ALBERT

Description: 〈span〉〈div〉Abstract〈/div〉Two Cenozoic magmatic cycles occurred in Sardinia separated by a 5 Ma gap: Oligo-Miocene (OM) subduction-related calc-alkaline magmatism associated with Sardinia migrating from the European continental margin to its current location, and Plio-Pleistocene (PP) intraplate alkaline magmatism associated with the opening of the southern Tyrrhenian basin. Based on an integration of new and published geochemical data on the Cenozoic volcanic rocks of Sardinia, and regional tectonics, we propose that a northward propagating slab tear formed south of Sardinia at the end of the OM cycle. This was responsible for the transition from subduction-controlled calc-alkaline to extension-controlled mildly alkaline to peralkaline magmatism in the Sulcis area (SW Sardinia), and for the end of the OM magmatism. The inflow of hotter material from the European Asthenospheric Reservoir (EAR) through the slab window could have produced the minor EAR-type alkaline lavas that erupted at the end of the OM cycle and at the beginning of the PP cycle. The dominant younger PP lavas with EMI-type compositions likely formed from decompression melting of a shallower lithospheric mantle with little influence from the EAR-forming event.〈strong〉Supplementary material:〈/strong〉〈a href="https://doi.org/10.6084/m9.figshare.c.4447802"〉https://doi.org/10.6084/m9.figshare.c.4447802〈/a〉〈/span〉

Description: 〈span〉Active fold-and-thrust belts can potentially accommodate large-magnitude earthquakes, so understanding the structure in such regions has both societal and scientific importance. Recent studies have provided evidence for large earthquakes in the Western Transverse Ranges of California, USA. However, the diverse set of conflicting structural models for this region highlights the lack of understanding of the subsurface geometry of faults. A more robust structural model is required to assess the seismic hazard of the Western Transverse Ranges. Toward this goal, we developed a forward structural model using Trishear in MOVE® to match the first-order structure of the Western Transverse Ranges, as inferred from surface geology, subsurface well control, and seismic stratigraphy. We incorporated the full range of geologic observations, including vertical motions from uplifted fluvial and marine terraces, as constraints on our kinematic forward modeling. Using fault-related folding methods, we predicted the geometry and sense of slip of the major faults at depth, and we used these structures to model the evolution of the Western Transverse Ranges since the late Pliocene. The model predictions are in good agreement with the observed geology. Our results suggest that the Western Transverse Ranges comprises a southward-verging imbricate thrust system, with the dominant faults dipping as a ramp to the north and steepening as they shoal from ∼16°–30° at depth to ∼45°–60° near the surface. We estimate ∼21 km of total shortening since the Pliocene in the eastern part of the region, and a decrease of total shortening west of Santa Barbara down to 7 km near Point Conception. The potential surface area of the inferred deep thrust ramp is up to 6000 km〈sup〉2〈/sup〉, which is of sufficient size to host the large earthquakes inferred from paleoseismic studies in this region.〈/span〉

Description: The WHO Thematic Platform for Health Emergency and Disaster Risk Management Research Network (TPRN) was established in 2016 in response to the Sendai Framework for Disaster Risk Reduction 2015–2030. The TPRN facilitates global collaborative action for improving the scientific evidence base in health emergency and disaster risk management (Health EDRM). In 2018, the WHO convened a meeting to identify key research questions, bringing together leading experts from WHO, TPRN, World Association for Disaster and Emergency Medicine (WADEM), and the Japan International Cooperation Agency, and delegates to the Asia Pacific Conference on Disaster Medicine (APCDM). The meeting identified research questions in five major areas for Health EDRM: health data management, psychosocial management, community risk management, health workforce development, and research methods and ethics. Funding these key research questions is essential to accelerate evidence-based actions during emergencies and disasters.

Description: 〈span〉〈div〉Abstract〈/div〉In this research work load-indentation tests with porewater pressure measurement were conducted to explore the unexpected differences due to water saturation on the linear cutting of a permeable quartzose sandstone using drag and disc type cutters. This was done to evaluate the probable role of porewater pressure on the rock fragmentation by drag and disc type cutters. The contrastive response to water saturation of these two types of cutters might be explained by the effects due to their different fragmentation mechanisms, such as the relative size of the crushed zone that forms beneath the cutters. The relationship between cutting speed and rock permeability was expected to be a major factor influencing the effective pressure beneath a cutter in saturated rock. However, load-indentation tests with pore pressure measurement at the same speed showed that the pore pressure within the tested sandstone remained too low to affect the rock fracture process. Other possible mechanisms are discussed.〈/span〉

Description: 〈span〉〈div〉Abstract〈/div〉Two Cenozoic magmatic cycles occurred in Sardinia separated by a 5 myr gap: Oligo-Miocene subduction-related calc-alkaline magmatism associated with Sardinia migrating from the European continental margin to its current location, and Plio-Pleistocene intraplate alkaline magmatism associated with the opening of the southern Tyrrhenian basin. Based on an integration of new and published geochemical data on the Cenozoic volcanic rocks of Sardinia, and regional tectonics, we propose that a northward propagating slab tear formed south of Sardinia at the end of the Oligo-Miocene cycle. This was responsible for the transition from subduction-controlled calc-alkaline to extension-controlled mildly alkaline to peralkaline magmatism in the Sulcis area (SW Sardinia), and for the end of the Oligo-Miocene magmatism. The inflow of hotter material from the European Asthenospheric Reservoir (EAR) through the slab window could have produced the minor EAR-type alkaline lavas that erupted at the end of the Oligo-Miocene cycle and at the beginning of the Plio-Pleistocene cycle. The dominant younger Plio-Pleistocene lavas with EMI-type compositions probably formed from decompression melting of a shallower lithospheric mantle with little influence from the EAR-forming event.〈strong〉Supplementary material:〈/strong〉 A summary of Sulcis rocks petrography, representative whole-rock analysis of Sulcis rocks, Sr, Nd and Pb isotope analytical methods and results, a list of sources of whole-rock geochemical data from the literature and complementary diagrams are available at 〈a href="https://doi.org/10.6084/m9.figshare.c.4447802"〉https://doi.org/10.6084/m9.figshare.c.4447802〈/a〉〈/span〉

Description: 〈span〉〈div〉Abstract〈/div〉A Jurassic extensional detachment associated with carbonated serpentinites and basalts is preserved at Falotta (Platta nappe, southeastern Switzerland). Structural data indicate that fluid circulation occurred during late increments of extension along the detachment plane at the contact between serpentinites and basalts. The homogeneity of the isotopic signatures (δ〈sup〉18〈/sup〉O ∼16‰ and δ〈sup〉13〈/sup〉C centered on 0‰–1‰) can be best explained by a single, sudden seawater-derived carbonation event at temperatures of ∼100 °C. Carbonation was focused in the high-permeability zone along the detachment. Our model yields new insights for carbonation processes related to mantle exhumation.〈/span〉

Description: 〈span〉〈div〉Abstract〈/div〉We analyzed the configurations of the lineaments derived from imagery and airborne light detection and ranging (lidar) data in the Koyna–Warna region of reservoir‐triggered seismicity (RTS). These lineaments generally correlate with aeromagnetic and gravity anomalies that may be caused by basement discontinuities and fracture systems that are expressed as north–south, northwest–southeast, and northeast–southwest features on the surface. Our results from Synthetic Aperture Radar (SAR) interferometry show displacement fields close to the Warna reservoir after M≥5.0 earthquakes in 2009. Direct evidence of faulting and slip surfaces is encountered as slickensides in deep boreholes in the region. Acoustic televiewer imaging in these boreholes shows varying patterns of fractures in the basement and in the overlying Deccan basalts. These new data support an inheritance model for basement faulting involving repeated reactivation and upward propagation of basement faults and fractures into the overlying Deccan Trap strata. We suggest that the Koyna and Warna reservoirs overlie a shear zone possibly connecting the eastern and western Dharwar cratons exposed in southern India. The repeated movements along basement faults in this shear zone enhance porosity and permeability of the fractures and provide conduits for water percolation and increase of pore fluid pressure. The presence of such fluid‐filled fractured basement rocks in the Koyna–Warna region may explain the continuously triggered earthquakes during the past five decades.〈/span〉

Description: 〈span〉〈div〉Abstract〈/div〉The weakly porphyritic, mesocratic to melanocratic brown and grey Stolzenfels Enderbite, charno-enderbite and granodiorite crops out as a northwest-trending, 13 km long elongate pluton that crosses the Orange River border between Namibia and South Africa. It is a member of the late- to post-tectonic Komsberg Suite (~1125 to 1105 Ma) that intruded the pre-tectonic gneisses (~1230 to 1150 Ma) in the Kakamas Domain of the Mesoproterozoic Namaqua-Natal Province. The Stolzenfels pluton shows significant, but generally gradational, variations in texture, mineralogy and degree of deformation. It is most commonly weakly K-feldspar porphyritic or coarse-grained equigranular but can, rarely, be strongly porphyritic. Quartz, plagioclase, antiperthite, hornblende and biotite are the predominant minerals whereas orthopyroxene is present in minor amounts in the charnockitic varieties. Most of the pluton is only weakly deformed but a penetrative Namaqua foliation is observed along the eastern margin. Variably oriented younger discrete shear zones and quartz-filled faults cross-cut the pluton. U-Pb zircon dating of the Stolzenfels Enderbite yielded a concordia age of 1115 ± 5 Ma. Despite the textural and mineralogical variations, the Stolzenfels pluton has a very consistent major and trace element geochemistry. It is has an intermediate composition (mean SiO〈sub〉2〈/sub〉: 60.5 ± 1.4 wt. %) and is strongly metaluminous (mean ASI: 0.78) which, together with the biotite-hornblende ± orthopyroxene mineralogy and the abundance of mafic xenoliths, suggests the source magma was produced by partial melting of older igneous rocks that have not undergone any significant amount of chemical weathering. The εNd and T〈sub〉DM〈/sub〉 values of -0.69 and 1602 Ma are typical of the Komsberg Suite and point to a significant contribution of older crustal material to the source magma.〈/span〉

Description: 〈span〉〈div〉Abstract〈/div〉Rock abrasivity is very much influenced by the petrographic and physico-mechanical properties of rock and hence its assessment from common geomechanical rock properties is helpful for rock engineers in estimating excavation costs. In this paper LCPC and CERCHAR abrasivity tests, as well as a complete suite of mechanical and physical rock properties tests, were conducted on 51 rock samples collected from different locations in Pakistan. Moreover, petrographical studies of 48 rock specimens were performed along with the computation of Schimazek's F-value (F-value) and Rock Abrasivity Index (RAI). For the analysis of test results least square regression was employed. Initially the LCPC abrasivity coefficient (ABR) values were correlated with CERCHAR abrasivity index tests and reasonable relationships were observed. Statistically meaningful relationships were found between ABR and geotechnical wear indices (F-value and RAI). Possible correlations of LCPC test results with rock properties are also discussed. Finally multiple regression analysis was applied to find statistically significant correlation of ABR with petrographical and physico-mechanical rock properties. Test results show that RAI, Brazilian tensile strength and mean quartz grain size (Ø-qtz) prove to be the statistically best predictors of ABR from the rock properties determined. The developed correlations are specifically intended for rock engineers involved in designing excavation projects.〈/span〉