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许靖华等人提出了有关中国两个下寒武统剖面上的地球化学波动的令人感兴趣的资料。在云南和三峡最低的含三叶虫岩组的底部或附近,他们找到一层粘土比上覆,下伏地层含超过5‰的δ~(13)c负值,并且铱、锇、和金含量增加。沿剖面向上数厘米发现δ~(18)O波动呈更大的负值。许靖华等人文章的图1,2和3显示的δ~(13)C、铱、饿和金的异常值恰好出现在中国c点界标处,而在正文指出的那些异常值出现在这一界标之上。许靖华等人在利用中国C点界标作为前寒武系—寒武系界限(显然应用古生物学标准把界限放在含
Xu Jinghua et al. Put forward interesting information about the geochemical fluctuations in the two Lower Cambrian sections of China. At or near the bottom of the lowest Trilobite group in Yunnan and the Three Gorges, they found a layer of clay with overburden with a negative delta δ ~ (13) c of more than 5 ‰, with iridium, osmium, and gold Increased content. A few centimeters upwards along the profile, it was found that δ ~ (18) O fluctuated more negatively. Figures 1, 2 and 3 of Xu et al.’s article show that the δ 13 C, Iridium, starvation and gold anomalies happen to be at the c site of China, while the anomalies indicated in the text appear at this site Above. Xu Jinghua and others in the use of China’s C landmark as a pre-Cambrian - Cambrian boundary (apparently the application of paleontological standards to the limit