Application Of Computed Tomography And Other Techniques In Gaojiashan Lagerst(?)tte

Gaojiashan Lagerst?tte,which located on the Northwest margin of Yangtze Plate,is mainly preserved in the Gaojiashan section of the Dengying Formation at the end of Ediacaran Period.Gaojiashan Lagerst?tte is composed of pyritized and phosphated tubular fossils,algae fossils,difficulty fossils and trace fossils.Many modern scientific techniques such as Scanning electron microscopy(SEM),energy disperse spectroscopy(EDS),computed tomography(CT),Laser Scanning Confocal Microscopy(LSCM)were used in this study,and some new discovers obtained as follows:With the help of industrial CT technology,the internal structure of pyritized Conotubus was observed.The ‘tentacle' of Conotubus was captured,which confirmed the predecessors' hypothese.Asexual reproduction of possible ‘resurrection',budding and dichotomous,were two primary models of Conotubus.Also,the longitudinal fusion in Conotubus tubes was found.Possible evidences of commensalism or parasitism in Conotubus.The asexual reproduction of Gaojiashania was discovered for the first time.Tough matrix sessile lifestyle occurred in Ediacaran.With the help of Micro-CT technology,the individual development and dichotomous asexual reproduction of phosphatized Cloudina were described.The ontogeny of Cloudina could be assigned to two stages,maternal growth and independent growth.The structure of phosphatized Sinotubulites was observed.The SEM figures and rended micro-CT data of some difficulty fossils supplemented the biodiversity of Gaojiashan Lagerst?tte.The best preserved sicula fossils of Conotubus and Cloudina were selected for geometric morphometric.And the geomric morphometric result confirmed the genetic relationship of Conotubus and Cloudina.Several phosphatized microfossil slices SEM-EDS results showed that the phosphatization and silication formed in different periods during the fossil mineralization.The SEM-EDS results of spherical fossils,discoid fossils and difficulty fossils showed the distribution of Si and P were different.EBSD analysis of several phosphatized microfossils showed the fossil's mineralization was directed and periodic.LSCM result turned out that auto fluorescence can reflect the texture variation in phosphate microfossils.