High pressure, near‐liquidus phase equilibria of the Home Plate basalt Fastball and melting in the Martian mantle
High pressure, near‐liquidus phase equilibria of the Home Plate basalt Fastball and melting in the Martian mantle
复制标题
本垒玄武岩快球的高压、近液相线相平衡和火星地幔的熔化
DOI：
10.1029/2010gl043999
复制
发表时间：
2010
影响因子：
5.2
通讯作者：
A. Treiman
中科院分区：
文献类型：
--
作者：
J. Filiberto;R. Dasgupta;W. Kiefer;A. Treiman
对合成的快球玄武岩成分进行了近液相线相平衡实验，如在火星主板高原(Gusev Crater)分析的那样，以测试它是否代表原始地幔来源的熔体，并对古代地幔的温度和火星的岩石圈-软流圈边界施加限制。快球玄武岩与橄榄石和斜方辉石在∼1.2Gpa和1430°C下多次饱和。根据熔融模型，我们预测快球成分可能是火星地幔13-23%的平衡熔融，并从∼10 5 km厚的岩石圈底部提取熔体。快球的多重饱和度也限制了火星地幔的潜在温度约为1480-1530°C，初始熔融压力为4.0-4.7 Gpa。这一潜在温度远低于源自类似古老岩浆的地幔，即科马提岩。
Near‐liquidus phase equilibria experiments have been conducted on a synthetic Fastball basalt composition, as analyzed at Home Plate plateau of Mars (Gusev Crater), to test if it represents a primitive mantle derived melt and place constraints on the temperature of the ancient mantle and on the lithosphere‐asthenosphere boundary of Mars. The Fastball basalt is multiply saturated with olivine and orthopyroxene at ∼1.2 GPa and 1430°C. Based on melting models, we predict that the Fastball composition could be produced by 13–23% equilibrium melting of the Martian mantle, with extraction of melt from the base of ∼105 km thick lithosphere. The multiple saturation for Fastball also constrains the potential temperature of the Martian mantle to be approximately 1480–1530°C with an initial melting pressure of 4.0–4.7 GPa. This potential temperature is much lower than that of the terrestrial mantle derived from similarly ancient magmas, i.e., komatiites.