Phosphate concretions from the Gezhongwu Formation at Sanjia, Zhijin County, China, were studied systematically in this work. In terms of the rules of variation of REE, trace elements, major elements and oxides, in co...Phosphate concretions from the Gezhongwu Formation at Sanjia, Zhijin County, China, were studied systematically in this work. In terms of the rules of variation of REE, trace elements, major elements and oxides, in combination with the concentration characteristics of small shelly fossils, it is considered that small shelly fossils occurring at the bottom of the Cambrian System contribute a lot to the phosphate concretions and that there are two stages of REE and phosphorus minerogenesis. The phosphate concretions have a good correlation with the contents of REE and phosphorus rather than the abundance of small shelly fossils.展开更多
The Meishucunian Stage is rich in fossils and is characterized by their distinct evolutionsequence, so based on the established zonation of small shelly fossils, the sequence of tracefossils and the stratotype point (...The Meishucunian Stage is rich in fossils and is characterized by their distinct evolutionsequence, so based on the established zonation of small shelly fossils, the sequence of tracefossils and the stratotype point (China "B", the dividing point between Units 6 and 7 or be-tween fossil zones Ⅰ and Ⅱ), the Meishucun section is more widely applicable to both region-al and intercontinental correlations. In this respect, the stage is well suited for both thecarbonate and the clastic-rock sedimentary regions. The Meishucunian small shelly fossil assem-blages are correlated with those found in Siberia of U.S.S.R., Mongolia, Central England,South Australia and Northwestern Canada. The Meishucunian trace fossil sequence can alsobe broadly correlated with that in the Russian Platform of U.S.S.R., Northwest Europe,Great Britain, Spain, Australia, the Western United States and Southeastern Canada.展开更多
We describe new material of three-dimensionally phosphatized small shelly fossils Acanthocassis and Xinlispina gen.nov.from the Fortunian Stage（early Cambrian） of southern Shaanxi and northern Sichuan Provinces.The ...We describe new material of three-dimensionally phosphatized small shelly fossils Acanthocassis and Xinlispina gen.nov.from the Fortunian Stage（early Cambrian） of southern Shaanxi and northern Sichuan Provinces.The new materials allow description of the delicate morphology of these skeletons, and also their skeletogenesis.Acanthocassis and Xinlispina have comparable morphological features： a main branch and radially arranged sub-branches.They differ from each other in many details, e.g., the presence of a single central branch only in Xinlispina, and the presence of small nodes only in Acanthocassis.Acanthocassis cannot be a naked anthopolyp or hydropolyp because of the more-or-less stiffened cuticle and the absence of a mouth.Acanthocassisand Xinlispina differ from coeval sponge spicules and chancelloriid sclerites and rosettes of crossed pedicellariae of echinoderms, and might be cuticular ornaments of animals of unclear affinities.They occur in the first small shelly fossil assemblage zone, and could be adopted as auxiliary fossils for biostratigraphic correlation in southern China.展开更多
In the late 1970s, small shelly fossils of the Precambrian-Cambrian transitional age in the western part of Yangtze Platform were widely studied. This note is the first report of Meishucunian small shelly fossils foun...In the late 1970s, small shelly fossils of the Precambrian-Cambrian transitional age in the western part of Yangtze Platform were widely studied. This note is the first report of Meishucunian small shelly fossils found in its eastern part (Fig. 1)展开更多
文摘Phosphate concretions from the Gezhongwu Formation at Sanjia, Zhijin County, China, were studied systematically in this work. In terms of the rules of variation of REE, trace elements, major elements and oxides, in combination with the concentration characteristics of small shelly fossils, it is considered that small shelly fossils occurring at the bottom of the Cambrian System contribute a lot to the phosphate concretions and that there are two stages of REE and phosphorus minerogenesis. The phosphate concretions have a good correlation with the contents of REE and phosphorus rather than the abundance of small shelly fossils.
文摘The Meishucunian Stage is rich in fossils and is characterized by their distinct evolutionsequence, so based on the established zonation of small shelly fossils, the sequence of tracefossils and the stratotype point (China "B", the dividing point between Units 6 and 7 or be-tween fossil zones Ⅰ and Ⅱ), the Meishucun section is more widely applicable to both region-al and intercontinental correlations. In this respect, the stage is well suited for both thecarbonate and the clastic-rock sedimentary regions. The Meishucunian small shelly fossil assem-blages are correlated with those found in Siberia of U.S.S.R., Mongolia, Central England,South Australia and Northwestern Canada. The Meishucunian trace fossil sequence can alsobe broadly correlated with that in the Russian Platform of U.S.S.R., Northwest Europe,Great Britain, Spain, Australia, the Western United States and Southeastern Canada.
基金supported by the National Natural Science Foundation of China (41072012 and 41102003)the State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (113115 and 20132107)+2 种基金the Key Project of Central University Fund (CHD2012ZD017)College Students’ Innovative Entrepreneurial Training Program (201410710144 and 201410710105)The Ninth "Challenge Cup" Competition of College Students’ Extracurricular Academic and Technological Achievements, Chang’an University
文摘We describe new material of three-dimensionally phosphatized small shelly fossils Acanthocassis and Xinlispina gen.nov.from the Fortunian Stage（early Cambrian） of southern Shaanxi and northern Sichuan Provinces.The new materials allow description of the delicate morphology of these skeletons, and also their skeletogenesis.Acanthocassis and Xinlispina have comparable morphological features： a main branch and radially arranged sub-branches.They differ from each other in many details, e.g., the presence of a single central branch only in Xinlispina, and the presence of small nodes only in Acanthocassis.Acanthocassis cannot be a naked anthopolyp or hydropolyp because of the more-or-less stiffened cuticle and the absence of a mouth.Acanthocassisand Xinlispina differ from coeval sponge spicules and chancelloriid sclerites and rosettes of crossed pedicellariae of echinoderms, and might be cuticular ornaments of animals of unclear affinities.They occur in the first small shelly fossil assemblage zone, and could be adopted as auxiliary fossils for biostratigraphic correlation in southern China.
文摘In the late 1970s, small shelly fossils of the Precambrian-Cambrian transitional age in the western part of Yangtze Platform were widely studied. This note is the first report of Meishucunian small shelly fossils found in its eastern part (Fig. 1)
