Modeling the multi-level plumbing system of the Changbaishan caldera from geochemical, mineralogical, Sr-Nd isotopic and integrated geophysical data

Changbaishan,an intraplate volcano,is characterized by an approximately 6 km wide summit caldera and last erupted in 1903.Changbaishan experienced a period of unrest between 2002 and 2006.The activity developed in three main stages,including shield volcano(basalts),cone-construction(trachyandesites to trachytes with minor basalts),and caldera-forming stages(trachytes to comendites).This last stage is associated with one of the more energetic eruptions of the last millennium on Earth,the 946 CE,VEI 7 Millennium Eruption(ME),which emitted over 100 km^(3) of pyroclastics.Compared to other active calderas,the plumbing system of Changbaishan and its evolution mechanisms remain poorly constrained.Here,we merge new whole-rock,glass,mineral,isotopic,and geobarometry data with geophysical data and present a model of the plumbing system.The results show that the volcano is characterized by at least three main magma reservoirs at different depths:a basaltic reservoir at the Moho/lower crust depth,an intermediate reservoir at 10-15 km depth,and a shallower reservoir at 0.5-3 km depth.The shallower reservoir was involved in the ME eruption,which was triggered by a fresh trachytic melt entering a shallower reservoir where a comenditic magma was stored.The trachytes and comendites originate from fractional crystallization processes and minor assimilation of upper crust material,while the less evolved melts assimilate lower crust material.Syn-eruptive magma mingling occurred during the ME eruption phase.The magma reservoirs of the caldera-forming stage partly reactivate those of the cone-construction stage.The depth of the magma storage zones is controlled by the layering of the crust.The plumbing system of Changbaishan is vertically extensive,with crystal mush reservoirs renewed by the replenishment of new trachytic to trachyandesitic magma from depth.Unlike other volcanoes,evidence of a basaltic recharge is lacking.The interpretation of the signals preceding possible future eruptions should consider the multi-level nature of the Changbaishan plumbing system.A new arrival of magma may destabilize a part of or the entire system,thus triggering eruptions of different sizes and styles.The reference model proposed here for Changbaishan represents a prerequisite to properly understand periods of unrest to potentially anticipate future volcanic eruptions and to identify the mechanisms controlling the evolution of the crust below volcanoes.

Mapk7 deletion in chondrocytes causes vertebral defects by reducing MEF2C/PTEN/AKT signaling

Mutation of the MAPK7 gene was related to human scoliosis.Mapk7 regulated the development of limb bones and skulls in mice.However,the role of MAPK7 in vertebral development is still unclear.In this study,we constructed Col2a1-cre;Mapk7 f/f transgenic mouse model to delete Mapk7 in cartilage,which displayed kyphosis and osteopenia.Mechanistically,Mapk7 loss decreased MEF2C expression and thus activated PTEN to oppose PI3K/AKT signaling in vertebral growth plate chondrocytes,which impaired chondrocyte hypertrophy and attenuated vertebral ossification.In vivo,systemic pharmacological activation of AKT rescued impaired chondrocyte hypertrophy and alleviated mouse vertebral defects caused by Mapk7 deficiency.Our study firstly clarified the mechanism by which MAPK7 was involved in vertebral development,which might contribute to understanding the pathology of spinal deformity and provide a basis for the treatment of developmental disorders of the spine.

A supplementary assessment system of AQI-V for comprehensive management and control of air quality in chemical industrial parks

Volatile organic compounds(VOCs)are the dominant pollutants in industrial parks.However,they are not generally considered as part of the air quality index(AQI)system,which leads to a biased assessment of pollution in industrial parks.In this study,a supplementary assessment system of AQI-V was established by analyzing VOCs characteristics with vehicle-mounted PTR-TOFMS instrument,correlation analysis and the standards analysis.Three hourly and daily scenarios were considered,and the hierarchical parameter setting was further optimized by field application.The hourly and daily assessments revealed the evaluation factors for the discriminability of different air quality levels,practiced value for regional air quality improvement,and the reservation of general dominant pollutants.Finally,the universality testing in ZPIP successfully recognized most of the peaks,with 54.76%,38.39%and 6.85%for O_(3),VOCs and NO_(2) as the dominant pollutant,and reflected the daily ambient air quality condition,togetherwith the dominant pollutant.The AQI-V systemwith VOCs sub-index is essential for air quality evaluation in industrial parks,which can further provide scientific support to control the pollution of VOCs and the secondary pollutant,therefore significantly improve the air quality in local industrial parks.