On the basis of the geological mapping, isotopic choronoogcal and petrological evidences, the authors suggested that the early Tertiary volcanic strata in the Fildes Peninsula could be divided into two formations and ...On the basis of the geological mapping, isotopic choronoogcal and petrological evidences, the authors suggested that the early Tertiary volcanic strata in the Fildes Peninsula could be divided into two formations and four members. The erupted centers in the peninsula were gradualy migrating from the western coast to the eastern and the subvolcanic intrusives were regularly distributed along a series of NWW-SEE trending faults. All of these were basically formed in two stages of volcanic activities from Paleocene to Eocene.展开更多
A new lithostratigraphic unit - Half Three Point Formation is determined on an inlet (62°13'40'S, 58°59'01'W) near Half Three Point of Fildes Peninsula of King George Island, South Shetland I...A new lithostratigraphic unit - Half Three Point Formation is determined on an inlet (62°13'40'S, 58°59'01'W) near Half Three Point of Fildes Peninsula of King George Island, South Shetland Islands. This formation consists of volcanic breccia, sediment- tuff, tuffaceous siltstones and mudstones about 5. 5m thick. The Palynomorph assemblage is of Late Cretaceous age (Campanian - Maastrichtian). Isotopic age of the tuffites by Rb -Sr whole rock method is 71.30±0. 3 Ma.The calcite of sand -sized tuffites formed by calcitization during early diagenesis has very light δ18C value of - 26. 24%,PDB, and δ13C value of -5. 130 to 5. 631%, PDB. It suggests that the calcitization is related to thermal freshwater originally. The tuffaceous mudstone contains lower B content of 48. 4 ppm, corresponding to that of lacustrine mudstones. Low87 Sr/86 Sr ratio (0. 703189 - 0. 703320) indicates the tuffites of continental origin. Therefore, the formation may represent a lacustrine deposit under low energy and reducing environment. This is only known to define the late Late Cretaceous lacustrine sediments in Antarctica展开更多
Volcanic geological,petrological and geochemical characteristics of the Tertiary volcanic rocks from the Fildes Peninsula,West Antarctica show that magma evolution was a process of dissipation of heat energy exchanged...Volcanic geological,petrological and geochemical characteristics of the Tertiary volcanic rocks from the Fildes Peninsula,West Antarctica show that magma evolution was a process of dissipation of heat energy exchanged energy and mass occurring between the magma system and its surrounding environments, and with the feature of dynamic equilibrium and periodicity(stage). In the study volcanic rocks of different types commonly exhibit a multi-grade composite texture and the derivative magmas produced by differentiation of parent magymas in the magma chamber show a zonal structure in the high--level--magma chamber which represent self-organization phenomenon of the nonequilibrium process in magmatism. The self-organization phenomenon is dissipative structure formed under given conditions.展开更多
Although temperature extremes have led to more and more disasters, there are as yet few studies on the extremes and many disagreements on temperature changes in Antarctica. Based on daily minimum, maximum, and mean ai...Although temperature extremes have led to more and more disasters, there are as yet few studies on the extremes and many disagreements on temperature changes in Antarctica. Based on daily minimum, maximum, and mean air temperatures(Tmin, Tmax, Tmean) at Great Wall Station(GW) and Zhongshan Station(ZS), we compared the temperature extremes and revealed a strong warming trend in Tmin, a slight warming trend in Tmean, cooling in Tmax, a decreasing trend in the daily temperature range, and the typical characteristic of coreless winter temperature. There are different seasonal variabilities, with the least in summer. The continentality index and seasonality show that the marine air mass has more effect on GW than ZS. Following the terminology of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change(IPCC AR5), we defined nine indices of temperature extremes, based on the Antarctic geographical environment. Extreme-warm days have decreased, while extreme-warm nights have shown a nonsignificant trend. The number of melting days has increased at GW, while little change at ZS. More importantly, we have found inverse variations in temperature patterns between the two stations, which need further investigation into the dynamics of climate change in Antarctica.展开更多
文摘On the basis of the geological mapping, isotopic choronoogcal and petrological evidences, the authors suggested that the early Tertiary volcanic strata in the Fildes Peninsula could be divided into two formations and four members. The erupted centers in the peninsula were gradualy migrating from the western coast to the eastern and the subvolcanic intrusives were regularly distributed along a series of NWW-SEE trending faults. All of these were basically formed in two stages of volcanic activities from Paleocene to Eocene.
基金by State Antarctic CommitteeNational Natural Science Foundation of China
文摘A new lithostratigraphic unit - Half Three Point Formation is determined on an inlet (62°13'40'S, 58°59'01'W) near Half Three Point of Fildes Peninsula of King George Island, South Shetland Islands. This formation consists of volcanic breccia, sediment- tuff, tuffaceous siltstones and mudstones about 5. 5m thick. The Palynomorph assemblage is of Late Cretaceous age (Campanian - Maastrichtian). Isotopic age of the tuffites by Rb -Sr whole rock method is 71.30±0. 3 Ma.The calcite of sand -sized tuffites formed by calcitization during early diagenesis has very light δ18C value of - 26. 24%,PDB, and δ13C value of -5. 130 to 5. 631%, PDB. It suggests that the calcitization is related to thermal freshwater originally. The tuffaceous mudstone contains lower B content of 48. 4 ppm, corresponding to that of lacustrine mudstones. Low87 Sr/86 Sr ratio (0. 703189 - 0. 703320) indicates the tuffites of continental origin. Therefore, the formation may represent a lacustrine deposit under low energy and reducing environment. This is only known to define the late Late Cretaceous lacustrine sediments in Antarctica
文摘Volcanic geological,petrological and geochemical characteristics of the Tertiary volcanic rocks from the Fildes Peninsula,West Antarctica show that magma evolution was a process of dissipation of heat energy exchanged energy and mass occurring between the magma system and its surrounding environments, and with the feature of dynamic equilibrium and periodicity(stage). In the study volcanic rocks of different types commonly exhibit a multi-grade composite texture and the derivative magmas produced by differentiation of parent magymas in the magma chamber show a zonal structure in the high--level--magma chamber which represent self-organization phenomenon of the nonequilibrium process in magmatism. The self-organization phenomenon is dissipative structure formed under given conditions.
基金funded by the National Natural Science Foundation of China (Grant Nos. 41476164, 41671073, 41425003, and 41671063)the State Key Laboratory of Cryospheric Science
文摘Although temperature extremes have led to more and more disasters, there are as yet few studies on the extremes and many disagreements on temperature changes in Antarctica. Based on daily minimum, maximum, and mean air temperatures(Tmin, Tmax, Tmean) at Great Wall Station(GW) and Zhongshan Station(ZS), we compared the temperature extremes and revealed a strong warming trend in Tmin, a slight warming trend in Tmean, cooling in Tmax, a decreasing trend in the daily temperature range, and the typical characteristic of coreless winter temperature. There are different seasonal variabilities, with the least in summer. The continentality index and seasonality show that the marine air mass has more effect on GW than ZS. Following the terminology of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change(IPCC AR5), we defined nine indices of temperature extremes, based on the Antarctic geographical environment. Extreme-warm days have decreased, while extreme-warm nights have shown a nonsignificant trend. The number of melting days has increased at GW, while little change at ZS. More importantly, we have found inverse variations in temperature patterns between the two stations, which need further investigation into the dynamics of climate change in Antarctica.
