中西太平洋金枪鱼围网高产渔区年间变化及其原因分析

金枪鱼类是中西太平洋海域重要的经济鱼种,其中鲣产量约占到总产量的50%。本研究利用1995-2010年16年的中西太平洋（20°S~20°N,120°E~155°W）鲣围网生产统计数据和Niño3.4海区（5°S~5°N,120°~170°W）海表温度异常数据,对这16年鲣产量最高的十大渔区（5°×5°）进行时空格局分析,讨论渔场分布差异及CPUE与ENSO指数的关系。结果表明:16年间十大作业渔区主要分布在5°S~5°N、130°~175°E区域,这十大渔区产量占总产量的比重达47.5%,其中5°S~0°、155°~160°E,0°~5°N、130°~135°E,0°~5°N、135°~140°E及5°S~0°、160°~165°E等4个渔区产量占高产渔区产量的比重均超过10%,是中西太平洋重要的鲣产区。高产渔区的分布受海表温度影响较大,在厄尔尼诺时期,高产渔区分布明显偏东,主要分布在155°~180°E海域;在拉尼娜时期,高产渔区分布明显偏西,主要分布在130°~160°E海域。     

龙陵-瑞丽断裂北段晚第四纪活动性特征及强震复发间隔

野外地质地貌调查表明,龙陵-瑞丽断裂(南支)北段是以左旋走滑为主兼具一定正断分量的区域性活动断裂.断裂晚更新世以来的平均水平滑动速率为2.2mm/a,平均垂直滑动速率为0.6mm/a;全新世以来的平均水平滑动速率为1.8-3.0mm/a,平均垂直滑动速率为0.5mm/a.断裂在晚更新世以来的滑动速率在不同的时间尺度上变化不大,反映出该断裂晚更新世以来的活动强度比较稳定.利用Poisson模型、Lognormal模型、BPT模型三种概率模型计算获得未来50a强震发震概率分别是:6.32％、0.08％、0.05％;三种模型分别取权重0.28、0.36、0.36,获得龙陵-瑞丽断裂北段未来50a特征地震发震概率为1.82％.     

内蒙古孟恩陶勒盖银铅锌矿床白云母Ar-Ar年龄及其意义

文章采用Ar_Ar同位素测年法对孟恩陶勒盖银铅锌矿云英岩化阶段形成的白云母进行了测试 ,获得白云母坪年龄为 (179.0± 1.5 )Ma ,等时线年龄为 (182 .3± 3.8)Ma。这组数据近似地代表了该矿床的形成年龄 ,同时也显示该地区除已知的晚侏罗_早白垩世构造_岩浆_成矿作用外 ,还有一期重要的早侏罗_中侏罗世构造_岩浆_热液成矿事件 ,这也是到目前为止所获得的大兴安岭中南段热液矿床最老的成矿年龄     

准噶尔盆地东部中二叠统平地泉组具“斑状”结构热水喷流沉积岩的成因及地质意义*

准噶尔盆地东部中二叠统平地泉组(相当于芦草沟组)发育一套陆内裂谷背景下的湖泊相砂岩、泥岩、灰岩、白云岩、凝灰岩互层以及它们的过渡岩石,是区内最主要的烃源岩和储集层。近年来,在帐北断褶带、石树沟凹陷和吉木萨尔凹陷中二叠统平地泉组暗色泥岩、泥晶白云岩中发现了一类特殊的沉积岩,该类岩石发育类似火山岩的斑状结构。“斑晶”主要为粗晶白云石、方解石、黄铁矿及方沸石等,在岩心标本上呈“树枝状”或“雪花状”散布于基质中;基质则主要由泥晶白云石或泥质沉积物构成,富含有机质,发育水平层理及小型变形层理等。岩石学和矿物学分析表明,“斑晶”往往为粗晶方解石或白云石的集合体,也常见黄铁矿、方沸石与碳酸盐矿物共生,“斑晶”方解石发育环带,而白云石未见明显环带。电子探针分析表明“斑晶”方解石具有低镁、低铁及锶分布不均匀的特点,而“斑晶”白云石(FeO含量介于7.272%~11.086%之间)与“基质”泥晶白云石(FeO含量为1.027%)相比具有明显富铁的特点。流体包裹体分析表明“斑晶”方解石均一温度平均为180.68,℃,“斑晶”白云石均一温度平均为320.95,℃。这种特殊 “斑状”白云岩和“斑状”泥质岩很可能是湖底热液喷流作用的结果。当湖水沿深大断裂下渗至地下深处,与围岩发生物质交换并被加热后再沿断裂返回地表喷涌而出,热液流体携带的离子达到过饱和后就会析出方解石、白云石及黄铁矿等集合体,随热液的喷涌作用上升并破碎散落于湖底细粒沉积物内。“斑状”白云岩的发现对新疆北部中二叠统热水喷流沉积作用及该区油气的成因研究具有重要的意义。     

大地测量学家 周江文教授

周江文教授是我国著名的大地测量学家和误差理论专家,八十有三的周老精神瞿铄,思维敏捷,充满着对我国大地测量事业和年轻同志成长的关心.他对我国大地测量的贡献更为学术界所赞赏.正如大地测量和固体地球物理学家许厚泽院士所评价:"周江文教授是我国大地测量和测量误差理论研究领域中最有造诣的一位优秀科学家.60多年来,他为大地测量学的发展作出了巨大贡献.他自1958年到中科院测地所工作,为我所科技事业发展和人才培养呕心沥血,作了很多贡献".他以严肃的态度治学育人,60年如一日,为我国大地测量学术界树立了一座丰碑.     

水流紊动对泥沙絮凝的影响

主要研究水流紊动对泥沙絮凝的影响。认为水处理方面的絮凝动力学理论可用于研究泥沙絮凝问题。根据试验实测资料及国外有关试验结果研究表明,在紊动状态下,泥沙絮凝存在两个阶段,每个阶段中紊动对泥沙絮凝的影响也有所不同。     

Tracing the 850-Ma continental flood basalts from a piece of subducted continental crust in the North Qaidam UHPM belt,NW China

A Paleozoic ultrahigh-pressure metamorphic (UHPM) belt extends along the northern margin of the Qaidam Basin, North Tibetan Plateau. Eclogites in the Yuka eclogite terrane, northwest part of this UHPM belt, occur as blocks or layers of varying size intercalated with granitic and pelitic gneisses. These eclogites have protoliths geochemically similar to enriched-type mid-ocean ridge basalts (E-MORB) and oceanic island basalts (OIB). On the basis of Ti/Y ratios, they can be divided into low-Ti and high-Ti groups. The low-Ti group (LTG) eclogites exhibit relatively low TiO₂ (most <2.5 wt%) and Ti/Y (<500) but comparatively high Mg# (48–55), whereas the high-Ti group (HTG) eclogites have high TiO₂ (most >2.5 wt%) and Ti/Y (>500) but lower Mg# (46–52). Zircons from two eclogite samples gave a magmatic crystallization (protolith) age of ∼850 Ma and a UHPM age of ∼433 Ma. The occurrence, geochemical features and age data of the Yuka eclogites suggest that their protoliths are segments of continental flood basalts (CFBs) with a mantle plume origin, similar to most typical CFBs. Our observation, together with the tectonic history and regional geologic context, lend support for the large scale onset of mantle plume within the Rodinia supercontinent at ∼850 Ma. The Qaidam block is probably one of the fragments of the Rodinia supercontinent with a volcanic-rifted passive margin. The latter may have been dragged to mantle depths by its subducting leading edge of the oceanic lithosphere in the Early Paleozoic.     

大姚6级双震前的地震前兆特征

在连续形变观测资料中除了存在于整个时间域的短周期潮汐信息(固体潮)外，还有出现在某个时间段的长周期非潮汐信息．如何从时间或空间上认识和提取这些信息．成为认识地震过程和进行地震预报关键和迫切的问题之一。利用小波分析的时一频特性和奇异性检测特性，对大姚6级双震前的连续形变观测资料进行了处理，提取潮汐资料中的非潮汐信息。发现在地震前震中附近的形变台站都接收到了相同频段的异常信号．周期为几天到十几天，出现在各个台站的时间也大致相同。这些在震前具有一定时、空分布的信息有可能是地震前兆。     

The influence of dam and lakes on the Yangtze River streamflow: long‐range correlation and complexity analyses

Employing long‐range correlation, complexity features and clustering, this study investigated the influence of dam and lake‐river systems on the Yangtze River flow. The impact of the Gezhouba Dam and the lake systems on streamflow was evaluated by analysing daily streamflow records at the Cuntan, the Yichang and the Datong station. Results indicated no evident influence of the Gezhouba Dam on streamflow changes. Distinct differences in scaling behaviour, long‐range correlation and clustering of streamflow at the Datong station when compared with those at the Cuntan and Yichang stations undoubtedly showed the influence of water storage and the buffering effect of the lake systems between the Datong station and other two hydrological stations on streamflow in the lower Yangtze River basin. Decreased regularity, enhanced long‐range correlation and increased clustering of streamflow in the lower Yangtze River basin due to the effect of water storage of the lake systems were corroborated. Copyright © 2011 John Wiley & Sons, Ltd.     

Teleportation and thermal entanglement in two-qubit Heisenberg XYZ spin chain with the Dzyaloshinski—Moriya interaction and the inhomogeneous magnetic field

This paper studies the average fidelity of teleportation and thermal entanglement for a two-qubit Heisenberg XYZ chain in the presence of both an inhomogeneous magnetic field and a Dzyaloshinski--Moriya interaction. It shows that for a fixed D_z, the increase of b_z will broaden the critical temperature at the cost of decreasing the thermal entanglement. And it can modulate the inhomogeneous magnetic field and the Dzyaloshinski--Moriya interaction for the average fidelity of teleportation to be optimal.