Distinguishing borings and burrows in intraclasts: Evidence from the Cambrian (Furongian) of North China

Hardgrounds represent synsedimentary cemented stratigraphic beds that form at or near the seafloor. Borings a key line of evidence for investigations hardground development and record evolution bioerosion boring organisms. The unequivocal identification borings is done through crosscutting relationship between proposed hard substrate, such as lithoclasts and/or shells, with morphological criteria able to be used when dealing homogeneous micritic hardgrounds. Bioeroded hardgrounds burrows micrite halo/lining are subject fracturing reworking, resulting in accumulations intraclasts flat-pebble conglomerates (FPC). recognition broken halo can challenging FPC. Using trace fossils preserved situ FPC from late Cambrian carbonates North China, we establish set distinguishing Features relative volume versus host pebble number traces per pebble, cross-cutting different colored laminae, presence pyrite glauconite encrustations all invoked aid borings. Examination encrustation not sufficient on their own. Our results suggest caution necessary defining FPC, particularly deformation create structures resemble