Carbon isotopic fractionation and precipitation kinetics of synthetic aragonite and calcite grown in dilute solutions /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | An open system chemo-stat technique was used to study the carbon isotope fractionation and kinetics associated with the heterogeneous growth of aragonite and calcite in dilute solutions. Pure aragonite or calcite seed material was used as the substrate for crystal growth. Aragonite and calcite overgrowths were precipitated at 10°, 25°, and 40°C from solutions at states of supersaturation that ranged between 2 and 37, depending on the mineralogical phase being generated. Values of average solution Pco2 for experimental runs ranged from less than 1% to greater than 14% and precipitation rates ranged from 10^2.3 to 10^4.8 μmol m^-2hr^-1. Precipitation rate is shown to be strongly a function of saturation state at each temperature. Empirical reaction orders calculated from the saturation state-precipitation rate relation for aragonite are independent of temperature while rate constants covary with temperature. Calcite reaction orders and rate constants are highly variable and show no relation to temperature. This variability may be explained in terms of the relationship of precipitation rate to solution P[CO2] but additional data must be collected over a wide range of saturation states and solution P[CO2] values to confirm these tentative results. Temperature and precipitation rate effects on carbon isotopic fractionation during the precipitation process were characterized from these same experimental runs... |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Geology." |
| Physical Description: | ix, 84 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |