山西垣曲盆地始新世轮藻植物群

EOCENE CHAROPHYTES FROM THE YUANQU BASIN, SHANXI PROVINCE, CHINA

记述山西垣曲盆地河堤组任村段至寨里段轮藻化石，计１１属、１４种、２未定种，建立了一个地区性轮藻化石组合：Ｒａｓｋｙｅｌａｓｉｎｅｎｓｉｓ－Ｌｉｎｙｉｅｃｈａｒａｄｅｃｏｒｏｓａ－Ｓｔｅｐｈａｎｏｃｈａｒａｇｌｏｂｕｌａ组合，该组合位于中国早第三纪轮藻植物群序列中Ｏｂｔｕｓｏｃｈａｒａｊｉａｎｇｌｉｎｇｅｎｓｉｓ－Ｇｙｒｏｇｏｎａｑｉａｎｊｉａｎｇｉｃａ植物群的上部。轮藻植物群反映的地质时代为始新世中－晚期，倾向于中始新世晚期巴尔顿期（Ｂａｒ－ｔｏｎｉａｎ）。含轮藻化石的层位可与渤海沿岸地区沙河街组四段上部至三段下部以及湖北江汉盆地潜江组下部对比。文中对中国Ｇｒｏｖｅｓｉｃｈａｒａ，Ｒａｓｋｙｅｌａ的有关种进行了讨论和归并。

The charophytes described in this paper were obtained from the Hedi Formation in the Yuanqu Basin, Shanxi Province, including 14 species and 2 species indeterminata, in which the predominant species are Stephanochara globula Lu et Gao, Sphaerochara rugulosa Z. Wang, Harrisichara dezhouensis Xinlun, Grambastichara tornata (Reid et Groves) Horn af Rantzien, Grovesichara kongdianensis Xinlun, Gobichara laticellula (Lu et Gao) n. comb., Gyrogona lemani (Brongniart) Pia, Linyiechara decorosa (Xinlun) Lu. One local charophyte assemblage, Raskyella sinensis Linyiechara decorosa Stephanochara globula Assemblage, is established. According to their stratigraphical distribution, the assemblage belongs to the upper part of Obtusochara jianglingensis Gyrogona qianjiangica charophyte flora in China. The age of the assemblage can be referred to the Middle to Late Eocene, corresponding probably to the Bartonian Stage in West Europe. The strata containing charophytes can be correlated with the upper part of the fourth member and the lower part of the third member of the Shahejie Formation in North China, and the lower part of the Qianjiang Formation in the Jianghan Basin. Previous studies have identified and named 14 species and 2 varietis of Grovesichara, i.e. G. yangii (S. Wang) Z. Wang, G. changzhouensis Huang et S. Wang, G. changzhouensis var. elongata Z. Wang, G.changzhouensis var. angularis Wu, G.yanchiensis Liu, G. minheensis Yang, G. kongdianensis Xinlun, G. changdeensis Hu et Zeng, G. chejiangensis Hu et Zeng, G. sinensis Z.R. Zhang et al., G.conica Z.R.Zhang et Guo, G. longa Z.R. Zhang et Guo, G. plata H.N. Li, G.anjihaiensis Liu et Wu, G. sphaeroides Xinlun and G. yanbeiensis. The present authors think G.changzhouensis, G. changzhouensis var. elonga, G. minheensis and G. kongdianensis are available, and G. changdeensis,G. chejiangensis, G. sinensis, G. conica, G. longa, G.plata and G. anjihaiensis as the synonyms of G. kongdianensis, regard G. yanchiensis as the synonym of G. changzhouensis. G. yangii, G.sphaeroides and G.changzhouensis var. angularis have been left in open nomenclature because of inadequate materials. G. yanbeiensis is transferred to Mesochara. In Raskyella, 8 species, 1 form and 1 variety have been proposed in China, namely R. sinensis Z.R.Zhang et al., R. sinensis f. stena Z.R.Zhang et al., R. globula Guo et al., R.stipitata Guo et al., R. machangensis Guo et al., R. ovaticonica Guo et al., R. dongpuensis Huang et Zhao, R. dongpuensis var. minor Huang et Zhao, R. machangensis Huang et Zhao and R. hezeensis Huang et Zhao. Among them only R. sinensis is retained and the others are the synonyms of R. sinensis.