Just out | Euendoliths versus ambient inclusion trails from Early Cambrian Kuanchuanpu Formation, South China @ Palaeogeography, Palaeoclimatology, Palaeoecology

Just out @ Palaeogeography, Palaeoclimatology, Palaeoecology

Euendoliths versus ambient inclusion trails from Early Cambrian Kuanchuanpu Formation, South China


Xiao-guang Yang, Jian Han, Xing Wang, James D. Schiffbauer, Kentaro Uesugi, Osamu Sasaki, Tsuyoshi Komiya


Abundant microstructures have been discovered in small skeletal fossils (SSFs) and embryo-like fossils collected from the Lower Cambrian Kuanchuanpu Formation (ca. 535 Ma) in Xixiang County, Shaanxi Province, China. These involve two co-occurring structures: (1) long, unbranched cylindrical filaments, which are comparable to phosphatic casts of microborings constructed by euendolithic cyanobacteria (Endoconchia lata) in morphology and preservation pathway; and (2) meandering micro-tubes or grooves on fossil moulds (and steinkerns) of a wide range of sizes and morphological diversities, perceived as ambient inclusion trails (AITs). Herein, we also report a new occurrence of organic carbon spherules as AIT-propelled material, which is rare in comparable fossils. From direct comparison of endolith fossils and AITs, we propose a mechanism to account for their notably different preservation, and further attempt to offer an explanation for their co-occurrence. Their differential preservation suggests a chronological, taphonomic sequence of their formation. We interpret that E. lata microborings formed prior to phosphate sedimentation, whereas AITs are likely generated in a later phase of (or after) phosphorite precipitation but before calcareous re-cementation. Dissecting the sequence of formation of these structures, in conjunction with detailed morphological observations, assists in distinguishing true biologically produced endoliths from otherwise abiogenically produced microstructures.

Keywords: CyanobacteriaEndoconchia lataMicroboringsSmall skeletal fossils; Phosphatized fossils

DOI: 10.1016/j.palaeo.2017.03.028

READ IT HERE: http://www.sciencedirect.com/science/article/pii/S0031018216304655

Lurdes Fonseca

Assistant Professor and Researcher at University of Lisbon
Sociologist (PhD), Paleontologist (Researcher in Micropaleontology), Majors in Sociology and Biology, Minor in Geology. Main interests in Paleontology: Microfossils, Molecular fossils, Paleobiology and Paleoecology. (read more about me)