Calcified roasting-acid leaching process of vanadium from low-grade vanadium-containing stone coal

The low-grade vanadium-containing stone coal used in this experiment was collected from Wuxi Coun- try, Chongqing City, China. The experiment focused on the vanadium recovery from roasted residue through opti- mizing the process conditions of an effective and environmentally-friendly technology, named calcified roast- ing-sulfuric acid leaching technology. By single-factor experiments and orthogonal experiments, the effects of roast- ing temperature, roasting time, sulfuric acid concentration and leaching time on the leaching ratio of vanadium were analyzed. The results showed that the leaching ratio of vanadium reached 85.5% under the proper technological con- ditions of roasting temperature=950℃, roasting time=4 h, 40% concentration of sulfuric acid and leaching time=6 h.     

Fluid inclusion studies of the Abawso gold prospect,near the Ashanti Belt,Ghana

The major Ghanaian lode gold deposits are preferentially aligned along the western and eastern contacts of the Kumasi Basin with the Ashanti and Sefwi Belts, respectively. The investigated area of the Abawso small-scale concession, covering the workings of the old Ettadom mine, is situated 3 km west of the lithological contact of the Birimian metavolcanic rocks of the Akropong Belt in the east with the Birimian metasedimentary rocks of the Kumasi Basin in the west. The rocks of the Abawso concession represent a steeply NW-dipping limb of a SE-verging anticline with an axis plunging to the SW. Quartz veining occurs predominantly in the form of en échelon dilatational veins along NNE–SSW-striking shear zones of a few metres width and shows evidence of brittle and ductile deformation. Also stockwork-style quartz veining occurs in the vicinity of the main shaft of the old Ettadom mine. Hydrothermal alteration includes sericitisation, sulphidation and locally carbonatisation. The auriferous quartz veins mainly follow the trend of brittle to ductile deformed quartz veins; however, some occur in stockwork. Fluid inclusion studies reveal a large number of H₂O inclusions along intragranular trails in auriferous quartz vein samples, as well as an overall dominance of H₂O and H₂O-CO₂ inclusions over CO₂ inclusions. Textural observations and physico-chemical fluid inclusion properties indicate post-entrapment modifications for all quartz vein samples due to grain boundary migration recrystallisation. This process is interpreted to be responsible for the generation of the CO₂ inclusions from a H₂O-CO₂ parent fluid. In comparison with mineralisation at the Ashanti and Prestea deposits, which are characterised by CO₂±N₂ inclusions, the observed inclusion assemblage may be due to a shallower crustal level of mineralisation, or different degrees and styles of recrystallisation, or a less pronounced development of laminated quartz veins due to comparably restricted pressure fluctuations. Furthermore, the microthermometric observations allow the reconstruction of a possible retrograde P-T path, depicting near-isothermal decompression in the P-T range of the brittle/ductile transition.Editorial handling: E. Frimmel     

P-T Paths Derived from Garnet Growth Zoning in Danba Domal Metamorphic Terrain, Sichuan Province, West China

Danba (丹巴) domal metamorphic terrain belongs to Songpan (松潘)-Ganze (甘孜) orogenic belt, where typical Barrovian and Buchan metamorphic zones are preserved. The former included chlorite, biotite, garnet, staurolite, kyanite and sillimanite zones, while the latter only developed silimanite+muscovite and sillimanite+K-feldspar zones. Integrated study has been carried on metamorphic reactions of garnet production and consumption, P-T paths and P-T-X-M phase relation and thermal tectonic model for Danba metamorphic zones. Petrological textures in thin sections show that garnet production and consumption in kyanite-sillimanite zone is mainly attributed to ChI+Ms+PI+Q=Grt+Bt+H2O and kyanite=sillimanite respectively. Based on mineral compositions, the geothermobarometry gives an average P, T condition of (4.9±0.3)×108 Pa, 543±30℃ for the first growth stage of the garnet and (5.8±0.3)±108 Pa, 534±29 ℃ for the second stage of garnet growth respectively. Anti-counter clockwise P-T paths were drawn using Gibbs method by NCMnKFMASH system for sample G98686 in the kyanite zone. The P-T-X-M modeling for the first mineral assemblages shows that the prediction is similar to the measured values in gossular, almandine and spessartine but mole fraction of pyrope and Fe/(Fe+Mg) deviated far from the contours; while that for the second mineral assemblages exhibits that the prediction is consistent with the measured value of pyrope, grossular content and Fe/(Fe+Mg) of garnet. A thermal tectonic model that there are at least three structure levels across the thrnst-decollement zones is presented according to the P-T paths, metamorphic grades and deformation styles for the staurolite-kyanite zone of the Barroviau type metamorphism, which will provide some constraints for the evolution of the nappe complex.     

中国南方古生界碳酸盐岩发育对页岩气成藏和开发控制问题

中国南方古生界有利暗色页岩发育,但现页岩气勘探取得突破较少,主要原因是南方地质条件复杂,尤其是南方暗色页岩与碳酸盐岩间互发育,页岩气勘探开发面临复杂的碳酸盐岩地质问题。文章从国外勘探经验及近年来南方地区页岩气勘探实践中总结并详细分析了碳酸盐岩发育对页岩气成藏和开发控制的5大问题:（1）地表或近地表岩溶地质问题对开采的影响;（2）页岩目的层顶底板及其内部碳酸盐岩层对成藏和开采的影响;（3）页岩中碳酸盐类矿物含量对开采压裂的影响;（4）页岩层中天然裂缝被方解石充填对成藏的影响问题;（5）常规碳酸盐岩储层与非常规页岩共同成藏问题。建议在南方古生界开展页岩气勘探开发中,把碳酸盐岩本身储集成藏和碳酸盐岩对页岩气成藏、开采、钻井施工等的影响综合考虑,以总含油气系统的思路,综合选井,以促进南方古生界页岩气的勘探开发。      

新疆北部古地磁研究

通过和布克赛尔、克拉玛依、玛纳斯—乌鲁木齐地区泥盆纪到白垩纪古地磁研究,主要取得以下结果:(1)首次建立了准噶尔西北缘及南缘石炭纪—白垩纪古地磁极移曲线,由石炭纪到二叠纪的古地磁极位置基本在同一区间,说明该时期这些地区为一个统一的构造单元,而其古地磁极明显与塔里木、哈萨克斯坦、西伯利亚地块存在着差异。(2)该地区侏罗纪及白垩纪古地磁结果与塔里木地块结果一致,侏罗纪乌鲁木齐与和布克赛尔磁偏角相差30°左右,说明和布克赛尔地区相对乌鲁木齐地区逆时针旋转了30°左右,晚古生代以后曾发生过南向移动,而侏罗、白垩纪以来均向北发生了相当规模的北向运动,并发生了相对旋转,目前东、西准噶尔的构造格局可能就是由于局部相对旋转造成的。(3)中国大陆在早二叠世还不是一个联合的整体,而是以相互分离的独立块体分布于45°N—15°S的古特提斯洋中。(4)该地区二叠纪的磁偏角为165°—168°,而塔里木为218°,哈萨克斯坦为229°,说明存在35°—55°的逆时针旋转,这个旋转可能是由于西部推覆构造造成的。如果将西准噶尔超基性岩带顺时针旋转35°—55°后,东准噶尔超基性岩带、西准噶尔超基性岩带和斋桑泊—鲁布佐夫斯克超基性岩带应在同一构造带上。(5)该地区晚古生代古纬度变化不明显,位于30°—45     

四川省巴塘县措普一带多金属成矿条件分析

义敦印支岛弧褶皱带地质构造演化复杂,岩浆活动十分活跃,成矿地质地球化学条件优越,金、银、铜、铅、锌、锡等金属矿产资源丰富。西南三江为有色、贵金属资源富集区,义敦为花岗岩型锡-银多金属矿集区。根据区域成矿环境及研究区成矿条件分析,找矿潜力巨大,有望取得找矿突破。     

毕节煤矿区晚二叠世煤层稀土元素的物质来源

对取自毕节地区晚二叠世11个可采煤层的13个样品的稀土元素(REE)的物质来源进行分析。发现:海洋来源对稀土元素的富集作用极其微弱;来自植物成因的物质来源小于1%;煤样中δEu负异常,而陆源岩具有Eu负异常的特点。结合晚二叠世多期喷发的峨眉山玄武岩,因此认为稀土元素的物质来源主要受陆源影响和控制。     

汶川地震序列动态跟踪与甘肃震情动态判定的预报实践感悟

在汶川地震序列的动态跟踪与甘肃震情的动态判定过程中,本文作者成功地把握了甘肃震情、一定程度上把握了汶川地震序列的动态发展变化,并对5月18日四川江油发生的6.0级地震作出了成功预测。这一预测实践使本文作者更加深刻地感悟到,地震预报虽然是一个十分复杂的没有被攻克的世界性难题,但对于一个特定的地区,如果预报思路和方法得当,要实现一次乃至数次成功的预报是可能的。这对地球科学家们如何认识地震预报问题有一定的意义。     

藏南冈底斯地体中段南缘构造演化

冈底斯岩浆带位于拉萨地体南缘, 是新特提斯洋盆演化和印度-亚洲陆陆碰撞的岩浆产物, 对冈底斯岩浆带的研究方兴未艾, 但一些基本问题仍然存在着激烈的争论(比如晚三叠世到早—中侏罗世新特提斯洋演化的极性, 冈底斯岩浆带中大型韧性剪切带形成的时代、动力学机制以及冈底斯中段新生代的隆升-剥蚀模式等等), 这都直接影响了对新特提斯域构造和青藏高原形成演化的理解, 以及对冈底斯构造成矿带的资源评价。     

浅谈阿舍勒黄铁矿型多金属矿的垂直分带

阿舍勒黄铁型多金属矿床位于阿尔泰地槽褶皱系的中泥盆统安山质—英安质火山—沉积岩中.矿体充填在火山管道内或火山口近侧,主矿体隐伏地下.矿化元素有铁、铜、铅、锌、金、银、硫、钡等,伴生有锗、镓、铟、硒、镉、铋等.矿体上部形态复杂并有分枝,向深部连成一体,是一个向北东侧伏的筒状体.矿体自上而下具垂宜分带,依次为:重晶石—硅化带;黄铁矿—多金属带;黄铁矿—铜、锌带等…