华南晚古生代Zoophycos时空分布及其控制因素

Spatiotemporal Distribution and Controlling Factor of the Late Paleozoic Zoophycos in South China

基于对华南晚古生代3条剖面Zoophycos的精细解剖和前人资料分析,识别了螺旋形和舌形Zoophycos两种形态,揭示了华南晚古生代Zoophycos时空分布具有3个方面的特征:(1)在时间上,Zoophycos广泛分布于早-中泥盆世(埃姆斯期-艾菲尔期)、密西西比亚纪(维宪期)及中二叠世(沃德期);(2)在空间上,Zoophycos主要发育于黔东南、湘中南、桂东北一带;(3)临滨至浅海下部是Zoophycos的主要产出环境。研究表明,华南晚古代Zoophycos的时空分布与大气含氧量(17%—24%),气候和温度(20—25℃),海水地球化学成分(方解石海Mg/Ca<2)以及生物灭绝事件等具有耦合关系。

Through studying on Zoophycos from three Late Paleozoic sections （the Dahekou Devonian section, the Ercengpuo Carboniferous section, and the Dongpan Permian section） and summarizing the previous related literatures on the Late Paleozoic Zoophycos in South China, the Zoophycos from these regions represent the complex spreiten with well-preserved major and minor lamellae, and consist of marginal tube and cylindrical tunnel. A systematic investigation of morphology and palaeoenvironment of Zoophycos is carried out. The study indicates that （1） both the spiral-like and tougue-like Zoophycos are identified. （2） Zoophycos are mainly distributed in the Early-Middle Devonian （Emsian-Eifelian）, Mississippian （Visean）, and Guadalupian （Wordian）; and mainly occur in the southeast of Guizhou Province, central-southern of Hunan Province, and northeastern of Guangxi Province, and are abundant in a condition with a lower energy and soft substrate from shoreface to subtidal shelf. It seems that the spatiotemporal distributions of the Late Paleozoie Zoophycos in South China are coupled with the Late Paleozoic evolution of atmosphere oxygen （17%--24%）, climate and temperature （20--25℃）, seawater geochemical compositions （calcite seas, Mg/Ca〈2）, and mass biological extinction events.