俯冲板片中微量元素的活动性:西天山榴辉岩相运输脉的制约   总被引：4，自引：1，他引：3  

熊贤明  Timm JOHN  高俊  Reiner KLEMD  黄德志 《地质学报》2006,80(1):53-60

西天山的基性高压变质岩显示互相连接的榴辉岩相脉体网络来源于蓝片岩的进变质脱水作用,通过这些网脉可以洞察在俯冲带高压条件下远程流体流动中的流体-岩石相互作用和元素负载。岩相学证据表明外来流体的渗透作用产生运输脉,而流体持续的沟道式流动导致主岩蓝片岩的淋滤。脉和蓝片岩蚀变带中锂(Li)的含量几乎是蓝片岩主岩中锂的两倍,它支持流体是外部来源的设想。这些流体触发了蓝片岩主岩的榴辉岩化作用而形成蓝片岩蚀变带。由于成脉流体中的微量元素含量低,所以导致与流体发生化学反应的主岩中所有微量元素的强烈淋滤。在此过程中有53%~81%的微量元素被活化,与大离子亲石元素和轻稀土元素的损失相符合,它们的损失量几乎是重稀土元素和高场强元素损失量的两倍。  相似文献   

Reconstructing past eutrophication trends from diatoms and biogenic silica in the sediment and the pelagic zone of Lake Constance, Germany     

Martin Wessels  Kirsten Mohaupt  Reiner Kümmerlin  Angela Lenhard 《Journal of Paleolimnology》1999,21(2):171-192

In Lake Constance, phosphorus concentrations and the seasonal development of phytoplankton communities in water samples from the pelagic zone were regularly recorded since the 1950's. Before the 1950's, there were occasional investigations of plankton communities since 1896. We compared these data with the sedimentary record in two sediment cores. Then, the eutrophication history of Lake Constance was inferred from diatoms. The record of biogenic silica in the cores is discussed with respect to diatom biomass increase.Diatom assemblages in the sediment cores precisely reflected the pelagic diatom development for the period 1971--1992. Both sediment cores and the water samples have a high interannual variability of diatom assemblages. Below a sediment depth of 27 cm (AD 1920), more than 50% of the diatoms were partly corroded, and we limited the reconstruction of trophic state changes to the interval of 1920--1993. Oligotrophic conditions of Lake Constance were indicated by the dominance of various Cyclotella taxa from 1920 to 1940. Since 1939/1940, increasing abundance of it Tabellaria fenestrata showed oligotrophic to mesotrophic conditions. Between 1953 and 1956, increasing Stephanodiscus hantzschii and disappearing Cyclotella indicated advanced eutrophication and total phosphorus values ranged between 8--10 mg m-3 during turnover in late winter. Further eutrophication was shown by disappearing T. fenestrata and increasing S. minutulus in 1963. Maximum TP concentrations of 87 mg m-3 occurred in 1979/80 and was accompanied by increasing abundances of Aulacoseira granulata. From 1986 to 1992, reoccurrence of Tabellaria fenestrata and Cyclotella indicate some recovery of Lake Constance.Biogenic silica and diatom abundances were similar among cores but indicate a 3--4 fold increase of diatom biomass only. This was far below the estimate of biomass increase from sedimentary pigment data (25 fold) and the estimate of phytoplankton data from the literature (70 fold).  相似文献   

Export Production in the Equatorial and North Pacific Derived from Dissolved Oxygen, Nutrient and Carbon Data     

Reiner Schlitzer 《Journal of Oceanography》2004,60(1):53-62

A global ocean inverse model that includes the 3D ocean circulation as well as the production, sinking and remineralization of biogenic particulate matter is used to estimate the carbon export flux in the Pacific, north of 10°S. The model exploits the existing large datasets for hydrographic parameters, dissolved oxygen, nutrients and carbon, and determines optimal export production rates by fitting the model to the observed water column distributions by means of the “adjoint method”. In the model, the observations can be explained satisfactorily with an integrated carbon export production of about 3 Gt C yr⁻¹ (equivalent to 3⋅10¹⁵ gC yr⁻¹) for the considered zone of the Pacific Ocean. This amounts to about a third of the global ocean carbon export of 9.6 Gt C yr⁻¹ in the model. The highest export fluxes occur in the coastal upwelling region off northwestern America and in the tropical eastern Pacific. Due to the large surface area, the open-ocean, oligotrophic region in the central North Pacific also contributes significantly to the total North Pacific export flux (0.45 Gt C yr⁻¹), despite the rather small average flux densities in this region (13 gC m⁻²yr⁻¹). Model e-ratios (calculated here as ratios of model export production to primary production, as inferred from satellite observations) range from as high a value as 0.4 in the tropical Pacific to 0.17 in the oligotrophic central north Pacific. Model e-ratios in the northeastern Pacific upwelling regions amount to about 0.3 and are lower than previous estimates. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

那拉提山北缘寒武纪玄武岩的元素地球化学特征及构造意义   总被引：3，自引：2，他引：3  

钱青徐守礼  何国琦Reiner KLEMD熊贤明  龙灵利高俊 《岩石学报》2007,23(7):1708-1720

我国西南天山地区那拉提北缘断裂北侧出露寒武纪（516.3±7.4Ma）橄榄拉斑玄武岩，其Al2O3（120.71％-14.14％）、P2O5（0.09％-0．21％）含量较低，TiO2（1.39％-2．35％）、MgO（5.35％-8.14％）含量中等，全Fe2O3（11.74％-16．03％）含量较高，球粒陨石标准化稀土分布型式平坦，（La／Sm）.和（Y／Nb）.比值接近1，为过渡型洋脊玄武岩（T-MORB）；并且Th／Ta比值（0．8—1.5）低，高场强元素（Nb，Ta，Zr，Hf，P）没有明显亏损，缺乏陆壳混染或俯冲带流体活动的印迹.部分T-MORB的Fe、Ti含量较高（FeO^T〉12％，TiO2〉2％，FeO^T／MgO〉1．75），Mg^#值（0．40—0.49）和Cr（53×10^-6-110×10^-6）含量较低，属于Fe-Ti玄武岩（ferrobasalt），应为岩浆依Fenner趋势发生较高程度结晶分离演化的产物，很可能形成于洋中脊的扩展型裂谷环境.我们认为，那拉提北缘寒武纪T-MORB和Fe-n玄武岩可能与境外吉尔吉斯斯坦境内北天山南缘的旱古生代Terskey蛇绿岩带相连，为Terskey蛇绿岩的残片；寒武纪我国境内发育Terskey洋.那拉提北缘断裂可能与尼古拉耶夫线相连，代表西南天山地区Terskey洋闭合形成的一条早古生代缝合带.  相似文献   

A model comparison in least squares collocation     

Reiner Rummel 《Journal of Geodesy》1976,50(2):181-192

The well known least squares collocation model (I) $$\ell = Ax + \left[ {\begin{array}{*{20}c} O \\ I \\ \end{array} } \right]^T \left[ {\begin{array}{*{20}c} s \\ {s' + n} \\ \end{array} } \right]$$ is compared with the model (II) $$\ell = Ax + \left[ {\begin{array}{*{20}c} R \\ I \\ \end{array} } \right]^T \left[ {\begin{array}{*{20}c} s \\ n \\ \end{array} } \right]$$ The basic differences of these two models in the framework of physical geodesy are pointed out by analyzing the validity of the equation $$s' = Rs$$ that transforms one model into the other, for different cases. For clarification purposes least squares filtering, prediction and collocation are discussed separately. In filtering problems the coefficient matrix R becomes the unit matrix and by this the two models become identical. For prediction and collocation problems the relation s′=Rs is only fulfilled in the global limit where s becomes either a continuous function on the earth or an intinite set of spherical harmonic coefficients. Applying Model (II), we see that for any finite dimension of s the operator equations of physical geodesy are approximated by a finite matrix relation whereas in Model (I) the operator equations are applied in their correct form on a continuous, approximate function \(\tilde s\) .  相似文献   

Proceedings of the 2^nd Hotine Marussi Symposium on Mathematical Geodesy
edited by F. Sacerdote—F. Sansò     

Athanasios Dermanis  Reiner Rummel 《Journal of Geodesy》1990,64(3):XI

InformationsPublication Available

Proceedings of the 2^nd Hotine Marussi Symposium on Mathematical Geodesy edited by F. Sacerdote—F. Sansò  相似文献   

Investigating the transport dynamics and the properties of bedload material with a hydro‐acoustic measuring system     

Andreas Krein  Holger Klinck  Michael Eiden  Wolfhard Symader  Reinhard Bierl  Lucien Hoffmann  Laurent Pfister 《地球表面变化过程与地形》2008,33(1):152-163

This article deals with the following two questions. Are acoustic measurements in running waters appropriate for a highly resolved investigation of the bedload transport? Which characterizations of the bedload regarding mass and shape are possible via the acoustic signals? The signals were recorded by means of data recorders (Tascam Inc. DAP1 Portable Data Recorder) and hydrophones (International Transducer Corp. ITC‐4001 A). The ITC‐4001 is a shallow water omnidirectional transducer containing a flexural disc transducer utilizing Channelite‐5400 ceramics mounted in a rugged corrosion‐resistant housing. These hydrophones were screwed onto the bottom side of stainless steel plates, serving as a contact surface for the bedload in motion above them. After more than 100 series of tests in the laboratory, which indicated the basic relations between the dimension, shape and weight of the bedload and the resulting signal, field tests of the measuring system were conducted. By artificially produced flood waves in the small brooks Riverisbach, Olewiger Bach and by a winter flood wave in the River Moselle, it is possible to elaborate similar structures of the signal course of the bedload movement. The highest transport rates can be observed at the beginning of the increasing limbs and behind the peaks of the waves. At the beginning of the waves, the increasing transport power of the water and the loose material can be considered as the cause for this result. The high stream velocity behind the wave peaks explains the increase in the bedload transport so that material from the channel beds is unfastened and will be mobilized. The characterization of the bedload regarding the shape and mass is still limited regarding the field measurements and could be solved only for homogeneous grain sizes and single stones under laboratory conditions. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Determination of the freshwater budget of tidal flats from measurements near a tidal inlet     

Reiner Onken  Rolf Riethmüller 《Continental Shelf Research》2010

The freshwater budget of a tidal flat area is evaluated from long-term hydrographic time series from an observation pole positioned in a tidal channel in the Hörnum Basin (Germany). For each tidal cycle, the freshwater budget is calculated from the total imported and exported water volumes and the corresponding mean densities. The variability of the budget on a tidal scale is characterised by a period of twice the tidal period, exhibiting a minimum when the tidal flats are dry around daylight hours during the foregoing low tide, and a maximum when low tide occurs at night; enhanced evaporation on the flats at daylight hours is identified as the driving process. On the average over one year, while winter observations are missing, the freshwater budget is negative for the years 2002–2005 and positive only for 2006. The interannual mean is negative and amounts to a freshwater loss of about 2 mm day⁻¹, although the large-scale climate in this region is humid. The results demonstrate that the bulk parametrisations for the latent and sensible heat flux between the ocean and the atmosphere must not be applied for the tidelands.  相似文献   

Solar particle events with helium-over-hydrogen enhancement in the energy range up to 100 MeV nucl−1     

J. Torsti  L. Kocharov  J. Laivola  S. Pohjolainen  S.P. Plunkett  B.J. Thompson  M.L. Kaiser  M.J. Reiner 《Solar physics》2002,205(1):123-147

Flux measurements of solar energetic particles (SEPs) in the ERNE instrument onboard SOHO indicate that the abundance of ⁴He-nuclei compared to protons in the energy range up to 100 MeV nucl^–1 was exceptionally high during the particle events on 27 May 1998 and 28 December 1999. The ⁴He/p ratio stayed between 0.15–0.50 for more than ten hours. There was also a prolonged enhancement in helium-3, ³He/⁴H 1%. Observations of EIT and LASCO on board SOHO confirm that the originators of both SEP events were western eruptions, flares and coronal mass ejections (CMEs). The onset of the SEP release took place close to the maximum of flares which were probably triggered by the rising CMEs. The observations suggest that the SEP events were started with the flare-(pre)accelerated particles, but impact of the CME-associated shocks might explain the continuation and modification of the helium and proton fluxes well after the flare production. These observations support the idea that the helium enhancements in the CME-associated events reflect the availability of seed particles that originate previously in flares.  相似文献   

Strain localization and large-scale block rotation in the lower continental crust, Kataragama area, Sri Lanka     

Reiner Kleinschrodt 《地学学报》1996,8(3):236-244

In Sri Lanka a suite of rocks is regionally exposed which once formed a part of the middle to lower crust of a collisional orogen with about doubled crustal thickness. A subhorizontal to gently west-dipping major thrust zone (Highland Basal Thrust) crosses Sri Lanka from NNE to SSW. It separates a granulite facies upper unit, the Highland Complex from an amphibolite facies lower unit, the Vijayan Complex with a displacement of more than 300 km. The basal Highland Complex was migmatized during thrusting. Rheological contrasts between dry granulites and migmatites were high in the presence of partial melts. Granulite facies fragments within the migmatites vary from the decimetre to kilometre scale. Granulites in the area of Kataragama, formerly interpreted as the Kataragama Klippe, are now identified as a large-scale raft within the migmatites, which is completely separated from the overriding Highland Complex. During thrusting strain was concentrated in the migmatized basal parts of the Highland Complex. After crystallization of the migmatites thrusting continued, and strain was still localized within the migmatites. Therefore, granulite facies parageneses, structures and textures are preserved in the granulite rafts. The deviation of the granulite facies structures in the Kataragama raft from the general trend in the Highland Complex is interpreted to indicate counterclockwise rotation of the whole raft by about 90° around a subvertical rotation axis.  相似文献