The δ13C excursions spanning the Cambrian explosion to the Canglangpuian mass extinction in the Three Gorges area, South China

Cadmium isotope variations in Neoproterozoic carbonates - A tracer of biologic production?

“…These values are characteristic of enhanced planktonic productivity and remineralisation and resemble previously published data from the Doushantuo (e.g., Ishikawa et al, 2013). In the cap dolostones d 13 C org and d 13 C carb are decoupled (Δ 13 C = 25 vs. 33 in overlying strata, Fig.…”

New 40 Ar/ 39 Ar dating of the Antrim Plateau Volcanics, Australia: clarifying an age for the eruptive phase of the Kalkarindji continental flood basalt province

“…Fig. 6 A comparison between the previously published data, the accepted Early-Middle Cambrian extinction (EMC), a composite δ13C curve (Zhu et al, 2006;Ishikawa et al, 2014) and the results of this study, with analyses from the APV labelled by sample name. a) Bultitude (1972) (Harvey et al, 2011), i) maximum age of the EMC boundary (Landing et al, 1998).…”

Early Cambrian chronostratigraphy and geochronology of South Australia

“…However, due to the unconformity between the Yanjiahe and Shuijingtuo formations this excursion is not fully developed at in the Three Gorges area. Tsunydiscus is amongst the oldest trilobites recovered from the Shuijingtuo Formation in the Three Gorges section (Ishikawa et al, 2014) and in the Xiaoyangba and Zengjiapo sections of Yang et al, Similarly, in the Anjiahe area, Hubei Province, there is a negative  13 C spike down to -9.3‰ post-ZHUCE, 1.4 m below the Yanjiahe-Shuijingtuo boundary (Ishikawa et al, 2008). These anomalously low values occur in a thin limestone bed that shows no evidence for diagenesis or alteration, and are interpreted as the original  C signature (Ishikawa et al, 2008), and may represent the SHICE.…”

“…5). As in the Three Gorges sections (Ishikawa et al, 2008(Ishikawa et al, , 2014, time breaks in the sections in Yunnan have resulted in an abbreviated  13 C curve, and excursions II and III are not developed. However, occurrence of P. huoi in the basal Yu'anshan in both the Xiaotan and Meishucun sections (Brasier et al, 1990 suggests that the  13 C values through the Shiyantou Formation likely lead into the basal CARE, which is not fully captured in the basal Yu'anshan.…”

“…The application of carbon isotope chemostratigraphy throughout the Cambrian is now well established (e.g. Brasier et al, 1992;Chang et al, 2017;Cremonese et al, 2014;Ishikawa et al, 2014;Maloof et al, 2005, 2010a,b andreferences therein;Schmid, 2017;Smith, et al, 2016). This method is recognised as an effective correlation tool because carbon isotopes are relatively resistant to diagenetic alteration, and provides a global signal that can temporally constrain endemic faunas and regional biostratigraphic schemes, especially in pretrilobitic lower Cambrian packages.…”