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Reply to ‘Uppermost Cambrian carbon chemostratigraphy: the HERB and undocumented TOCE events are not synonymous’

Published online by Cambridge University Press:  12 October 2020

Maoyan Zhu Open the ORCID record for Maoyan Zhu [Opens in a new window] ,
Loren E. Babcock ,
Shanchi Peng  and
Per Ahlberg
Maoyan Zhu*
Affiliation:
State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology & Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing210008, China College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing100049, China
Loren E. Babcock
Affiliation:
School of Earth Sciences, The Ohio State University, Columbus, OH43210, USA
Shanchi Peng
Affiliation:
State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology & Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing210008, China
Per Ahlberg
Affiliation:
Department of Geology, Lund University, SE 22362, Lund, Sweden
*
Author for correspondence: Maoyan Zhu, Email: myzhu@nigpas.ac.cn
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Abstract

In a recent communication on carbon isotope chemostratigraphy of the uppermost Cambrian strata, it was claimed that the Top of Cambrian Excursion (TOCE) is (1) an undocumented negative δ13Ccarb excursion; (2) ambiguously defined; (3) deliberately fictitious or, in the authors’ words, a ‘nihilartikel’; and (4) not synonymous with the Hellnmaria–Red Tops Boundary (HERB) Event. As the authors who have been involved in much of the discussion surrounding the TOCE since its introduction and in subsequent clarification, we wish to emphasize that the recent communication overlooks the fact that the TOCE is in fact a well-documented and clearly defined negative δ13Ccarb excursion, and that the term ‘HERB Event’ was originally used informally, without definition or reference data, for a negative δ13Ccarb peak, a peak later shown to occur within the TOCE excursion. Nearly a decade after the TOCE was named, the concept of the HERB Event was modified from a negative δ13Ccarb peak to a negative δ13Ccarb excursion, making it conceptually synonymous with the TOCE excursion. The recently published commentary is misleading and replete with misconceptions, as we discuss here.

Keywords

CambrianChemostratigraphyTOCEHERB
Type
Discussion - Reply
Information
Geological Magazine , Volume 158 , Issue 7 , July 2021 , pp. 1323 - 1326
Copyright
© The Author(s), 2020. Published by Cambridge University Press

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