Arc Basalt Simulator version 2, a simulation for slab dehydration and fluid‐fluxed mantle melting for arc basalts: Modeling scheme and application
Year: 2009
Type: article
Abstract: Convergent margin magmas typically have geochemical signatures that include elevated concentrations of large‐ion lithophile elements; depleted heavy rare earth elements and high field strength elements; and variously radiogenic Sr, Pb, and Nd isotopic compositions. These have been attributed to the melting of depleted mantle peridotite by the fluxing of fluids or melts derived from subducting oceanic crust. High Mg # basalts and high Mg # andesites are inferred to make up the bulk of subduction‐related primary magmas and may be generated by fluid or melt fluxing of mantle peridotite. The difference in contributions from the subducted slab found among various arcs appears to be mostly controlled by thermal structure. Cold slabs yield fluids, and hot slabs yield melts. Recent experimental studies and thermodynamic models better constrain the phase petrology of the slab components during prograde metamorphism and melting, mantle wedge melting, and mantle slab melt reaction. Experimental results also constrain the behavior of many elements in these processes. In addition, geodynamic models allow increasingly realistic, quantitative modeling of the temperature and pressure in the subducted slab and mantle wedge. These developments together enable generation of forward models to explain arc magma geochemistry. The Arc Basalt Simulator (ABS) version 2 (ABS2) uses an Excel® spreadsheet‐based calculator to predict the partitioning of incompatible element and Sr‐Nd‐Pb isotopic composition in a slab‐derived fluid and in arc basalt magma generated by an open system fluid‐fluxed melting of mantle wedge peridotite. The ABS2 model is intended to simulate high Mg # basalt geochemistry in relatively cold subduction zones. The modeling scheme of ABS2 is presented and is applied to primitive arc magmas.
DOI: 10.1029/2008gc002217
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: bronze
Funder: National Science Foundation
Awards: CSEDI: Collaborative Research: Thermal, Petrological, and Seismological Study of Subduction Zones, Collaborative Research: 3D modeling of subduction in the Pacific, Collaborative Research: Earthscope integrated investigation of Cascadia subduction zone tremor, structure and process, Mantle Inputs to the Subduction Factory: Assessing Scales of Spatial Variability along and across the IBM Convergent Margin
OpenAlex ID: W1947685651