Melt Extraction and Crustal Accretion at Mid-Ocean Ridges: Continued Study of the Mantle and Lower Crust in the Oman Ophiolite

这笔赠款将资助一项为期3年的关于扩张海脊洋壳成因的研究，该研究基于来自阿曼大洋地壳和上地幔逆冲片的地幔和下地壳的证据。我们的主要目标是限制(1)从地幔熔体提取的多孔流动和/或破裂机制，以及(2)通过两种端元可能性的组合形成火成岩下洋壳：(A)在单一岩浆室中结晶加上韧性向下和向外流动形成下地壳，以及(B)在许多接近其当前侵位深度的小岩浆室中下地壳深成岩的结晶。此外，我们还试图解决与以下问题有关的问题：(3)下地壳的熔体提取机制；(4)下地壳的变形机制和应变分配；(5)大洋扩张脊轴线以下的火成冷却和结晶速率。

This grant will fund a 3 year study of the genesis of the oceanic crust at spreading ridges, based on evidence from the mantle and lower crust of a thrust slice of oceanic crust and upper mantle in Oman. Our main objectives are to constrain (1) porous flow and/or fracture mechanisms of melt extraction from the mantle, and (2) formation of the igneous lower oceanic crust via combinations of two end-member possibilities: (a) crystallization in a single magma chamber plus ductile flow downward and outward to form the lower crust, and (b) crystallization of lower crustal plutonic rocks in many small magma chambers close to their current depth of emplacement. In addition, we seek to address related questions concerning (3) melt extraction mechanisms in the lower crust, (4) deformation mechanisms and strain partitioning in the lower crust, and (5) igneous cooling and crystallization rates beneath the axis of an oceanic spreading ridge.