SEM tests were conducted on four kinds of typical deep rocks in Meilinmiao Mine, and the micro properties were analyzed. The particles of gritstone are unbroken and particle diameter ranges from 80 lam to 400 pro, and...SEM tests were conducted on four kinds of typical deep rocks in Meilinmiao Mine, and the micro properties were analyzed. The particles of gritstone are unbroken and particle diameter ranges from 80 lam to 400 pro, and the void between particles is wide. The macroscopic failure of gritstone is caused by breakage of the dung distributed between particles, and po- tassium feldspars contained in gritstone are not leached. The failure of medium sandstone is caused by micro cracks distributed in sandstone particles, and potassium feldspars are leached seriously, so the pores penetrate each other and there is close hy- draulic connection in medium sandstone. The particles of fine sandstone are broken, and the particle diameters range from 60 pm to 300 pm, which determines the pores have good connectivity between particles. The dolomites contained in fine sand- stone are corroded, and the micro fracture form belongs to inter-granular fracture. There are no particles and blocks in micro- structure of sandy mudstone, but there are diverse micro cracks. The failure of mudstone arises from the extension of micro cracks, and the microstructure is different from the other three kinds of sandstones obviously.展开更多
Cretaceous amber from Myanmar(～99 Ma Burmese amber) has become a valuable supplement to the traditional skeletal record of small theropod dinosaurs preserved in sedimentary rocks, particularly for coelurosaurs and en...Cretaceous amber from Myanmar(～99 Ma Burmese amber) has become a valuable supplement to the traditional skeletal record of small theropod dinosaurs preserved in sedimentary rocks, particularly for coelurosaurs and enantiornithines. The specimens recovered from this deposit preserve skeletal material and soft tissues in unmatched detail. This provides opportunities to study three-dimensional preservation of soft tissues, microstructure, and pigmentation patterns that are seldom available elsewhere in the fossil record. Ultimately, this line of research provides insights into life stages that are difficult to preserve, the ecology and appearance of the groups involved, and the evolutionarydevelopment of structures such as feathers. Here we describe the most recent discovery from Burmese amber, an articulated skeleton of an enantiornithine bird. This individual has been sectioned along the coronal plane, providing a unique view inside multiple body regions. Osteological observations and plumage patterns support placement within the Enantiornithes, and suggest that the animal may have been a juvenile at the time of death. The specimen has a complex taphonomic history that includes exposure at the surface of a resin flow prior to encapsulation, and may include scavenging by some of the insects trapped within the same amber piece. The chemical composition observed along surface exposures and shallowly buried regions of the body indicate that the specimen has not undergone significant exchange with its surroundings. High iron concentrations are present in regions that preserve soft tissues as carbon films, and calcium distribution corresponds to regions where bones breach the surface of the amber.展开更多
基金Supported by the Coal Joint Fund of the National Natural Science Foundation of China and Shenhua Group （U1261126） the Fundamental Research Fund for the Central Universities （2010YL09）
文摘SEM tests were conducted on four kinds of typical deep rocks in Meilinmiao Mine, and the micro properties were analyzed. The particles of gritstone are unbroken and particle diameter ranges from 80 lam to 400 pro, and the void between particles is wide. The macroscopic failure of gritstone is caused by breakage of the dung distributed between particles, and po- tassium feldspars contained in gritstone are not leached. The failure of medium sandstone is caused by micro cracks distributed in sandstone particles, and potassium feldspars are leached seriously, so the pores penetrate each other and there is close hy- draulic connection in medium sandstone. The particles of fine sandstone are broken, and the particle diameters range from 60 pm to 300 pm, which determines the pores have good connectivity between particles. The dolomites contained in fine sand- stone are corroded, and the micro fracture form belongs to inter-granular fracture. There are no particles and blocks in micro- structure of sandy mudstone, but there are diverse micro cracks. The failure of mudstone arises from the extension of micro cracks, and the microstructure is different from the other three kinds of sandstones obviously.
基金funded by the National Natural Science Foundation of China(41790455,41772008,31672345,Special Subjects in Animal Taxonomy,NSFC-J1210002)Natural Sciences and Engineering Research Council of Canada(201500681)+1 种基金Scientific Research Equipment Development Project of Chinese Academy of Sciences(YZ201509)the National Geographic Society,USA(EC0768-15)
文摘Cretaceous amber from Myanmar(～99 Ma Burmese amber) has become a valuable supplement to the traditional skeletal record of small theropod dinosaurs preserved in sedimentary rocks, particularly for coelurosaurs and enantiornithines. The specimens recovered from this deposit preserve skeletal material and soft tissues in unmatched detail. This provides opportunities to study three-dimensional preservation of soft tissues, microstructure, and pigmentation patterns that are seldom available elsewhere in the fossil record. Ultimately, this line of research provides insights into life stages that are difficult to preserve, the ecology and appearance of the groups involved, and the evolutionarydevelopment of structures such as feathers. Here we describe the most recent discovery from Burmese amber, an articulated skeleton of an enantiornithine bird. This individual has been sectioned along the coronal plane, providing a unique view inside multiple body regions. Osteological observations and plumage patterns support placement within the Enantiornithes, and suggest that the animal may have been a juvenile at the time of death. The specimen has a complex taphonomic history that includes exposure at the surface of a resin flow prior to encapsulation, and may include scavenging by some of the insects trapped within the same amber piece. The chemical composition observed along surface exposures and shallowly buried regions of the body indicate that the specimen has not undergone significant exchange with its surroundings. High iron concentrations are present in regions that preserve soft tissues as carbon films, and calcium distribution corresponds to regions where bones breach the surface of the amber.
