摘要
研究的底栖介形类化石采自湖南锡矿山剖面晚泥盆世地层,共30属61种,含1新属,2未定属,13新种和20未定种。在晚泥盆世F/F生物集群灭绝事件之前和以后,根据底栖介形类的演化特征,分为正常期,包括3—5层;灭绝期,即6层;残存期,包括7,8,9a-c,11—13,15层;和复苏期,即20层以上地层。在湖南锡矿山上泥盆统剖面上,底栖介形类动物群遭受到F/F灭绝事件的重创,正常期的37种中仅11种在残存期中幸免于难,24种在本剖面上消失,灭绝种约占65%。对于F/F生物集群灭绝事件的发生机制,虽有多种解释,但造成底栖介形类灭绝的主要原因更可能是缺(贫)氧或含毒环境和气候变化。根据底栖介形类生态组合特征,正常期的介形类动物群代表近岸浅水开阔海台地环境;复苏期的介形类动物群可能代表半局限海台地环境。根据正常期、残存期和复苏期介形类动物群的组成特征,它们所生存的海底为正常的含氧环境。
The benthic ostracodes under study were collected from the Upper Devonian at the Xikuangshan section of Hunan, with a total of 61 species assigned to 30 genera. Of them, 1 genus （Microhunanella） and 13 species are described as new and 2 genera and 20 species are dealt with under open nomenclature. At the Xikuangshan section, 3 evolutionary stages of the benthic ostracodes in relation to the F/F mass extinction event are proposed in this paper, i. e. extinction, survival and recovery intervals. The extinction interval includes Bed 6; the survival interval Beds 7, 8, 9a-c, 11-13, 15; and the recovery interval Beds 20, 21, 23, 34, 35. The radiation interval after the F/F mass extinction event may be absent at this section. In terms of the ben-thic ostracodes, the F/F mass extinction appears to be a catastrophic event. There are 37 species from Beds 3-5, of which only 11 species persisted into the survival interval after the F/F mass extinction event; 24 species are not found in the recovery interval. In this event, the extinction suggests a delete rate of the benthic ostracodes accouning for about 65%. The causes for the F/F mass extinction were discussed by Liao （2002）, including extraterrestrial and terrestrial events. The causes for the benthic ostracode extinction might mainly be linked to climatic change and, especially, to the influx of oxygen-depleted water into the shelf during the latest Frasnian. The ostracode fauna from Beds 3-5 may indicate a nearshore, shallow water and open marine environment based on the ratio of bairdiids to plaeocopids and kloedenellaceans; ostracode fauna from Beds 20, 21, 23, 34, 35 may represents a semi-restricted carbonate platform environment because it is dominated by the plaeocopids and kloedenellaceans （64% of total number of species）. The ostracode faunas from Beds 3-5, Beds 7, 8, 9a-c, 11- 13, 15 and Beds 20, 21, 23, 34, 35 generally indicate well-oxygenated conditions on the sea floor according to the presence of palaeocopid （including kloedenellacans）, ma
出处
《古生物学报》
CAS
CSCD
北大核心
2007年第1期1-32,共32页
Acta Palaeontologica Sinica
基金
现代古生物学和地层学国家重点实验室项目(043109)
国家重点基础研究发展规划项目(G2000077700)
国家自然科学基金项目(40172006
40472009)联合资助
