秦岭及邻区磷矿成矿问题研讨

秦岭及其邻区地处华北地台南缘、秦岭地槽、松潘 甘孜地块、扬子地台北缘 ,可划分皖鄂、鄂西、陕南、什 (邡 )绵 (竹 )等 4个磷矿密集区。成矿时代自元古宙至泥盆纪 ,以震旦纪、寒武纪为高峰期。矿床以沉积型为主 ,次为沉积变质型及岩浆型。特大型、大型矿床成矿受海盆地控制 ,中、小型矿床则受海沟、海槽或海湾制约。区内可归纳出 3级成矿远景区 ,8个成矿域     

江西雅山富氟高磷花岗岩中的磷酸盐矿物及其成因意义

江西雅山黄玉锂云母花岗岩属典型的华南[富氟高磷花岗岩（P2O5＝0．15％－0．55％），表现为富氟（F＝1．07％－2．04％），强过铝性（A／NKC＝1．26－1．60），具有很高的Li,Rb,Cs,Be,Nb,Ta含量和很低的Y、REE含量.磷锂铝石是雅山黄玉锂云母花岗岩中的主要磷酸盐矿物，其产出与否同体的Li,Rb,Cs含量密切相关；磷锂铝石和长石矿物都是雅山黄玉锂云母花岗岩中磷的主要贮体，并且相互之间呈互补关系，当出现磷锂铝石时，磷锂铝石为全岩磷的主要贡献者，当无磷锂铝石晶出时，长石矿物为全岩磷的主要贡献者，体系的强过铝性以及很低的REE，Y，Ca含量使得磷灰石，独居石，磷钇矿都难以达到饱和结晶，磷灰石为少量出现，并且大部分为晚期形成；独居石和磷钇矿都为极少出现，反映出雅山岩体演化过程中具有独居石，磷钇矿等稀土磷酸盐矿物的结晶分离，铍磷酸盐矿物－羟磷铍钙石的出现反映了雅山黄玉锂云母花岗岩存在岩浆期后的含Be,Ca热液流体的作用。     

一种罕见的铍矿物—红磷锰铍石

红磷锰铍石是一种很罕见的铍磷酸盐矿物,在国外,目前仅知发现于芬兰等几个国家,其量也极少。我国是1984年首次发现于福建南平花岗伟晶岩田中的白云母—钠长石—锂辉石型伟晶岩中,沿粗粒原生绿柱石中的微裂隙分布,是伟晶岩形成晚期热液蚀变作用的产物。本文较系统地研究了南平伟晶岩中红磷锰铍石的矿物学特征,包括产状及共生组合、物性及光性、化学成分、X射线衍射特征和红外吸收光谱分析等,最后概述了该矿物的鉴定特征。     

Phosphate-rich deposits associated with the Mio-Pliocene unconformity in south-east Australia

Phosphates are present on the surface of the Mio-Pliocene unconformity in the Otway, Port Phillip and Gippsland basins of south-east Australia. The phosphates occur as lenticular lag deposits and include reworked phosphatic intraclasts, vertebrate bone and teeth. In situ phosphatized burrows are also found in sediments of Late Miocene and Early Pliocene age. The phosphatic intraclasts on the unconformity are interpreted as reworked phosphatized burrows derived from latest Miocene sediments (6 to 5 Ma). The phosphatization of these intraclasts is temporally related to the unconformity. The timing of phosphogenesis coincides with a period of transgression across the south-east Australian margin following Late Miocene uplift. This transgression is responsible for initial marine erosion of the underlying Miocene sequence, creation of a period of very slow sedimentation that was favourable to phosphate formation and subsequent deposition of the latest Miocene through to Pliocene sediments. The continental weathering of the uplifted highlands adjacent to the sedimentary basins, global phosphorus enrichment in the Late Miocene oceans and localized upwelling may all have contributed to phosphatization in south-eastern Australia.     

Modelling sediment and total phosphorus export from a lowland catchment: comparing sediment routing methods

Bank erosion is the main source of suspended sediment (SS) and diffuse total phosphorus (TP) in many lowland catchments. This study compared a physically based sediment routing method (Physical method), which distinguishes between stream bed and bank erosion, with the original sediment routing method (Original method) within the Soil and Water Assessment Tool (SWAT) version 2009, for simulating SS and TP losses from a lowland catchment. A SWAT model was set up for the lowland River Odense catchment in Denmark and calibrated against observed stream flow and phosphate (PO₄) loads. On the basis of an initial calibration of hydrological and PO₄ parameters, the SWAT model with the Original method (Original model) and the SWAT model with the Physical method (Physical model) were calibrated separately against observed SS and TP loads. The SWAT model simulated daily stream flow well but underestimated PO₄ loads. The Physical model simulated daily SS and TP better than the Original model. The simulated contribution of bank erosion to SS in the Physical model (99%) was close to the estimated contribution from in situ erosion measurements (90–94%). Compared with the Original method, the Physical method is not only more conceptually correct but also improves model performance. Copyright © 2014 John Wiley & Sons, Ltd.     

Authigenesis of vivianite as influenced by methane-induced sulfidization in cold-seep sediments off southwestern Taiwan

Authigenesis of iron-rich phosphate nodules occurs in iron-rich cold-seep sediments (MD052911 core) at Yung-An Ridge offshore southwestern Taiwan. Raman, FTIR, and quantitative X-ray energy-dispersive spectroscopic analyses indicate that the phosphate mineral is vivianite (or barićite) and shows Fe/Mg molar ratios spanning from ca. 0.6 to 4.0 and a general down core trend of increasing Fe/Mg ratios. The formation of vivianite is limited to a depth interval of 13–17 mbsf (meters below seafloor) and is most prominent at ∼16 mbsf in association with high dissolved iron concentrations and depleted dissolved sulfide below a peak sulfidization zone (enriched in mackinawite and greigite). Alternate growths of vivianite and iron monosulfides and compositional zoning with Mg enriched towards the peripheries of individual nodules occur in the transition from the zone of vivianite mineralization to the sulfidization zone. The crystallization of vivianite below the sulfidization front could have been favored by scavenging of downward diffusive dissolved sulfide from pore waters in the sulfidization zone. Alternate growths and overlapping of the zones of iron monosulfides and vivianite can be attributed to fluctuations of the sulfidization front and methane flux. The discovery of vivianite in the Yung-An Ridge sediments implies that authigenic vivianite can be an important sink for phosphorus burial in cold-seep sediments that have high reactive-iron contents and high sedimentation rates.     

基于LA-ICP-MS多元素成像技术的早寒武世磷结核成因研究

我国下寒武统底部广泛发育磷结核、磷块岩等富磷沉积,为早寒武世最为重要的化学标志层之一,也代表了隐生宙—显生宙转折期地球表层系统的重大变革。当前对磷来源和富集机制的解释不一。为进一步明确该时期富磷沉积的形成机制,本文利用激光剥蚀电感耦合等离子体质谱联用技术(LA-ICP-MS)对贵州金沙地区牛蹄塘组黑色页岩中的磷结核进行多元素原位微区成像研究。结果表明:磷结核中各元素富集情况清晰地记录了磷结核形成过程中微环境的变化趋势。其中,磷结核内部Ca、P共富集以及Si亏损,指示P富集缘于自生磷灰石生成,P则来自于有机质含氧或厌氧降解释放;Mn、Zn与P共富集于磷结核内部,指示结核形成时的底部水体为含氧水体;As、Mo、V等元素主要富集于围岩或黑色页岩,指示缺氧含H_2S水体形成终止了结核生长。本研究显示,LA-ICP-MS原位多元素成像技术能够获取微区内丰富的地球化学信息,并提供高精度可视化证据,未来将在地质勘探和古环境研究等领域得到更广泛应用。     

DIETARY PHOSPHORUS REQUIREMENT OF YOUNG ABALONE, HALIOTIS DISCUS HANNAI INO

An experiment was performed to determine the dietary phosphorus requirement of the young abalone,Haliotis discus hannai. Five semi-purified diets were formulated to provide a series of graded levels of dietary total phosphorus (0.23%–1.98) from monobasic potassium phosphate (KH2P04). The brown alga,Laminaria japonica, was used as a control diet. Similar size abalone were distributed in a single-pass, flow-through system using a completely randomized design with six treatments and three replicates each treatment. The abalone were hand-fed to satiation with appropriate diets in excess, once daily at 17:00. The feeding trial was run for 120-d. Survival rate and soft-body to shell ratio (SB/S) were constantly maintained regardless of dietary treatment. However, the weight gain rate (WGR), daily increment in shell length (DISL), muscle RNA to DNA ratio (RNA/DNA), carcass levels of lipid and protein, soft-body alkaline phosphatase (SBAKP), and phosphorus concentrations of whole body (WB) and soft body (SB) were significantly (ANOVA, P<0.05) affected by the dietary phosphorus level. The dietary phosphorus requirements of the abalone were evaluated from the WGR, DISL, and RNA/DNA ratio respectively, by using second-order polynomial regression analysis. Based on these criteria, about 1.0%–1.2% total dietary phosphorus, i.e. 0.9%–1.1% dietary available phosphorus is recommended for the maximum growth of the abalone. Project 39670572 supported by the NSFC.     

铁锰氧化物/硅藻土复合物的制备及其对磷的吸附性能研究

采用氧化还原共沉淀法制备铁锰氧化物/硅藻土复合物,考察原料配比、反应温度、焙烧温度及溶液pH值、离子强度对该复合物吸附磷性能的影响,同时开展吸附等温线、XRD和IR等分析。结果表明,2. 5 g硅藻土与1. 0 mmol锰、3. 0 mmol二价铁、3. 0 mmol三价铁制备的复合物在20℃、pH值为6时对磷的吸附量为10. 84 mg/g,较硅藻土提高约3. 6倍;沉淀反应温度对复合物吸附性能影响很小,焙烧温度400～500℃有利于复合物对磷的吸附;吸附量随溶液pH值的增大而减小,pH值较低时吸附作用主要是静电吸引和内层络合,pH值较高时减弱的静电吸引和内层络合与有利于吸附的内层络合共吸附综合作用,表现为吸附量减小;吸附等温线符合Langmuir方程,饱和吸附量34～37 mg/g,与D-R方程、R-P方程有较好相关性,平均吸附能9. 9～11. 3 kJ/mol,复合物具有微孔结构,有单层也有多层吸附。