Late Paleozoic faunal, climatic, and geographic changes in the Baoshan block as a Gondwana-derived continental fragment in southwest China
Late Paleozoic faunal, climatic, and geographic changes in the Baoshan block as a Gondwana-derived continental fragment in southwest China
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DOI：
10.1016/s0031-0182(01)00228-0
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发表时间：
2001-06
期刊：
影响因子：
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通讯作者：
Xiangdong Wang;K. Ueno;Y. Mizuno;T. Sugiyama
中科院分区：
文献类型：
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作者：
Xiangdong Wang;K. Ueno;Y. Mizuno;T. Sugiyama
宝山地块石炭系和二叠系由三个主要沉积层序组成：下石炭统碳酸盐岩层序、下二叠统硅屑岩层序和中二叠世碳酸盐岩层序。这三个序列被两个主要的海退事件打断：第一，纳穆尔期的隆升，年龄范围从Serpukoian到Gzhelian；第二，保山地块的后萨克玛利亚海退可能发生在Artinskian时间，尽管后者的确切时间间隔尚不清楚。保山地块早石炭世具有温水、高度多样性和丰富的动物群特征，早二叠世具有冷水、低多样性的动物群特征，中二叠世可能具有温水、低多样性的动物群特征。Sweetogns buaramangus牙形刺动物群将含斜长花岗岩的硅屑矿床(丁家寨组)的上界限定在萨克马里期至阿尔丁斯基早期，并将裂谷玄武岩(沃牛斯组)的喷发约束到至少阿尔丁斯基期后。在古地理上，保山地块的动物群组合由早石炭世的欧亚系，到早二叠世的近海贡瓦期，到中二叠世的华夏/西默边缘期。在石炭纪和二叠纪，西默利亚地块之间的地史大致相似。在中二叠世，东西海陆块如西布玛苏(S.S)、保山和腾冲距离古赤道不远，但明显比西西西海地块更远，这是因为有或没有一些索引分类群，如金丝藻Eopolydiexodina和Neoschwagerina，珊瑚ThomasiPhyllum和Wentzellophyllum persicum。
The Carboniferous and Permian of the Baoshan block consist of three major depositional sequences: a Lower Carboniferous carbonate sequence, a Lower Permian siliciclastic sequence, and a Middle Permian carbonate sequence. These three sequences were interrupted by two major regressive events: first, the Namurian Uplift ranging in age from Serpukovian to Gzhelian, and second, the Post-Sakmarian Regression occurring probably at Artinskian time in the Baoshan block, although the precise time interval of the latter event is still unclear. The Baoshan block is characterized by warm-water, highly diverse and abundant faunas during the Early Carboniferous, by cold-water and low diversity faunas during the Early Permian, and by possibly warm-water but low diversity faunas during the Middle Permian. The Sweetognathus bucaramangus conodont fauna constrains the upper boundary of the diamictite-bearing siliciclastic deposits (Dingjiazhai Formation) to the Sakmarian to early Artinskian, as well as the eruption of the rifting basalts (Woniusi Formation) to, at least, the post-early Artinskian. Paleozoogeographically, affiliation of the faunas in the Baoshan block changed from Eurasian in the Early Carboniferous, to Peri-Gondwanan in the Early Permian, and to Marginal Cathaysian/Cimmerian in the Middle Permian. Cimmerian blocks have more or less comparable geohistory to one another in the Carboniferous and Permian. During the Middle Permian, the eastern Cimmerian blocks such as Sibumasu (s.s), Baoshan, and Tengchong are not far from the palaeoequator, but apparently more distant than the western Cimmerian blocks based on the presence or absence of some index taxa such as the fusulinaceans Eopolydiexodina and Neoschwagerina, and the corals Thomasiphyllum and Wentzellophyllum persicum.