Two pieces of fossil turtle from Tongshan, Anhui Province, probably of Late Pliocene, were sent to the present author for determination by the Anhui Provincial Museum. In view of the absence of bony bridge, the hexago...Two pieces of fossil turtle from Tongshan, Anhui Province, probably of Late Pliocene, were sent to the present author for determination by the Anhui Provincial Museum. In view of the absence of bony bridge, the hexagona1 neural plates with short-sided behind, and the hinged hyoplastra and hypoplastra of plastron, the fossils were recognized as a member of Cuora, a living genus of Emydidae distributed in East and Southeast Asia, chiefly in China. So far as it is known, no Pliocene fossil record of this genus has been reported.展开更多
LA-ICPMS zircon U-Pb dating of intrusive rocks from the Shizishan ore field,Tongling,Anhui Province shows that the crystallization ages of Baimangshan pyroxene diorite,Shizishan and Dongguashan quartz diorite are 139&...LA-ICPMS zircon U-Pb dating of intrusive rocks from the Shizishan ore field,Tongling,Anhui Province shows that the crystallization ages of Baimangshan pyroxene diorite,Shizishan and Dongguashan quartz diorite are 139±1.9,138.0±1.7,and 138.4±1.7 Ma,respectively.These three intrusions are high-potassium,alkali-rich,meta-aluminous,and are characterized by enrichment of light rare earth elements and large-ion lithophile elements,depletion of heavy rare-earth elements(HREE) and high field strength elements,and slightly negative Eu anomalies.In-situ Hf analysis of zircon for these three intrusions shows large ranges of Hf isotope compositions:the ε Hf(t) values are ε Hf(t)= 3.3 to 14.4 for Baimangshan,14.1 to 23.9 Dongguashan,and 14.7 to 26.9 for Shizishan.The ε Hf(t) values of both the Dongguashan and Shizishan quartz diorites are significantly lower than those of Baimangshan pyroxene diorite.Elemental geochemistry and in-situ zircon Hf isotope analyses indicate that the three intrusions were formed through mixing of granitic magma formed by partial melting of the lower crust and water-rich basic magma derived from the enriched lithospheric mantle.The Dongguashan and Shizishan quartz diorites involved greater crustal components than Baimangshan pyroxene diorite.The Dongguashan and Shizishan quartz diorites have geochemical features similar to the adakite,such as high Sr,low Y,and high Sr/Y ratios.Such geochemical features can be attributed to some fractional crystallization of apatite and sphene,and insignificant plagioclase fractional crystallization after magma mixing.These three intrusions are the products of complex crust-mantle interaction during the regional tectonic regime transition from compression to extension.展开更多
文摘Two pieces of fossil turtle from Tongshan, Anhui Province, probably of Late Pliocene, were sent to the present author for determination by the Anhui Provincial Museum. In view of the absence of bony bridge, the hexagona1 neural plates with short-sided behind, and the hinged hyoplastra and hypoplastra of plastron, the fossils were recognized as a member of Cuora, a living genus of Emydidae distributed in East and Southeast Asia, chiefly in China. So far as it is known, no Pliocene fossil record of this genus has been reported.
基金supported by National Basic Research Program of China (GrantNo. 2012CB416702)National Natural Science Foundation of China(Grant No. 40930742)+1 种基金Key Project of Natural Science Foundation of Jiangsu Province (Grant No. BK2008026)National Key Technology R&D Program (Grant No. 2009BAB43B03)
文摘LA-ICPMS zircon U-Pb dating of intrusive rocks from the Shizishan ore field,Tongling,Anhui Province shows that the crystallization ages of Baimangshan pyroxene diorite,Shizishan and Dongguashan quartz diorite are 139±1.9,138.0±1.7,and 138.4±1.7 Ma,respectively.These three intrusions are high-potassium,alkali-rich,meta-aluminous,and are characterized by enrichment of light rare earth elements and large-ion lithophile elements,depletion of heavy rare-earth elements(HREE) and high field strength elements,and slightly negative Eu anomalies.In-situ Hf analysis of zircon for these three intrusions shows large ranges of Hf isotope compositions:the ε Hf(t) values are ε Hf(t)= 3.3 to 14.4 for Baimangshan,14.1 to 23.9 Dongguashan,and 14.7 to 26.9 for Shizishan.The ε Hf(t) values of both the Dongguashan and Shizishan quartz diorites are significantly lower than those of Baimangshan pyroxene diorite.Elemental geochemistry and in-situ zircon Hf isotope analyses indicate that the three intrusions were formed through mixing of granitic magma formed by partial melting of the lower crust and water-rich basic magma derived from the enriched lithospheric mantle.The Dongguashan and Shizishan quartz diorites involved greater crustal components than Baimangshan pyroxene diorite.The Dongguashan and Shizishan quartz diorites have geochemical features similar to the adakite,such as high Sr,low Y,and high Sr/Y ratios.Such geochemical features can be attributed to some fractional crystallization of apatite and sphene,and insignificant plagioclase fractional crystallization after magma mixing.These three intrusions are the products of complex crust-mantle interaction during the regional tectonic regime transition from compression to extension.
