Early Metamorphic History of the Oceanic Lower Crust

早期高温变质变形作用 大洋辉长岩记录了大洋中下部地壳的演化 山脊 破译这份记录 证明难以 原因有两个：（1）不精确 变质作用的温度估计;（2）矿物组合平衡状态的不确定性。本研究采用实验，分析和统计方法相结合，以解决这些问题。 实验研究的重点是温度和时间依赖性的次生矿物成分使用自然变质辉长岩形成于东太平洋隆起。 该项目的岩石学和统计部分将确定来自蛇绿岩和大洋中脊的一套辉长岩的变质矿物成分。 这项研究将有助于更好地了解洋中脊附近下地壳过程的时间尺度和扩展率依赖性。

Early high-temperature metamorphism and deformation of oceanic gabbros record the evolution of the lower crust near mid-ocean ridges. Deciphering this record has proven difficult for two reasons: (1) imprecise temperature estimates for metamorphism, and (2) uncertainties about the equilibrium state of mineral assemblages. This study employs a combination of experimental, analytical, and statistical methods to address these issues. Experimental studies focus on the temperature and time dependence of secondary mineral compositions using natural metamorphosed gabbros formed at the East Pacific Rise. The petrologic and statistical component of this project will determine metamorphic mineral compositions from a suite of gabbros from ophiolites and mid ocean ridges. This study will yield a better understanding of the time scales and spreading-rate dependence of lower crustal processes near mid-ocean ridges.