摘要
Abundant siliceous micro-fossils were found from the Dalong Formation,Xinmin section,Guizhou,which include nine species of radiolarians belonging to seven genera as well as nine types of siliceous spongy spicules.The radiolarian fauna consists of all spherical radiolarians,without any species of Albaillellaria and Latentifistularia,indicating a relative shallow water sedimentary environment.The high relative co-efficient between the radiolarian abundance and total organic carbon(TOC)shows that the radiolarian assemblage represented by Copicyntra and Paracopicyntra can be used as a proxy to the paleo-productivity.However,the relative co-efficient between biogenic silica and the radiolarian and sponge spicule abundances is low.A possible explanation is that an oceanic circulation has changed the biogenic silica content after radiolarian test and siliceous spongy spicule were dissolved.
Abundant siliceous micro-fossils were found from the Dalong Formation, Xinmin section, Guizhou, which include nine spe- cies of radiolarians belonging to seven genera as well as nine types of siliceous spongy spicules. The radiolarian fauna consists of all spherical radiolarians, without any species of Albaillellaria and Latentifistularia, indicating a relative shallow water sedimentary environment. The high relative co-efficient between the radiolarian abundance and total organic carbon （TOC） shows that the radiolarian assemblage represented by Copicyntra and Paracopicyntra can be used as a proxy to the paleo-productivity. However, the relative co-efficient between biogenic silica and the radiolarian and sponge spicule abun- dances is low. A possible explanation is that an oceanic circulation has changed the biogenic silica content after radiolarian test and siliceous spongy spicule were dissolved.
基金
supported by the National Natural Science Foundation of China (Grant Nos. 40839903,40921062)
special funding from the GPMR
