Cation ordering of orthopyroxenes from the Skaergaard Intrusion: implications for the subsolidus cooling rates and premeabilities
Article Abstract:
The quenched cation ordering states of five orthopyroxene crystals have been determined from the marginal border group and the lower zone a and b of the Skaergaard intrusion. These data help in retrieving the closure temperatures of Fe-Mg ordering and cooling rates. Cooling rates strictly apply to temperatures around 340 to 400 degree celsius of the ordering states. The results of cooling rates agree with a thermal model computed using an average permeability of 10 to the -12th power square centimeters.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1996
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Volume and grain boundary diffusion of calcium in natural and hot-pressed calcite aggregates
Article Abstract:
Calcium is the slowest volume diffusing species in natural in hot-pressed calcite aggregates. The calcium grain boundary diffusion rates in natural and hot-pressed calcite aggregates are similar. Activation energy for calcium grain boundary diffusion is nearly 2/3 of the activation energy for volume diffusion. Calcium grain boundary diffusion rates are six times faster than the volume diffusion rates over the temperature range of the experiments.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1996
User Contributions:
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