Paleoproterozoic compression-like structures from the Changzhougou Formation, China: Eukaryotes or clasts?

The Paleoproterozoic Changzhougou Formation (Changcheng Group) of North China contains compression-like structures, millimeters to centimeters in diameter and about a millimeter thick that are circular, elliptical, elongate, and irregular in shape. These structures were interpreted to be carbonaceous compressions of megascopic eukaryotes by Zhu et al. (2000). Some of the compression-like structures were reported to contain masses of cellular material with well-preserved cell walls. Further investigation of these structures, including plane light investigations of thin sections and macerates, petrographic study of thin sections, SEM, EDS, CHN, XRD, and biomarker analyses, indicates that they are pseudo-fossils.