Unusual Secondary Ca‐Mg‐Carbonate‐Kerolite Deposits in Basaltic Caves, Kauai, Hawaii
| Autor: | Richard J. Léveillé, William S. Fyfe, Fred J. Longstaffe |
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| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | The Journal of Geology. 108:613-621 |
| ISSN: | 1537-5269 0022-1376 |
| DOI: | 10.1086/314417 |
| Popis: | Aragonite, calcite, monohydrocalcite, dolomite, magnesite, hydromagnesite, and talc‐like kerolite have been identified in speleothems from basaltic caves on the island of Kauai, Hawaii. These secondary minerals have crystallized in the presence of freshwater seeping from the basaltic host rock, and the mineralization process is ongoing at some locations. The deposits are extremely variable in macroscopic character, ranging from millimeter‐thin, powdery coatings to hard crusts several centimeters thick. Many deposits are associated with actively forming microbial mats, and stromatolitic structures are common in the thicker deposits. Formation of the mineral deposits is a result of a combination of direct precipitation from solution by evaporation and CO2 degassing, alteration of precursor minerals, and (or) microbial processes and physicochemical conditions within the mats. These unusual deposits provide important insights into the mineralogy and geochemistry of low‐temperature alteration and carb... |
| Databáze: | OpenAIRE |
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