迭代法计算H2O-CO2-NaCl包裹体均一压力的改进及其应用

文章在宋玉财等于2007年提出的利用迭代法计算流体包裹体成分及均一压力的基础上,结合Duan等通过热力学模拟研究所获得的最新的热力学方程及H2O-CO2-NaCl包裹体pVtx计算程序,对宋玉财等所提出的H2O-CO2-NaCl包裹体成分及均一压力的迭代计算法提出了改进意见,同时对其进行了适当的修改。文章利用中-低温条件下求解CO2在盐水中的溶解度及摩尔体积的方程,提高了原方法的计算精度,并将原方法的适用范围（均一温度≥300 ℃）扩展到中_低温（0～260 ℃）、中_低压力（0～1 000×105Pa）以及中等盐度的范围。本方法适用于求解CO2部分均一温度高于笼形物融化温度、不含石盐子矿物且完全均一到水溶液相的H2O-CO2-NaCl包裹体。     

In situ U–Pb SIMS (IN-SIMS) micro-baddeleyite dating of mafic rocks: Method with examples

An in situ U–Pb SIMS (IN-SIMS) method to date micro-baddeleyite crystals as small as 3 μm is presented with results from three samples that span a variety of ages and geologic settings. The method complements ID-TIMS geochronology by extending the range of dateable crystals to sizes smaller than can be recovered by physical separation. X-ray mapping and BSE imaging are used to locate target grains in thin section, followed by SIMS analysis on a CAMECA ims 1270, using the field aperture in the transfer column to screen out ions from host phases. Internal age precisions for the method are anticipated to range from 0.1% for Precambrian rocks to 3–7% for Phanerozoic rocks. Results establish a 2689 ± 5 Ma age for mafic dikes in the Wyoming craton, USA, a 1540 ± 30 Ma age for a subaerial lava flow from the Thelon Basin of northern Canada, and a 457 ± 34 Ma age for mafic dikes in the platform sequence of southeastern Siberia. The method is ideal for relatively non-destructive dating of small samples such as extraterrestrial rocks and precious terrestrial samples.     

西大滩地区光合有效辐射的基本特征

利用青藏高原多年冻土北界西大滩地区2005年度的辐射及气象观测资料,分析探讨了该地区光合有效辐射(PAR)的基本特征.结果显示:PAR日变化与总辐射(Q)日变化趋势一致,表现为中午大,早晚小;晴天的日变化曲线呈单峰型,变化相对比较平滑,阴天的日变化曲线不稳定,晴天的PAR大于阴天日.PAR具有明显的季节变化特征,表现为春夏季大,秋季次之,冬季最小,最大值出现在5月,最小值出现在12月.光合有效辐射系数ηQ值阴天大,晴天小;ηQ的日变化是中午小,早晚大,年变化呈双峰型,在1.75~1.96 mol.MJ-1之间变化,年平均值为1.88 mol.MJ-1.最后,提出了适合本地区PAR的气候学计算方法.     

青藏高原纳木错流域扎当冰川度日因子特征及其应用

根据青藏高原念青唐古拉峰北坡纳木错流域扎当冰川2007和2008年消融期的物质平衡和气象观测资料,计算了冰川冰和雪的度日因子值,分析了冰川度日因子的时空变化及影响因素.结果表明:扎当冰川雪的度日因子值为5.3mm·d-1·℃-1;不同海拔冰的度日因子在4.0～14.0mm·d-1·℃-1之间,平均为9.2mm·d-1·℃-1.扎当冰川冰的度日因子值随着海拔的升高有所下降,但季节变化规律不明显.利用度日模型对扎当冰川物质平衡进行了模拟,得到2006/2007年度和2007/2008年度该冰川的物质平衡值分别为-534mmw.e.和247mmw.e.,其中2007/2008年度的模拟值接近观测值.     

渝利铁路青石岩段边坡危岩体稳定性评价及防治措施研究

渝利铁路青石岩段为深切河谷型边坡,该边坡表部岩体在风化缷荷作用下结构复杂且稳定性差。此外,浅表层岩体在降雨、地震及工程开挖等影响下,局部已经出现了不同模式不同规模的变形失稳现象,严重影响工程建设和运营期间的安全。因此,本文根据边坡岩体结构特征及风化缷荷特征等工程地质条件,结合不同失稳模式的危岩体,提出了相应的稳定性评价理论和方法。最后,针对不同规模和不同稳定状态下的危岩体提出了有效的防治措施。     

泸沽湖机场北东端高填方稳定性分析

泸沽湖机场的北东端存在高填方边坡,其稳定性对机场影响重大,笔者对填方边坡的稳定性做了计算,并进行了有限元分析,列举了提高边坡稳定性的一些具体措施,为该机场的建设提供参考。     

带结构面围岩山岩压力计算探讨

岩体内存在着节理、断层、软弱夹层、岩层层面、片理、片麻理等各种结构面,结构面的不同组合,形成了形状不一、规模不等的各种结构体。给出了两组同倾向结构面、多组同倾向结构面、两组反倾向结构面,在不同倾角组合、不同计算条件下山岩压力的计算模式,并进行了比较分析,得出了有益的结论。     

Nature of the Ore-Forming Fluid at the Quaternary Noya Gold Deposit in Kyushu,Japan

We discuss the nature of the ore-forming hydrothermal fluid in the Noya gold-bearing calcite-quartz-adularia veins of central Kyushu, Japan on the basis of oxygen, carbon, and strontium isotope ratios, and aqueous speciation calculations for the present-day geothermal fluid. The isotopic values of the Noya ore-forming fluid were estimated to be −6.5‰ for δ¹³C and −7.5‰ for δ¹⁸O. The oxygen isotopic equilibrium temperatures for vein calcite are more than 180°C at the bottom of the Noya mineralization zone, and decrease with increasing elevation. As the temperature decreased, the dominant carbon species in the fluid changed from H₂CO₃ to HCO₃^- at about 120°C. The equilibrium temperatures for vein quartz are consistent with the calcite calculations. The carbon and oxygen isotope trends of the Noya vein calcite and the isotope ratios of strontium suggest that the fluids that precipitated the Noya veins were controlled by an andesite-dominated geology. Chondrite-normalized REE patterns for the white-colored veins from wells 51-WT-1 and 51-WT-2 displayed a light REE-rich pattern with positive Eu anomalies, suggesting the existence of a reducing environment for the fluid. The pyrite-rich gray-colored veins and a silicified rock from well 51-WT-2 showed higher REE concentrations than did the white veins. Altered host andesitic rocks have similar REE patterns to that of the silicified rock, and have higher REE contents than the others in the drill cores. Aqueous speciation calculations showed that the fluid in the hydrothermal reservoir is currently in muscovite stability. The fluid at the ore-mineralization stage may have contained more potassium or have had a higher pH, so that adularia precipitated with calcite and quartz, as well as gold. Fluid boiling at depth in the system produced the gold-bearing calcite-quartz-adularia veins.     

转换点位置对转换波速度分析精度的影响

在多波地震勘探中,转换点位置的求取精度直接影响共转换点道集的抽取,进而影响转换波速度分析的精度。利用DSR方程,对比了用不同的转换点计算方法进行转换波速度分析,分析其计算精度。     

水下滑翔机在识别水团新结构中的应用

本研究基于中国科学院沈阳自动化研究所自主研发的水下滑翔机在热带东太平洋观测获取的连续剖面温盐数据,并通过与多套不同数据的比测,证实国产水下滑翔机观测的温盐数据准确可靠,未来可大范围应用于深海大洋。观测结果首次发现该海域北太平洋中央水（NPCW）（50~100 m）的60~80 m层分布着中间层低盐水,分析认为该低盐水来源于水团下方的加利福尼亚流系水（CCS）,中间层低盐水形成的动力机制主要受跃层附近的内波控制,并与内波强度密切相关,同时受上层（20~60 m）障碍层的影响,该中间层低盐水仅仅出现在60~80 m。本研究发现内波与障碍层能够通过影响动能与热能的传输进而促进水团新结构的形成,相关成果丰富了内波与障碍层对上层海洋响应的研究,具有重要的科学价值。