Twenty million years of continuous deformation along theKarakorum fault, western Tibet: A thermochronological analysis.

The role of the Karakorum fault zone (KFZ) is debated. South of 33°N, ongoing dextral-oblique slip along the SW edge of the Gar basin exhumes metamorphic and magmatic rocks of the Ayilari range. Minerals have recorded a continuum of deformation from temperatures >600–400°C down to 20 Ma of deformation along the fault. Greenschist facies deformation superimposed upon the medium- to high-grade deformation marks a kinematic change from pure dextral to dextral-normal motion associated with the onset of rapid cooling. At the regional scale, the coexistence of transtension in the Gar basin with transpression documented along the Pangong range farther north suggests another example of the ‘‘zipper tectonics'' model developed along the Red River fault. The kinematic shift induced the rise of the Ayilari range starting at 16–12 Ma and the incision of major river courses. The Indus River might have become captive of the relief at this time. The river's 120 km of apparent offset implies dextral motion at a long-term rate of ca 8.5 ± 1.5 mm/yr

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Décrochement lithosphériques dans l'ouest du plateau du Tibet (géométrie, âge, décalages cumulés et vitesse de glissement long-terme sur la Faille du Karakorum)

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Sci.Terre recherche (751052114) / SudocSudocFranceF

Source and tectono-metamorphic evolution of mafic and pelitic metasedimentary rocks from the central Quetico metasedimentary belt, Archean Superior Province of Canada.

A study of the Jean Lake area of the Quetico metasedimentary belt, Superior Province, Canada, was conducted in order to evaluate the origin, source and evolution of sedimentary rocks, including mafic rocks previously mapped as ultramafics rocks. Bulk chemical compositions of these rocks show a mixing with two end members: quartzo-feldspathic sediments and komatiitic basalts. High CaO and MgO contents of the rocks suggest a proximal source of komatiitic basalts, probably from the southern Wabigoon subprovince. The rocks in the Jean Lake area record a pressure-temperature (P-T) path with three tectono-metamorphic stages. The first stage formed staurolite (500-700°C) under medium P-T (MP-MT) metamorphic conditions shortly after the sedimentation. The second stage yielded the biotite-sillimanite-garnet assemblage under the peak condition of 0.6 0.1 GPa and 700 70°C during transpressional deformation. The third stage, low P- medium T (0.25 0.11 GPa, 540 80°C) metamorphism, was associated with regional south-southeast compression and its timing is constrained by a new U-Th-Pb monazite age of 2667 20 Ma. Combining the regional deformation events, we suggest that the sediments in the Jean Lake area were buried up to MP-MT conditions during the D1 deformation at 2698-2689 Ma. They attained the peak metamorphic condition during the regional transpressive D2-D3 deformation (2689-2671 Ma), and retrograded to LP-MT condition during the south-southeast compression of the regional D4 at 2671-2667 Ma. The tectono-metamorphic history of the study area is consistent with the sedimentation in an accretionary prism followed by its docking to the Wabigoon subprovince to the north and Wawa greenstone belt to the south. The P-T-time path of this Archean accretionary prism is similar to that in modern arc accretion systems, except for a higher temperature gradient, ~ 30°C/km, recorded in the Quetico belt compared to ~10°C/km in modern counterparts. The high temperature gradients in the Quetico belt explain the lack of high-pressure metamorphic rocks, such as blueschist, that are common in modern accretionary prisms

Source and tectono-metamorphic evolution of mafic and pelitic metasedimentary rocks from the central Quetico metasedimentary belt, Archean Superior Province of Canada.

A study of the Jean Lake area of the Quetico metasedimentary belt, Superior Province, Canada, was conducted in order to evaluate the origin, source and evolution of sedimentary rocks, including mafic rocks previously mapped as ultramafics rocks. Bulk chemical compositions of these rocks show a mixing with two end members: quartzo-feldspathic sediments and komatiitic basalts. High CaO and MgO contents of the rocks suggest a proximal source of komatiitic basalts, probably from the southern Wabigoon subprovince. The rocks in the Jean Lake area record a pressure-temperature (P-T) path with three tectono-metamorphic stages. The first stage formed staurolite (500-700°C) under medium P-T (MP-MT) metamorphic conditions shortly after the sedimentation. The second stage yielded the biotite-sillimanite-garnet assemblage under the peak condition of 0.6 0.1 GPa and 700 70°C during transpressional deformation. The third stage, low P- medium T (0.25 0.11 GPa, 540 80°C) metamorphism, was associated with regional south-southeast compression and its timing is constrained by a new U-Th-Pb monazite age of 2667 20 Ma. Combining the regional deformation events, we suggest that the sediments in the Jean Lake area were buried up to MP-MT conditions during the D1 deformation at 2698-2689 Ma. They attained the peak metamorphic condition during the regional transpressive D2-D3 deformation (2689-2671 Ma), and retrograded to LP-MT condition during the south-southeast compression of the regional D4 at 2671-2667 Ma. The tectono-metamorphic history of the study area is consistent with the sedimentation in an accretionary prism followed by its docking to the Wabigoon subprovince to the north and Wawa greenstone belt to the south. The P-T-time path of this Archean accretionary prism is similar to that in modern arc accretion systems, except for a higher temperature gradient, ~ 30°C/km, recorded in the Quetico belt compared to ~10°C/km in modern counterparts. The high temperature gradients in the Quetico belt explain the lack of high-pressure metamorphic rocks, such as blueschist, that are common in modern accretionary prisms

Source and tectono-metamorphic evolutionnext term of mafic and pelitic metasedimentary previous termrocksnext term from the central Quetico metasedimentary belt, Archean Superior Province of Canada

International audienceA study of the sedimentary previous termrocksnext term in the Jean Lake area of the Quetico metasedimentary belt, Superior Province, Canada, was conducted in order to evaluate the origin, previous termsource, and evolution of rocks,next term including mafic previous termrocksnext term previously mapped as previous termultramafics rocks.next term Bulk compositions of these sedimentary previous termrocksnext term show a mixing between two end members: quartzo-feldspathic sedimentary previous termrocknext term and komatiitic basalt. High CaO and MgO contents of the previous termrocksnext term suggest a proximal previous termsourcenext term of the komatiitic basalt. The previous termrocksnext term in the study area record a pressure–temperature (P–T) path with three previous termtectono-metamorphicnext term stages. The first stage formed staurolite (500–700 °C) under medium P–T (MP–MT) metamorphic conditions shortly after the sedimentation. The second stage yielded the biotite–sillimanite–garnet assemblage under the peak conditions of 0.6±0.1 GPa and 700±70 °C during transpressional deformation. The third stage, low P–medium T (LP–MT; 0.25±0.11 GPa, 540±80 °C) metamorphism, was associated with regional south-southeast compression and its timing is constrained by a new U–Th–Pb monazite age of 2667±20 Ma. Combining the regional deformation events, we suggest the burial metamorphism of sediments up to MP–MT conditions during the D1 deformation at 2698–2689 Ma. They attained the peak metamorphic conditions during the regional transpressive D2–D3 deformation (2689–2671 Ma), and retrograded to LP–MT condition during the south-southeast compression (regional D4) at 2671–2667 Ma. A short time span between the sedimentation and MP–MT metamorphism accompanied by D1 deformation suggest that the Quetico sedimentary previous termrocksnext term formed in an acretionary prism. The studied previous termrocksnext term in the Jean Lake area deposited close to the Wabigoon Subprovince, transported towards the south, and buried up to not, vert, similar20 km by rapid underthrusting to amphibolite facies conditions. Subsequent dextral transpressive deformation (D2–D3) during the oblique docking of the Quetico belt to the Wabigoon Subprovince to the north and Wawa greenstone belt from the south resulted in the displacement of the sedimentary previous termrocksnext term to the west from the original depositional site. The P–T–time path of the Quetico sedimentary previous termrocksnext term is similar to that in modern arc accretion prisms, except for a high geothermal gradient of not, vert, similar30 °C/km recorded in the former compared to not, vert, similar10 °C/km in modern counterparts. The high temperature gradient in the Archean accretionary prism explains the lack of high-pressure metamorphic previous termrocks,next term such as blueschist, that are common in modern accretionary prisms