Shell composition of Terreneuvian tubular fossils from north‐east Sichuan, China

60 1 January 15 26 10.1111/pala.12268

PANG, Y., STEINER, M., SHEN, C., FENG, M., LIN, L., LIU, D. 2017. Shell composition of Terreneuvian tubular fossils from north‐east Sichuan, China. Palaeontology, 60, 1, 15-26. DOI: 10.1111/pala.12268

Yanchun Pang, Michael Steiner, Cen Shen, Mingshi Feng, Li Lin, and Dingkun Liu
  • Yanchun Pang - Institute of Sedimentary Geology Chengdu University of Technology Chengdu China (Email: pangyanchun06@cdut.cn)
  • Michael Steiner - Institute für Geologische Wissenschaften Freie Universität Berlin Berlin Germany
  • Cen Shen - Faculty of Land Resources Engineering Kunming University of Science and Technology Kunming China
  • Mingshi Feng - State Key Laboratory of Oil Gas Reservoir Geology and Exploitation Chengdu University of Technology Chengdu China
  • Li Lin - Institute of Sedimentary Geology Chengdu University of Technology Chengdu China
  • Dingkun Liu - Institute of Sedimentary Geology Chengdu University of Technology Chengdu China
  • Manuscript Accepted: 27 September 2016
  • Manuscript Received: 09 July 2016
National Natural Science Foundation of China. Grant Numbers: 41173058, 41302012 Chengdu University of Technology. Grant Number: JXGG201214 Kunming University of Science and Technology. Grant Number: 14118761

Identification of the primary constituents of small shelly fossil (SSF) shells is important for explaining the evolution of SSF faunas. The characteristics and constituents of Terreneuvian tubular SSFs found in north‐east Sichuan, China, are revealed using light microscopy, scanning electron microscopy and energy dispersive X‐ray spectroscopy. Petrographic thin sections indicate that the chemical composition of the shells is mainly calcium carbonate with smaller amounts of phosphorus, silica and pyrite. Most of the tubular shells composed of calcium carbonate have a distinct layered structure. Evidence of replacement of the original shell by phosphatization, pyritization and silicification, and recrystallization of calcium carbonate have been found, all of which destroyed the shell's original layered structure. Most fossils treated with acetic acid are phosphatic casts or steinkerns, with some preserving organic textures of the shell as phosphatic casts. We conclude that the Terreneuvian tubular SSFs from north‐east Sichuan were originally composed mainly of calcium carbonate; indeed, most Terreneuvian small skeletal fossils appear to have had an originally calcareous composition. The fossil casts or internal core fossils are composed of phosphate, which is related to local taphonomic processes.

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