安徽庐枞盆地泥河铁矿床与膏盐层的成因联系及矿床成矿模式

安徽庐枞盆地位于长江中下游断陷带内,地处扬子板块北缘,是长江中下游成矿带中重要的铁铜多金属成矿区和玢岩型铁矿的集中产地。庐枞盆地西北部勘探发现了大型泥河铁矿床,其硫铁矿和硬石膏矿床也达到了中大型规模,矿床中硬石膏在不同蚀变-矿化阶段均广泛发育,具有鲜明的成矿特色。深部勘探揭示庐枞盆地深部存在含石膏沉积地层(膏盐层),但目前膏盐层与成矿作用关系尚未引起研究重视。本文总结和分析了泥河铁矿床的地质地球化学特征,着重分析了膏盐层与铁矿床形成的关系,并在阐明成矿流体系统演化过程和成矿机理的基础上,提出泥河矿床的形成与三叠系膏盐层有着重要的成因关系,膏盐层是泥河铁矿床形成的重要地质条件之一。铁矿床及蚀变围岩中的大量硬石膏主要来自膏盐层;膏盐层为铁的成矿作用提供了大部分硫和矿化剂元素。在此基础上,建立了泥河铁矿床的两期成矿模式,即中晚三叠世含膏盐地层的沉积作用期(预备成矿期)和早白垩世的岩浆热液成矿期。     

芥川龙之介《水虎》三元比较研究

芥川龙之介的《水虎》与果戈理的《狂人日记》、鲁迅的《狂人日记》均采用了现实主义与象征主义相结合的创作方法，一针见血地揭露了社会制度的黑暗与腐朽。但他们在创作方法上使用的象征主义和对社会现实揭露的广度与深度不完全相同，主人公的思想高度更是各不相同。作品创作的背景、历史条件，作者的思想高度、性格特点和创作风格是造成这些差别的根源。     

Structural and stratigraphical constraints on the kinematics history of the Southern Tan–Lu Fault Zone during the Mesozoic Anhui Province, China

The Tan–Lu Fault Zone (TLFZ) extends in a NNE–SSW direction for more than 2000 km in Eastern China. It has been considered either as a major sinistral strike-slip fault, as a suture zone or as a normal fault. We have conducted a structural analysis of the southern segment of this fault zone (STLFZ) in the Anhui Province. The ages (Triassic to Palaeocene) of the formations affected by the faults have been re-appraised taking into account recent stratigraphical studies to better constraint the ages of the successive stages of the kinematics of the STLFZ. Subsequently, the kinematics of the faults is presented in terms of strain/stress fields by inversion of the striated fault set data. Finally, the data are discussed in the light of the results obtained by previous workers.We propose the following history of the STLFZ kinematics during the Mesozoic. At the time of collision, a  NNE orientated Tan–Lu margin probably connected two margins located north of the Dabie and Sulu collision belts. During the Middle–Late Triassic, the SCB has been obliquely subducted below the NCB along this margin which has acted as a compressional transfer zone between the Dabie and Sulu continental subduction zones. The STLFZ has been initiated during the Early Jurassic and has acted as a sinistral transform fault during the Jurassic, following which the NCB/SCB collision stopped. A  NW-trending extension related to metamorphic domes was active during the basal Early Cretaceous ( 135–130 Ma); it has been followed by a NW–SE compression and a NE–SW tension during the middle–late Early Cretaceous ( 127 to  105 Ma, possibly  95 Ma); at that time the TLFZ was a sinistral transcurrent fault within the eastern part of the Asian continent. During the Late Cretaceous–Palaeocene, the STLFZ was a normal fault zone under a WNW–ESE tension.     

Lu–Hf constraints on pre-, syn,and post-collision associations of the Gurupi Belt,Brazil: Insights on the Rhyacian crustal evolution

The Gurupi Belt (together with the São Luís cratonic fragment), in north-northeastern Brazil, has been described in previous studies that used extensive field geology, structural analysis, airborne geophysics, zircon U–Pb dating, and whole-rock Sm–Nd isotope and geochemical data as a polyphase orogenic belt, with the Rhyacian being the main period of crust formation. This was related to a 2240 Ma to 2140 Ma accretionary processes that produced juvenile crust, which has subsequently been reworked during a collisional event at 2100 ± 20 Ma, with little evidence of Archean crust. In this study, we use Lu–Hf isotopic data in zircon from granitoids (including gneiss) of variable magmatic series, and amphibolite to improve the knowledge of this scenario, and investigate additional evidence of recycling of Archean basement. Pre-collisional high Ba-Sr and ferroan granitoids and amphibolite formed in island arc (2180–2145 Ma), show only zircons with suprachondritic εHf values (ca. +1 to +8) indicating the large predominance of juvenile magmas. Only 10% of the data show slightly negative εHf values (0 to ?4), which have been observed in granodiorite-gneiss formed in continental arc (2170–2140 Ma), and in strongly peraluminous collisional granites (2125–2070 Ma), indicating the rework of older Paleoproterozoic to Archean components (Hf_TDM = 2.11–3.69 Ga). A two-component mixing model using both Hf and published Nd isotope data are in line with this interpretation and indicate more than 90% of juvenile material, and less influence of Archean materials. Comparing with other Rhyacian terranes that are interpreted to have been close to Gurupi in a pre-Columbia configuration (ca. 2.0 Ga), our results differ from those of SE-Guiana Shield, which show strong influence of Archean protoliths, and are very similar to those of the central-eastern portion of the Baoulé-Mossi Domain of the West African Craton, which has also been formed largely by juvenile magmas in an accretionary-collisional orogen.     

Zircon U-Pb Geochronology and Geochemical Characteristics of the Volcanic Host Rocks from the Tongyu VHMS Copper Deposit in the Western North Qinling Orogen and Their Geological Significance

Precise in situ zircon U-Pb dating and Lu–Hf isotopic measurement using an LA-ICP-MS system, whole-rock major and trace element geochemistry and Sr–Nd isotope geochemistry were conducted on the volcanic host rocks of the Tongyu copper deposit on the basis of further understanding of its geological characteristics. Three zircon samples from the volcanic host rocks yielded 206Pb/238 U weighted average ages ranging from 436±4 Ma to 440±5 Ma, which are statistically indistinguishable and coeval with the ca. 440 Ma northward subduction event of the Paleo-Qinling oceanic slab. The volcanic host rocks were products of magmatic differentiation that evolved from basalt to andesite to dacite to rhyolite, forming an integrated tholeiitic island arc volcanic rock suite. The primitive mantle-normalized trace element patterns for most samples show characteristics of island arc volcanic rocks, such as relative enrichment of LILE(e.g. Th, U, Pb and La) and depletion of HFSE(e.g. Nb, Ta, Ti, Zr and Hf). Discrimination diagrams of Ta/Yb vs Th/Yb, Ta vs Th, Yb vs Th/Ta, Ta/Hf vs Th/Hf, Hf/3 vs Th vs Nb/16, La vs La/Nb and Nb vs Nb/Th all suggest that both the volcanic host rocks from the Tongyu copper deposit and the volcanic rocks from the regional Xieyuguan Group were formed in an island arc environment related to subduction of an oceanic slab. Values of ISr(0.703457 to 0.708218) and εNd(t)(-2 to 5.8) indicate that the source materials of volcanic rocks from the Tongyu copper deposit and the Xieyuguan Group originated from the metasomatised mantle wedge with possible crustal material assimilation. Most of the volcanic rock samples show good agreement with the values of typical island arc volcanic rocks in the ISr-εNd(t) diagram. The involvement of crustal-derived material in the magma of the volcanic rocks from the Tongyu copper deposit was also reflected in the zircon εHf(t) values, which range from-3.08 to 10.7, and the existence of inherited ancient xenocrystic zircon cores(2616±39 Ma and 1297±22 Ma). The mineralization of the Tongyu copper deposit shows syn-volcanic characteristics such as layered orebodies interbedded with the volcanic rock strata, thus, the zircon U-Pb age of the volcanic host rocks can approximately represent the mineralization age of the Tongyu copper deposit. Both the Meigou pluton and the volcanic host rocks were formed during the ca. 440 Ma northward subduction of the Paleo-Qinling Ocean when high oxygen fugacity aqueous hydrothermal fluid released by dehydration of the slab and the overlying sediments fluxed into the mantle wedge, triggered partial melting of the mantle wedge, and activated and extracted Cu and other ore-forming elements. The magma and ore-bearing fluid upwelled and erupted, and consequently formed the island arc volcanic rock suite and the Tongyu VHMS-type copper deposit.     

互补的神话--鲁迅与张爱玲文学与人生观之比较

鲁迅和张爱玲 ,创造了二十世纪中国文学的两个神话。对照各自的文学创作与人生观 ,两者有着颇含默契的互补意味。不同的文学视角与精神关怀赋予彼此人格我不同的深度与质感 ;乡镇意识与城市情结使得两者的文学创作风格各异却又相得益彰 ;迥异的文化背景与人生阅历造成了彼此截然不同的人生态度     

Constraints on the176Lu cosmochronometer

In an endeavour to resolve reported discrepancies in the value of the branching ratio of¹⁷⁶Lu at astrophysical energies, a new determineation of the¹⁷⁵Lu (nγ)^176mLu capture cross section has been measured as 958 ± 58 mb. This gives a value of the branching ratio of 0.21 ±0.05. This result indicates that some reequilibration of the ground and isomeric states of¹⁷⁶Lu occurs in stellar environments undergoing s-process nucleosynthesis, and confirms that¹⁷⁶Lu is not a reliable cosmochronometer. However the very existence of¹⁷⁶Lu in the solar system implies that the ground state of¹⁷⁶Lu was not completely depopulated, and provides the possibility of using this nuclide as a sensitive thermometer for stellar processes.     

庐山2008和2009年两次冰冻天气对比分析

利用高空与地面观测资料,主要从形势场、温度层结、地理形势及地面气象要素等方面,对庐山2008年和2009年两次冰冻天气过程进行对比分析。结果表明,庐山2009年冰冻灾害与2008年初中国南方出现的大范围冰冻灾害有些不同特点,2009年冰冻灾害更具有明显的庐山局部性特征。认为庐山冰冻灾害的出现主要决定于925—850hPa层次的温度层结,当层结温度降为0℃以下并伴有较明显降水时,并不一定需要太长时间和明显逆温层的存在庐山就可以出现冰冻灾害。     

潍北-莱州湾凹陷郯庐断裂带新生代走滑特征

横切潍北-莱州湾凹陷郯庐断裂带的地震反射剖面和断裂带内的凹陷断层、沉积相和油气特征,直接或间接显示了郯庐断裂带的延伸、运动性质和活动时限。郯庐断裂带在海域和陆上的几何形态及其组合基本一致,根据切过断裂带的剖面和平面上断层的组合特征,判断其为兼具垂直位移的走滑运动断层系。走滑断裂带的活动控制着凹陷内同构造沉积以及构造样式,表明郯庐断裂带的活动时限具分段性,相当于渤海湾盆地孔店组(E1?2k)-沙四段(E2?3s4)沉积期(古新世-早始新世)-孔店组-沙二段(E2?3s2)沉积期(古新世-始新世)-孔店组-沙一段(E2?3s1)(古新世-渐新世)沉积时期,走滑拉分活动由南向北迁移; 活动方式也由古新世-早始新世的左旋走滑活动,被早始新世之后的右旋走滑活动所替代。     

S?o Francisco-Congo Craton break-up delimited by U-Pb-Hf isotopes and trace-elements of zircon from metasediments of the Ara?uaí Belt

Detrital zircon U-Pb geochronology combined with Hf isotopic and trace element data from metasedimentary rocks of the Aracuai Belt in southeastern Brazil provide evidence for break-up of the Congo-Sao Francisco Craton. The U-Pb age spectra of detrital zircons from metasediments of the Rio Doce Group(RDG) range from 900-650 Ma and define a maximum depositional age of ca. 650 Ma. Zircon trace element and whole rock data constrain an oceanic island arc as source for the deposition setting of the protoliths to the metasediments. Zircon ε_(Hf)(t) values from these rocks are positive between +1 and +15, supporting previous evidence of a Neoproterozoic extensional phase and oceanic crust formation in a precursor basin to the Aracuai Belt. Recrystallization of detrital zircon at ca. 630 Ma is compatible with a regional metamorphic event associated with terrane accretion to the Paleoproterozoic basement after transition from an extensional to a convergent regime. The juvenile nature, age spectra and trace element composition recorded in detrital zircons of metasediments from the Aracuai Belt correspond with zircons from metasedimentary rocks and oceanic crust remnants of other orogenic belts to its south. This suggests that rifting and oceanic crust formation of the entire orogenic system, the so-called Mantiqueira Province, was contemporaneous, most likely related to the opening of a large ocean. It further indicates that the cratonic blocks involved in the orogenic evolution of the Mantiqueira Province were spatially connected as early as 900 Ma.