An Ideal Frasnian/Famennian Boundary in Ma-Anshan, Zhongping, Xiangzhou, Guangxi, South China

Abstract

Abstract The Frasnian/Famennian boundary beds in the middle part of the “Rongxian Formation” in Ma-anshan section, Xiangzhou, Guangxi are continuous, the lithology is the same, and conodont zones are generally identical with the conodont sequence of the Schmidt section in West Germany. But the Schmidt section has also a barren bed between the first occurrence of the primitive Pa. d. delicatula and the typical Pa. d. delicatula, whereas the situation for Ma-anshan section is better, between these occurrences there exist 76 cm of continuous deposits of limestone with a continuous evolutionary lineage from Morphotype 1 (primitive morphotype) to Morphotype 2 (typical morphotype). Therefore, the lower limit of Morphotype 2 Pa. d. delicatula occurrence is an ideal indicator of the Frasnian/Famennian boundary.