Tectono‐metamorphic history recorded in garnet porphyroblasts: insights from thermodynamic modelling and electron backscatter diffraction analysis of inclusion trails     

E. SKRZYPEK  K. SCHULMANN  P. ŠTÍPSKÁ  F. CHOPIN  J. LEHMANN  O. LEXA  J. HALODA 《Journal of Metamorphic Geology》2011,29(4):473-496

In a Barrovian metamorphic sequence, garnetiferous mica schists document a heterogeneously developed superposition of sub‐orthogonal fabrics and multiple garnet growth episodes. In the variably deformed domains, four types of garnet porphyroblasts have been defined based on inclusion trail patterns. Modelled garnet zoning in the MnNCKFMASHTO system indicates a prograde evolution from 4–4.5 kbar and 490–510 °C to 5–6 kbar and 520–550 °C in the earliest subhorizontal fabric progressing towards 6.5–7.5 kbar and 560–590 °C in the subsequent subvertical foliation. This fabric is heterogeneously deformed into a shallow‐dipping retrograde foliation associated with garnet resorption. In situ electron backscatter diffraction measurements of ilmenite inclusions in individual garnet grains yield precise data on included planar and linear elements. Consistent orientations of internal foliations, lineations and foliation intersection axis sets indicate a superposition of three sub‐orthogonal foliation systems. Weak variations of internal records with increasing intensity of deformation suggest that a moderate buckling stage occurred, but apparent lack of porphyroblast rotation is interpreted as a result of dominant passive flow. Coupling the orientation of internal fabric sets with P–T estimates is used to complement the tectono‐metamorphic evolution of the thickened crust. We demonstrate that garnet porphyroblasts preserve features which reflect large‐scale tectonic processes in orogens.  相似文献   

STUDY ON DYNAMICS OF TROPICAL CISK-ROSSBY WAVES AND MECHANISM OF 30-50 DAY OSCILLATIONS     

张韧  余志豪  蒋全荣 《热带气象学报(英文版)》2001,7(1):69-79

To add to the growing mature research on the tropical 30-50 day oscillations from a new prospective, the current work bases on dynamic analysis of baroclinic quasi-geostrophic models to discuss dynamic mechanisms for the generation and propagation of CISK-Rossby waves, and to understand restraints and effects of different wave structures and thermodynamic forcing on the 30-50 day oscillations in the tropical atmosphere. Some important properties of the oscillation propagation have been explained and, in detail, with respect to its meridional propagation and vertical “baroclinic” structure. The work has come up with some new opinions and viewpoints. New opinions about the propagation and energy dispersion are to be proved by more observations and study.  相似文献   

NUMERICAL STUDY ON THE DYNAMIC AND THERMODYNAMIC EFFECTS OF THE QINGHAI-XIZANG PLATEAU ON THE SEASONAL TRANSITION IN THE EARLY SUMMER IN EAST ASIA   总被引：6，自引：0，他引：6       下载免费PDF全文

Zheng Qinglin  Wu Jun 《Acta Meteorologica Sinica》1995,9(1):35-47

By employing a five-layer seasonal numerical weather prediction model and utilizing the National MeteorologicalCenter (NMC) objective analysis data on May 10,1991 as the initial field,three numerical experiments——diabatic withorography,adiabatic with orography and adiabatic without orography——have been carried out to investigate the dy-namic and thermodynamic effects of the Qinghai-Xizang Plateau (hereafter the Plateau) on the seasonal transition inthe early summer in East Asia.The results show that the typical seasonal transition features such as the northward shiftof the subtropical westerly jet stream,the adjustment of the long-wave in middle and high latitudes and the changes ofthe circulation in the lower troposphere can be well simulated,if the dynamic and thermodynamic effects of the Plateauare both considered in the model as in the experiment adiabatic with orography.In other two experiments,it is failed tosimulate out the seasonal transition features.The results also show that the thermodynamic effect of the Plateau acts on the atmosphere as a gradually enhancedheating source in the early summer,which makes the air temperature in 500 hPa over the Plateau increase by nearly 10℃in a month and accelerates the northward shift of the subtropical westerly jet stream about seven latitudes more north-ward in twenty days and helps the shifted jet maintain at the northern periphery of the Plateau.It is also helpful to theformation and maintenance of the Lake Balchas trough and the northward and westward extension of the Pacificsubtropical high.On the other hand,the dynamic effect of the Plateau weakens the northward shift of the subtropicalwesterly jet stream and barricades the westward extension of the Pacific subtropical high.If only the dynamic effect ofthe Plateau is considered in the model without consideration of the thermodynamic effect of the Plateau,not only theshifted jet withdraws southward but also the simulated Lake Balchas trough is 10 longitudes more eastward than that inthe diabatic experiment,and the simulated Pacific subtropical high is more eastward and northward.However,the dy-namic effect of the Plateau strengthens the vertical movements in the west and east of the Plateau and makes thelow-level jet maintain in the southeast of the Plateau.The path of the cold air and the tunnel of the water vapor in thelower troposphere during the seasonal transition period in the early summer in East Asia are determined by the couplingof the dynamic and thermodynamic effects of the Plateau.  相似文献   

Li_xNiO中锂离子扩散行为研究     

彭正顺  高海春 《盐湖研究》1993,(1)

本文利用单阶跃电流法测得了Li_xNiO(0相似文献   

1991年江淮暴雨期间环流异常的动力延伸预报试验   总被引：10，自引：1，他引：10  

章基嘉  李维京  徐祥德  苗俊峰 《气象学报》1994,52(2):180-186

介绍了利用Ｔ４２Ｌ９模式对１９９１年夏季江淮流域暴雨期间旬和月平均环流异常的动力延伸预报（ＤＥＲＦ）试验和利用ＯＳＵ－ＡＧＣＭ进行青藏高原热力异常敏感性试验的结果，指出Ｔ４２Ｌ９模式对造成暴雨的环流异常有一定的预报能力，并证实高原的热力异常是引起江淮暴雨的一个重要因子。  相似文献   

矿物热力学数据的获取     

殷辉安 《地球科学进展》1993,8(2):33-39

简介矿物热力学数据获取方法发展现状,重点评述量热法和相平衡法的近期发展状况。  相似文献   

A new method to calculate end-member thermodynamic properties of minerals from their constituent polyhedra II: heat capacity, compressibility and thermal expansion   总被引：1，自引：0，他引：1  

V. J. VAN  HINSBERG  S. P. VRIEND  J. C. SCHUMACHER 《Journal of Metamorphic Geology》2005,23(8):681-693

Thermodynamic calculations in petrology are generally performed at pressures and temperatures beyond the standard state conditions. Accurate prediction of mineral equilibria therefore requires knowledge of the heat capacity, thermal expansion and compressibility for the minerals involved. Unfortunately, such data are not always available. In this contribution we present a data set to estimate the heat capacity, thermal expansion and compressibility of mineral end‐members from their constituent polyhedra, based on the premise that the thermodynamic properties of minerals can be described by a linear combination of the fractional properties of their constituents. As such, only the crystallography of the phase of interest needs to be known. This approach is especially powerful for hypothetical mineral end‐members and for minerals, for which the experimental determination of their thermodynamic properties is difficult. The data set consists of the properties for 35 polyhedra in the system K–Na–Ca–Li–Be–Mg–Mn–Fe–Co–Ni–Zn–Al–Ti–Si–H, determined by multiple linear regression analysis on a data set of 111 published end‐member thermodynamic properties. The large number of polyhedra determined allows calculation of a much larger variety of phases than was previously possible, and the choice of constituents together with the large number of thermodynamic input data results in estimates with associated uncertainty of generally <5%. The quality of the data appears to be sufficiently accurate for thermodynamic modelling as demonstrated by modelling the stability of margarite in the CASH system and the position of the talc–staurolite–chloritoid–pyrope absent invariant point in the KMASH system. In both cases, our results overlap within error with published equivalents.  相似文献   

Admium and lead sorption and desorption characteristics of four soils from the Yangtze Delta, East China     

《中国地球化学学报》2006,25(B08):79-79

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An internally consistent thermodynamic data set for phases of petrological interest   总被引：102，自引：8，他引：94  

T. J. B. HOLL  & R. POWELL 《Journal of Metamorphic Geology》1998,16(3):309-343

The thermodynamic properties of 154 mineral end-members, 13 silicate liquid end-members and 22 aqueous fluid species are presented in a revised and updated data set. The use of a temperature-dependent thermal expansion and bulk modulus, and the use of high-pressure equations of state for solids and fluids, allows calculation of mineral–fluid equilibria to 100  kbar pressure or higher. A pressure-dependent Landau model for order–disorder permits extension of disordering transitions to high pressures, and, in particular, allows the alpha–beta quartz transition to be handled more satisfactorily. Several melt end-members have been included to enable calculation of simple phase equilibria and as a first stage in developing melt mixing models in NCKFMASH. The simple aqueous species density model has been extended to enable speciation calculations and mineral solubility determination involving minerals and aqueous species at high temperatures and pressures. The data set has also been improved by incorporation of many new phase equilibrium constraints, calorimetric studies and new measurements of molar volume, thermal expansion and compressibility. This has led to a significant improvement in the level of agreement with the available experimental phase equilibria, and to greater flexibility in calculation of complex mineral equilibria. It is also shown that there is very good agreement between the data set and the most recent available calorimetric data.  相似文献   

ISORROPIA: A New Thermodynamic Equilibrium Model for Multiphase Multicomponent Inorganic Aerosols   总被引：16，自引：0，他引：16  

Athanasios Nenes  Spyros N. Pandis  Christodoulos Pilinis 《Aquatic Geochemistry》1998,4(1):123-152

A computationally efficient and rigorous thermodynamic model that predicts the physical state and composition of inorganic atmospheric aerosol is presented. One of the main features of the model is the implementation of mutual deliquescence of multicomponent salt particles, which lowers the deliquescence point of the aerosol phase.The model is used to examine the behavior of four types of tropospheric aerosol (marine, urban, remote continental and non-urban continental), and the results are compared with the predictions of two other models currently in use. The results of all three models were generally in good agreement. Differences were found primarily in the mutual deliquescence humidity regions, where the new model predicted the existence of water, and the other two did not. Differences in the behavior (speciation and water absorbing properties) between the aerosol types are pointed out. The new model also needed considerably less CPU time, and always shows stability and robust convergence.  相似文献