Previous studies proposed thermal simulation experiment to investigate the annealing characteristics of fission tracks in igneous zircon samples.However,basic research about detrital zircon fission track was relativel...Previous studies proposed thermal simulation experiment to investigate the annealing characteristics of fission tracks in igneous zircon samples.However,basic research about detrital zircon fission track was relatively weak.This study discussed the initial track length,annealing temperature and annealing model of zircon fission track by using the measured track lengths obtained from natural borehole samples in the sedimentary basins with different thermal background.The results show that the initial track length of zircon fission track is 12.97 μm.The total annealing temperature(Ttotal) of zircon fission track derived from the evolutionary curve of the mean track lengths is approximately 400 ℃.The temperature ranges of 120-230 ℃ corresponds to the partial annealing zone(PAZ),and is lower than the range obtained through thermal annealing experiments.The annealing model is modified based on the measured track lengths.In addition,a functional formula about the mean track length,annealing temperature,and geological time is proposed,and the fitted values of track lengths consist with the measured track lengths in this study.By properly understanding the initial track length and annealing behavior of zircon fission track can provide a significant guidance for the study of hydrocarbon accumulation in sedimentary basins.展开更多
The Sanjiang Tethys orogenic belt is located in the southeast side of the Qinghai-Tibet Plateau. It has undergone the opening and closing movements in different periods of Tethys oceans, complex accretive orogeny and ...The Sanjiang Tethys orogenic belt is located in the southeast side of the Qinghai-Tibet Plateau. It has undergone the opening and closing movements in different periods of Tethys oceans, complex accretive orogeny and strong mineralization from Paleozoic to Mesozoic. Using zircon fission track(ZFT) thermochronology, this study reveals the Sanjiang Tethys has experienced multi-stage tectonic activities during the Late Triassic–Cenozoic. The 15 ZFT ages with their decomposition components obtained from Sanjiang Tethysian region range from 212 to 19 Ma, which not only shows 6 age groups of 212, 179–172, 156–133, 121–96, 84–70 and 50–19 Ma, but also constrains the age limit of the tectonothermal events. These age groups recorded the Paleo-Tethys main and branches ocean opening/closure time. The age-elevation plot indicates the Sanjiang region had differential uplifting and exhumation and fast uplifting times of ca. 133, 116 and 80 Ma, coinciding with the age groups mentioned above. These results show new geochronological evidences and viewpoints.展开更多
Considerable attention has been paid in recent years to the study of geothermal histo-ry by using spontaneous fission tracks of 238U recorded in minerals. Apatite and zircon were used for fission track study in this p...Considerable attention has been paid in recent years to the study of geothermal histo-ry by using spontaneous fission tracks of 238U recorded in minerals. Apatite and zircon were used for fission track study in this paper because apatite has been widely used as a natural geothermometer (Wang Shicheng et al., 1994) to reveal the thermal evolution of sedimentary rocks based on its low annealing temperature of fission tracks and zircon is characterized by a closing temperature above 700℃. The samples were collected from ferruginous, siliceous slate wall rock at the upper levels of the orebody and Nb-REE-Fe ores from deep tunnels. The age and thermal evolution of the orebody were discussed in terms of fission track characters and their length variations observed in the coexisting apatite and zircon in the same specimen.展开更多
The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different,but also fall into the Hercynian epoch.This study has achieved 9 zircon and 7 apatite fission track analysis resu...The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different,but also fall into the Hercynian epoch.This study has achieved 9 zircon and 7 apatite fission track analysis results.The zircon fission track ages range from 158 Ma to 289 Ma and the apatite ages are between 64 Ma and 140 Ma.The mineralization accords with the regional tectonics in the copper district.We consider that the zircon fission track age could reveal the mineralization age based on annealing zone temperature of 140―300℃ and retention temperature of ～250℃ for zircon fission track,and metallogenetic temperature of 120―350℃ in this ore district.Total three mineralization epochs have been identified,i.e.,289―276 Ma,232―200 Ma and 165―158 Ma,and indicate occurrence of the min-eralization in the Indosinian and Yanshan epochs.Corresponding to apatite fission track ages,the three tectonic-mineralizing epochs are 140―132 Ma,109―97 Ma and 64 Ma,which means age at about 100℃ after the mineralization.The three epochs lasted 146 Ma,108 Ma and about 100 Ma from ～250℃ to ～100℃ and trend decrease from early to late.It is shown by the fission track modeling that this district underwent three stages of geological thermal histories,stable in Cretaceous and cooling both before Cretaceous and after 20 Ma.展开更多
Although it is more difficult to reveal spontaneous fission tracks in zircon than in apatite by chemical etching, the obvious advantages of zircon for fission track dating, such as relatively high uranium content, goo...Although it is more difficult to reveal spontaneous fission tracks in zircon than in apatite by chemical etching, the obvious advantages of zircon for fission track dating, such as relatively high uranium content, good track-stability and common occurrence, have been encouraging people to develop and improve etching technique of fission tracks in展开更多
Ⅰ. INTRODUCTION When developing the technique of fission track dating, people found that the etching rates vary markedly with the crystallographic orientation of the etched surfaces so that the shapes of tracks are d...Ⅰ. INTRODUCTION When developing the technique of fission track dating, people found that the etching rates vary markedly with the crystallographic orientation of the etched surfaces so that the shapes of tracks are different, and that even on the same Crystalline surface the etching展开更多
基金supported by the National Natural Science Foundation of China(Nos.41802154 and 41830424)the State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing(No.PRP/open-1902)+1 种基金the Natural Science Foundation Project of Chongqing,Chongqing Science and Technology Commission(No.cstc2019jcyj-msxm X0764)the Science and Technology Research Program of Chongqing Municipal Education Commission(No.KJQN201901533)。
文摘Previous studies proposed thermal simulation experiment to investigate the annealing characteristics of fission tracks in igneous zircon samples.However,basic research about detrital zircon fission track was relatively weak.This study discussed the initial track length,annealing temperature and annealing model of zircon fission track by using the measured track lengths obtained from natural borehole samples in the sedimentary basins with different thermal background.The results show that the initial track length of zircon fission track is 12.97 μm.The total annealing temperature(Ttotal) of zircon fission track derived from the evolutionary curve of the mean track lengths is approximately 400 ℃.The temperature ranges of 120-230 ℃ corresponds to the partial annealing zone(PAZ),and is lower than the range obtained through thermal annealing experiments.The annealing model is modified based on the measured track lengths.In addition,a functional formula about the mean track length,annealing temperature,and geological time is proposed,and the fitted values of track lengths consist with the measured track lengths in this study.By properly understanding the initial track length and annealing behavior of zircon fission track can provide a significant guidance for the study of hydrocarbon accumulation in sedimentary basins.
基金supported by the National Program on Key Basic Research Project(973 Program)(No.2015CB452606)the National Natural Science Foundation of China(Nos.41730427,41172088)
文摘The Sanjiang Tethys orogenic belt is located in the southeast side of the Qinghai-Tibet Plateau. It has undergone the opening and closing movements in different periods of Tethys oceans, complex accretive orogeny and strong mineralization from Paleozoic to Mesozoic. Using zircon fission track(ZFT) thermochronology, this study reveals the Sanjiang Tethys has experienced multi-stage tectonic activities during the Late Triassic–Cenozoic. The 15 ZFT ages with their decomposition components obtained from Sanjiang Tethysian region range from 212 to 19 Ma, which not only shows 6 age groups of 212, 179–172, 156–133, 121–96, 84–70 and 50–19 Ma, but also constrains the age limit of the tectonothermal events. These age groups recorded the Paleo-Tethys main and branches ocean opening/closure time. The age-elevation plot indicates the Sanjiang region had differential uplifting and exhumation and fast uplifting times of ca. 133, 116 and 80 Ma, coinciding with the age groups mentioned above. These results show new geochronological evidences and viewpoints.
文摘Considerable attention has been paid in recent years to the study of geothermal histo-ry by using spontaneous fission tracks of 238U recorded in minerals. Apatite and zircon were used for fission track study in this paper because apatite has been widely used as a natural geothermometer (Wang Shicheng et al., 1994) to reveal the thermal evolution of sedimentary rocks based on its low annealing temperature of fission tracks and zircon is characterized by a closing temperature above 700℃. The samples were collected from ferruginous, siliceous slate wall rock at the upper levels of the orebody and Nb-REE-Fe ores from deep tunnels. The age and thermal evolution of the orebody were discussed in terms of fission track characters and their length variations observed in the coexisting apatite and zircon in the same specimen.
基金Supported by the National Basic Research Priorities Program (Grant No 2001CB409804)the National Natural Science Foundation of China (Grant Nos 10475093,10175076 and 40072068)
文摘The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different,but also fall into the Hercynian epoch.This study has achieved 9 zircon and 7 apatite fission track analysis results.The zircon fission track ages range from 158 Ma to 289 Ma and the apatite ages are between 64 Ma and 140 Ma.The mineralization accords with the regional tectonics in the copper district.We consider that the zircon fission track age could reveal the mineralization age based on annealing zone temperature of 140―300℃ and retention temperature of ～250℃ for zircon fission track,and metallogenetic temperature of 120―350℃ in this ore district.Total three mineralization epochs have been identified,i.e.,289―276 Ma,232―200 Ma and 165―158 Ma,and indicate occurrence of the min-eralization in the Indosinian and Yanshan epochs.Corresponding to apatite fission track ages,the three tectonic-mineralizing epochs are 140―132 Ma,109―97 Ma and 64 Ma,which means age at about 100℃ after the mineralization.The three epochs lasted 146 Ma,108 Ma and about 100 Ma from ～250℃ to ～100℃ and trend decrease from early to late.It is shown by the fission track modeling that this district underwent three stages of geological thermal histories,stable in Cretaceous and cooling both before Cretaceous and after 20 Ma.
基金Project supported by the National Natural Science Foundation of China.
文摘Although it is more difficult to reveal spontaneous fission tracks in zircon than in apatite by chemical etching, the obvious advantages of zircon for fission track dating, such as relatively high uranium content, good track-stability and common occurrence, have been encouraging people to develop and improve etching technique of fission tracks in
基金Project supported by the National Natural Science Foundation of China
文摘Ⅰ. INTRODUCTION When developing the technique of fission track dating, people found that the etching rates vary markedly with the crystallographic orientation of the etched surfaces so that the shapes of tracks are different, and that even on the same Crystalline surface the etching
