中国侏罗纪叶肢介动物群及古生物地理区系划分

The Chinese well-developed Jurassic strata are mainly of non-marine origin, which yield abundant non-marine fossil records including representatives of almost all of the major clades of terrestrial and freshwater vertebrates, a wide variety of invertebrate faunas and diverse floras. The Chinese non-marine Jurassic biotas provide a rare, incredibly detailed picture of a terrestrial ecosystem under a greenhouse climate conditions. The proposed project is intended to choose the well-developed, non-marine Jurassic stratigraphically continuous type sections in key araes in China, through high-resolution sampling of rich fossil clam shrimps, to carry out a detail study on the palaeontology and high resolution biostratigraphy on clam shrimps by the examination of type and newly collected specimens under the help of a scanning electron microscope. At the same time we would conduct a faunal analysis of the Chinese Jurassic clam shrimps in comparison with those from the Purbeck beds of UK and the Morrison Formation of the US. By the help of recently published, a large number of high-precision radiometric dating data from the Jurassic strata, and referring to the latest published research results on non-marine Jurassic magnetostratigraphy and chemostratigraphy, we would try to improve and perfect the Chinese non-marine Jurassic lithological and biostratigraphical time scale, to delineate the evolutionary stages of the Chinese Jurassic clam shrimp faunas. Futher more, we would like to carry out studies on the recent and fossil clam shrimp taphonomy, autecology, population ecology, to discern the Jurassic clam shrimp evolutionary events and to capture the relevant environmental information, which would link the clam shrimp faunal turnover with the rapid palaeoclimate change. Then, through getting use of the over a long period of time accumulated Chinese recent clam shrimp records and the Jurassic fossil clam shrimp data, we would like to undertake an analysis and delineate the Jurassic clam shrimp biogeographic provinces. So that we could dipict the spatial and temporal distribution of the Chinese clam shrimp faunas during the Jurassic “greenhouse” climate, and their feedback processes and mechanism to rapid climate warming disturbances. At last, we can decipher the controlling environmental factors that led to the Jurassic clam shrimp faunal crisis, extinction, recovery and palaeogeographic distribution differentiation during rapid palaeoclimate change.

项目以我国关键地区侏罗系陆相连续地层剖面和丰富叶肢介化石记录为基础平台，结合大量高精度测年数据，参考磁性地层学和化学地层学最新研究成果，以扫描电镜为基础研究手段，开展叶肢介系统分类学和高分辨率生物地层学研究，通过叶肢介生物地层学国际对比研究，建立和完善我国侏罗系高精度岩石地层学序列和生物地层学格架，详细系统划分叶肢介动物群演化阶段。加强现生和化石叶肢介个体生态学和居群生态学研究，捕捉侏罗纪叶肢介演化事件和古环境信息，建立叶肢介动物群演替事件与快速气候变化的对应关系，发挥我国侏罗纪丰富叶肢介化石记录的材料优势，开展生物古地理学研究，详细划分我国侏罗纪叶肢介古地理区系，结合现生叶肢介地理区系划分，深入总结叶肢介在侏罗纪温室气候条件下的时空规律，从而达到揭示叶肢介对快速气候变化的反馈过程和应对机制。最终揭示导致侏罗纪叶肢介动物群发生危机、灭绝、复苏和古地理分异的古气候-古环境控制因素。

项目以我国关键地区侏罗系陆相连续地层剖面和丰富叶肢介化石记录为基础平台，结合高精度测年数据，参考磁性地层学和化学地层学最新研究成果，以扫描电镜为手段，对关键叶肢介属种开展系统分类学和高分辨率生物地层学研究取得了系列研究成果。我们描述了针孔叶肢介（Punctatestheria）。通过叶肢介壳体详细扫描电镜微细装饰等重要分类学特征研究，揭示早侏罗世针孔叶肢介与中侏罗世三饰叶肢介(Triglypta)的祖裔演化关系。通过叶肢介和介形类生物地层学与英国 Purbeck beds 的国际对比研究，揭示我国北方非海相侏罗/白垩系界线的地层层位。通过开展藏南地区海相侏罗/白垩系界线剖面新发现的底栖有孔虫动物群研究，揭示我国藏南江孜地区床德剖面日朗组顶部已经达到晚凡兰今阶至早哥特里夫阶，而真正的侏罗/白垩系界线层应该在此化石层之下寻找。黑龙江省东北部那丹哈达地体晚侏罗世 Cinguloturris carpatica 放射虫动物群的新发现说明饶河增生杂岩的形成和拼贴年代在晚侏罗世。黑龙江省东部虎林地区龙爪沟群菊石动物群早阿普特期的时代确定指示了早阿普特期海侵海水达到了鸡西地区沉积了城子河组下部的 Aucellina 化石层。为热河群、鸡西群和龙爪沟群的对比和时代确定提供了海相化石关键证据。本项目以上述海、陆地层对比新证据为突破口，建立和完善了我国侏罗系和白垩系高精度岩石地层学序列和生物地层学格架，从而为详细系统划分我国侏罗纪叶肢介动物群演化阶段和古生物地理区系划分提供了精确的时代格架。我国早、中侏罗世受到温暖湿润的古气候控制，南北方发育了统一的古渔乡叶肢介动物群，中侏罗世我国南北方发育了自流井真（或三饰）叶肢介动物群。到了晚侏罗世，古气候明显变干旱，而且南北方古气候发生分异，导致北方发育了假线叶肢介动物群，而四川盆地发育了似东方叶肢介动物群，而在青海柴达木盆地发育了青海–茫崖叶肢介动物群。从而形成了我国晚侏罗世南北分化的叶肢介古生物地理区系。项目完成学术论文22篇，编辑两部学术论文专辑，在青岛举办一次国际学术会议。在缅甸与IGCP 668合办一次国际会议。