盐穴储气库水溶造腔夹层垮塌力学机制研究

盐岩矿床中难溶泥质夹层的存在给地下储库水溶造腔带来了诸多不利影响,如何有效地预测与控制水溶造腔过程中泥质夹层的垮塌成为亟待解决的技术难题。夹层垮塌力学机制研究以该问题为背景,建立了水溶造腔过程中夹层垮塌分析的力学模型,并应用弹性板壳理论进行了求解,根据求解结果对夹层因局部破损及整体失稳引起垮塌的力学机制分别进行了论述,对夹层垮塌的力学机理进行了总结,给出了一种计算夹层极限跨度的方法。研究成果对水溶造腔过程中夹层垮塌的预测与控制有重要指导意义。     

Methane-rich fluid inclusions and their hosting volcanic reservoir rocks of the Songliao Basin, NE China

Methane-rich fluids were recognized to be hosted in the reservoir volcanic rocks as primary inclusions.Samples were collected from core-drillings of volcanic gas reservoirs with reversed δ12C of alkane in the Xujiaweizi depression of the Songliao Basin. The volcanic rocks are rhyolite dominant being enriched in the more incompatible elements like Cs, Rb, Ba, Th, U and Th with relative high LREE, depleted HREE and negative anomalies of Ti and Nb,suggesting a melt involving both in mantle source and crustal assimilation. Primary fluids hosted in the volcanic rocks should have the same provenance with the magma. The authors concluded that the enclosed CH4 in the volcanics are mantle/magma-derived alkane and the reversed δ13C of alkane in the corresponding gas reservoirs is partly resulted from mixture between biogenic and abiogenic gases.     

激发极化法在早前寒武纪变质岩系找水中的应用

通过对在早前寒武纪变质岩系进行抗旱找水中利用地球物理勘探定井的实例分析,阐述了利用激发极化法在早前寒武纪变质岩分布区辨认含水层,确定含水层埋深,最终确定较好井位的方法。该方法对解决早前寒武纪变质岩系的干旱缺水现状有广泛深远的意义。     

铁矿床中黑柱石富集特例剖析

黑柱石是一种少见的含钙铁硅酸盐矿物。通过富含黑柱石的青海省双庆铁矿区与仅含少量黑柱石的福建省马坑铁矿区矿床地质特征的对比,认为矿床中黑柱石的产生与中基性火成岩的参与有关;黑柱石的解体与硼的参与有关。     

泥质烃源岩密度分级分离与有机碳分配

选取东营凹陷第三系11 块泥质烃源岩样品,粉碎后按小于1.6 g/cm3,1.6~2.2 g/cm3 和大于2.2 g/cm3 的密度,分离成1,2,3 三个组分,希望可以把烃源岩中游离的有机质、无机矿物与有机黏土复合体分别提取出来。对各组分进行质量、有机碳及扫描电镜分析,探讨不同密度组分中有机质赋存形式及有机碳分配方式的差异性。密度分组后各组分的质量、有机碳量回收率基本上达到100%,表明密度分离方法可信,且对烃源岩的破坏较弱。通过扫描电镜观察发现,1 组分中存在大量的生物碎屑有机质,经盐酸处理后,有机质颗粒表面干净,而2,3 组分中只见有大量的矿物颗粒,但能谱分析显示了C 元素的存在。这些特征表明1 组分为生物碎屑有机质,而2,3 组分中有机质与无机矿物相混合。有机碳分析表明,1 组分有机碳含量平均高达14.24％,但其仅占全岩有机碳量的1.11%;2,3 组分中有机碳含量分别为3.26%,2.77%,两者占全岩有机碳量的90% 以上。由此看来与无机矿物相结合是烃源岩中有机质较为重要的赋存方式,这部分有机质对全岩生烃量的贡献不容忽视。     

Petrogenesis of extension-related alkaline volcanism in Karaburhan (Sivrihisar–Eskisehir), NW Anatolia, Turkey

Alkaline lavas were erupted as phonolites and trachytes around Karaburhan (Sivrihisar–Eskisehir, NW Anatolia) within the Izmir–Ankara–Erzincan suture zone. These volcanic rocks were emplaced as domes, close and parallel to the ophiolite thrust line. According to ⁴⁰Ar/³⁹Ar geochronological analyses of sanidine crystals from the phonolites, the age of the alkaline volcanics is 25 Ma (Late Oligocene–Early Miocene).The flow-textured phonolites are porphyritic and consist mainly of sanidine, clinopyroxene, and feldspathoid crystals. The clinopyroxenes show compositional zoning, with aegirine (Na_0.82–0.96Fe⁺³_0.68–0.83) rims and aegirine–augite cores (containing calcium, magnesium, and Fe⁺²). Some aegirine–augites are replaced with sodium-, calcium-, and magnesium-rich amphibole (hastingsite). Feldspathoid (hauyne) crystals enriched with elemental Na and Ca have been almost completely altered to zeolite and carbonate minerals. The fine-grained trachytes with a trachytic texture consist of feldspar (oligoclase and sanidine) phenocrystals and clinopyroxene microphenocrystals within a groundmass made up largely of alkali feldspar microlites.Although there are some differences in their element patterns, the phonolites and trachytes exhibit enrichment in LILEs (Sr, K, Rb, Ba, Th) and LREEs (La, Ce, Pr, Nd) and negative anomalies in Nb and Ta. These geochemical characteristics indicate a lithospheric mantle enriched by fluids extracted from the subduction component. In addition, the high ⁸⁷Sr/⁸⁶Sr (0.706358–0.708052) and low ¹⁴³Nd/¹⁴⁴Nd (0.512546–0.512646) isotope concentrations of the alkaline lavas reflect a mantle source that has undergone metasomatism by subduction-derived fluids. Petrogenetic modeling indicates that the alkaline lavas generated from the subduction-modified lithospheric mantle have undergone assimilation, fractional crystallization, and crustal contamination, acquiring high Pb, Ba, Rb, and Sr contents and Pb isotopic compositions during their ascent through the thickened crust in an extensional setting.     

商丹断裂带东段基性岩、超基性岩中的铁铬镍资源潜力预测

对商丹断裂带东段基性-超基性岩带（体）及其中的铁、铬等矿化特征作了概述,在岩带中圈出了A、B、C、D四个基性-超基性岩体集中区,对该带中铁铬镍等矿产资源潜力作了地质预测,认为该基性-超基性岩带是岩浆型铁、铬、镍等矿产的良好找矿远景区,提出了下步找矿工作思路、方法手段的建议.     

纵观近代岩矿测试分析技术

本文就近代岩矿测试分析技术作了较为全面的介绍。文章指出，地矿部从８０年代起，由于引进了大批现代先进仪器设备，使岩矿测试分析技术出现了崭新面貌，形成为多学科相结合的新格局，从而促进地质科学在理论上和实践上均取得显著进步，在某些学科领域已发生了根本性变化，并为地质或其它市场提供了大量信息，为促进科技成果转化为生产力作出了巨大贡献。纵观近代岩矿测试分析技术，文章提出了多机联用、整体分析和拓宽测试分析领域的建议，以更好地为祖国经济主战场服务。     

Sr isotopic composition of Paleoproterozoic C-rich carbonate rocks: The Tulomozero Formation,SE Fennoscandian Shield

Rb–Sr systematics has been studied in ¹³C-rich carbonate rocks of the Paleoproterozoic (2.09 ± 0.07 Ga) Tulomozero Formation in the northern Onega Lake area, the SE Fennoscandian Shield. The formation is divided into eight members (A–F) consisting of greenschist-facies-grade, variegated sandstones, siltstones, mudstones, stromatolitic dolostones and subordinate crystalline limestones. Samples of carbonate rocks were obtained from two overlapping drillholes intersecting the entire thickness of the Tulomozero Formation. Prior to isotope analysis, the rocks powders were treated with 1N ammonium acetate for partial removal of the late epigenetic carbonate phases. Major resetting of the Rb–Sr systems in the Tulomozero carbonate rocks appears to take place during the Svecofennian regional metamorphic event, and it was screened by using Mn/Sr, Fe/Sr, Mg/Ca, and ¹⁸O/¹⁶O ratios. High Sr content (up to 2080 μg/g in limestones, and 530 μg/g in dolostones) coupled with low Fe/Mn (<0.40) ratios in the Tulomozero carbonate rocks of Members A, B (the lower part), D, F, and E are consistent with accumulation of original carbonate sediments in evaporitic lacustrine, playa, and sabkha environments. A decrease in the Sr content with concurrent increase in the Fe/Mn ratio (>0.40) in dolostones of the upper part of Member B, and of Members G and H is indicative of seawater influxes (sea transgression) into the Tulomozero basin. The ⁸⁷Sr/⁸⁶Sr values in the least altered (Mn/Sr < 2.0) marine dolostones are 0.70418–0.70442 and 0.70343–0.70409 for the earlier and late phases of the marine transgression, respectively. The decrease in the ⁸⁷Sr/⁸⁶Sr ratio in ca. 2.1 Ga seawater is attributable to an increase in hydrothermal flux Sr into the Palaeoproterozoic ocean.     

川西高原地区岩石中硒的地球化学特征和影响因素

川西高原土壤、水体等多种介质研究表明,该地区的硒含量偏低,天然土壤剖面硒为0.06～0.16μg/g,表层土壤中硒含量为0.075～0.204μg/g,沉积物中硒含量为0.069～0.310μg/g,地表水中硒含量为nd～0.096μg/L,地下水中硒含量为nd～0.058μg/L,均低于我国相应环境介质中硒的平均含量,影响到当地人体健康。本文采集川西高原地区80件岩石样品,同时采集6套岩心样品,这些样品主要以板岩、砂岩、灰岩和页岩为主。采用原子荧光光谱法(AFS)测定硒含量,研究川西高原阿坝地区岩石与岩心样品中硒的地球化学特征和低硒的影响因素。结果表明:岩石硒含量范围为0.030～0.282μg/g,平均值0.09μg/g,低于硒土壤背景值。不同类型岩石中的硒含量大小为:页岩灰岩板岩砂岩。岩石中硒含量在不同地区也表现出较大的差异:松潘阿坝壤塘马尔康九寨沟若尔盖红原,可能是受到岩石类型及有机质和地质环境的影响所致。岩心各剖面的硒含量最小值为0.02～0.07μg/g,最大值为0.21～0.34μg/g,平均值为0.06～0.17μg/g,各钻孔的硒含量明显低于硒的地壳丰度。本研究认为,硒的分布受地质环境、有机质、岩石致密性等条件限制,低硒的地质环境是导致岩石中的硒含量较低的最主要因素。