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41.
新疆北山南缘金矿成矿信息分析 总被引:1,自引:0,他引:1
本文采用地、物、化、遥等多学科有机结合的方式,利用多种新技术方法手段,从多方位、多层次定性定量提取资源体自然特征成矿信息,据新疆北山南缘金矿床(点)研究结果表明,该金矿床具构造、蚀变、矿化“三位一体”之空间格局的特征 相似文献
42.
Remote sensing of particle backscattering in Chesapeake Bay: A 6-year SeaWiFS retrospective view 总被引:1,自引:0,他引:1
David G. Zawada Chuanmin Hu Tonya Clayton Zhiqiang Chen John C. Brock Frank E. Muller-Karger 《Estuarine, Coastal and Shelf Science》2007,73(3-4):792-806
Traditional field techniques to monitor water quality in large estuaries, such as boat-based surveys and autonomous moored sensors, generally provide limited spatial coverage. Satellite imagery potentially can be used to address both of these limitations. Here, we show that satellite-based observations are useful for inferring total-suspended-solids (TSS) concentrations in estuarine areas. A spectra-matching optimization algorithm was used to estimate the particle backscattering coefficient at 400 nm, bbp(400), in Chesapeake Bay from Sea-viewing Wide-Field-of-view Sensor (SeaWiFS) satellite imagery. These estimated values of bbp(400) were compared to in situ measurements of TSS for the study period of September 1997–December 2003. Contemporaneous SeaWiFS bbp(400) values and TSS concentrations were positively correlated (N = 340, r2 = 0.4, P < 0.0005), and the satellite-derived bbp(400) values served as a reasonable first-order approximation for synoptically mapping TSS. Overall, large-scale patterns of SeaWiFS bbp(400) appeared to be consistent with expectations based on field observations and historical reports of TSS. Monthly averages indicated that SeaWiFS bbp(400) was typically largest in winter (>0.049 m−1, November–February) and smallest in summer (<0.031 m−1, June–August), regardless of the amount of riverine discharge to the bay. The study period also included Hurricanes Floyd and Isabel, which caused large-scale turbidity events and changes in the water quality of the bay. These results demonstrate that this technique can provide frequent synoptic assessments of suspended solids concentrations in Chesapeake Bay and other coastal regions. 相似文献
43.
西藏冈底斯东段扎雪地区林子宗群帕那组火山岩锆石U-Pb年龄、地球化学特征及其构造意义 总被引:1,自引:0,他引:1
本文对扎雪地区林子宗群帕那组火山岩进行主微量地球化学和锆石U—Pb—Hf同位素研究,以探讨其形成时代、岩石成因及其构造意义。锆石U Pb年龄表明,扎雪地区帕那组火山岩形成于~52 Ma,与冈底斯东段帕那组火山岩形成时代相似,暗示了帕那组在时空上具有相对一致的活动时限。研究区火山岩高硅、富钠、富碱,A/CNK值为130~173,属于过铝质钾玄岩系列。同时,这些火山岩富集大离子亲石元素和轻稀土元素,亏损高场强元素,有岛弧岩浆的亲属性,且其低Mg#(1977~3896)及低含量的Cr(300~343 μg/g)、Ni(290~156 μg/g)、Co(220~958 μg/g),La/Sm值随La含量升高而无明显变化,表明这些火山岩在成岩过程中经历了明显的分离结晶作用。此外,扎雪地区帕那组火山岩锆石εHf(t)平均值 -44~-36,表明该火山岩起源于新生地壳物质的部分熔融,有古老壳源物质加入源区中,形成了相对富集的Hf同位素特征。结合前人在林周盆地及邻区的研究结果,表明冈底斯东段林子宗群火山岩母岩浆随时间由岛弧环境的亏损地幔源区向碰撞环境壳源物质加入相对富集型源区的转变,指示其形成环境经历了由岛弧向陆陆碰撞的转变;帕那组火山岩形成于印度板块与欧亚板块碰撞的初期阶段,是记录这种体制转换的主要载体。 相似文献
44.
Brian E. Lapointe Richard Langton Arthur C. Potts Chuanmin Hu 《Marine pollution bulletin》2010,60(3):334-343
Tobago’s fringing coral reefs (FR) and Buccoo Reef Complex (BRC) can be affected locally by wastewater and stormwater, and regionally by the Orinoco River. In 2001, seasonal effects of these inputs on water-column nutrients and phytoplankton (Chl a), macroalgal C:N:P and δ15N values, and biocover at FR and BRC sites were examined. Dissolved inorganic nitrogen (DIN, particularly ammonium) increased and soluble reactive phosphorus (SRP) decreased from the dry to wet season. Wet season satellite and Chl a data showed that Orinoco runoff reaching Tobago contained chromophoric dissolved organic matter (CDOM) but little Chl a, suggesting minimal riverine nutrient transport to Tobago. C:N ratios were lower (16 vs. 21) and macroalgal δ15N values higher (6.6‰ vs. 5.5‰) in the BRC vs. FR, indicating relatively more wastewater N in the BRC. High macroalgae and low coral cover in the BRC further indicated that better wastewater treatment could improve the health of Tobago’s coral reefs. 相似文献
45.
我国大量堆存和正在排放的煤矸石,既是一种矿业排量最大的废弃物,又可以被认为是一种可利用的巨型资源。阜新煤矸石主要由石英、长石、伊利石等矿物组成,化学成分含60%~67%SiO2,13%~18%Al2O3,具有高硅低铝特征,属于目前难以利用煤矸石。本文实验采用了C3S—C4A3S—C2S—C4AF体系,利用煤矸石的Al2O3煅烧成无水硫铝酸钙而不是铝酸三钙。添加BaSO4、CaF2和铬渣,使硅酸三钙和无水硫铝酸钙能在1300-1360℃共生,制备出了阿利特-硫铝酸盐水泥。水泥熟料在1360℃,保温1小时烧成。研制的煤矸石水泥3天和28天抗压强度分别达到了34.7~36.8MPa和52.2~54.4MPa,达到了525#早强型高性能水泥指标。 相似文献