Abstract Ediacaran-aged (635–541 million years ago) marine sediments contain a large
negative carbon isotope (δ 13 C) excursion, in which carbonate δ 13 C values reach−
12‰(VPDB). Known as the 'Shuram'excursion, many workers have interpreted this δ 13 C
record as an unprecedented perturbation to the global carbon cycle, leading to speculation
about a causal connection to the broadly contemporaneous rise of animal life. Others have
interpreted the δ 13 C signal as a product of diagenesis, thereby minimizing its relevance for …

Abstract Ediacaran-aged (635-541 Ma.) sediments record a large negative carbon isotope
excursion, with marine carbonate δ 13 C values reaching-12‰(VPDB). Known as the"
Shuram" excursion, many have interpreted it as an unprecedented perturbation to the global
carbon cycle and have debated a causal connection to the broadly concordant rise of animal
life. Other models interpret the signal as a product of diagenesis. Discriminating between
these hypotheses is important for understanding paleoenvironmental evolution during the …