岩石地球化学测量在北山找金中的应用效果

实践证明,不仅大比例尺岩石地球化学测量可以为圈定矿体、揭露工程的设计提供依据,在区调普查中,中、小比例尺的岩石地球化学测量同样可以提供足够的找矿信息。在干旱荒漠区岩石地球化学测量是一种比较理想的找矿方法。     

漳州盆地水热系统的氢氧稳定同位素研究

本文对我国东南沿海地区温度最高的典型花岗岩裂隙热水盆地——漳州盆地水热系统的地下热水及各类相关的其它类型天然水的氢氧稳定同位素(δD和δ~(18)O)特征进行了研究。对漳州地区的大气降水线、地下热水起源、地下热水的补给源(区)以及影响地下热水同位素成分的形成与演化的海水与大气降水的混合等地球化学作用问题进行讨论。     

重盐化咸水区人工生态系统稳定性研究*

北丘浅层咸水盐碱洼地是黄淮海平原河间浅平洼地的一种类型,是旱涝碱咸薄多种矛盾最集中、最典型的地区.盐渍化导致大片土地长期荒芜,分布在洼地南部的万亩试验区内的盐碱荒地面积达4076亩,耕层含盐量在0.6%以上,除盐荒地外,已耕地为含盐量0.2-0.4%的中低产田.1987-1990年采用引淡淋盐、覆盖抑盐、浅群井抽咸、混林农业和培肥改土等技术措施,按照土壤含盐量程度进行分区治理,五年期间治理开发盐碱荒地3650亩,试区内人均增加耕地1.45亩.1993年新开发的盐碱荒地粮食作物亩产已达到550kg,试验田亩产已达1000kg,中低产田已向高产农田转变.经过治理,北丘洼的农业生产条件已得到改善,一个荒芜盐碱的生态景观正转向良性循环的生态系统.     

Isotopic variations of the nitrogen in Lake Superior

The isotopic compositions of nitrogen in lake water, plankton samples and the organic-N fractions extracted from sediments at selected stations in Lake Superior are presented. The δ¹⁵N values of the Kjeldahl total-N and acid hydrolyzable-N in the lake sediments are similar (range, +4.7–+6.7; mean, +5.5 %.). The δ¹⁵N data for the various extracts are independent of the age and concentration of nitrogen in the sediments. On the other hand, the δ¹⁵N values of lake water (+ 0.6‰), phytoplankton (+ 1.6 %.) and Zooplankton (+ 5.0‰) in the water column suggest significant discrimination against the heavier nitrogen isotope in the food chain of the lacustrine environment. The data emphasize the need for a better understanding of the autogenous isotopic fractionation before the isotopic method can be used to fingerprint the sources of nitrogen in a limnetic ecosystem.     

Performance of a pickax

Summary Single and multiple impact tests were conducted with a commerically available 3.58 kg pickax with a 60° conical tip and a 30° wedge tip in the input energy range from 1.01 to 59.4 J. Five target materials were employed: (1) 2024-0 aluminum, (2) diorite, (3) sandstone, (4) cement-sand, and (5) green shale. Force and penetration data were collected using strain gages and a non-contact displacement probe. It was found that when the impact process involves cracking and chipping, the maximum penetration was linearly proportional to the input energy and the forcepenetration relation exhibited non-linear characteristics. When the impact process does not involve cracking or chipping, the penetration was related to the square root of the input energy and the force-penetration relation exhibited a nearly linear relation. Thus, empirical models involving a linear spring resistive force or a constant resistive force were found to reasonably describe the penetration and input energy data. In addition, an analytical model involving a pickax mass inertia term and a piecewise linearized force-penetration function was constructed that portrayed the force and penetration histories. Good results were obtained for both conicaland wedge-tip cases. From the multiple impact tests it was found that the efficiency of the pickax operation decreases by about 50 to 60 percent after ten impacts, suggesting that the impact point be moved in order to obtain an improved performance.     

中国区域地质研究的十大进展

今年，欣逢中国地质学会成立100周年，特以此文恭贺中国地质学会百年来所取得的光辉成就和对中国地质事业发展做出的卓越贡献。2008年，中国地质调查局下达了重编中国区域地质志的科研项目。经过十多年志书的编写获得了诸多创新性的区域地质研究成果，主要成果可以概括为十个方面：① 大幅度地提高了全国地质研究程度和地质科技水平；② 提出发展洋板块地质的学术思想，初步建立了洋板块地质构架； ③ 地层研究取得重要新进展，完成全国显生宙构造- 地层区划和地层格架研究； ④ 开启了蛇绿岩研究新思路，拓宽了蛇绿岩研究范围； ⑤ 前寒武纪地质研究获颠覆性科学成果，阐明了太古宙地壳演化规律，提出中—新元古界新的划分方案； ⑥ 取得多项岩浆岩创新性科研成果，建立了中国及邻区侵入岩时空演化格架；⑦ 中国地质构造研究获突破性进展；⑧ 地球深部探测研究步入国际先进行列，建立了全方位“深地”探测研究科技支撑体系；⑨ 为资源环境评价开辟了新方向，海洋地质与第四纪地质调查研究取得长足进展； ⑩ 探索了地质图件研编新模式，总结了地质制图的基本经验。     

川西坳陷中段须家河组四段砂岩中碳酸盐胶结物碳、氧同位素特征及成因探讨

碳酸盐胶结物是川西坳陷须家河组四段砂岩中最常见的成岩矿物。应用激光微区取样碳、氧同位素测试方法，对研究区须四段砂岩中不同类型的碳酸盐胶结物的碳、氧同位素特征进行了精细分析，结合岩相学特征和流体包裹体分析，查明了不同类型碳酸盐胶结物的形成时间和成因机制。研究表明，研究区须四段砂岩中发育Ⅰ、Ⅱ、Ⅲ三期碳酸盐胶结物。第Ⅰ期方解石的δ13CPDB值为-0. 13‰~1. 53‰，δ18OPDB值为-9. 92‰~-6. 41‰；第Ⅱ期方解石的δ13CPDB值为-2. 44‰~1. 85‰，δ18OPDB值为-13. 97‰~-10. 06‰；第Ⅲ期方解石的δ13CPDB值为-5. 34‰~0. 75‰，δ18OPDB值为-16. 55‰~-14. 44‰，第Ⅲ期白云石的δ13CPDB值为-0. 97‰~-0. 81‰，δ18OPDB值为-13. 32‰~-12. 91‰。从早期到晚期，碳酸盐胶结物的碳、氧同位素均表现为逐渐变轻，说明其沉淀温度逐渐升高，受有机流体影响逐渐加深。第Ⅰ期碳酸盐胶结物形成于晚三叠世末，储层处于浅埋藏阶段，是从早期过饱和碱性孔隙流体中直接沉淀出来的，其“碳”源主要来自沉积水中溶解的CO32-。第Ⅱ期碳酸盐胶结物形成于早侏罗世，沉淀温度约45~70℃，其形成有少量有机流体的参与，有机轻“碳”、原始孔隙水中溶解的“碳”以及少量溶蚀作用释放出的重“碳”共同为该期碳酸盐胶结物提供“碳”源。第Ⅲ期碳酸盐胶结物形成于晚侏罗世，沉淀温度约100~140℃，其成因与有机酸性流体关系密切，有机成因的轻“碳”和部分由溶蚀作用释放的重“碳”是该期方解石的主要“碳”源；而该期白云石的沉淀受砂岩中碳酸盐岩岩屑溶蚀的控制更明显，由溶蚀作用产生的重“碳”是其主要“碳”源。     

湖北鸡冠咀隐伏铜金矿床勘查地球化学概念模型

文章据鸡冠咀铜金矿床的岩石、矿石等介质中元素的分布,阐明了该矿床的地球化学特征,确定了与矿床有关的指示元素和元素的分带序列。应用矿上和矿下元素组累乘比值从上至下的递减规律,建立了异常的评价指标,制定了该矿床勘查地球化学异常的概念模型。     

吐哈盆地水文地球化学分带与铀矿化关系浅析

确立了吐哈盆地水中铀的存在形式，分析了铀在水中的迁移规律和沉淀条件。并运用层间氧化带的成矿机理，阐述了各地球化学分带的水文地球化学特征，引用“饱和指数”把铀在水中的饱和程度给予量化，从而确定了盆地水中铀的沉淀区间。利用γNa＋／γCl─和γCa＋＋／γCl─划分出水文地球化学分带及综合岩石地球化学分带，为寻找层间氧化带型铀矿提供了水文地球化学依据。指出艾丁湖自流水斜地为形成层间氧化带型铀矿的有利地段。     

Quantitative evaluation of coal as source rocks

Gas generated and expelled from coals often results in economic gas accumulations. As a consequence, it is important to consider the theoretical aspects of these processes and to develop methods that can be used to assess coal as a potential source rock. On the basis of results of modeling hydrocarbon generation, expulsion, and retention in coals, two comprehensive indexes are proposed for assessing the quality and the nature of coal as a potential source rock. Theoretical charts of the two indexes are used to assess coals as potential source rocks in the Turpan-Hami Basin in northwestern China.