Chemical fingerprints and microbial biomineralization of fish muscle tissues from the Late Cretaceous Muzquiz Lagerstatte, Mexico
Por:
Riquelme, F, Alvarado-Ortega, J, Ruvalcaba-Sil, JL, Aguilar-Franco, M, Porras-Muzquiz, H
Publicada:
1 ago 2013
Categoría:
Geology
Resumen:
Fossil fish specimens from the Muzquiz Lagerstatte (Late Cretaceous) of
northern Mexico have been analysed using UV light-induced visible
fluorescence microscopy, Particle-induced X-ray Emission (PIXE), X-Ray
Diffraction (XRD), and Scanning Electron Microscopy (SEM). Specimens
examined with UV light microscopy show tightly packed trunk muscle
tissues and digestive tract contents, as well as a color gradient from
pink to orange to brown associated with the chemical state of the muscle
tissues. PIXE analysis shows a 0.346 P/Ca ratio in muscle tissues, as
well as a phosphorus increase by a factor of more than four compared to
surrounding sediment. Quantitative XRD analysis shows that
cryptocrystalline flourapatite (FAP) is the predominant mineral phase
and calcite is complementary in the muscle tissues. Nucleation of FAP
and calcite may have occurred simultaneously with organic decay, forming
adhesive pellets in the soft watery carbonate mud, and caused
immobilization of the carcasses. Electron microscope scans show muscle
tissues preserved with cellular and subcellular features as well as
digestive tract contents with calcareous nanoplankton. Fossil biofilms
with bacteria have also been exceptionally preserved as intact cells,
casts and molds. This cell-specific, rapid mineralization can be
explained by a crystal seed process, which is discussed here.
Filiaciones:
Riquelme, F:
Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 04510, DF, Mexico
Alvarado-Ortega, J:
Univ Nacl Autonoma Mexico, Inst Geol, Mexico City 04510, DF, Mexico
Ruvalcaba-Sil, JL:
Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 04510, DF, Mexico
Aguilar-Franco, M:
Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 04510, DF, Mexico
|