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排序方式: 共有93条查询结果,搜索用时 26 毫秒
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Annealing behavior of alpha recoil tracks in phlogopite 总被引:1,自引:0,他引:1
Wanming Yuan Richard A. Ketcham Shaokai Gao Jinquan Dong Zenkuan Bao Jun Deng 《Chemical Geology》2009,266(3-4):343-349
In this study we present and interpret a new experimental data set documenting thermal annealing of alpha recoil tracks (ARTs) in phlogopite. Through improvements in experimental technique, difficulties in obtaining useable data from material with an uneven distribution of U and Th were overcome. The resulting annealing pattern was well organized on an Arrhenius plot, allowing construction of a simple, 3-parameter annealing model of parallel contours of constant annealing with a linear progression. Our data and model indicate that phlogopite ARTs anneal at very low temperatures on geological time scales. At the million-year time scale, full annealing requires a temperature of only 33 °C, and we infer closure temperatures from 26–37 °C for cooling rates of 10–100 °C/m.y. Phlogopite ART analysis is thus likely to be primarily useful in relatively young (<1 Ma) terrains featuring either recent volcanism or recent, fast exhumation. In such situations, however, it may provide unique information on the timing of the final stages of unroofing. Comparison of our results with previous studies on ART and fission-track annealing in phlogopite and biotite indicates that these two types of radiation damage anneal at disparate time and temperature conditions in biotite-series micas. 相似文献
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本文采取动静结合、时空并举的方法,从地震应变能释放的时空分布入手,对晋陕豫交界区分时段进行了空间扫描计算,研究分析了1970年以来,该区的应变能释放的时空动态演变过程及其与地震的关系。指出该区地震活动存在着长趋势增强的背景。 相似文献
44.
矿物中U、Th及其子核进行α衰变释放出α粒子时,剩余重核受到反冲而产生辐射损伤。在适当条件下经化学蚀刻,这些辐射损伤成为在光学显微镜下可观测的核径迹。通过建立适当的蚀刻模型和定年模型,计算径迹面密度和体密度,并测量U、Th含量,便可得到年龄。Alpha反冲径迹年代学的特点是可以确定较年轻的时代(百万年至数百年),故在资源环境、地理、考古等领域具有广泛的应用前号。 相似文献
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Evolution of Sedimentation and Tectonics of the Youjiang Composite Basin, South China 总被引:10,自引:0,他引:10
Zeng Yunfu Liu Wenjun Cheng Hongde Zheng Rongcai Zhang Jinquan Chengdu Institute of Technology Chengdu SichuanLi Xiaoquan Jiang Tingcao Regional Geological Survey Party of Guangxi Guilin Guangxi Jiang M inxi 《《地质学报》英文版》1995,69(4):358-371
Located at the southern margin of the South China plate, the Youjiang basin is a closely related to the NW- and NE-trending syndepositional faults in respect to the configuration and structure of the basin. The evolution of the Youjiang basin progressed through two stages. In the Hercynian period, the opening of the Ailaoshan-Honghe ocean basin gave rise to a number of NW-trending rift belts in the Youjiang area. During this period, deep-water sediments were dominant and the basin was possesed of the characteristics of the rift system of passive continental margins. In the early Indosinian after the Dongwu movement, the circum - Pacific tectonism led to a major change in the configuration and structure of the basin. In the meantime, the Ailaoshan ocean basin began to be subducted towards the northeast, thus causing the basin to be split and expand again, and then the basin developed into the stage of the back -arc basin. At the end of the Indosinian period, the basin gradually closed from east to west, 相似文献
47.
根据地质结构、遥感解译、物探、微震观测、地震硅热流值等资料分析,确定厦门岛属于较稳定地块-安全岛;由于断裂活动性,新构造运动、工程地质、水文地质和地貌单元等特征的差异,可进一步划分为4个稳定性亚区。 相似文献
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