Origin and distribution of hydrogen sulfide in the Yuanba gas field,Sichuan Basin,Southwest China

The Yuanba gas field in the Permian Changxing Formation (P₂c), which exhibits wide variations in its hydrogen sulfide (H₂S) concentration (1.20–12.16%), is a typical sour gas field in the northern Sichuan Basin. The sulfur-rich reservoir's solid bitumen (atomic S/C ratios are 0.032–0.142), and late calcite cement δ¹³C values, which are smaller than the δ¹³C values of the host dolostone, indicate that the H₂S originated from thermal sulfate reduction (TSR) and oil was involved in TSR. The gas souring index (GSI) of P₂c's gases is generally lower than 0.1. The ethane δ¹³C values increase as the GSI increases, although no obvious increase was observed in the methane δ¹³C values. The calcite cements' δ¹³C values (−15.36 to +4.56‰) in dolostone are heavier than the typical reported values, which implies that only limited heavy hydrocarbon gases were involved in TSR. No anhydrites developed in P₂c's reservoirs, and dissolved sulfate anions (SO₄²⁻) were mainly enriched during dolomitization. Insufficient dissolved SO₄²⁻ most likely caused the lower H₂S concentrations in the Permian to Triassic reservoirs in the northeastern Sichuan Basin compared to the Permian Khuff Formation in Saudi Arabia and the Jurassic Smackover Formation in Mississippi. Except for the SO₄²⁻ in residual water in paleo-oil zones, SO₄²⁻ from bottom water may also be involved in TSR; therefore, oil reservoirs with bottom water have more SO₄²⁻ and can produce more H₂S than pure oil reservoirs. This phenomenon may be the main cause of the great difference in the H₂S concentrations between reservoirs, while gravitational differentiation during late uplift most likely creates differences in H₂S concentrations in a single reservoir. Carbon dioxide (CO₂), which has a relatively heavy δ¹³C value (−3.9 to −0.3‰), may be the combined result of TSR, the balance between CO₂ and inorganic fluid systems, and carbonate decomposition.     

Risks for poisoning of coastal and inland population due to asteroid impacts in Southern regions of Black Sea

The hydrogen sulfide rich waters of the Black Sea pose a potential danger for the surrounding land regions. The impact of an asteroid exceeding tens of meters in size may cause both a tsunami wave and a catastrophic poisonous gas release in the atmosphere. Some effects of this last phenomenon on the Southern Black Sea coastal regions are evaluated in this paper. The initial surface area of the poisonous cloud depends on asteroid size. The initial thickness of the cloud depends, in addition, on sea depth at impact location. The wind speed plays an important role in H₂S cloud dynamics. At 10 m/s wind speed, the cloud margins reach 185 km from the impact location in about 3 h. The maximum distance traveled by the hydrogen sulfide cloud increases by increasing the asteroid size and wind speed. The influence of the impact position on the distance traveled by hydrogen sulfide clouds is rather weak, as long as the seawater depth does not change significantly. The land surface area covered by the H₂S cloud generated by a 1,000 m size asteroid ranges between about 6,400 and 12,000 km². This may affect up to 3,000,000 people. When a 250 m size asteroid is considered, the covered land surface area ranges between about 1,400 and 2,100 km² and up to 120,000 people may be affected. In case of a 70 m size asteroid, the cloud covers up to 280 km² of land. This may affect up to about 70,000 people. These evaluations do not include the population of the towns on or near the seashore. A simple methodology to estimate the environmental risks of the potential asteroid impact was proposed. Sites less than 160 km from the impact place are at risk.     

微细金属硫化物分选提纯方法研究

对某些微细金属硫化物进行分选和提纯,按照一般的工作流程,可能会改变矿物表面形态,影响测试效果。本文作者对我国广西金牙卡林型金矿的微细毒砂和黄铁矿进行分选和提纯时,改用纯粹水淘洗法工作流程,所选单矿物保存了矿物表面的自然形态,满足了测试工作的需要,为该矿床的研究提供了可靠的资料。      

Petrogenesis and mineralization of the Hulu Ni-Cu sulphide deposit in Xinjiang,NW China: constraints from Sr-Nd isotopic and PGE compositions

The Permian Hulu intrusion is one of several sulphide-bearing Permian mafic–ultramafic intrusions in the eastern part of the eastern Tianshan located at the southern margin of the Central Asian Orogenic Belt (CAOB) in Xinjiang, NW China. The intrusion is composed of lherzolite, olivine websterite, gabbro, and gabbro-diorite. Disseminated and net-textured Ni-Cu sulphide ores are located at the bottom of the lopolith complex. Negative Zr, Hf, Nb, and Ta anomalies, whole-rock εNd(t) values of +5.7 to +8.8, and variable (Th/Nb)_PM values (from 1.06 to 8.13) suggest that the source of the Hulu complexes is depleted mantle metasomatized by subducted slab-derived fluid and/or melt (~5% global subducted sediment and 15% slab fluid) that has experienced approximately 3% lower crustal and 10% upper crustal contamination. The Hulu intrusion is characterized by low PGE abundances i.e. 0.03–1.08 ppb Ir, 0.04–0.69 ppb Ru, 0.02–2.15 ppb Rh, 0.30–48.71 ppb Pt, and 0.21–344 ppb Pd. Our calculations indicate that if the Pd, Os, Ir, and Cu contents of the primary magma were 2.1 ppb, 0.03 ppb, 0.05 ppb, and 200 ppm, respectively, a variable R-factor between 200 and 1600 with residual magma that had experienced 0.01% early-sulphide segregation can explain the variation in Pd, Os, and Ir contents of sulphide-poor and disseminated sulphide samples of the Hulu deposit. Basaltic magma fractionation and assimilation and/or contamination of sulphur-bearing crustal materials might have triggered sulphur saturation to form Cu-Ni sulphide ores. Tarim basaltic PGE contents cannot be used as the mineralized parent magma for the Hulu intrusion because of the differing evolutionary trends of the Ni/Pd and Cu/Ir values. However, similar Cu/Ni and Pd/Ir values in Tarim basalts and Hulu Cu-Ni sulphide ores, as well as the same early sulphide segregation process, show that certain genetic relationships between them and magma sources are probably similar to each other.     

蒙古中部巴彦洪古尔蛇绿岩带乌兰布拉格新块状硫化物矿床

The Bayankhongor ophiolite zone, a NW-SE strik-ing linear structure 400 km long and up to 25 km wide, is the largest ophiolite association in Central Mongolia and possibly in all of Central Asia. The Bayankhongor cop-per mineralization was investigated by us in connection with detailed research of the ophiolite complexes in 1997-2011. With regard to their origin the ore formations belong to genetic type of gold-bearing massive sulphide deposit with magmatic seat of the island arc.     

High mortality of Zostera marina under high temperature regimes but minor effects of the invasive macroalgae Gracilaria vermiculophylla

The present study tested for density-dependent effects of the invasive drift macroalgae Gracilaria vermiculophylla (Ohmi) Papenfuss on growth and survival of the native eelgrass, Zostera marina L., under different temperature levels. Three weeks laboratory experiments were conducted in Odense, Denmark, combining three algae densities (control, low 1.9 kg WW m⁻², high 4.5 kg WW m⁻²) with typical Danish summer temperatures (18 °C) and elevated temperatures (21 °C and 27 °C). There was a significant effect of temperature on shoot survival with on average 68% mortality in the high temperature treatment but almost no mortality at the two lower temperatures. The higher mortality was probably caused by high sulphide levels in the sediment pore water (0.6 mmol l⁻¹ at 18 °C compared to 3.7 mmol l⁻¹ at 27 °C). Above-ground growth of the surviving shoots was also significantly affected by temperature, with leaf elongation rates being negatively affected, while the leaf plastochrone interval increased. Relative growth rate was significantly higher at 21 °C than at 18 °C or 27 °C, whereas rhizome elongation was significantly lowest at 27 °C. Elemental sulphur content in the plant tissues increased significantly with temperature and was up to 34 times higher (S⁰ in rhizomes) at 27 °C compared to the lower temperatures. In contrast to the temperature effects, cover by G. vermiculophylla did not cause significant effects on any seagrass responses. However, there was a (non-significant) negative effect of algal cover at the highest temperature, where the seagrass is already stressed. The latter results suggest that more studies should test for interaction effects between temperature and other anthropogenic stressors given that temperature is predicted to increase in the near future.     

盐场卤水氧化-吸附联合脱色工艺的研究

以天津汉沽盐场高镁卤水为研究对象,分析其成色原因,建立了过氧化氢氧化-氢氧化锆吸附联合脱色工艺,分别考察了脱色剂用量、温度、pH值等因素对卤水色度、CODCr及镁离子损失率的影响,确定了最佳的脱色工艺条件:用卤水处理量1%(体积比)的过氧化氢于室温下将卤水氧化2 h后,在pH值为2～3的条件下经氢氧化锆吸附脱色40 min,氢氧化锆用量为60 g/L。在此条件下,卤水色度及CODCr去除率分别可达99%和85%,镁离子的损失率可控制在1%以下,均高于目前使用的工艺方法。吸附剂氢氧化锆经脱附后可循环使用,大大降低了工艺运行成本。     

Spectral Diagnostics of the Magnetic Field Orientation in a Prominence Observed with SOHO/SUMER

During several campaigns focused on prominences we have obtained coordinated spectral observations from the ground and from space. The SOHO/SUMER spectrometer allows us to observe, among others, the whole Lyman series of hydrogen, while the Hα line was observed by the MSDP spectrograph at the VTT. For the Lyman lines, non-LTE radiative-transfer computations have shown the importance of the optical thickness of the prominence – corona transition region (PCTR) and its relation to the magnetic field orientation for the explanation of the observed line profiles. Moreover, Heinzel, Anzer, and Gunár (2005, Astron. Astrophys. 442, 331) developed a 2D magnetostatic model of prominence fine structures that demonstrates how the shapes of Lyman lines vary, depending on the orientation of the magnetic field with respect to the line of sight. To support this result observationally, we focus here on a round-shaped filament observed during three days as it was crossing the limb. The Lyman profiles observed on the limb are different from day to day. We interpret these differences as being due to the change of orientation of the prominence axis (and therefore the magnetic field direction) with respect to the line of sight. The Lyman lines are more reversed if the line of sight is across the prominence axis as compared to the case when it is aligned along its axis.     

过氧化氢对全铁测定的影响

由过氧化钠分解试样的熔融物，经水提取后，会产生大量的过氧化氢。它对重铬酸钾测定全铁的结果，会产生偏高的影响。如果加热煮沸或以饿驱除它，则所得结果将令人满意。