西藏玉龙铜矿床次生氧化富集作用机制

作文阐述了西藏玉龙铜矿床成矿过程中的“沉积初步富集期”和“西藏玉龙铜矿床次生氧化成矿作用模式”,这不仅对指导当前生产具有重要的现实意义,而且为在玉龙铜矿带进一步找矿共作劈了新的方向。     

滇西南澜沧江带红豆山铜矿床蚀变分带及其找矿意义

红豆山铜矿床是南澜沧江带新发现的矿床之一。通过野外地质工作和系统构造—|蚀变岩相填图,发现该矿床蚀变类型主要以钾长石化、硅化、绿泥石化、绿帘石化为主,其次为碳酸盐化、绢云母化、黄铁矿化等,且在空间上呈现一定规律,各蚀变带具有明显的叠加现象。依据区内岩石蚀变矿物组合等特点,自断裂带→上盘围岩,共出现4个典型蚀变带,依次为碎裂岩化带→长英岩化—碳酸盐化—绢云母化带→硅化—绿泥石化—绿帘石化带→弱长英岩化安山岩带。矿（化）体主要分布在长英岩化、碳酸盐化、绢云母化带和硅化、绿泥石化、绿帘石化带。由斑岩脉中心至边缘发育钾化带→硅化带→青磐岩化带→绢云母化带,斑岩旁侧围岩中发育放射状石英—方解石—黄铜矿脉。     

黄土高原西部兰州市郊人工林地水分亏缺与调控研究

通过定位监测与对比分析,对兰州市南北两山不同水分管理人工林地植物水分亏缺度及植物水分亏缺补偿度的时空分布进行了研究。结果表明：灌溉林地的植物水分亏缺度最小,亏缺度大部分时间都在20％以下,有自然坡面集雨的林地植物水分亏缺状况好于不灌溉的林地,侧柏林地喷灌、自然坡面集雨和不灌三种处理方式下的植物水分亏缺度虽然稍有差异,但都处于水分极度亏缺的状况。补充灌溉除满足林地正常生长所需要的水分外,对土壤水分也有一定的补偿,补偿度在70％左右。其他不灌溉地块补偿度都为负值,说明这些地块整个雨季没有对水分进行补偿,还将土壤以前贮藏的部分土壤水分利用。植物水分亏缺度在空间上的变化与植物根系的分布相一致。既在水平方向上,随着离树干距离的加大,植物水分亏缺度依次降低。在垂直方向上,表层植物水分的亏缺度最低,随着深度的增加,亏缺度逐渐增大,100~120 cm深达到最大,以后又缓慢降低。植物水分补偿度是降雨与植物水分亏缺程度的反映,植物水分亏缺度越高,补偿度越大。     

西藏扎布耶湖ZK91-2钻孔沉积特征与气候环境演化

扎布耶盐湖位于西藏高原腹地,1991年在其南部干盐滩中钻取了20m深湖相沉积,以5～10cm/个的密度进行高分辨率取样,详细探讨了沉积标志、矿物组合（尤其Mg、Ca、Li碳酸盐）、干旱与潮湿两种气候类型的元素组合等气候环境指标,推导了晚更新世以来该湖区湖面涨缩、水质咸谈及气温高低变化。     

TRANSVERSE STRUCTURES FEATURES OF DIFFERENT DEPTHS DERIVED FROM BOUGUER GRAVITY ANOMALIES IN THE SOUTHERN SEGMENT OF TAN-LU FAULT ZONE

To research the faults distribution and deep structures in the southern segment of Tan-Lu fault zone(TLFZ) and its adjacent area, this paper collects the Bouguer gravity data and makes separation by the multi-scale wavelet analysis method to analyze the crustal transverse structure of different depths. Meanwhile Moho interface is inversed by Parker variable density model. Research indicates that the southern segment of TLFZ behaves as a NNE-directed large-scale regional field gravity gradient zone, which separates the west North China-Dabie orogen block and the east Yangtze block, cutting the whole crust and lithosphere mantle. There are quite differences of density structures and tectonic features between both sides of this gradient belt. The sedimentary and upper crustal density structure is complex. The two east branches of TLFZ behave as linear gravity anomalous belt throughout the region, whereas the two west branches of TLFZ continue to extend after truncating the EW-trending gravity anomaly body. The lower crustal density structure is relatively simple. TLFZ behaves as a broad and gentle low abnormal belt, which reflects the Cretaceous-Paleogene extension environment caused graben structure. The two west branches of TLFZ, running through Hefei city, extend southward along the west margin of Feidong depression and pinch out in Shucheng area due to the high density trap occlusions in the south of Shucheng. The Feizhong Fault, Liu'an-Hefei Fault, and Feixi-Hanbaidu Fault intersect the two west branch faults of TLFZ without extending to the east. Recent epicenters are mainly located in conversion zones between the high-density and the low-density anomaly, especially in TLFZ and the junction of the faults, where earthquakes frequently occurred in the upper and middle crust. As strong earthquakes rarely occur in the southern segment of TLFZ, considering its deep feature of abrupt change of the Moho and intersections with many EW-trending faults, the hazard of strong earthquake cannot be ignored.     

基于GF-2影像西藏桑耶地区岩性-构造遥感解译

西藏桑耶地区位于青藏高原中南部,区内切割强烈,地势陡峻,属于高山峡谷区。为提高区域地质调查野外工作效率,在调查中率先开展了遥感解译研究。在充分收集已有资料的基础上,通过对GF-2卫星数据进行预处理和影像增强,结合野外验证建立了各地质要素的遥感解译标志,实现了区内不同地层岩性、侵入岩、断裂和褶皱等地质要素的提取,最终编制了研究区1:5万遥感地质解译图,为区域地质调查提供了数据支撑。结果表明: 各地质要素在GF-2数据上均有良好反映,完全满足1:5万尺度的遥感地质解译和编图的需要,充分显示出该卫星数据在区域地质调查等工作中具有良好的应用前景。     

Zircon U–Pb and Wolframite Sm–Nd Dating of the Bayinsukhtu Tungsten Deposit in Southern Mongolia and its Geological Significance

The Bayinsukhtu tungsten deposit is a newly discovered quartz‐vein tungsten deposit in the Xing'an–Mongolia Orogenic Belt (XMOB) in southern Mongolia, hosted by the Bayinsukhtu granite porphyry. The granite porphyry is located mainly south of the study area, over 3 km². The rock consists of quartz and feldspar phenocrysts in a fine‐grained matrix, also mainly composed of feldspar and quartz. The granite porphyry samples demonstrate high SiO₂ and high alkalinity. All samples also straddle the high‐potassium calc‐alkaline series. In a plot of the molar ratios of A/NK versus A/CNK, the granites are metaluminous. The chondrite‐normalized REE patterns are characterized by large negative Eu anomalies and fractionated LREEs. The U–Pb age of zircons from the granite porphyry is 298.8 ± 1.8 Ma, and the Sm–Nd age of the five wolframite samples from the tungsten deposit is 303 ± 19 Ma. The cooling age of the granite porphyry and tungsten mineralization is within the error of measurement and is of the Late Carboniferous age. Geological and geochronological evidence shows that the tungsten mineralization and the granite porphyry at Bayinsukhtu are genetically closely related and that they are results of Carboniferous magmatism. Their tectonic setting is related to the accretion of the Central Asian Orogenic Belt during the late Paleozoic era.     

Isotopic tracers for water masses in the coastal region of eastern Hokkaido

In this study we used two stable isotopes, δ¹³C and δ¹⁸O, for water mass classification in the coastal region off eastern Hokkaido. δ¹³C* values, which were corrected for the biological effect, and δ ¹⁸O values up to 300 m depth suggested that the isotopic character of the onshore and offshore water in the southern Okhotsk Sea, the Nemuro Strait and the western North Pacific could be explained by the mixing of three source waters: the Oyashio water (OYW), Soya Warm Current water (SWCW) and East Sakhalin Current water (ESCW). In summer, δ ¹³C*-δ ¹⁸O plots indicated mixing between SWCW from the southern Okhotsk Sea and OYW in the Pacific coast of southeastern Hokkaido, while temperature-salinity plots of the onshore water showed minimal difference from the offshore OYW. In winter, on the other hand, the mixed water of ESCW and OYW (or SWCW) appeared in the Pacific coastal region, distributed as cold, low salinity onshore water. Finally, we estimated mixing ratios of OYW, SWCW and ESCW in the coastal region of western North Pacific using their mean values of δ ¹³C* and δ ¹⁸O as endmembers. These results suggest seasonal and yearly changes of water mass combination en route from the southern Okhotsk Sea to the western North Pacific.     

Évolution géodynamique messino-pliocène en Languedoc central : le paléo-réseau hydrographique de l’Orb et de l’Hérault (Sud de la France)

Résumé

En Languedoc central, la cartographie des sédiments formés lors de la crise messinienne et de ceux de la séquence pliocène, ainsi que les données patées paléontologiques nouvelles (Aigues-Vives et Servian) permettent de proposer une reconstitution du tracé messimeli des rivières actuelles (Orb et Hérault) transformées en rias à la suite du relèvement eustatique pliocène. L’Hérault messinien se singularise par une incision beaucoup plus faible que celle des autres rivères. En effet, la nature karstique de l’arinère-pays immédiat permet un enfouissement des eaux météoriques au profit d’aquifères profonds sous-jacents au drainage aérien du réseau hydrographique messinien. Le Languedoc central illustre, entre Roussillon et Rhône, le modèle géodynamique messino-pliocène de Clauzon. © Elsevier, Paris     

藏南地名佐证门巴与珞巴的民族归属

继不久前对《中国地图》藏南地名开展补白研究、将藏南地区东段内的图上地名点由原来的9个增加到36个之后,依据门巴族与珞巴族族名与居住地地名相重合的特点、以及藏南地名"巴昔卡"的珞巴语含义与四川地名"扎昔卡"的藏语含义相吻合的特点,论证了门巴族和珞巴族与藏南地域和祖国内地在人文地理上的密切联系,进一步说明了世代居住在藏南地区的门巴族和珞巴族人非跨界民族。