宣龙地区中元古代铁岩建造成因探讨

“宣龙岩”铁岩建造是中元古代早期形成的肾状，鲕状铁岩建造，它属于地球上较早的铁岩建造。铁的物质来源是大陆风化壳上的铁质，以氢氧化铁胶体形式搬运至内陆海中，肾状铁岩在生物和胶体化学共同作用下形成于滩后低能带；鲕状铁岩在物理搅动和胶体化学联合作用下形成于高能浅滩。     

Magmatism and metallogeny of the Ridanj-Krepoljin belt (eastern Serbia) and their correlation with northern and eastern analogues

In the southwestern Carpathians of SW Romania and E Serbia calc-alkaline Upper Cretaceous-Paleogene subduction related magmatic rocks occur in two main zones. The Ridanj-Krepoljin belt (E Serbia) represents the southern part of the western zone. In this belt Early Maastrichtian dacites and subordinate andesites occur, but there are indications of an unexposed granodioritic (?) magmatism about 60 Ma old. Pb-Zn-Ag and only subordinate Cu mineralization is associated with this igneous activity. The Timok magmatic complex (E Serbia) composed of Upper Cretaceous (-Paleocene?) andesites and analogue intrusives represents the eastern zone south of the Danube. Associated with this magmatism are Cu (+Au) and very subordinate Zn (±Pb) mineralization. To the north (SW Romania) in both zones mainly intrusive bodies (diorites, quartz diorites, granodiorites, monzonites) of Campanian-Paleocene age are exposed. Porphyry copper (+Mo) and in north Pb-Zn (±Cu) mineralization are related to those intrusives. The petrological and geochemical features of all these calc-alkaline rocks are very similar. It appears, however, that the associated polymetallic and the copper mineralization are both spatially and vertically separated.     

Phytogenic lacustrine sedimentation - oil shales in Neogene from Serbia, Yugoslavia

Lacustrine basins of Neogene age in Serbia were formed either in intramountain valleys-graben and half-graben structures or in the marginal part of the Pannonian sea during Oligocene or at the beginning of Miocene, lasted and ended at the end of Miocene or Pliocene. The formation of the numerous depressions of the Balkan Peninsula, due to tectonic activity, gave lake basins with alluvial, swamp and lacustrine facies. The cycle with these facies was repeated several times. The lakes are mostly meromictic, often permanently stratified (oil-shale). A high rate of sedimentation with thickness up to 2000 m is characteristic for many of these basins. In many lakes phytogenic sedimentation occurs, giving facies with coal and with oil-shales. In this paper only some basins with oil-shales will be discussed, e.g. Valjevo-Mionica, Jadar and Pranjani basin. The characteristics of Vranje and Aleksinac basin will be discussed only in general. The organic rich sequences (oil shales) are characterized by the thin lamination, preservations of fish remains and plant leaves and absence of bioturbation, which needed permanent stratification of water body and anoxic conditions. Paleoclimatic regimes at the time of deposition and diagenesis were warm, subtropic with the changes of humid and dry periods.     

Effects of dietary carbohydrate-to-lipid ratio on the growth performance and feed utilization of juvenile turbot (<Emphasis Type="Italic">Scophthalmus maximus</Emphasis>)

A 9-week feeding trial was conducted to investigate the effects of dietary carbohydrate to lipid ratio(CHO:LIP) on the growth performance and feed utilization of juvenile turbot Scophthalmus maximus(initial body weight 8.75 g ± 0.04 g). Four isonitrogenous and isoenergetic low protein level(39%) diets were formulated with increasing ratios of dietary carbohydrate to lipid(2:18, 6:18, 18:12 and 28:6). A high protein level(50%) diet with the 2:12 ratio of carbohydrate to lipid was used as the control. Results showed that the survival rate, contents of moisture, crude protein and ash in muscle were not significantly affected by dietary treatments. With the dietary CHO:LIP ratio increased from 2:18 to 18:12, weight gain rate significantly increased(P < 0.05). Higher dietary CHO:LIP ratio(28:6) resulted in the significantly decreased weight gain rate(P < 0.05). Meanwhile, this treatment also resulted in the highest daily feed intake and liver glycogen content, as well as the lowest feed efficiency(P < 0.05). Muscle glycogen content in fish fed the diet with 2:12 or 2:18 CHO:LIP ratio was significantly lower than those fed with the other three diets(P < 0.05). The present results confirmed that the juvenile turbot can utilize carbohydrate. Furthermore, the appropriate ratio of dietary carbohydrate to lipid was important to the growth and feed utilization of turbot. The proper CHO:LIP ratio based on the growth performance in the present study was determined to be 18:12 when the dietary protein level was 39%.     

Thermal stability of extended clusters in dravite: a combined EMP,SREF and FTIR study

A dravite from Yemen of near end-member composition was treated in air and hydrogen atmospheres at 600–900 °C to reveal changes in Mg and Al order over the octahedrally coordinated Y and Z sites, and to explore related changes in the characteristic vibrational bands in the principal (OH)-stretching frequency. Relevant information was obtained using electron microprobe analysis (EMPA), structural refinement (SREF) and polarized infrared (IR) single-crystal spectroscopy. Overall, the EMPA, SREF and IR data show that only minor changes occur during thermal treatment up to at least 800 °C, including variations in structural parameters, Mg–Al order–disorder and (OH)-stretching bands, indicating limited hydrogen loss. Untreated and treated dravite samples have very similar long-range and short-range atomic structures, which may be related to the occurrence of stable Al–Mg extended clusters around the O1 (=W) and O3 (=V) sites: ^W(F)–^Y(MgMgMg)–^V(OH)₃–^Z[AlAlAlAlAl(Al,Mg)]; ^W(OH)–^Y(MgMgAl)–^V(OH)₃–^Z[AlAlAlAlAl(Al,Mg)]; ^W(O^2–)–^Y(AlAlAl)–^V(OH)₃–^Z[AlAlAlAlAl(Al,Mg)]. These extended clusters remain stable to temperatures close to the observed start of decomposition (~900 °C).     

2014年2月北京PM2.5污染过程及天气形势分析

2014年2月19—27日,北京出现了重度污染及以上水平的霾天气,严重危害着人们的身体健康。以北京该段持续污染过程为研究对象,基于同期气象数据与PM2.5 观测数据,利用SPSS统计软件分析了PM2.5浓度与气象因子间的相关性,探究区域周边城市PM2.5 污染变化特征及其与地面天气形势之间的关系。研究结果表明,在一定的气象条件下,PM2.5 浓度与风速、相对湿度分别呈显著的负相关、正相关,与气压呈负相关,与气温无显著相关关系。同时,比较该时段北京市与周边区域7个城市的PM2.5 浓度变化趋势及后向轨迹分析,发现北京市与周边城市在相似的气象背景条件下,污染过程具有区域性特征。华北地区处于地面高压均压场控制时,地面风速小,逆温层明显,大气层结稳定,区域扩散条件差,弱偏南气流主导时间长,受局地源积累和区域输送的影响,污染物浓度累积上升,可形成持续霾天气。     

A method for estimating microporosity of fine‐grained sediments and sedimentary rocks via scanning electron microscope image analysis

This study presents a method of two‐dimensional scanning electron microscope image analysis that directly quantifies microporosity abundance in clay‐rich, fine‐grained sediments. The method is novel in that it is specifically designed to circumvent the challenge to porosity quantification posed by mineral surface charging and topographical artifacts created during Ar‐ion cross‐section polishing. It utilizes the finding that differences in circularity values can be used to distinguish micropores from blemishes in a thresholded image. This method is powerful because it is fast and provides a direct microporosity estimation technique to augment or replace experimental data. The pore size range to which the method is applicable is clear and can be selected depending on the application of the analysis. When used appropriately, the method can be implemented on microporous sediments and sedimentary rock in general. The method is developed using marine muds of Pliocene and Miocene ages from the Nankai margin (burial depths from approximately 200 to 1100 m). The close match between imaging‐derived microporosity and bulk N₂ microporosity measurements shows that porosity in these young and relatively shallowly buried sediments is dominated by pores of sizes that can be imaged by scanning electron microscopy. In Kumano, forearc basin sediments of the Nankai Trough, results of this method show a significant increase in microporosity with burial depth, probably due to microporosity preservation during compaction and possibly early volcanic ash diagenesis.