Characterization of calcite spines of planktonic foraminifers (Globigerinidae)

Abstract

Calcitic spines ∼1 μm in diameter are projecting from a trochospiral test of a spinose planktonic foraminifer. According to electron diffraction, Raman spectra, and detailed electron microscope observation, the spines were found to be a single-crystal-like calcite that has a nanogranular texture containing microstrain. An organic envelope protects the biogenic calcite against dissolution in water. Their unique mechanical and chemical properties are ascribed to the specific micro- and nanoscopic structures.