Cretaceous Chert-Hosted Microfossils Visualized With Synchrotron Ptychographic X-Ray Computed Tomography (PXCT)

Area of Science:

• Paleontology
• Geochemistry
• Microbiology

Background:

• Silicification of microfossils is crucial for understanding Earth's ancient microbial ecosystems.
• Mechanisms of silica precipitation and organic material preservation in microfossils remain incompletely understood.
• Identifying factors contributing to microfossil preservation is key to reconstructing past life.

Purpose of the Study:

• To investigate microfossil preservation using synchrotron ptychographic X-ray computed tomography (PXCT).
• To characterize diverse morphologies and preservation styles of microfossils from the Cretaceous Barra Velha Formation.
• To elucidate silica-organic relationships and taphonomic processes in ancient silicifying environments.

Main Methods:

• Application of synchrotron ptychographic X-ray computed tomography (PXCT) for high-resolution imaging.
• Generation of 2D and 3D reconstructions of microfossils and silica-organic textures at nanometer resolution.
• Analysis of microfossil morphology and preservation variability.

Main Results:

• PXCT revealed previously uncharacterized silica textures and organic-silica relationships.
• Nanometer-resolution imaging provided insights into microfossil morphologies and preservation styles.
• Preservational variability was linked to potential physiological or biochemical differences in ancient microbes.

Conclusions:

• PXCT is a powerful tool for analyzing microfossil fine structures and taphonomic processes.
• The study enhances understanding of microbial diversity and complexity in the Cretaceous pre-salt basin.
• Findings contribute to knowledge of microfossil preservation mechanisms in silicifying environments.