黄渤海带鱼(Trichiurus lepturus)渔业生物学参考点估计研究

It is important to find a reliable method to estimate maximum sustainable yield(MSY) or total allowable catch(TAC) for fishery management, especially when the data availability is limited which is a case in China. A recently developed method(CMSY) is a data-poor method, which requires only catch data, resilience and exploitation history at the first and final years of the catch data. CMSY was used in this study to estimate the biological reference points for Largehead hairtail(Trichiurus lepturus, Temminck and Schlegel) in the Yellow Sea and Bohai Sea, based on the fishery data from China Fishery Statistical Year Books during 1986 to 2012. Additionally,Bayesian state-space Schaefer surplus production model(BSM) and the classical surplus production models(Schaefer and Fox) performed by software CEDA and ASPIC, were also projected in this study to compare with the performance of CMSY. The estimated MSYs from all models are about 19.7×104–27.0×104 t, while CMSY and BSM yielded more reasonable population parameter estimates(the intrinsic population growth rate and the carrying capacity). The biological reference points of B/BMSY smaller than 1.0, while F/FMSY higher than 1.0 revealed an over-exploitation of the fishery, indicating that more conservative management strategies are required for Largehead hairtail fishery.     

赣北石门寺钨多金属矿床成矿流体演化过程：白钨矿微区成分限定

大湖塘钨矿地处江南造山带中段,为一大型钨-钼-铜多金属矿田,由4个矿床组成,其中石门寺矿床规模最大.文章利用LA-ICP-MS对石门寺矿床石英脉型钨矿中的白钨矿进行单矿物原位微区分析,以揭示成矿流体演化过程.研究表明,石英脉中的白钨矿可划分为2期,其中,早期白钨矿与黑钨矿、黑云母及石英共生,而晚期白钨矿在石英大脉中仅与石英共生.前者表现为右倾型稀土元素配分模式,而后者则显示平坦型稀土元素配分模式,两者均具Eu正异常.此外,早期白钨矿较晚期白钨矿具有较高的ΣREE、Mo、Sn、Nb、Ta、Y含量,但Sr含量较低.早期白钨矿表现出LREE富集型和较高的ΣREE、Nb、Ta含量,说明成矿流体来源于岩浆热液,从早期到晚期成矿流体中Eu由Eu2+为主转变为Eu3+为主,表明流体演化过程中氧逸度升高,暗示成矿晚期有氧化性大气降水加入.早期高LREE、Sn、Nb、Ta含量的白钨矿的沉淀以及辉钼矿结晶显著改变成矿流体的组成,导致晚期白钨矿具平坦型REE配分模式和低Mo、Sn、Nb、Ta的特征.此外,在流体演化过程中,新元古代花岗闪长岩中斜长石因为蚀变分解持续为成矿热液提供Eu和Sr,造成白钨矿Eu正异常和晚期白钨矿中Sr含量的升高.     

福建行洛坑钨矿床黑钨矿LA-ICP-MS U-Pb年龄和微量元素地球化学特征北大核心CSCD

为精确厘定福建行洛坑钨矿床成矿时代和揭示其成矿流体演化特征,利用LA-ICP-MS对矿床中的浸染状石英细脉和大脉中的黑钨矿进行了U-Pb年代学和微量元素地球化学研究。结果表明,石英细脉和大脉中黑钨矿的原位U-Pb年龄分别为(151.3±5.8)Ma和(150.5±8.1)Ma。钨成矿时代与南岭地区钨矿化幕次相吻合,表明华南晚侏罗世大规模钨成矿作用可能从南岭地区向东延伸至武夷山成矿带。细脉黑钨矿较大脉黑钨矿具有更低的δEu值,但Nb、Ta含量更高,暗示早期的浸染状石英细脉形成于相对还原环境,晚期可能由于大气降水的增加使氧逸度升高。此外,黑钨矿Y/Ho、Zr/Hf值的非CHARAC行为及其稀土模式四分组效应暗示钨成矿过程中氟对钨等元素的迁移、富集起着重要作用。黑钨矿稀土总量和稀土配分曲线与南岭地区石英脉型钨矿相似,均为重稀土富集型。研究表明行洛坑钨矿属于石英脉型钨矿而非以往认为的斑岩型钨矿。