25 resultados para 1508-2008
Resumo:
National Key Technology R&D Program of China [2008BAK50B05]; Chinese Academy of Sciences [KZCX-YW-Q06, KZCX2-YW-Q03-06]
Resumo:
P>In the Yellow Sea of China, large-scale green tides have broken out for three consecutive years from 2007 to 2009. As part of the efforts to localize the algal source, two cruises were conducted in the early stage and the outbreak stage of the bloom in 2009. We analyzed the morphological and genetic diversity of drifting Ulva specimens and culture-derived isolates from seawater sampled in different localities. For phylogenetic analyses, the nuclear encoded ribosomal DNA internal transcribed spacer region (ITS nrDNA) and the plastid encoded large subunit of ribulose-1, 5-bisphosphate carboxylase/oxgenase gene (rbcL) were used. Our molecular and morphological data indicate that the dominant free-floating Ulva species in 2008 and 2009 possibly belonged to a single strain of the U. linza-procera-prolifera (LPP) clade. The ITS sequences from bloom-forming algal samples with dense branches were identical to those from U. linza-like specimens without branches derived from the Yellow Sea. Microscopic individuals of the dominant Ulva strain were detected in eight stations, revealing that spore dispersal in the water helped to enlarge biomass in the water during the outbreak stage of green tide in the Yellow Sea.
Resumo:
The region of Qingdao, China, experienced the world's largest green tide from May to July 2008. More than one million tons of fresh algal biomass of the green alga Ulva prolifera was harvested, while more was suspected to have sunk to the bottom. The original source of this seaweed was suspected to be from the south as revealed by satellite images. The floating biomass drifted with the water current northward and flourished in nearshore waters around Qingdao. However, direct biological evidence for "seed" source is lacking. It is still unclear whether this alga could survive the Qingdao local coastal environment and pose future danger of potential blooming. Systematic and seasonal sampling of waters in the intertidal zone at six collection sites along the Qingdao coast was conducted from December 2008 to April 2009. Forty-eight water samples were analyzed. From these, nine different morphotypes of Ulva were grown in the laboratory under standard temperature and light regimes. Growth of Ulva was observed in all water samples. However, molecular phylogenetic analyses revealed that the dominant U. prolifera strain of the 2008 bloom was absent in all the water-derived cultures during the sampling period. These results provide evidence that the dominant bloom-forming alga was unlikely able to survive the coastal waters (the minimal surface water temperature in February is 2A degrees C) in winter conditions in Qingdao, even though all the sampling locations were heavily covered by this alga in June 2008.
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大牛地气田是中石化在“十五”期间探明的一个大型岩性气田,成藏主要受储层发育程度的控制。储层为低孔低渗的致密碎屑岩储层,具有非均质性强,变化快的特点。由于地震资料分辨率比较低、砂泥阻抗差微弱、煤层屏蔽现象严重,造成砂体的地震响应特征不明显,加大了储层识别的难度,制约了气藏的勘探进程,因此,采用合适的储层预测技术对储层进行描述便显得尤为重要。 论文研究的总体思路是在地质沉积相研究的基础上,利用地震储层预测技术从定性—半定量—定量对储层进行雕刻。 论文总的研究内容分为地质沉积相研究和地震储层预测技术研究两大部分。 地质沉积相研究是地震预测的基础。利用地质资料和钻井资料对沉积相进行研究,证实在大牛地气田的西南部,发育二叠系山西组、下石盒子组的2条主河道,砂体纵向相互叠置,平面的分布受河道的控制。 在沉积相研究的基础上,利用地震预测技术对大牛地气田下石盒子组和山西组的储层进行预测,概括起来,有3大核心技术:核心技术之一:相控地震属性分析技术,对储层的宏观分布从地震上进行识别;核心技术之二:基于地质统计学理论的储层反演描述技术,对储层进行半定量的预测;核心技术之三:多信息融合的储层建模技术,对储层的岩性、物性、含气性进行定量的预测。 论文的创新点有3点:1、利用地震属性定性预测储层分布,通过岩石地球物理分析及地震属性优化,筛选出不同层系反映河道砂体的敏感地震属性;2、利用地震反演对储层半定量预测, Gr和中子的重构曲线反演和中子和密度曲线重构反演加大了岩性和气层识别的力度,克服了砂泥阻抗差微弱的困难,探索出一条煤系地层储层半定量预测的新方法;3、储层建模研究将沉积相研究和地震预测技术进行了有机的融合,把沉积相,属性预测和地震反演成果作为输入,定量的对储层的岩性、物性、含气性进行预测,达到了量化储层的目的。 通过上述研究,从宏观—微观,从定性—定量实现了对致密碎屑岩储层的预测。
Resumo:
In this paper, the Xiaodonggou porphyry molybdenum deposit located in the Xarmoron molybdenum metallogenic belt is chose as the research area. We have analyzed the petrology of the Xiaodonggou pluton in detail and made chemical analysis of the major and trace elements, Rb-Sr and Sm-Nd isotope, common lead isotope and SHRIMP zircon U-Pb dating et al; in the other hand, we use the molybdenite to make common lead analysis and Re-Os isotopic dating. The Xiaodonggou pluton is rich in silicon, potass, zirconium, and low in REE. In addition, it has no minus Eu abnormity and show a isotopic composition high in εNd(t) and low in Sri, indicating its magma origining from the melting of juvenile thicken lower crust. In the meanwhile, it contained the features of high temperature, quick melting, quick segregation and quick emplacement. The common lead analysis of the pluton orthoclase and molybdenite show that the former transfer from orogen to mantle and the latter come from mantle, which is consistent to the molybdenite sulfur isotopic and quartz oxygen isotopic composition, demonstrating that the rock and ore-forming materials of deposit having different sources, magma from the lower crust mixing with mantle fluid. In plus, we use the physical experiments results of the water-magma reaction to explain the interaction of magma and mantle fluid. In the deep crust, these two systems uplifted in a immiscible state; when they reached low depth, the stream film between fluid-magma collapsed, and the magma was broken into small agglomerates by the fluid, then they mixed thoroughly. The SHRIMP zircon U-Pb dating gave a result of 142±2Ma and the molybdenite Re-Os dating result is 138.1±2.8Ma, corresponding to the big tectonic transition period of 140Ma, when the major stress field changing from south and north to west and east. At this time, the Da Hinggan ling ranges area was under an extensive background, underplating proceeded and mantle materials could add into the magmas forming in the lower crust. So, from the above analysis, we propose the following model for the Xiaodonggou porphyry molybdenum deposit: in the early Cretaceous period, the Da Hinggan ling ranges area was under a extensive background, the adding of mantle fluid containing ore materials into heated lower crust made it melting to produce magmas. Following more mantle fluid got into the magma room and urged the magma to segregate from the source quickly. The fluid and magma uplifted together, when they arrived at shallow depth, the fluid-magma became unstable and the latter was broken into many small agglomerates with fluid connecting them in the interspaces. Because of the H+, K+ and various elements existing in the fluid, it would reacted with the magma and the rock through alteration and ore minerals crystallized out, forming the Xiaodonggou porphyry deposit with disseminated mineralization phenomenon.