东准噶尔和尔赛斑岩铜矿成岩成矿时代与形成的构造背景

东准噶尔和尔赛铜矿是近年来新发现的斑岩型铜矿,位于野马泉-琼河坝古生代岛弧带东段。成矿岩体为侵位于花岗闪长岩中的花岗闪长斑岩,花岗闪岩中包含有钾长花岗岩体。锆石CAMECA U-Pb测年结果显示,钾长花岗岩年龄为429Ma,并含有405Ma的锆石;花岗闪长岩年龄为411Ma,并含432Ma的碎屑锆石;花岗闪长斑岩主体年龄为410.5Ma。研究区经历了3期岩浆与热液活动,且至少在早志留世就已开始,琼河坝岛弧是开始于早古生代的岛弧。辉钼矿Re-Os等时线年龄为409Ma,与花岗闪长斑岩年龄一致。和尔赛斑岩铜矿的主成岩成矿时代为早泥盆世,年龄约为410Ma。和尔赛铜矿的花岗闪长岩和花岗闪长斑岩具有埃达克岩与岛弧岩浆岩的地球化学特征,包括63.79%～68.86%SiO2、14.91%～17.48%Al2O3、0.68%～2.35%MgO、高Sr(383×10-6～971×10-6)与Sr/Y比值(48.3～111)、低Y(7.92×10-6～9.69×10-6)与Yb(0.76×10-6～0.98×10-6),Ba、U、K、Sr等大离子元素富集,Th、Nb、Ta、Ti等高场强元素亏损,较低的(87Sr/86Sr)i值(0.703852～0.704565)、正的εNd(t)值(6.1～7.4)、与亏损地幔接近的较低的初始铅同位素比值((206Pb/204Pb)i=17.58～17.91,(207Pb/204Pb)i=15.40～15.48,(208Pb/204Pb)i=37.25～37.47)。这些地球化学特征说明其形成于岛弧环境,可能为古俯冲洋壳部分熔融的产物。琼河坝地区以花岗闪长岩和花岗闪长斑岩为代表的岩浆岩带是形成和寻找斑岩铜矿的有利地区。     

Granite-cored domes and gold mineralisation: Architectural and geodynamic controls around the Archaean Scotia-Kanowna Dome,Kalgoorlie Terrane,Western Australia

Granite-cored domes are associated with many of the larger gold deposits of the Archaean Eastern Yilgarn Craton of Western Australia. The Scotia-Kanowna Dome is eroded to sufficiently deep levels to provide insights into the role granite-cored domes play in controlling fluid flow and gold deposition. At the centre of the Scotia-Kanowna Dome is a granite batholith, which is surrounded by outward-dipping greenstone belts and associated shear zones. This upper-crustal dome sits above mid-crustal domes, providing a series of stacked geometries favourable to focussed fluid flow. A number of small- to medium-sized gold deposits occur on the limbs and the centre of the dome, and the world-class Kanowna Belle gold mine occurs on the nose of the dome. At least three separate gold mineralising events are defined, each of regional significance, which can be correlated with other well known gold deposits of the Eastern Yilgarn Craton.     

Neoproterozoic SHRIMP U–Pb zircon ages of silica-rich Dokhan Volcanics in the North Eastern Desert,Egypt

Chronology of Neoproterozoic volcanosedimentary successions remains controversial for many regions of the Arabian–Nubian Shield, including the Dokhan Volcanics of NE Egypt. New U–Pb zircon SHRIMP ages have been obtained for 10 silica-rich ignimbrites and two subvolcanic dacitic bodies, mapped as Dokhan Volcanics, from the North Eastern Desert of Egypt. Crystallization ages range between 592 ± 5 and 630 ± 6 Ma (Early Ediacaran). Apparently, the late consolidation of the Arabian–Nubian Shield was accompanied by the evolution of isolated volcanic centres and basin systems which developed during a period of approx. 40 Ma, independently in space and time and probably under changing tectonic regimes. The obtained age data together with other previously published reliable ages for Dokhan Volcanics suggest two main pulses of volcanic activity: 630–623 Ma and 618–592 Ma. Five samples contain inherited zircons, with ages of 669, 715–746, 847 and 1530 Ma, supporting models that North Eastern Desert crust is mainly juvenile Neoproterozoic crust.     

Shear wave splitting in the Eastern Alps observed at the TRANSALP network

Data from the temporary TRANSALP seismic network were analysed to investigate the seismic anisotropy in the upper mantle beneath the Eastern Alps. We operated mostly short period and some broadband stations in a dense linear array, which transects the Eastern Alps at 12° E longitude. Recorded SKS and SKKS phases with different backazimuths were used simultaneously to calculate the splitting parameters of delay time and fast axis direction for each seismic station. While we found variations in the delay times between 0.8 and 2.0 s, the determined fast axis directions prove to be rather consistent along the profile (60°–70° N). They coincide well with the trend of the Eastern Alps, thus suggesting orogen-parallel flow in the upper mantle. Our findings support the earlier proposed idea that the Adriatic indenter which was forced northwards into the European plate during the late stage of the Alpine orogeny, triggered an escape movement to the less constrained Pannonian basin to the east.     

Transient Eastern Mediterranean deep waters in response to the massive dense-water output of the Aegean Sea in the 1990s

We present a detailed account of the changing hydrography and the large-scale circulation of the deep waters of the Eastern Mediterranean (EMed) that resulted from the unique, high-volume influx of dense waters from the Aegean Sea during the 1990s, and of the changes within the Aegean that initiated the event, the so-called ‘Eastern Mediterranean Transient’ (EMT). The analysis uses repeated hydrographic and transient tracer surveys of the EMed in 1987, 1991, 1995, 1999, and 2001/2002, hydrographic time series in the southern Aegean and southern Adriatic Seas, and further scattered data. Aegean outflow averaged nearly 3 × 10⁶ m³ s⁻¹ between mid-1992 and late 1994, and was largest during 1993, when south and west of Crete Aegean-influenced deep waters extended upwards to 400 m depth. EMT-related Aegean outflow prior to 1992, confined to the region around Crete and to 1800 m depth-wise, amounted to about 3% of the total outflow. Outflow after 1994 up to 2001/2002, derived from the increasing inventory of the tracer CFC-12, contributed 20% to the total, of 2.8 × 10¹⁴ m³. Densities in the southern Aegean Sea deep waters rose by 0.2 kg/m³ between 1987 and 1993, and decreased more slowly thereafter. The Aegean waters delivered via the principal exit pathway in Kasos Strait, east of Crete, propagated westward along the Cretan slope, such that in 1995 the highest densities were observed in the Hellenic Trench west of Crete. Aegean-influenced waters also crossed the East Mediterranean Ridge south of Crete and from there expanded eastward into the southeastern Levantine Sea. Transfer into the Ionian mostly followed the Hellenic Trench, largely up to the trench’s northern end at about 37°N. From there the waters spread further west while mixing with the resident waters. Additional transfer occurred through the Herodotus Trough in the south. Levantine waters after 1994 consistently showed temperature–salinity (T–S) inversions in roughly 1000–1700 m depth, with amplitudes decreasing in time. The T–S distributions in the Ionian Sea were more diverse, one cause being added Aegean outflow of relatively lower density through the Antikithira Strait west of Crete. Spreading of the Aegean-influenced waters was quite swift, such that by early 1995 the entire EMed was affected. and strong mixing is indicated by near-linear T–S relationships observed in various places. Referenced to 2000 and 3000 dbar, the highest Aegean-generated densities observed during the event equaled those generated by Adriatic Sea outflow in the northern Ionian Sea prior to the EMT. A precarious balance between the two dense-water source areas is thus indicated. A feedback is proposed which helped triggering the change from a dominating Adriatic source to the Aegean source, but at the same time supported the previous long-year dominance of the Adriatic. The EMed deep waters will remain transient for decades to come.     

Mercury speciation in sediments at a municipal sewage sludge marine disposal site

Mercury speciation was performed in excess activated sewage sludge (ASS) and in marine sediments collected at the AAS disposal site off the Mediterranean coast of Israel in order to characterize the spatial and vertical distribution of different mercury species and assess their environmental impact. Total Hg (HgT) concentrations ranged between 0.19 and 1003ng/g at the polluted stations and 5.7 and 72.8ng/g at the background station, while the average concentration in ASS was 1181+/-273ng/g. Only at the polluted stations did HgT concentrations decrease exponentially with sediment depth, reaching background values at 16-20cm, the vertical distribution resulting from mixing of natural sediment with ASS solids and bioturbation by large populations of polycheates. Average Methyl Hg (MeHg) concentration in ASS was 39.7+/-7.1ng/g, ca. 3% of the HgT concentration, while the background concentrations ranged between 0.1 and 0.61ng/g. MeHg concentrations in surficial polluted sediments were 0.7-5.9ng/g (ca. 0.5% of the HgT) and decreased vertically, similar to HgT. A positive correlation between MeHg and Hg only at the polluted stations, higher MeHg concentrations at the surface of the sediment and not below the redoxline, and no seasonality in the concentrations suggest that the MeHg originated from the ASS and not from in situ methylation. By doing selective extractions, we found that ca. 80% of the total Hg in ASS and polluted sediments was strongly bound to amorphous organo-sulfur and to inorganic sulfide species that are not bioavailable. The fractions with potential bioaccessible Hg had maximal concentrations in the range in which biotic effects should be expected. Therefore, although no bioaccumulation was found in the biota in the area, the concentration in the polluted sediments are not negligible and should be carefully monitored.     

Size‐based differences in isotopic niche width (δ13C and δ15N) of green turtles (Chelonia mydas) nesting on Príncipe Island,Gulf of Guinea

Within the same population, nesting green turtles (Chelonia mydas) might exploit different niches by exhibiting polymorphic foraging strategies and/or inhabiting geographically distinct foraging areas. This is crucial information for the conservation of this species. Here, we used stable carbon and nitrogen isotope ratios (δ¹³C and δ¹⁵N) to test for differences in a population of green turtles nesting on Príncipe Island (1°37′N; 7°24?′E), Central Africa. A total of 60 nesting females were sampled on the two main nesting beaches of the island in December 2012. Minimum curved carapace length (CCL) was recorded, and δ¹³C and δ¹⁵N values were measured in the epidermis of each individual. Overall, CCL varied from 87.0 to 108.0 cm (mean ± SD =100.0 ± 5.1), δ¹³C values from ?19.4 to ?8.6‰ (?17.3 ± 1.8) and δ¹⁵N values from 7.9 to 17.3‰ (13.6 ± 1.5). Despite the large variation in both isotopic ratios, their distributions were unimodal, showing an absence of polymorphic foraging strategies and isotopically distinct foraging areas. However, smaller females (< median, 100.8 cm) occupied a much larger isotopic niche (i.e., four times greater) than larger females. These results suggest that nesting green turtles may forage opportunistically on the resources available in each of their foraging home ranges, with smaller females venturing to more isotopic‐diversified areas and/or exhibiting broader foraging strategies than larger females. In addition, and in accordance with other studies, findings suggest that the foraging grounds used by the Príncipe green turtle nesting females are distributed mainly throughout the Gulf of Guinea.     

A corundum–quartz assemblage from the Eastern Ghats Granulite Belt,India: evidence for high P–T metamorphism?

Corundum+quartz-bearing assemblages occur in small lenses in granulite facies metapelites in Rayagada, north-central part of the Eastern Ghats Granulite Belt, India. Corundum porphyroblasts and quartz coexist with porphyroblastic almandine-rich garnet, hercynite spinel, ilmenite and magnetite. Corundum and quartz are separated by sillimanite or a composite corona consisting of sillimanite and garnet, whereas corundum shows sharp grain boundaries with spinel, ilmenite and magnetite. Porphyroblastic corundum contains prismatic sillimanite inclusions in which irregularly shaped quartz is enclosed. Two distinct reactions are inferred from the textural features: corundum+quartz=sillimanite and spinel+quartz=garnet+sillimanite. From the petrographical features, we infer that corundum–quartz–garnet–spinel was the peak metamorphic assemblage. Although large uncertainties exist regarding the positions of the respective reactions in P–T  space, from several published experimental results and theoretical calculations a peak metamorphic condition of 12  kbar and 1100  °C is estimated as the lower stability limit of the corundum–quartz assemblage. Decompression from the peak P–T  condition to c .  9  kbar, 950  °C is inferred.     

Influence of the Eastern Indian Ocean Warm Pool Variability on the Spring Precipitation in China

The relationship between the variability of the Eastern India Ocean Warm Pool （EIWP） and the spring precipitation in China is studied in the paper based on an analysis of the Simple Ocean Data Assimilation （SODA） Sea Surface Temperature （SST） data, the reanalysis data of monthly grid wind field at 925 hPa with a resolution of 2.5^＊ latitude and longitude from the National Center for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR）, and the monthly mean rainfall data from 160 observational stations in China. The results show that there is a strong correlation between the EIWP variability and the spring precipitation in China. The area, volume and intensity indices of the EIWP are negatively correlated with the spring precipitation in southwestern China, while they are positively correlated with the spring precipitation in the rest of China, especially in the northeast. For this correlation between the EIWP variability and the spring precipitation in China, it is found that the correlative relationship is mainly connected with the variations of the moisture transport by the warm air flow, which is under the influence of the EIWP variability, into the inland of China in spring. Two causative factors may influence this transport. One is the variation of the moisture transport carried by the warm air flow from the Arabian Sea influenced by the EIWP variability. The other is the variation of the equator-crossing flow （70^＊-90^＊E） influenced by the EIWP anomaly in the previous winter which exerts its effect on the moist warm air transported from the Southern Hemisphere. The position and intensity of the Western North Pacific Subtropical High （WNPSH） variability caused by EIWP variation also influence the spring precipitation in China.     

闽东地区滨海软土静力触探与十字板剪切试验相关性的探讨

根据现场原位静力触探和十字板剪切试验成果的分析研究.得出闽东地区滨海软土静力触探锥尖阻力值与不排水抗剪强度值存在线性相关关系.