Calibration and applications of the dolomite clumped isotope thermometer to high temperatures
Year: 2011
Type: article
Abstract: Carbonate clumped isotope paleothermometry is based on the temperature-dependent formation of ^(13)C^(18)O^(16)O_2 ^(2-) ion \ngroups within solid carbonate minerals. This thermometer has now been calibrated for various synthetic and natural biogenic \nand abiogenic minerals (calcite, aragonite and carbonateapatites [e.g., 1, 2]) at temperatures below ~ 50°C. Here we \nextend the use of the carbonate clumped isotope thermometer to shallow crustal environments by determining the Δ_(47) values \nof CO_2 extracted from natural and synthetic dolomites grown at know temperatures from 25 to 350ºC. The experimental \ntemperature dependance is not linear in the Δ_(47) vs T^(-2) plot and resembles the predicted theoretical temperature dependence, \nboth in shape and absolute value [3]. These data for synthetic dolomites overlap the previous calibrations for inorganic \ncalcite and some forms of biogenic carbonates between 25 and 50˚C, and are consistent with a single trend that also intersects \ndata for synthetic calcite equilibrated at 1200˚C. These observations suggest that a single temperature dependant \nrelationship reasonably approximates the calibration for both phases. Data from a variety of slowly-cooled (i.e., over \ngeological timescales) natural marbles and rapid (i.e., laboratory timescales) heating experiments provide insights \ninto the kinetics of solid-state ^(13)C-^(18)O bond reordering in carbonates and its closure temperature. More generally, our \nnew calibration and constraints on high-temperature kinetics have implications for the application of this technique to burial \nand metamorphic processes. These issues will be illustrated through estimates of the thermal history and oxygen isotopic \ncompositions and abundances of pore fluids for several suites of late Neoproterozoic carbonates [e.g., 4].
Authors: Bonifacie, Magali, Ferry, John M., Horita, Juske, Vasconcelos, Crisogono, Passey, Ben H., Eiler, John M.
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W628383759