable normal fault relicts of the Mesozoic Palmyride rift, likely controlled the development of individual Neogene thrusts. The new subsurface image shows important structural features not identified in outcrop. Short, WNW-trending transcurrent, or transfer, faults link the short, en echelon NE-trending thrust faults and blind thrusts of the Palmyrides. A pervasive regional decollement is not observed, even though Triassic evaporites host local detachments. There has been no wholesale transport of shallower strata on a regional decollement that decouples Mesozoic and Cenozoic rocks from underlying Paleozoic rocks. Unlike topographic relief, which only roughly resembles subsurface structures, the Bouguer gravity signature of the southwestern Palmyrides closely mimics underlying shallow geologic structures both on a large (~50 km wavelength) and a small (~5-10 km) scale. Relatively uncommon reflections from deformed Paleozoic rocks and the excellent correlation between Bouguer gravity and shallow structures indicate a general concordance between shallow Mesozoic and Cenozoic rocks and deeper Paleozoic rocks. Hence, Paleozoic rocks either deformed together with shallower strata, or structures within Paleozoic rocks controlled the development of shallower Neogene and younger structures. Our structural analysis and many other recent studies of the region are indicative of minor right-lateral shear coupled with compression in the Palmyrides

Inhibition of glucose metabolism selectively targets autoreactive follicular helper T cells.

Follicular helper T (TFH) cells are expanded in systemic lupus erythematosus, where they are required to produce high affinity autoantibodies. Eliminating TFH cells would, however compromise the production of protective antibodies against viral and bacterial pathogens. Here we show that inhibiting glucose metabolism results in a drastic reduction of the frequency and number of TFH cells in lupus-prone mice. However, this inhibition has little effect on the production of T-cell-dependent antibodies following immunization with an exogenous antigen or on the frequency of virus-specific TFH cells induced by infection with influenza. In contrast, glutaminolysis inhibition reduces both immunization-induced and autoimmune TFH cells and humoral responses. Solute transporter gene signature suggests different glucose and amino acid fluxes between autoimmune TFH cells and exogenous antigen-specific TFH cells. Thus, blocking glucose metabolism may provide an effective therapeutic approach to treat systemic autoimmunity by eliminating autoreactive TFH cells while preserving protective immunity against pathogens

Sarilumab in patients admitted to hospital with severe or critical COVID-19: a randomised, double-blind, placebo-controlled, phase 3 trial

Background: Elevated proinflammatory cytokines are associated with greater COVID-19 severity. We aimed to assess safety and efficacy of sarilumab, an interleukin-6 receptor inhibitor, in patients with severe (requiring supplemental oxygen by nasal cannula or face mask) or critical (requiring greater supplemental oxygen, mechanical ventilation, or extracorporeal support) COVID-19. Methods: We did a 60-day, randomised, double-blind, placebo-controlled, multinational phase 3 trial at 45 hospitals in Argentina, Brazil, Canada, Chile, France, Germany, Israel, Italy, Japan, Russia, and Spain. We included adults (≥18 years) admitted to hospital with laboratory-confirmed SARS-CoV-2 infection and pneumonia, who required oxygen supplementation or intensive care. Patients were randomly assigned (2:2:1 with permuted blocks of five) to receive intravenous sarilumab 400 mg, sarilumab 200 mg, or placebo. Patients, care providers, outcome assessors, and investigators remained masked to assigned intervention throughout the course of the study. The primary endpoint was time to clinical improvement of two or more points (seven point scale ranging from 1 [death] to 7 [discharged from hospital]) in the modified intention-to-treat population. The key secondary endpoint was proportion of patients alive at day 29. Safety outcomes included adverse events and laboratory assessments. This study is registered with ClinicalTrials.gov, NCT04327388; EudraCT, 2020-001162-12; and WHO, U1111-1249-6021. Findings: Between March 28 and July 3, 2020, of 431 patients who were screened, 420 patients were randomly assigned and 416 received placebo (n=84 [20%]), sarilumab 200 mg (n=159 [38%]), or sarilumab 400 mg (n=173 [42%]). At day 29, no significant differences were seen in median time to an improvement of two or more points between placebo (12·0 days [95% CI 9·0 to 15·0]) and sarilumab 200 mg (10·0 days [9·0 to 12·0]; hazard ratio [HR] 1·03 [95% CI 0·75 to 1·40]; log-rank p=0·96) or sarilumab 400 mg (10·0 days [9·0 to 13·0]; HR 1·14 [95% CI 0·84 to 1·54]; log-rank p=0·34), or in proportions of patients alive (77 [92%] of 84 patients in the placebo group; 143 [90%] of 159 patients in the sarilumab 200 mg group; difference −1·7 [−9·3 to 5·8]; p=0·63 vs placebo; and 159 [92%] of 173 patients in the sarilumab 400 mg group; difference 0·2 [−6·9 to 7·4]; p=0·85 vs placebo). At day 29, there were numerical, non-significant survival differences between sarilumab 400 mg (88%) and placebo (79%; difference +8·9% [95% CI −7·7 to 25·5]; p=0·25) for patients who had critical disease. No unexpected safety signals were seen. The rates of treatment-emergent adverse events were 65% (55 of 84) in the placebo group, 65% (103 of 159) in the sarilumab 200 mg group, and 70% (121 of 173) in the sarilumab 400 mg group, and of those leading to death 11% (nine of 84) were in the placebo group, 11% (17 of 159) were in the sarilumab 200 mg group, and 10% (18 of 173) were in the sarilumab 400 mg group. Interpretation: This trial did not show efficacy of sarilumab in patients admitted to hospital with COVID-19 and receiving supplemental oxygen. Adequately powered trials of targeted immunomodulatory therapies assessing survival as a primary endpoint are suggested in patients with critical COVID-19. Funding: Sanofi and Regeneron Pharmaceuticals

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity