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391.
Synthesis and Preliminary Characterisation of New Silicate, Phosphate and Titanite Reference Glasses 总被引:3,自引:0,他引:3
Stephan Klemme Stefan Prowatke Carsten Münker Charles W. Magee Yann Lahaye Thomas Zack Simone A. Kasemann E. Joan A. Cabato Benjamin Kaeser 《Geostandards and Geoanalytical Research》2008,32(1):39-54
Eleven synthetic silicate and phosphate glasses were prepared to serve as reference materials for in situ microanalysis of clinopyroxenes, apatite and titanite, and other phosphate and titanite phases. Analytical results using different micro-analytical techniques showed that the glass fragments were homogeneous in major and trace elements down to the micrometre scale. Trace element determinations using inductively coupled plasma-mass spectrometry (ICP-MS), multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS), laser-ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) and secondary ionisation mass spectrometry (SIMS) showed good agreement for most elements (Li, Be, B, Cs, Rb, Ba, Sr, Ga, Pb, U, Th, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Er, Tm, Yb, Lu, Zr, Hf, Ta, Nb) studied and provide provisional recommended values. 相似文献
392.
磷灰石裂变径迹定年作为揭示岩石低温热年代学的一种重要方法,能够有效重塑地壳浅部约3~5 km内数百万年以来的热演化历史,已经被广泛应用于地球科学的相关研究中。依托于中国地质科学院地质力学研究所建立的裂变径迹实验室,同时采用外探测器法和LA-ICP-MS/FT法对国际上普遍使用的Durango磷灰石进行了测定,得到2个Durango磷灰石外探测器法年龄为:32.9±1.6 Ma、31.9±2.3 Ma; 7个Durango磷灰石LA-ICP-MS/FT法年龄为:31.97±0.82 Ma、30.9±1.5 Ma、32.3±1.4 Ma、30.6±1.1 Ma、30.7±1.4 Ma、29.7±1.9 Ma、31.1±1.3 Ma,两种方法测得的年龄均与国际推荐值在误差范围内一致;此外,我们也应用这两种方法对采集于天山的花岗岩样品18HS-5进行了测试,年龄分别为126.7±3.8 Ma、126.4±3.6 Ma,两种方法得到的年龄在误差范围内一致。实验对比分析表明,实验流程可靠,可推广测试。 相似文献
393.
Shengbiao Hu Barry P. Kohn Asaf Raza Jiyang Wang Andrew J.W. Gleadow 《Tectonophysics》2006,420(3-4):409-429
The crystalline terrane of the Tongbai–Dabie region, central China, comprising the Earth's largest ultrahigh-pressure (UHP) exposure was formed during Triassic collision between the Sino–Korean and Yangtze cratons. New apatite fission-track (AFT) data presented here from the UHP terrane, extends over a significantly greater area than reported in previous studies, and includes the (eastern) Dabie, the Hong'an (northwestern Dabie) and Tongbai regions. The new data yield ages ranging from 44 ± 3 to 142 ± 36 Ma and mean track lengths between 10 and 14.4 μm. Thermal history models based on the AFT data taken together with published 40Ar/39Ar, K–Ar, apatite and zircon (U–Th)/He and U–Pb data, exhibit a three-stage cooling pattern that is similar across the study region, commencing with an Early Cretaceous rapid cooling event, followed by a period of relative thermal stability during which rocks remained at temperatures within the AFT partial annealing zone (60–110 °C) and ending with a possible renewed phase of accelerated cooling during Pliocene to Recent time. The first cooling phase followed large-scale transtensional deformation between 140 and 110 Ma and is related to Early Cretaceous eastward tectonic escape and Pacific back arc extension. Between this phase and the subsequent slow cooling phase, a transition period from 120 to 80 Ma (to 70 to 45 Ma along the Tan–Lu fault) was characterised by a relatively low cooling rate (3–5 °C/Ma). This transition is likely related to a tectonic response associated with the mid-Cretaceous subduction of the Izanagi–Pacific plate as well as lithospheric extension and thinning in eastern Asia. The present regional AFT age pattern is therefore basically controlled by the Early Cretaceous rapid cooling event, but finally shaped through active Cenozoic faulting. Following the transition phase the subsequent slow cooling phase pattern implies a net reduction in horizontal compressional stress corresponding to increased extension rates along the continental margin due to the decrease in plate convergence. Modelling of the AFT data suggests a possible Pliocene–Recent cooling episode, which may be supported by increased rates of sedimentation observed in adjacent basins. This cooling phase may be interpreted as a response to the far-field effects of the frontal India–Eurasia collision to the west. Approximate estimates suggest that the total amount of post 120 Ma denudation across the UHP orogen ranged from 2.4 to 13.2 km for different tectonic blocks and ranged from 0.8 to 9.7 km during the Cretaceous to between 1.7 and 3.8 km during the Cenozoic. 相似文献
394.
The apatite fission track (AFT) ages and thermal modeling of the Longshoushan and deformation along the northern Hexi Corridor on the northern side of the Qinghai-Tibetan Plateau show that the Longshoushan along the northern corridor had experienced important multi-stage exhumations during the Late Mesozoic and Cenozoic. The AFT ages of 7 samples range from 31.9 Ma to 111.8 Ma. Thermal modeling of the AFT ages of the samples shows that the Longshoushan experienced significant exhumation during the Late Cretaceous to the Early Cenozoic (~130–25 Ma). The Late Cretaceous exhumation of the Longshoushan may have resulted from the continuous compression between the Lhasa and Qiangtang blocks and the flat slab subduction of the Neo-Tethys oceanic plate, which affected wide regions across the Qinghai-Tibetan Plateau. During the Early Cenozoic, the Longshoushan still experienced exhumation, but this process was caused by the Indian-Eurasian collision. Since this time, the Longshoushan was in a stable stage for approximately 20 Ma and experienced erosion. Since ~5 Ma, obvious tectonic deformation occurred along the entire northern Hexi Corridor, which has also been reported from the peripheral regions of the Qinghai-Tibetan Plateau, especially in the Qilianshan and northeastern margin of the plateau. The AFT ages and the Late Cenozoic deformation of the northern Hexi Corridor all indicate that the present northern boundary of the Qinghai-Tibetan Plateau is situated along the northern Hexi Corridor. 相似文献
395.
396.
新疆博格达--哈尔里克山白垩纪以来剥露历史的裂变径迹证据 总被引:27,自引:2,他引:25
对新疆博格达-哈尔里克山火山岩和花岗岩的15个磷灰石样品和5个锆石样品的裂变径迹年龄测定表明,磷灰石的裂变径迹年龄变化于109.3~11.9 Ma之间,锆石的裂变径迹年龄变化于81.7~56.8 Ma之间.矿物对法计算得到,该地区晚白垩世至新生代中期的视剥露速率为0.157~0.222 mm/a.热史模拟结果表明,博格达-哈尔里克山自白垩纪以来经历了多期冷却剥露,分别是早白垩世(119~105 Ma)、晚白垩世晚期(67~65 Ma)、新生代早中期(47~31 Ma)和新生代晚期(12~7 Ma).白垩纪以来的天山变形作用,与亚洲南缘多期的地体碰撞增生有关. 相似文献