Geochemistry of trace metals associated with sedimentary pyrite from anoxic marine environments /
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| Other Authors: | , , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1989.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | A new method for the quantitative extraction of trace metals from sedimentary pyrite, derived from the technique of Lord (1982) for pyrite-Fe measurement, was developed. Application of this new method to As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb and Zn diagenesis in different sedimentary environments from the Gulf of Mexico area is presented. The region covered included sediment cores from a Fe-poor, H2S-rich coastal lagoon on the coast of Texas (Baffin Bay), the Fe-rich, H2S-poor sediments from the Mississippi-Atchafalaya delta complex, a transect in the southern portion of the Gulf of Mexico and two isolated cores in the western part of the Gulf of Mexico. The results obtained were in good agreement with previous estimates of trace metal contents in sedimentary pyrite. In order to account for the trace metal partitioning among the different reactive phases, the operationally-defined term degree of trace metal pyritization (DTMP) was introduced. This term, used in conjunction with the degree of pyritization (DOP) was a useful parameter for assessing the transformation of reactive-trace metals to the pyrite phase. Results indicate that all the trace metals considered increased in DTMP with increasing DOP. However, As, Hg, and Mo exhibited a rapid and almost complete incorporation into the pyrite fraction. Several transition metals displayed a close to linear increase in DTMP and moderate pyrite incorporation. Chromium and class B metals were also gradually incorporated into the pyrite phase but without reaching the DTMP levels exhibited by the rest of the trace elements. These results indicate that transition and class B metals exhibit distinctly different behavior that is characteristic of the chemical attributes of these different classes of trace elements. Analysis of piston core and marsh sediments showed that high DOP and DTMP values are not a characteristic restricted to Fe-poor, H2S-rich sediments. However, availability of dissolved trace metals and high organic matter content are apparently important factors controlling the incorporation of Co, Cr, Cu and Ni in these environments. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Oceanography." |
| Physical Description: | xxii, 299 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |