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61.
研究区早石炭世经历了中天山古陆北缘被动陆缘向活动陆缘沟弧盆体系演化的全过程。阿齐山-雅满苏岛弧带于维宪期发育在广宽陆棚海之上。岛弧为大型背形结构,雅满苏断裂带为火山喷发的主要通道,弧前盆地生成于弧沟间隙部位。晚石炭世早期,弧后区发生扩张作用而塌陷形成向形的边缘盆地。晚石炭世末,北侧康古尔洋区以弧弧对接方式关闭,弧区伴有深成花岗岩浆侵位。早二叠世早期进入松弛阶段,在弧间及弧后南缘产生上叠断陷盆地。晚二叠世右旋走滑变动席卷全区,最后大型造山带与地块之间发生块体右旋滑移错位,由此奠定了现今的盆山构造格局初貌。 相似文献
62.
During magnetic storms an anomalous increase in the ionization density of the nighttime E region is observed at low and middle latitudes. It has been suggested that this effect is caused by the precipitation of neutralized ring current particles. Here a coupled ring current decay-ionosphere model is used to confirm the validity of this explanation. 相似文献
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新疆地区重力变化与伽师6.8级地震 总被引:18,自引:7,他引:11
分析了新疆地区1998~2002年重力变化,研究了重力变化与伽师6.8级地震活动的关系,认为:重力场动态图像对伽师6.8级地震有较好的反映,重力测量可以较好地反映活动断层的物质迁移和构造形变引起的地表重力变化。 相似文献
66.
云南地区现今地壳水平运动与变形特征 总被引:10,自引:4,他引:6
利用云南地区 1999、2 0 0 0、2 0 0 1年共 10 0余个测站的GPS资料 ,获得了该区现今水平运动与形变的特征图像。研究结果认为 :①根据变形与运动特征 ,云南地区可划分为 4个运动单元 ,即滇西地区、滇东地区、滇中东北地区和滇中西南地区 ;剔除整体运动后 ,它们的优势水平运动分别为 :滇西地区以 5 .2± 0 .6mm/a向W 31°N运动 ,滇东地区以 4 .8± 1.8mm/a向E2 6°N运动 ,滇中东北地区以 5 .2± 0 .6mm/a向S4 4°E运动 ,滇中西南地区则基本不动。②相邻单元的平均差异运动分别为 :滇西地区相对滇中东北地区的运动为 10 .9± 1.1mm/a ,方向为W 39°N(张性右旋 ) ,相对滇中西南地区的运动为 5 .3± 1.3mm/a ,方向为W 4 1°N(右旋 ) ;滇中东北地区相对滇中西南地区的运动为 5 .6± 1.6mm/a ,方向为E36°S(左旋 ) ;滇东地区相对滇中东北地区的运动为 6 .2± 1.6mm/a ,方向为N3°E(左旋 )。③从断裂走滑活动看 ,红河断裂两侧的差异运动并不是由红河断裂的活动所形成的 ,而是在很广阔的空间上自西向东渐变而成的 ,跨距达数百km ;小江断裂两侧的差异运动也非完全是小江断裂本身的活动 ,差异运动的渐变空间至少在 6 0km以上。④云南地区的地壳运动方式可能是“断块活动”和“连续变形”的组合 ,或许“连续变形” 相似文献
67.
SHRIMP U-Pb Zircon Age of the Ka''erjiao Intrusion in the Sawur Region in West Junggar,Xinjiang 下载免费PDF全文
ZHOU Taof TAN Lugui FAN Yu YUAN Feng YANG Wenping HE Lixin YUE Shucang School of Resources Environmental Engineering Hefei University of Technology Hefei Anhui No. Geological Party Xinjiang Bureau of Geological Exploration Altay Xinjiang 《《地质学报》英文版》2007,81(2)
Acid intrusions are widespread in the Sawur region, Xinjiang. The Ka'erjiao intrusion is mainly composed of albite granite porphyry, K-feldspar granite porphyry, ivernite and granite porphyry. Being a transitional product between magma intrusion and eruption in the Sawur region, the Ka'erjiao intrusion was formed at the telophase of the late Carboniferous to the begining of early Permian as determined by the SHRIMP U-Pb zircon dating, with an age of 302.6±7.6 Ma (1σ). The intrusion consists of alkali-enriched rock, whose REE distribution patterns are of the LREE enrichment type, theδEu value is low and Nd, Sr, Pb isotopes reflect its mantle source characteristics. Theδ18O value of intrusion is low as a result of isotope exchange with meteoric water. The geochemical characteristics show that it was formed in a post-collisional tectonic setting. Taking combined considerations of current studies of A-type granites and Permian volcanic rocks, we think that in the telophase of the late Carboniferous to the beginning of the early Permian, the Sawur region was within the extension or compressional to extensional period of a post-collisional stage. The Ka'erjiao intrusion from mantle sources can confirm the vertical continental crust growth in the late Paleozoic. The Sawur region in west Junggar is consistent with east Junggar in post-collisional tectonic evolution process. 相似文献
68.
ZHU Kaijun YAO GuolongTianjin Geological Academy State Bureau of Metallurgical Industry No. Youyi R Tianjin 《《地质学报》英文版》2000,74(3):534-539
Sinian is one of the main periods of the formation of manganese deposits in China. Sinian manganesedeposits are mainly hosted in carbon-rich black shale and siliceous shale formed during the Sinian interglacial period. The composition of manganese ore is simple. The main ore mineral is manganiferous carbonates. The grade of manganese ore is about 16-25%, with Mn/Fe>5 and P/Mn=0.006-0.14. Based on the tectonic setting and geological and geochemical characteristics of manganese deposits, this paper discusses the process of migration and concentration of manganese and ore-forming conditions of Sinian manganese deposits in China. 相似文献
69.
The most problematic variable in the course of human-biometeorological comfort assessment — the mean radiant temperature 总被引:2,自引:0,他引:2
This paper gives a review on the topic of the mean radiant temperature T mrt , the most important parameter influencing outdoor thermal comfort during sunny conditions. T mrt summarizes all short wave and long wave radiation fluxes reaching the human body, which can be very complex (variable in spatial and also in temporal manner) in urban settings. Thermal comfort researchers and urban planners need easy and sound methodological approaches to assess T mrt . After the basics of the T mrt calculation some of the methods suitable for obtaining T mrt also in urban environments will be presented.. Two of the discussed methods are based on instruments which measure the radiation fluxes integral (globe thermometer, pyranometer-pyrgeometer combination), and three of the methods are based on modelling the radiation environment with PC software (RayMan, ENVI-met and SOLWEIG). 相似文献
70.
Lisa M. Campbell Noëlle Boucquey Joshua Stoll Henry Coppola Martin D. Smith 《社会与自然资源》2014,27(1):88-106
Community-supported fisheries (CSF) projects show signs of rapid growth. Modeled on community-supported agriculture (CSA) projects, CSFs share objectives of reducing social and physical distance between consumers and producers and re-embedding food systems in social and environmental contexts. This article offers a comparison of CSF and CSA, situated in the differences between seafood and agricultural products, and fishing and farming. We draw on economic and resource theory, past research on CSA, and a member survey from a case study CSF. Survey results show CSF members are interested in accessing high-quality, fresh, local seafood, and in supporting fishing communities, and they believe that participating in a CSF achieves both. They are less certain that a CSF can address environmental concerns, and few identify environmental motives as their primary reason for participating. The latter contrasts with CSA research results, and we contextualize these findings in our broader comparison. 相似文献