The proterozoic and earliest cambrian trace fossil record; patterns, problems and perspectives.

Area of Science:

• Paleontology
• Stratigraphy
• Sedimentology

Background:

• Trace fossil diversity is often analyzed by cataloging ichnogenera.
• A morphological and interpretive grouping approach offers a clearer view of diversity and complexity.
• Similarities between Neoproterozoic and Cambrian trace fossils are key to understanding evolutionary trends.

Purpose of the Study:

• To re-evaluate trace fossil diversity across the Neoproterozoic-Cambrian boundary.
• To explore similarities between Neoproterozoic and Cambrian trace fossils.
• To establish a preliminary trace fossil zonation for the terminal Neoproterozoic.

Main Methods:

• Grouping trace fossils by morphology and interpretation.
• Analyzing trace fossils from Neoproterozoic siliciclastic sediments.
• Comparing Neoproterozoic trace fossils with known Cambrian forms.

Main Results:

• Enigmatic structures like Palaeopascichnus and Yelovichnus show similarities to trace fossils.
• A preliminary two or tripartite terminal Neoproterozoic trace fossil zonation is proposed.
• The earliest trace fossils (older than ~560 Ma) are short, unbranched forms.
• By ~550 Ma, trace fossil diversity increased, including rare 3D burrow systems (treptichnids) and trilobed traces.

Conclusions:

• Grouping trace fossils enhances understanding of diversity and complexity.
• Neoproterozoic trace fossils exhibit similarities to algal structures and early Cambrian forms.
• A refined zonation of Neoproterozoic trace fossils is possible, aiding biostratigraphic correlation.