4 research outputs found
A record of spontaneous subduction initiation in the IzuāBonināMariana arc
The initiation of tectonic plate subduction into the mantle is poorly understood. If subduction is induced by the push of a distant mid-ocean ridge or subducted slab pull, we expect compression and uplift of the overriding plate. In contrast, spontaneous subduction initiation, driven by subsidence of dense lithosphere along faults adjacent to buoyant lithosphere, would result in extension and magmatism. The rock record of subduction initiation is typically obscured by younger deposits, so evaluating these possibilities has proved elusive. Here we analyse the geochemical characteristics of igneous basement rocks and overlying sediments, sampled from the Amami Sankaku Basin in the northwest Philippine Sea. The uppermost basement rocks are areally widespread and supplied via dykes. They are similar in composition and ageāas constrained by the biostratigraphy of the overlying sedimentsāto the 52ā48-million-year-old basalts in the adjacent IzuāBonināMariana fore-arc. The geochemical characteristics of the basement lavas indicate that a component of subducted lithosphere was involved in their genesis, and the lavas were derived from mantle source rocks that were more melt-depleted than those tapped at mid-ocean ridges. We propose that the basement lavas formed during the inception of IzuāBonināMariana subduction in a mode consistent with the spontaneous initiation of subduction
Replication Data for: Observation of an environmentally insensitive solid state spin defect in diamond
Engineering coherent systems is a central goal of quantum science. Color centers in diamond are a promising approach, with the potential to combine the coherence of atoms with the scalability of a solid state platform. We report a color center that shows insensitivity to environmental decoherence caused by phonons and electric field noise: the neutral charge state of silicon vacancy (SiV0). Through careful material engineering, we achieve over 80% conversion of implanted silicon to SiV0. SiV0 exhibits spin-lattice relaxation times approaching one minute and coherence times approaching one second. Its optical properties are excellent, with approximately 90% of its emission into the zero-phonon line and near-transform-limited optical linewidths. These combined properties make SiV0 a promising defect for quantum networks
Reply to 'Unclear causes for subduction'
Arculus et al. reply ā Keenan and
EncarnaciĆ³n suggest that the absence of
pre-subduction inception basement in
the drill core data taken from site U1438
raises ambiguity in our conclusion of
spontaneous subduction initiation in the
IzuāBonināMariana system