Thermodynamic modeling of melt addition to peridotite: Implications for the refertilization of the non-cratonic continental mantle lithosphere
نویسندگان
چکیده
In a classic model of evolution the non-cratonic continental mantle lithosphere, harzburgites represent refractory (<5% clinopyroxene) residues high degrees partial melting fertile mantle, while lherzolites (>5% lesser melting. However, is not only process that could explain peridotite compositional variability ranges from (>2 wt% Al2O3, <45 MgO) to (<2 >45 MgO). refertilization process, harzburgite protolith (potentially previously formed by mantle) undergoes reactive percolation silicate melts derived underlying asthenosphere, resulting in crystallization new generation minerals (mostly clinopyroxene). A simple but critical first step towards understanding examine how modal and major element compositions evolve as are added peridotites. Here we use thermodynamically-constrained two-component mixing independently evaluate roles five different parameters: pressure, temperature, redox conditions, initial basaltic melt (hereafter referred P-T-fO2-Xπ-Xmelt), during addition. We compare results with observed suites The main observations follows: (1) produced consistent global database, (2) T, fO2 small variations pressure have almost no impact on system. contrast, mineralogy percolated has substantial effect variation proportions. parameter most significant Xmelt, which directly linked geodynamic context conditions. This controls reaction so, phase proportions bulk-rock composition. Elements partition preferentially (e.g., Na) display depletions natural assemblages stronger than those predicted model, fact occurs an open system, likely incompatible enrichment associated melt. Our corroborate suggestion spectrum lithospheric peridotites can be explained impregnation primitive harzburgites.
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ژورنال
عنوان ژورنال: Chemical Geology
سال: 2022
ISSN: ['0009-2541', '1872-6836']
DOI: https://doi.org/10.1016/j.chemgeo.2022.121050