Electronic Supplementary Material to this paper can be obtained by using the Springer LINK server located at. This effect continues until nucleation lag is overcome, whereupon a period of rapid growth from supersaturated liquid follows which is similar to that in F-absent compositions. Increasing fluorine contents tend to exacerbate the effects of undercooling by inhibiting feldspar nucleation, causing both K/K+Na ratios and compatible trace-element partitioning behavior in feldspar to deviate from equilibrium values. Such zoning patterns may mimic normal patterns produced by fractionation with decreasing temperature under near-equilibrium (near-liquidus) conditions. The Five Elements Wood, Fire, Earth, Metal, and Water are representations in nature that have been observed over time to help humans explain and understand the interactions of phenomenon, situations, and human interactions. Hence, high supersaturation accompanying undercooling produces feldspar compositions by isothermal growth which record a vestige of the liquid line of descent (i.e., an ontogeny within zoned crystals which approximately tracks the feldspar liquidus from high temperature to the final low temperature of actual crystal growth). versus K/K+Na varies linearly between the average value at 850 ☌ and the equilibrium value appropriate to the temperature of growth. Feldspars produced by strong undercooling (ΔT≥100 ☌) are heterogeneous, such that D Ba Afs/m. Whereas the partitioning behavior of Cs (incompatible) is not measurably affected, strong undercooling apparently causes the partitioning of Ba (highly compatible) to deviate from equilibrium behavior. Progressively greater undercooling is manifested in the run products by increasingly skeletal to cuneiform crystal morphologies, increased compositional zonation of Afs, and the development of compositional boundary layers in glass. (≤0.10) from experiments at all temperatures. (~10–20) fall within the range of previous investigations, as do values of D Cs Afs/m.
At low degrees of undercooling (ΔT~50 ☌), values of D Ba Afs/m. Barium expands the liquidus stability field of potassic feldspar to higher temperatures, such that liquidi for the Ba-rich (~0.5 wt% BaO) compositions used are ~100 ☌ higher than for Ba-absent analogues. The investigation is motivated by trace-element distribution patterns in granitic pegmatites which cannot be simulated by fractionation models using "equilibrium" partition coefficients, and thus its purpose is to assess if, how, and why partition coefficients for compatible and incompatible trace elements may vary when crystal growth commences far from the crystal–melt equilibrium boundary.
This study examines the effects of increasing supersaturation, attained by single-step liquidus undercooling (ΔT), on the partitioning of barium and cesium between potassic alkali feldspar (Afs) and hydrous granitic liquid at 200 MPa.
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