Plagioclase geothermometry for some mesozoic and tertiary basalts, northeasr Brazil
DOI:
https://doi.org/10.5902/2179460X24848Abstract
Chemical data of some Tertiary olivine basaltic samples from the States of Rio Grande do Norte and Paraíba, and of Mesozoic tholeiitic basalts from the Maranhão sedimentary basin as well, allowed a preliminar estimate of the crystalization temperatures of their plagioclases through the KUDO and WELL’s geothermometer (5).
In the calculation of the equilibrium temperatures between the plagioclase crystals and the liquid, the chemical composition of their edges and the composition of the rock matrix were used.
In olivine basalts, temperatures rangibg from 1078 °C to 11680 ° C at 1 Kbar water pressure were recorded, in accordance with previously determined temperatures through HAKLI and WRIGHT’s (3) approach (SIAL, 8). For the tholeiitic basalts, temperature estimates ranged from 1140 °C to 1230 ° C, at 1 Kbar water pressure.
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References
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