Chapter 7 An Observational and Theoretical Synthesis of Magma Chamber Geometry and Crustal Genesis along a Mid-ocean Ridge Spreading Center

摘要: Publisher Summary This chapter reviews seismological evidence and other geophysical that the axial magma chamber beneath a fast spreading ridge is narrow, thin, lens lies at sheeted-dike/gabbro cumulate transition region roughly 1.2–1.5 km seafloor overlies broader of hot rock with most ∼3–5% partial melt fraction. appears to contradict earlier ophiolite-based studies used dip relations within gabbro layer argue for broad, gabbro-layer-thickness body deposited cumulates along its base sides. However, it compatible an emerging theoretical paradigm crustal accretion occurs by emplacement solidification this lens, subsiding flowing form lower crust. The presents thermal mechanical model genesis incorporates successfully explains observed depth dependence rate (and fact no has been seen in median valley morphology), as well relationships among morphology, rate, supply. existence) morphology center share common origin, which function