Composition and Structure of Phosphate-Rich Parietal Crusts and Nodules in Monte Corchia Cave, Alpi Apuane (Central Italy)
| Autor: | Chiara Vigiani, Pilario Costagliola, Alessia Nannoni, Mario Paolieri, Leonardo Piccini |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
010504 meteorology & atmospheric sciences
Science Geochemistry cave deposit Speleothem 010502 geochemistry & geophysics 01 natural sciences chemistry.chemical_compound Cave Paleoclimatology apatite group Phreatic speleothem 0105 earth and related environmental sciences Calcite geography geography.geographical_feature_category karst Apuan Alps Karst chemistry Clastic rock General Earth and Planetary Sciences Carbonate Geology |
| Zdroj: | Frontiers in Earth Science, Vol 9 (2021) |
| ISSN: | 2296-6463 |
| DOI: | 10.3389/feart.2021.673109/full |
| Popis: | Cave environment allows long-term processes of rock weathering and chemical deposition that cannot occur on Earth surface directly exposed to meteoric and external biochemical agents. Apart from the common carbonate speleothems, chemical precipitation from infiltration water can also produce phosphate-rich formations usually occurring as parietal dark crusts or spheroidal nodules. Despite the potential purposes of these kind of deposits as paleoenvironmental proxies, they have been still poorly investigated by cave scientists. Monte Corchia cave (NW Tuscany, Central Italy) is one of the most studied caves in the world, particularly for paleoclimate reconstructions from calcite speleothems. Several samples of parietal formations were collected in relict phreatic and epiphreatic passages at different altitudinal levels that reflect different evolutionary stages of this large cave system. Samples were analyzed by diffractometry and SEM-EDS possibly revealing the occurrence of hydroxyapatite or fluorapatite mixed with Fe/Mn incrustations and allogenic clastic particles. Crusts often cover the entire section of relict phreatic or epiphreatic passages and can be related to precipitation during waterfilled phases. Phosphate nodules are almost entirely composed by hydroxyapatite or fluoroapatite and could be the result of long-term chemical (or bio-chemical) precipitation in air-filled environments. |
| Databáze: | OpenAIRE |
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