Chemical structures of coal lithotypes before and after CO2 adsorption as investigated by advanced solid-state C nuclear magnetic resonance spectroscopy

Four lithotypes (vitrain, bright clarain, clarain, and fusain) of a high volatile bituminous Springfield Coal from the Illinois Basin were characterized using advanced solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy. The NMR techniques included quantitative direct polarization/magic angle spinning (DP/MAS), cross polarization/total sideband suppression (CP/TOSS), dipolar dephasing, CH_n selection, and recoupled C-H long-range dipolar dephasing techniques. The lithotypes that experienced high-pressure CO₂ adsorption isotherm analysis were also analyzed to determine possible changes in coal structure as a result of CO₂ saturation at high pressure and subsequent evacuation. The main carbon functionalities present in original vitrain, bright clarain, clarain and fusain were aromatic carbons (65.9%-86.1%), nonpolar alkyl groups (9.0%-28.9%), and aromatic C-O carbons (4.1%-9.5%). Among these lithotypes, aromaticity increased in the order of clarain, bright clarain, vitrain, and fusain, whereas the fraction of alkyl carbons decreased in the same order. Fusain was distinct from other three lithotypes in respect to its highest aromatic composition (86.1%) and remarkably small fraction of alkyl carbons (11.0%). The aromatic cluster size in fusain was larger than that in bright clarain. The lithotypes studied responded differently to high pressure CO₂ saturation. After exposure to high pressure CO₂, vitrain and fusain showed a decrease in aromaticity but an increase in the fraction of alkyl carbons, whereas bright clarain and clarain displayed an increase in aromaticity but a decrease in the fraction of alkyl carbons. Aromatic fused-rings were larger for bright clarain but smaller for fusain in the post-CO₂ adsorption samples compared to the original lithotypes. These observations suggested chemical CO₂-coal interactions at high pressure and the selectivity of lithotypes in response to CO₂ adsorption.     

Pyrrhotite Re–Os and SHRIMP zircon U–Pb dating of the Hongqiling Ni–Cu sulfide deposits in Northeast China

The Hongqiling (HQL) magmatic Ni–Cu sulfide deposits (Jilin Province, NE China) are located at the southern margin of the eastern Xing'an–Mongolian Orogenic Belt (XMOB) of the eastern Central Asian orogenic belt (CAOB), situated between the Siberian Craton (SC) and the North China Craton (NCC). The HQL ore-bearing mafic–ultramafic intrusions intrude into the metamorphic rocks of the lowermost Huangyingtun Formation of the Hulan Group (HLG), whose lithology is herein identified as a hornblende–zoisite gneiss. SHRIMP zircon U–Pb dating for the HLG, country rock of the HQL deposits, indicated a maximum deposition age of 272.2 ± 4.3 Ma (95% confidence level, MSWD = 2.6, n = 14).Six pyrrhotite samples separated from massive Ni–Cu sulfide ores of the Fujia (No. 7) deposit yielded a Re–Os isotopic isochron age of 208 ± 21 Ma (95% confidence level, MSWD = 2.4, n = 6), indicating that the ore-formation age was Late Triassic. Re–Os isotope analyses showed an initial ¹⁸⁷Os/¹⁸⁸Os ratio of 0.315 ± 0.050. The γ_Os values ranged from + 137 to + 161 with an average of + 151, indicating that its ore-forming materials were mainly derived from mantle with possibly < 30% crustal Os contamination. Large scale magmatic Ni–Cu mineralization in eastern Jilin occurred in post-collisional tectonic setting in the Late Triassic.Our new results suggest that the ages of the Ni–Cu sulfide deposits in the CAOB within China tended to become younger from west to east, as manifested by the Late Caledonian (~ 440 Ma), through the Late Hercynian (300–265 Ma) to the Late Indosinian (225–200 Ma). Such variation could reflect the gradual closure and post-collisional orogeny between the SC and the NCC from west to east.     

http://www.sciencedirect.com/science/article/pii/S1674987110000344

The structural stability of methane hydrate under pressure at room temperature was examined by both in-situ single-crystal and powder X-ray diffraction techniques on samples with structure typesⅠ,Ⅱ,and H in diamond-anvil cells.The diffraction data for typesⅡ(sⅡ) and H(sH) were refined to the known structures with space groups Fd3m and P6_3/mmc,respectively.Upon compression,sⅠmethane hydrate transforms to the sⅡphase at 120 MPa,and then to the sH phase at 600 MPa.The sⅡmethane hydrate was found to coexist...     

Gravel Image Segmentation in Noisy Background Based on Partial Entropy Method

INTRODUCTIONImage thresholding has been widely used in many areas,and there are many methods for thresholding. But it is verydifficult to segmentgravel objects,because of wide variation ingray levels and particle dimensions and the presence of manysmall objects in the background corrupting the image bystationary or white noise. Shannon’s entropy is a concept ininformation theory,which means the more information,theless the entropy value. By m eans of entropy concept,researchers have prop…     

苏州市区多种地下地质资源协同开发利用研究

地下空间、地下水、浅层地热能和地质材料是重要的地下地质资源,协同开发利用是大势所趋。苏州既是历史文化名城又是现代国际大都市,城市发展至今对地下地质资源的需求相当迫切。通过对苏州各类地下地质资源的的识别分析,表明其具备分别开发地下空间、地下水、浅层地热能和地质材料资源的能力。若多种资源协同开发,平面上开发利用条件较好,竖向尺度地下浅层到次深层适宜地下空间和地质材料的协同开发,而深层适宜以浅层地热能为主的协同开发。结合苏州国土空间发展格局和地下资源的优势分布特征,城镇空间建议采取“地下空间+浅层地热能”的协同利用模式;农业空间建议采取以“浅层地热能”为主的协同利用模式;生态空间予以生态环境保护。     

青藏高原东缘龙门山山系构造隆起的地貌表现

龙门山山系是青藏高原东缘新生代造山作用的体现,是理解青藏高原向东扩展动力学过程的窗口.龙门山隆升机制研究因而成为青藏高原地学领域的热点问题之一,并形成了地壳缩短与下地壳管道流两种截然不同的观点,进一步的讨论期待着对龙门山隆升特征作出更深入地认识.夷平面与河流地貌忠实地记录了山地隆升的过程,其形态能够客观地反映山地隆升的几何特征.文章通过数字高程资料分析了龙门山地区的第三纪夷平面,并沿横穿龙门山的大渡河流域测量了河流阶地、山麓剥蚀面及其同期宽谷地貌.夷平面、宽谷地貌与河流阶地的变形特征显示,晚新生代以来,龙门山山系一方面相对东侧四川盆地发生显著的冲断式隆升,隆起幅度达4500m左右;同时相对青藏高原腹地发生了一定的挠曲式隆升,挠曲的枢纽大致沿龙日坝断裂带展布,隆起幅度为500m至1000m,即龙门山山系的构造隆升由东翼的冲断作用与西翼的挠曲作用联合完成,龙门山山系因而构成了青藏高原与四川盆地之间的一道地形屏障.文章最后讨论了导致龙门山山系拱曲冲断作用的可能因素,包括上地壳的断弯褶皱作用、下地壳物质上涌作用和地表侵蚀导致的重力均衡效应.鉴于沿龙门山隆升带东西两翼发现了纵向逆冲断裂或逆走滑断裂,而没有发现纵向张性构造,推断断弯褶皱可能为主导因素.     

豫西沙沟脉状Ag-Pb-Zn矿床地质特征和成矿流体研究

豫西沙沟薄脉状Ag-Pb-Zn硫化物矿床位于华北陆块南缘熊耳山地区,主要由多金属硫化物-石英-碳酸盐脉型和石英-碳酸盐-绢云母-多金属硫化物蚀变岩型两种矿化类型组成。主要矿脉的矿物共生序列可以分为成矿前的石英-黄铁矿阶段(Ⅰ)、闪锌矿-石英-方铅矿-少量银矿物阶段(Ⅱ1)、方铅矿-石英-闪锌矿-含铁白云石-银矿物阶段(Ⅱ2)和成矿后的方解石-(石英)阶段(Ⅲ)。对不同阶段的成矿流体研究表明,石英-黄铁矿阶段(Ⅰ)中的含氯化钠子晶三相(LVH)包裹体(Ⅰ1)可能是直接从饱和水的结晶岩浆熔体中出溶形成或是由岩浆流体的减压沸腾形成,显示该区很可能存在岩浆流体端元。多金属硫化物阶段(Ⅱ1Ⅱ2)捕获富液相包裹体(LV型)和个别CO2包裹体(C型),这两个阶段流体包裹体反映了主成矿阶段流体的基本特征,结合包裹体气相和液相成分色谱分析以及包裹体初融温度,认为成矿流体应该为中-低温低盐度含CO2的H2O-NaCl体系。其中,阶段(Ⅱ2)的均一温度(145～288℃,平均为194℃)比阶段(Ⅱ1)的均一温度(185～357℃,平均240℃)低46℃;同时,阶段(Ⅱ2)的盐度(1.91%～10.86%,平均6.38%)较阶段(Ⅱ1)盐度(4.65%～10.11%,平均7.77%)略低。对这一温度和盐度的总体下降趋势的合理解释是大气水的逐渐混入。多金属硫化物阶段(Ⅱ1Ⅱ2)之后的方解石-(石英)阶段普遍为富液相包裹体(LV型),该阶段显著降低的温度(129～208℃,平均165℃)和盐度(1.40%～4.03%,平均2.50%),进一步佐证大气水的不断混入。而且,流体混合可能在引起矿石矿物从热液中沉淀方面起到重要作用。     

百色盆地油气综合化探工作方法及异常特征研究

研究百色盆地油气综合化探异常 ,指出断块 (断鼻 )型、演化型、断层裂隙型、浅层油藏、浅层气藏等油气藏的异常特征 ,是评价油气藏的基础和寻找油气藏的地球化学依据     

贵州省镇远县土地信息系统

本文从贵州省镇远县农业区划部门在农业用地规划中所存在的问题着手,探讨了如何建立土地信息系统,对图形、图象、文字资料进行计算机管理以辅助土地规划,为今后我国南方岩溶山区的综合治理提供了科学依据。      

东尼日尔盆地Tenere坳陷上白垩统海相烃源岩评价及勘探潜力

东尼日尔盆地是中西非裂谷系中典型的中—新生代裂谷盆地。Tenere坳陷位于盆地西北部,包括西部凹陷、东Ⅰ凹陷和东Ⅱ凹陷。对Saha-1井上白垩统岩屑样品的分析揭示,干酪根显微组分以不发荧光或弱荧光的无定形体为主,岩石抽提物中C29甾烷优势明显,说明该井上白垩统泥岩有机质输入以陆源植物为主。岩石热解分析表明上白垩统Yogou组泥岩大多数为中等—好烃源岩,有机质以Ⅱ2-Ⅲ型为主,Donga组泥岩大部分为差—中等烃源岩,以Ⅲ型为主;岩石热解峰温指示烃源岩成熟门限深度为2300 m左右。生烃史模拟显示,Saha-1井Yogou组泥岩尚未开始生烃,Donga组在白垩纪末期开始生烃,下部已进入生气阶段。综合研究认为Tenere坳陷的西部凹陷勘探潜力较大,而东Ⅰ凹陷和东Ⅱ凹陷潜力有限。