Search

Early Permian fusulinids from both northern and southern parts of the Baoshan Block (western Yunnan, Southwest China) are illustrated and compared with coeval fusulinid faunas from other northern peri-Gondwana areas to disclose paleogeographic information. Systematic study of collected fusulinid materials and examination of published data from the Dingjiazhai area, northern Baoshan Block, show that fusulinids there includeEoparafusulina pseudosimplexandPseudofusulina macilenta.Fusulinids from the Aluotian Section, southern Baoshan Block, consist ofP. minitumidisculan. sp.,P. macilenta, P. tumidiscula, E. pseudo simplex, E.aff.E. laudoni, andE.sp. Early Permian fusulinids from both northern and southern Baoshan Blocks are dominated byPseudofusulinaandEoparafusulinaspecies and they are similar to those from Central Pamir, South Afghanistan, East-Central Iran, Central Oman, East Hindu Kush and northern Karakorum, revealing a Sakmarian to Artinskian age. Moreover, detailed comparison shows that the Early Permian fusulinid assemblage from the Baoshan Block is more similar to those from East-Central Iran, Central Pamir and South Afghanistan. This implies that the Baoshan Block may have been near those areas during the Early Permian.

The study of the diversification shallow-sea benthos as well as its coupled relationship to changes in sea level is important for revealing the effect of global environmental changes on biological evolution and for discovering the coevolution of life and environment during geological time. This paper makes a detailed analysis of the diversification of fusulinid fauna from the Dian-qian-gui Basin during the early to middle Permian. It also compares the diversification of fusulinids with relative sea-level changes over that interval. The results show that during the Asselian to Sakmarian stages of the early Permian, when relative sea level in the Dian-qian-gui district slowly rose, the number of fusulinid species increased rapidly. In contrast, during the Wordian Stage when sea level changed frequently, the number of fusulinid genera increased rapidly.

The rarefaction analysis has been conducted to test the species diversity changes of the Early and Middle Permian fusulinacean fauna in South China. The results reveal that the number of species dramatically increased since the earliest Permian and quickly reached the maximum value in the early Zisongian representing the highest species diversity for the whole Early and Middle Permian. The species diversity stabilized in the plateau through the Zisongian; however, it started to decline in the following Longlinian and sustained a longstanding low level during the mid-Early Permian. With the appearance of new fusulinacean taxa with septulum structures, the number of species raised again in the late-Early Permian, followed by a decline in the Middle Permian Neoschwagerina simplex zone. Although the species diversity increased apparently in the Kuhfengian, it never rebounded back to the same level as in the Early Permian. In the mid-Middle Permian, species diversity began to decrease continuously and led to the disappearance of most fusulinacean species by the end of the Middle Permian.