Major Element, REE, and Other Trace Element Behavior in Amphibolite Weathering under Semiarid Conditions in Southern India

A body of komatiitic amphibolite, an enclave within the Archean high-grade orthogneisses in southern India, shows mild chemical weathering under semiarid conditions. Along fractures, chemical weathering has advanced (Chemical Index of Alteration &sqbl0;CIA&sqbr0;=53; CIA of fresh rock approximately 26) to the extent that secondary Mg-Fe-Al clay minerals have formed and the rock has turned brownish red, soft, and fine grained. The weathering process has resulted in the mobilization and redistribution of the so-called immobile elements Fe, Al, Ti, and REE effected by the nature of secondary mineral formation (talc vs. aluminous clay minerals) and also possibly by soil microbes. In the initial stages of secondary mineral formation, there is a small loss of Fe, Al, and REE (noticeably Eu). However, in the fracture zone as well as in the incipiently altered zone, there is significant REE enrichment, probably affected by a different precipitation mechanism. Mobilized REE may have come from a minor alteration of clinopyroxene.     

Do benthic biofilters contribute to sustainability and restoration of the benthic environment impacted by offshore cage finfish aquaculture?

Benthic biofilters were deployed under a cage fish farm and in two reference locations to assess the influence of the farm on the biofilters and the surroundings, as well as to verify the usefulness of this technology as a mitigation tool. The biofilters underneath the farm recruited a fouling community practically identical to that of the control biofilters, which included a variety of trophic strategies. The former showed a higher ¹⁵N enrichment, indicating that fouling beneath the farm was benefiting from the farm waste. The waste retention efficiency was low (0.02 g N m⁻² month⁻¹) beneath the farm. Benthic biofilters aggregated demersal wild fish around and within them. Pelagic wild fish also frequently used the biofilters beneath the farm, forming compact shoals around them. The increased complexity of the habitat below the fish farm enhanced biodiversity, but this improvement did not lead to the recovery of the sediments around the biofilters.     

波西米亚块体西部长周期电磁研究(英文)

在波西米亚块体西南部做了一条长周期电磁剖面 ,它靠近德国超深钻的位置。用一个二维合成模型对数据做了大体的拟合 ,模型走向东西 ,近地表盖层高度地不均匀畸变。畸变层显示强烈的各向异性 ,优势电导方向为NW -SE至NNW -SSE。讨论了深部区域结构的几个不同的模型 ,其中一个模型可以解释由MT和GDS数据显示的主方向的偏差 ,还讨论了沿特别剖面得到的结果与区域地电结构的关系     

地震台阵监测能力综述

根据各大网站地震目录和前人研究成果,分析全球地震台网与地震台阵、我国区域台网与地震台阵的监测能力,阐述了地震台阵与密集台网/台阵的区别。研究表明,对同一地区所检测的地震数,地震台阵是地震台网的3—10倍,而震级下限可降低1.2—2级。一般情况下,以微弱信号检测为目的的地震台阵监测能力均优于以结构研究为目的的密集台网/台阵,2种台阵是目的、性质、孔径、形状、台间距、技术手段、研究方法均不同的监测系统。     

2004年2月11日Cluster卫星和CUTLASS雷达同时观测的磁通量传输事件

本文分析了2004年2月11日11:00～11:40 UT期间Cluster卫星簇的磁通门磁力计FGM）、等离子体电子及电流试验仪（PEACE）和CUTLASS 芬兰雷达对多个磁通量传输事件(FTEs)的同时观测. 在此期间,Cluster卫星簇位于北半球外极隙区附近,并于11:18 UT左右穿出磁层顶进入磁鞘,四颗卫星同时观测到了多个FTEs, 其出现具有准周期性,周期约为130 s. 利用Cluster四颗卫星的多点同时观测数据,采用最小方向微分法和时空微分方法,我们推断这些FTEs是尺度大小约为(0.87～1.81)RE的准二维结构,其运动方向为东北方向,与Cooling模型预测方向基本一致. CUTLASS芬兰雷达在相应的电离层区域观测到了明显的“极向运动雷达极光”结构,这些结构与Cluster卫星簇观测的FTEs有着很好的对应关系,它们是FTEs的雷达观测特征.     

前寒武纪迭层石的生物地层潜力

引言自化石记录中承认迭层石以来,迭层石在生物地层上的应用具有一定意义。早期的研究者,例如霍尔(Hall,1883)、沃尔科特(Walcott,1914)和芬顿兄弟(Fentons),使用双重命名法来记述迭层石,并出版了古生物资料。早期的研究,例如沃尔科特对于迭层石中保存藻类化石的研究,布莱克(Black,1933)对巴哈马斯(Bahamas)地区现代藻层(mats)的研究,都证明了藻类在造成有机沉积构造中所起的作用。布莱克强     

The Momentum Turbulent Counter-Gradient Transport in Jet-like Flows

Ⅰ. INTRODUCTIONIt is very well known from the observations that some atmospheric motions are accompanied by jets in the boundary layer, for example, breezes and circulations in the mountain valleys (Gutman, 1969); nocturnal increasing of wind (Byzova et al., 1989); cross-equatorial flow during the summer Indian monsoon (Das, 1986) and others. One of the important questions concerning a mathematical modelling of such motions is the problem of the turbulent closure of the equations set which describes the jet dynamics. It is still popular to use for the momentum turbulent flow (u＇w＇) a closure, based within the framework of K-theory on the Boussinesq hypothesis     

南极自动气象站

一、引言建立自动气象站(AWS)对在广阔的无人居住的南大洋区域扩大资料覆盖是一件引人向往的事情,在南极尤其如此。澳大利亚科学技术部南极处过去在冰原上曾使用过自动地球物理观测站(Bird和HumPhreys,2972),但是这些站用的是观测现场的磁带记录,而本文所讲的自动气象站则利用     

MaxLinerCLS系统帮助城市完成支管修复

本文简要介绍了一种新型的管线修复技术MaxLinerCLS系统,其主要应用于支管修复。     

俄罗斯远东岗仁地体金铜矿床地质、地球化学特征及其LA-ICP-MS锆石U-Pb年龄

岗仁地体位于额尔古纳超地体北部边缘,蒙古—鄂霍茨克构造带南部,该区分布着大量的大型、超大型金矿床,这些矿床在成因上与中酸性侵入岩和浅成次火山岩关系密切。岩石地球化学研究表明,花岗闪长岩-闪长岩组合明显富集大离子亲石元素、不相容元素和轻稀土元素,亏损高场强元素和重稀土元素。球粒陨石标准化稀土配分模式为轻稀土元素富集、重稀土元素亏损的右倾型,具有微弱的负Eu异常或基本无Eu异常,无Ce异常,元素地球化学性质反映出花岗闪长岩-闪长岩组岩浆具有壳幔混合的特征,且形成于大陆边缘的火山弧环境。LA-ICP-MS锆石U-Pb测年结果揭示,皮奥涅尔金银矿床含矿闪长玢岩的206Pb/238U年龄加权平均值为113.8±2.0Ma,博尔古利坎铜金钼矿床赋矿二长闪长斑岩的206Pb/238U年龄加权平均值为112.7±2.8Ma,与皮奥涅尔金银矿床和博尔古利坎铜金钼矿床成矿有关的奥列佳花岗闪长岩体的年龄分别为117.2±1.3Ma和117.0±3.6Ma。由此可知,皮奥涅尔金银矿床和博尔古利坎铜金钼矿床形成于燕山早期,与中国黑龙江地区三道湾子金矿、东安金矿等金矿床形成时代一致。