The earliest brachiopods across the Cambrian palaeocontinents and their ... the Chiungchussian Stage (Series 2, Stage 3), and higher up succeeded by rich ...
The earliest brachiopods across the Cambrian palaeocontinents and their implications for “Traditional Lower Cambrian correlation” 3
ZHIFEI ZHANG1, 2, LARS. E. HOLMER2, GUOXIANG LI AND ZHILIANG ZHANG1 1
Early Life Institute, State Key Laboratory for Continental Dynamics, Northwest University, Xi’an,
710069, China ,
2
Department of Earth Sciences, 3
LPS, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China. Palaeobiology, Villav. 16, S-75236 Uppsala, Sweden, ,
Linguliform brachiopods were important components of early Cambrian skeletal communities, and they can be easily extracted from fine grained clastic and carbonate lithologies from across the Cambrian palaeocontinents. Most linguloid taxa have a wide geographic distribution, which is probably due to their planktonic larval dispersal, and thus may be used in global correlations and palaeogeographic reconstructions. Brachiopods have generally been considered to be of little use in regional and global correlations within the Cambrian, probably mostly due to the lack of detailed taxonomic and biostratigraphic studies. Recently, great advances have been achieved in terms of the taxonomy, diversity and stratigraphic range of Cambrian brachiopods, which permit us to discuss the biostratigraphy of Cambrian brachiopods on a global scale. In the Meishucun section of eastern Yunnan, South China, the earliest Cambrian brachiopod is the Botsfordiidae Diandongia pista, which is known from throughout the Chiungchussian Stage (Series 2, Stage 3), and higher up succeeded by rich records of Eoobolus and Eohadrotreta in Tsanglangpuan Stage (Series 2, Stage 4). In Siberia, the earliest brachiopod occurrence is of the Paterinidae Aldanotreta sunnaginensis in Tommotian Stage, which is succeeded by the brachiopod assemblage of Obolella and Cryptotreta in the Atdabanian Stage, and subsequently by the assemblage of Botsfordia and Eoobolus in the lower Botomian, as well as Kutorgina and Homotreta in the upper Botomian Stage. It is suggested that occurrences of abundant lingulids and acrotretids constitute key evidence of a Botomian age across the known Cambrian palaeocontinents, and correlation with the Tsanglangpuan as well. Brachiopod-based correlation of "the Traditional Lower Cambrian" further corroborate that the units of Yu'anshan Formation, Hongjingshao and Wulongqing Formation (Chiungchussan—Tsanglangpuan Stage) in Eastern Yunnan of southwestern China could tentatively be of Late Atdabanian-Botomian age in Siberia. This might imply there is a considerable hiatus and that a significant lower part of the Atdabanian strata are missing in eastern Yunnan. Nevertheless, the suggested correlation is still of preliminary supposition and awaits to be testified by other relative faunal correlation.
