Supplementary data from: Constraining the Ediacaran–Cambrian boundary in South China using acanthomorphic acritarchs and uniserial modular microfossils

The Ediacaran–Cambrian boundary, representing one of Earth's most
critical transitions, is currently defined by the Fortune Head
(Newfoundland, Canada) GSSP at a point once regarded as the first
appearance of the branching trace fossil Treptichnus pedum (Seilacher,
1955) Jensen, 1997. However, T. pedum has subsequently been found below
the GSSP, and its global distribution is primarily restricted to
siliciclastic facies where application of alternative biostratigraphic and
chemostratigraphic correlation tools is challenging. Investigations of
acanthomorphic acritarchs in basal Cambrian strata of South China suggest
that these microfossils could provide a robust complementary
biostratigraphic marker for the Ediacaran–Cambrian boundary. The data
provided here describe and detail the occurrences of taxa across 14
measured sections in South China. The earliest Cambrian
Asteridium-Heliosphaeridium-Comasphaeridium (AHC) assemblage biozone is
identified at 11 localities within the Yanjiahe, lower Niutitang, and
upper Liuchapo formations, representing diverse depositional environments.
Two latest Ediacaran microfossils, both characterized by uniserially
chained modules and representing a characteristic Ediacaran assemblage
(the Horodyskia minor – Nenoxites jiumenensis, or HmNj, assemblage
biozone), are also identified in the Liuchapo Formation, but do not
overlap with the Cambrian AHC acritarch biozone. The AHC assemblage
biozone is demonstrated to be stratigraphically equivalent to basal
Cambrian small shelly fossils and a negative δ13C excursion known to occur
at the Ediacaran–Cambrian boundary. Thus, in South China, the AHC and HmNj
assemblage biozones can be used to effectively and reliably constrain the
Ediacaran–Cambrian boundary.