SUMMARY The post-spreading magmatic activities in the northeastern South China Sea (SCS) margin are very strong, evidenced by widely distributed high-velocity lower crust (HVLC) and numerous volcanoes. However, there are large contrasts in magmatic activities and crustal structure between the Southern Depression (TSD) of the Tainan Basin and the volcanic continental slope area further south. We analyse their crustal P-wave velocity structures based on a newly acquired wide-angle ocean bottom seismic data set. The Cenozoic strata below the TSD, a Cenozoic failed rift, are relatively thick (∼3–4.5 km) with velocities from 1.6 to 3.6–3.9 km s–1, whereas the Mesozoic strata are relatively thin (∼1–2.5 km) with velocities from 4.3 to 4.6–5.2 km s–1. In the TSD, magmatic activities are relatively weak and the crust is severely thinned (∼4 km). The crust is 9–15 km thick below the volcanic continental slope area, which shows extensive volcanism. We identified HVLC below the failed rift of the TSD (Zone 1) and attributed it to mantle serpentinization, whereas the imaged HVLC below the volcanic continental slope (Zone 3) and HVLC adjacent to the failed rift of the TSD (Zone 2) are due to post-spreading magmatic underplating/intrusions. At the model distance ∼90 km, lateral transition from magmatic underplating/intrusions to mantle serpentinization occurred abruptly. We concur that post-spreading cooling and thermal contraction in the nearby SCS oceanic lithosphere can trigger decompressive melting and deformation in the thinned continental slope zone. Our study shows that, in addition to mantle serpentinization in the continent–ocean transition (COT) zone, mantle can also be serpentinized below the rift during early-stage rifting. Weak syn-rifting magmatism and mantle serpentinization below the failed rift support that the northeastern SCS has a magma-poor margin.

No abstract

No abstract

No abstract

In this work, a boronate affinity-functionalized hierarchical mesoporous metal–organic framework adsorbent with boronate sites only in the small mesopore has been structured based on UiO-66@Fe3O4. The introduction of large mesopores in the adsorbent can promote the diffusion of small cis-diol-containing compounds (cis-diols) into small mesopore channels, and the removal of the adsorption sites on the external surface of materials and in large mesopores can enhance the size-exclusion effect of the adsorbent. In addition, the adsorbent has faster adsorption kinetics and excellent selectivity to small cis-diols. Finally, a magnetic dispersive solid-phase extraction coupled with high-performance liquid chromatography was established for the enrichment and detection of nucleotides in plasma. Four nucleotides achieve the recoveries from 93.25 to 118.79%, the limits of detection from 0.35 to 1.26 ng·mL–1, and the intra-day and inter-day relative standard deviations of less than 10.2%. In conclusion, this method can be directly used for the detection of small cis-diol targets in complex biological samples without protein precipitation prior to the extraction.