青海省玛沁县友后青地区钴铜矿化带成矿地质特征及找矿前景

青海玛沁县友后青地区大地构造位置处于阿尼玛卿缝合带内,在友后清地区发现了与基性-超基性岩体关系密切的钴铜矿化带。本文主要分析了友后青地区钴铜矿化带的成矿地质特征,认为华力西-印支期NW-NWW向的深大断裂控制着钴铜成矿作用。高精度磁测显示,区内有一条近NWW走向的磁异常带,异常强度中等偏高,呈串珠状分布。水系沉积物测量表明,以镍钴铬为主的多金属综合异常规模大,元素组合齐全,镍钴铬元素异常套合好。水系沉积物地球化学异常与高精度磁测异常可以很好的叠合在一起,在空间上与基性-超基性岩关系密切。沿NW-NWW向断裂带,与基性-超基性岩叠合较好的物化探异常区是该地区寻找钴铜矿的有利地段。     

Determination of Gallium Isotopic Compositions in Reference Materials

The interest in the study of gallium (Ga) stable isotope fractionation in low‐ and high‐temperature environments has increased significantly in the last few years. However, a unified reference material (RM) is still lacking for the Ga isotope research community, which hinders interlaboratory comparison between different groups. Consequently, certification of Ga isotopic reference materials for interlaboratory comparison is of high priority. In this study, Ga isotope ratio data for ten geological RMs including silicates, shales and ferromanganese nodules, and two pure Ga RMs including NIST SRM 994 and NIST SRM 3119a reported by three different groups, were determined by MC‐ICP‐MS. Sample matrices of geological RMs were separated by a two‐column separation method with the use of AG MP‐1M and AG 50‐X8 resin, separately, and quantitative recoveries of > 99% Ga were obtained for all geological RMs. Instrumental mass bias was corrected by the combined calibrator‐sample bracketing and internal normalisation model. Validation of the proposed method was performed by analysing synthetic solutions. After normalisation of all available δ⁷¹Ga data of geological RMs to a single Ga RM, results obtained in our study are in agreement with previously reported results.     

ENHANCING GROUND RESOLUTION OF TM6 BASED ON MULTI-VARIATE REGRESSION MODEL AND SEMI-VARIOGRAM FUNCTION

1　ＩｎｔｒｏｄｕｃｔｉｏｎＩｔｉｓｗｅｌｌｋｎｏｗｎｔｈａｔＬａｎｄｓａｔＴＭｉｍａｇｅｓａｒｅｐｒｏｂａ ｂｌｙｔｈｅｍｏｓｔｉｍｐｏｒｔａｎｔｒｅｍｏｔｅｓｅｎｓｉｎｇｉｍａｇｅｓｆｏｒｇｅｏ ｌｏｇｉｃａｌｐｕｒｐｏｓｅｓ(Ｃｈｅｎｅｔａｌ.,1 994) .Ｕｓｕａｌｌｙ ,ｔｈｅｒｅａｒｅ7ｄｉｆｆｅｒｅｎｔｅｌｅｃｔｒｏｍａｇｎｅｔｉｃｓｐｅｃｔｒｕｍｂａｎｄｓｉｎＴＭｉｍ ａｇｅｓ,ａｍｏｎｇｗｈｉｃｈｔｈｒｅｅｂａｎｄｓｃｏｖｅｒｔｈｅｖｉｓｉｂｌｅｒａｎｇｅｏｆｔｈｅｅｌｅｃｔｒｏｍａｇｎｅｔ…     

Determination of the 13C/12C Isotope Ratio of Organic Compounds for the Biological Degradation of Tetrachloroethene (PCE) and Trichloroethene (TCE)

With the method used here, it was possible to determine the isotope content of both the initial compounds and their metabolites formed due to microbial degradation. The chemical analysis showed that the dominating degradation metabolite for both PCE and TCE degradation was cis-1,2-dichloroethene (cis-1,2-DCE). Apart from this, the formation of TCE, trans-1,2-DCE, 1,1-DCE, chloroethene (VC), ethene and ethane was observed. The isotope analysis showed no measurable fractionation of stable carbon isotopes, for the microbial degradation of PCE and TCE to cis-1,2-DCE. There was a small effect for trans-1,2-DCE and a stronger one for VC as metabolite of TCE.     

14C测年技术新进展

¹⁴C测年技术的进展主要表现为3个方面：1)¹⁴C常规测定技术向高精度发展比较成熟，目前已可以普及；2)加速器质谱技术的建立和普及，使测定要求的样品碳量减少到mg级，甚至μg级，虽然目前的精度尚未超过常规方法，但由于所需样品量极少，测定时间短而工效高，大大拓宽了应用范围；3)高精度¹⁴C－树轮年龄校正曲线的建立，不但可将样品的¹⁴C年龄转换到日历年龄，而且对有时序的系列样品的¹⁴C年龄数据通过曲线拟合方法转换到日历年龄时年龄误差大为缩小。     

C^＋＋重载技术在物化探计算中的应用

本文以正交多项趋势分析算法为例，描述了在ＤＯＳ操作系统下，当数组占有字节数大于６４Ｋ时，利用Ｃ＋＋重载技术进行地球物化探计算的方法     

若尔盖RM孔有机碳、总氮和碳氮比值的垂直分布

分析了ＲＭ孔岩心样５９５个．孔内总有机碳含量ＴＯＣ变动范围较大，低者１—２％，高者１０—２０％；总氮含量ＴＮ多０．１—０．２％，少数０．４—０．８％；碳氮比值Ｃ／Ｎ较低（≤８）段属浅湖沉积，Ｃ／Ｎ较高（＞８）段属湖滨沼泽沉积；ＴＯＣ，ＴＮ和Ｃ／Ｎ明显有四个波动段．     

贡嘎山亚高山林地碳的累积和消散

Based on biomass investigations, soil respiration and plant photosynthesis measurement ofdominant trees in Hailuogou valley of Mt. Gongga, Southwest China, the carbon (C) storage,absorption and release for several typical woodlands in sub-alpine zones have been discussed. ForAbies fabri forest of 3,000 m above sea level, the C storage amount is 177.4 t/ha for above-groundbiomass and 143.2 t/ha for soil below-ground biomass. The annual gross C fixed by vegetationphotosynthesis is 20-24 t/ha. The C release by canopy respiration is 3.0-5.5 t/ha for arbors and 10-19t/ha for surface soil and roots. The annual net C fixed of forest ecosystem is about 6.0-7.1 t/ha. Atlower elevations, the amount of C released by woodlands is higher than that of woods at higherelevations. The C fixed capacity of renewed forest with middle-aged trees is higher than that of matureforest. Before becoming over-matured forest, woodland is an important sink of C whereas bareland inwoods is the source of atmospheric C.     

The carbon accumulation and dissipation features of sub-alpine woodland in Mt. Gongga

Based on biomass investigations, soil respiration and plant photosynthesis measurement of dominant trees in Hailuogou valley of Mt. Gongga, Southwest China, the carbon (C) storage, absorption and release for several typical woodlands in sub-alpine zones have been discussed. For Abies fabri forest of 3,000 m above sea level, the C storage amount is 177.4 t/ha for above-ground biomass and 143.2 t/ha for soil below-ground biomass. The annual gross C fixed by vegetation photosynthesis is 20-24 t/ha. The C release by canopy respiration is 3.0-5.5 t/ha for arbors and 10-19 t/ha for surface soil and roots. The annual net C fixed of forest ecosystem is about 6.0-7.1 t/ha. At lower elevations, the amount of C released by woodlands is higher than that of woods at higher elevations. The C fixed capacity of renewed forest with middle-aged trees is higher than that of mature forest. Before becoming over-matured forest, woodland is an important sink of C whereas bareland in woods is the source of atmospheric C.     

Sr、C同位素对苏皖北部上前寒武系时代的界定

对苏皖北部上前寒武系碳酸盐岩地层系统采集灰岩样品 ,采用弱酸处理方法测定清液部分的 Sr同位素组成 ,对全岩样品测定 C同位素组成。测定结果与 Shields(1999)发表的新元古代古海水 Sr、C同位素组成随时间的演化曲线对比表明 ,苏皖北部上前寒武系是跨越北方青白口系与南方震旦系之间的一段连续地层 ,其时代约从70 0 Ma到 85 0 Ma,该研究进一步印证了淮南生物群属于先伊迪卡拉期的学术观点。