内陆湖沼相和近海沼泽相沉积环境煤中微量元素和矿物的对比研究—以辽宁北票、江西建新和桥头煤研究为例

Using knowledge of geology, geochemistry, coal petrology, mineralogy, by means of a variety of advanced measuring methods such as inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled atomic emission spectrometry (ICP-AES), X-ray powder diffraction (XRD), scanning electron microscopy with energy-dispersive spectrometer(SEM-EDS), sequential chemical extract and density fractions, the characteristics of trace elements and minerals in Jurassic Beipiao coal mine under inland limnetic sedimentary environment and in late Permian Jianxin and Qiaotou coal mines under paralic swamp sedimentary environment were studied. Compared with the average concentration in the world bituminous coals, the Beipiao coal was characterized by relatively high contents of Sc, Ti, Cr, Co, Ni, Zn, Se, Sr, Zr, Y, Ba, REE and Th, and lower contents of V, Rb, Cd, Sn, Pb, Bi and U; while the Jianxin coal was relatively enriched in Li, Sc, Ga, Sr, Y, Nb, Sb, Th and U, with low concentration of Be, Co, Ni, Cu, Ge, Zr, Mo, Cd, Cs, Ba, Pb and Bi; and the Qiaotou coal was enriched in Li, Sc, Sr, Nb, Ta, Zr, REE, Hf, Th and U, with low concentration of Be, V, Co, Ni, Cu, Ge, Mo, Cd, Cs, Ba, Tl, Pb and Bi. The concentrations of Ca, Mg and K in Beipiao coal are higher than those in Jianxin coal and Qiaotou coal, while Fe, S and Ti in Beipiao coal are lower than those in Jianxin coal and Qiaotou coal. The proximate analysis of coal samples was carried out, which indicated that Beipiao coal was medium- to high- ash (5.92-60.68%) with low sulphur coal, and Jianxin coal and Qiaotou coal was medium to high ash (8.85-46.33%) with high sulphur. The reflectivity was measured, which explained that Beipiao coal belonged to high volatile bituminous coal, Jianxin coal was low volatile bituminous coal and Qiaotou coal was low volatile anthracite. Quantitative maceral analyses were studied. The characteristics of rare earth elements (REE) were investigated, which showed that the total contents of REE were higher than that of the world's average content. With the increase of coal's metamorphic grade, the total contents of REE decreased from 98.5 X 10"6 of Beipiao coal to 94.2 X 10"6 of Jianxin coal, and to 75.9 X 10"6 of Qiaotou coal, and 5Eu reduced which indicated that the element Eu depleted. The characteristics of REE was controlled by the metamorphic grade of coal. And REE were mainly absorbed in clay minerals in Beipiao coal samples, while in Jianxin and Qiaotou coal mines, REE were primarily related to clay mineral and pyrite. The variation of trace elements in vertical direction of coal seams was studied, and the results showed that different trace elements differed greatly. The correlation between trace elements and ash were determined. Four major trace elements (aluminium-silicates, sulphide, carbonate and phosphate) accounted for the occurrence and distribution of most elements studied were determined. Coal samples were separated by density fraction, which showed that Cr, Cu, Mo and Pb were closely related to inorganic matters mainly distributed in P >2.6 and dropped remarkably in the density fractions P <2.3 . The occurrences of Co, Cr, Ni, As, Se, Mo, U were studied directly and quantitatively using sequential chemical extract with six steps, which showed that Co. Ni, Mo and U were mainly in the form of mineral, and As, Se chiefly in the form of organic state, while Cr mostly in the form of organic state and mineral. Major mineral phases presented in the Beipiao coal were Kaolinite, illite, quartz, calcite, and small amount of siderite, barite. While major mineral phases in Jianxin and Qiaotou coal were pyrite, kaolinite, and small amount of marcasite, rutile, sphalerite. This is the first time that the chromite in the coal was discovered in China, which indicates that Cr occurrence appeared in the form of chromite. The ratio of Sr/Ba, Sr/Ca and V/Ni in Beipiao coal mine under inland limnetic is smaller than that of in Jianxin and Qiaotou coal mines under paralic swamp. The ratio of K/Na and Th/U of Beipiao coal mine is higher than that of Jianxin and Qiaotou coal mine, which proved that Beipiao coal was not affected by sea water and Jianxin and Qiaotou coal were affected by sea water. Trace elements such as Cr, Ni, Mo in minerals were analyzed by SEM-EDS. The factors controlling the enrichment of trace elements can be divided into syngenetic stage factors and epigenetic stage factors.

贵州喀斯特山区植物营养元素和碳、氮、硫同位素组成研究--以贵阳花溪杨中流域为例

喀斯特的面积分布很广，占全球总面积的10%。我国喀斯特面积占国土面积的13%，主要集中在我国的南方。而贵州喀斯特山区位于西南喀斯特地貌最集中成片分布的中心区，是我国乃至世界热带、亚热带喀斯特地貌连续分布面积最大、发育最强烈的高原山区。和非喀斯特地区相比，贵州喀斯特山区由于碳酸盐岩的特殊理化特性，造成土层浅薄、土被不连续、岩石裸露率高、持水量低，适生树种少、群落结构单一、植被生长极其缓慢，生态环境十分的脆弱。加之人类不合理的活动，使得喀斯特山区植被退化非常严重。因此，开展贵州喀斯特山区植物的营养元素和碳、氮、硫同位素的研究是为了更好的了解该区植被的营养元素状况、生理生态特性以及营养元素的生物地球化学循环，更好地为该区森林、植被的治理、恢复以及生态系统的保护等提供决策依据。本研究选择典型喀斯特山区作为研究点，并以非喀斯特山区为对照。研究喀斯特山区植物的营养元素含量水平、分布状态、变异特征以及营养元素之间的相互关系和碳、氮、硫的同位素组成的种间差异、生境差异特征以及时空变化特征进行了研究。主要得到以下几点认识： 1、植物的N、P、K、Ca、Mg、S的平均含量大于1000 μg∙g-1； Fe、Mn、Al的平均含量在100 μg∙g¬-1～1000 μg∙g¬-1之间；Zn、Sr的平均含量为10 μg∙g¬-1～100 μg∙g¬-1之间；Cu和Mo的含量小于10 μg∙g¬-1，Mo最低(仅为0.17 μg∙g¬-1)。Ca、P、K、 Fe、Mn、S、Sr高于所报道的陆生植物元素的含量；Mg低于陆生植物的元素含量；其它元素在元素含量范围内。植物营养元素的特点为Ca>K>Mg型，和我国其它地区相比，喀斯特山区植被具有高钙的特征。 2、N、P、K、Mg为正态分布；Ca、Al、Fe、Mn、Cu、Zn、Sr、Mo、S为对数正态分布。Al、Fe、Mn、Sr的变异系数大于100%；N、P、K、Ca、Mg、S、Cu的变异系数小于60%。其中，Ca的变异系数最小(为11.8%)。P和K、P和Cu、Al和Fe、Al和Zn、Fe和Zn之间具有极显著的相关关系；N和P、P和Mg、K和Al、K和Cu、Ca和Sr、S和Mo之间具有显著的相关关系。 3、不同的生境下植物营养元素存在差异，差异在2倍范围内。其中，Mn、Al、Sr元素差异较大，分别达到2.1、1.5、1.4倍。 4、植物δ13C、δ15N、δ34S值的分布范围分别为-26.98‰～-29.15‰、-4.08‰～-0.79‰、-8.69‰～-6.04‰；平均值分别为-28.14‰、-2.41‰、-7.53‰。δ13C除了高于我国热带雨林区植物外，均低于其它地区，且变化范围较窄；不同地区之间植物的δ15N、δ34S值存在较大差异。 5、不同植物种之间的δ13C、δ15N、δ34S值存在较大的差异，不同生境条件下植物的δ13C、δ15N、δ34S值也存在差异。植物的δ13C值从生长初期到末期有降低的趋势；δ15N、δ34S则无一定的变化规律，不同的植物种的季节变化不同。植物的δ13C、δ34S随海拔的升高而增大，但δ15N随海拔的升高而降低。