| Autor: |
Alcalde-Fuentes, María Rosario, López-Acevedo, Victoria, López-Andrés, Sol, Perles, Josefina, Pérez-Valera, Juan Alberto |
| Předmět: |
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| Zdroj: |
Historical Biology; Oct2024, Vol. 36 Issue 10, p2226-2232, 7p |
| Abstrakt: |
A comparative study has been made between some cidaroid fossil spines from Lower Cretaceous of southern Spain and other contemporary ones. The modern spines are a composite material formed by calcite nanocrystals oriented with their optical axes parallel to the elongated direction, which behave as a single crystal. Transmission Petrographic Microscopy (TPM) observations of the fossil spines prove that it is a calcite single crystal, whose optical axis coincides with the direction of elongation (as in the current spines). This paper presents a crystallographic approach to propose a secondary crystallisation mechanism, specifically the Ostwald ripening process, through a structural analysis that compares the spines and the conditions observed during the fossilisation process. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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