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1.
Privatization of rural industry and de facto urbanization from below in southern Jiangsu, China 总被引：4，自引：0，他引：4
At the heart of China’s economic transformation from plan to market is the institutional rearrangement of the ownership of property rights. Privatization of collectively owned township and village enterprises (TVEs) in recent years has significantly changed the rural economy and affected small town development in China. Located mainly in villages and small towns and producing 62% of the total industrial output in Jiangsu in 1994, TVEs played a crucial role in southern Jiangsu (Sunan)’s economic development and urbanization, giving rise to the well-known “Sunan model” of regional development during the 1980s. Since the mid-1990s, ownership transition (zhuanzhi) of the TVEs from collective to private in Sunan has altered the nature of the regional economy and the pattern of small town development. The privatization of TVEs in Sunan has been so pervasive that it can be seen as the “second industrial divide” in the region’s economy. This paper traces the evolution of ownership reform in Sunan’s rural industries leading to the current phase of privatization and analyzes the effects of privatization on de facto urbanization from below in Sunan. Given the importance of privatization, continuous scholarly monitoring of its relationship to regional economic development and urbanization from below is necessary. 相似文献
2.
A wealth of data on the state of the environment is being created in innumerable programmes world-wide. Optimal use of this data requires that information on its existence is available, that it can be readily accessed and — most important — that the data be compiled and classified in a compatible way. Achieving this is the basic aim of harmonization of environmental measurement. Although great care is generally taken to harmonize data collected within programmes, harmonization between programmes remains a major goal for the future.In 1989 UNEP established an office as a basis for the planned Harmonization of Environmental Measurement Project under the auspices of the Global Environmental Monitoring System (GEMS). The office describes the mission, rationale, and objectives of the project and the concepts underlying the harmonization of information on the environment collected at different levels and in different programmes. 相似文献
3.
Ayodele Owoade 《Journal of African Earth Sciences》1995,20(3-4)
Aquifer systems in tropical hard rock catchments generally comprise a sequence of three layers — an upper layer of weathered material (regolith), an intermediate zone of semi-weathered material and a basal zone of fresh, but often fractured, rocks. There is evidence that all three are hydraulically connected and for the purpose of this paper the three zones are referred to as ‘regolith-fractures aquifer’ (RFA). Field evidence is presented which shows that the bulk of the drawdown in boreholes in RFA systems is generally incurred during the early period of pumping — usually within 200 minutes of pump start-up. Well losses are an important part of this early drawdown and a judicious management of the pumping scheme during the early period could result in a reduction in the drawdown. One way of managing the pumping scheme is through phased pumping, whereby a desired total discharge (Q) is imposed in incremental steps (Q1, Q2, …, Q) during the early period of pumping (generally the first 200 to 300 minutes). This paper presents field data which shows reductions in drawdons arising from phased pumping during the early period. 相似文献
4.
The study deals with the theoretical approach to anthropoecological stabilization of landscape (ASL). It describes a method consisting of four stages including detailed differentiation from the viewpoint of aim, objectives of investigation, and means of evaluation and processing. Application of the method requires to provide: the preparatory, analytical ground — I. stage (analytical part), the structural — functional evaluation of the territory under solution — II. stage (analytical-synthetical part), the solution of ecooptimization relations and bonds by way of material and energy flows — III. stage (regulative part), the monitoring and signalling activities, determination of all-system biogeoindications — IV. stage (ensuring part).The results are exemplified by application to model territories in South Bohemia region. 相似文献
5.
The recent recognition that long period (i.e., of the order of hours) electromagnetic induction studies could play a major role in the detection of the asthenosphere has led to much interest amongst the geophysical and geological communities of the geomagnetic response functions derived for differing tectonic environments. Experiments carried out on the ocean bottom have met with considerable success in delineating the “electrical asthenosphere”, i.e., a local maximum in electrical conductivity (minimum in electrical resistivity) in the upper mantle.In this paper, observations of the time-varying magnetic field recorded in three regions of Scandinavia, northern Sweden (Kiruna—KIR), northern Finland/northeastern Norway (Kevo—KEV) and southern Finland (Sauvamaki—SAU), are analysed in order to obtain estimates of the inductive response function, C(ω), for each region. The estimated response functions are compared with one from the centre of the East European Platform (EEP), and it is shown that the induced eddy currents, at periods of the order of 103–104 s, in the three regions flow much closer to the surface than under the platform centre. Specifically, at a period of ~3000 s, these currents are flowing at depths of the order of: KEV—120 km; KIR—180 km; SAU—210 km; EEP—280 km; implying that the transition to a conducting zone, of σ -0.2 S/m, occurs at around these depths. One-dimensional inversion of
and
shows that there must exist a good conducting zone, of σ = 0.1–1.0 S/m, under each of the two regions, of 40 km minimum thickness, at depths of: KEV 105–115 km; KIR 160–185 km. This is to be contrasted with EEP, where the ρ-d profile displays a monotonically decreasing resistivity with depth, reaching σ~0.1 S/m at > 300 km.Finally, a possible temperature range for the asthenosphere, consistent with the deduced conducvitity, is discussed. It is shown that, at present, there is insufficient knowledge of the conditions (water content, melt fraction, etc.) likely to prevail in the asthenosphere to narrow down the probable range of 900°–1500°C. 相似文献
6.
Ravi P. Gupta 《Tectonophysics》1977,38(3-4)
Based on studies of images obtained from LANDSAT-1 and 2, several seemingly active movement zones have been delineated in a section of the eastern Alps and are being reported in the present paper for the first time. These zones, trending W—E to NW—SE, cut across all earlier Alpine boundaries and contacts and on either side along their length, are marked with drag effects, indicating their post-Alpine neotectonic nature. Their relation with the present-day central European stress field, as determined from fault-plane studies and in-situ stress measurements, has been sought. In conjunction with the evidence from neighbouring areas, a dextral shear tendency of the present-day Mediterranean is indicated. Further, a number of extensive lineaments have been observed in the Alpine section. Statistically, there are three major lineation sets trending N45°, N15°, N345°. They appear to have developed cogenetically as a result of shear and tensile failures due to a stress field with maximum principal stress oriented averagely at N15°. This direction of the maximum principal stress, deduced from the above lineation analysis of the eastern Alps, is in striking conformity with the one believed to have been in existence for the development of the Rhinegraben (N20°). It appears that the Rhinegraben and the Alpide belt have evolved cogenetically and concurrently under the same dominant stress field (P1 = N—NNE, P2 = vertical and P3 = E—ESE) and hence the two geotectonic features are really not antagonistic and mutually incompatible as usually believed on the grounds that one involves tension (taphrogenesis — Rhinegraben) and the other compression (orogenesis — Alpide belt) but are different manifestations of the same stress field. Besides, some additional light has been thrown on the possible controls of development of the Giudicaria Line and cause of predominance of NE—SW trending sinistral faults. 相似文献
7.
The petrochemistry of kimberlites from Yakutia and Lesotho has been studied using a silicate melt model with the SiO2, CO2 and H2O derivatives as the main anions.A model has been developed, according to which the dissolution of H2O in an ultramafic melt results in orthosilicates (H2SiC
4
-2
, H3SiO
4
–
, H4SiO4 etc.) rather than metasilicates, while the dissolution of CO2 produces additional hydrocarbonate complexes. It suggests that at high PCO
2
1
, and where the orthosilicic calcium salt clusters are likely to be present in the magma, the kimberlite melt can break down into carbonate and silicate liquids. Therefore, the composition of kimberlite magma will be determined by the H2O/CO2 ratio under the relatively constant fluid pressure. This can be seen from the distinct fluidrs trend in the H2O-CO2-SiO2 diagram for the Yakutia and Lesotho diamond-bearing kimberlites. The H2O/CO2 ratio changes with the liquidus temperature along this trend (Perchuk and Vaganov 1977) which suggests that liquid immiscibility predominates over the simple CO2 solubility in the melts of kimberlite composition. The well-known Boyd's diagrams for the equilibrium PT-conditions in peridotites have been applied along with new experimental data to natural Cpx and Opx, and the PT-parameters were correlated for peridotite inclusions in kimberlite pipes in Yakutia and Lesotho. The liquidus temperatures for the extrapolated area of these correlations gave depths (pressures) at which kimberlite magmas are formed (200–250 km).The hypothesis on SiO2 partitioning between the melt and the fluid was used to calculate the composition of dry initial kimberlite which characterised the average mantle composition: SiO2 — 45.12; TiO2 — 2.49; Al2O3 — 3.58; Cr2O3 — 0.12; FeO — 9.32; MnO — 0.16; CoO — 0.11; MgO — 23.47; CaO — 13.44; Na2O — 0.20; K2O — 1.12; P2O5 — 0.69; S — 0.18; sum — 100 wt.%. This kimberlite is close to wehrlite in composition. 相似文献
8.
Martin Okrusch 《Contributions to Mineralogy and Petrology》1971,32(1):1-23
Three garnet-biotite pairs and eleven garnet-cordierite-biotite triplets from the Steinach aureole (Oberpfalz, North-East Bavaria) were analyzed using an electron probe microanalyzer.The regional metamorphic muscovite-biotite schists contain garnets strongly zoned with Mn-Ca-rich centers and Fe-rich edges, the average composition being almandine 67 — spessartine 4 — pyrope 4 — grossular (+andradite) 25.The first contact garnet that is formed in mica schists of the outermost part of the aureole is small, virtually unzoned, and has an average composition of almandine 52 — spessartine 37 — pyrope 8 — grossular (+andradite) 3. With increasing metamorphic grade, there is a consistent trend to form garnets richer in Fe ending up with a composition almandine 84.5 — spessartine 5.5 — pyrope 7.5 — grossular (+andradite) 2.5. This trend is accompanied by a general increase in grain size and modal amount of garnet. Associated cordierites and biotites also become richer in Fe with increasing grade. While the garnets in the highest grade sillimanite hornfelses are poorly zoned, the transitional andalusite-sillimanite hornfelses contain garnets with distinct but variable zonation profiles.These facts can possibly be explained by the time-temperature relationships in the thermal aureole. In a phase diagram such as the Al-Fe-Mg-Mn tetrahedron, the limiting mineral compositions of a four-phase volume or a three-phase triangle are fixed by T and P (the latter remaining effectively constant within a thermal aureole). Thus, in garnet-cordierite-biotite assemblages, garnet zonation should be controlled by temperature variation rather than by a non-equilibrium depletion process. Taking into account the experimental data of Dahl (1968), a zoned garnet from a transitional andalusite-sillimanite hornfels would reflect a temperature increase of about 40° C during its growth. A hypothetical P-X diagram is proposed to show semi-quantitatively the compositional variation of garnet-cordierite pairs with varying pressures (T constant). 相似文献
9.
Woods left on good farmland in Ohio and neighboring states are likely to be beech-maple woods. There may well be a dozen or more tree species present, but the most obvious, because the most common, will be beeches and sugar maples … these trees exhibit the phenomenon of ecological dominance. There can be little doubt that the other plants of the wood are adapted to the presence of the abundant beeches and maples so that to describe them as dominants in this way is good use of language. The beeches and maples determine the micro climate, and even the soil, to which all the other living things must adapt - PAUL COLINVAUX.In the social reality, despite all change, the domination of man by man is still the historical continuum that links pre-technological and technological reason. However, the society which projects and undertakes the technological transformation of nature alters the base of domination by gradually replacing personal dependence … with dependence on the “objective order of things” (on economic laws, the market, etc…) … domination now generates a higher rationality — that of a society which sustains its hierarchic structure while exploiting ever more efficiently the natural and mental resources… - HERBERT MARCUSE 相似文献
10.
R.A. Facer 《Tectonophysics》1981,74(3-4)
A section 300 m thick across the Permian—Triassic boundary has been sampled in the Southern Coalfield of the Sydney Basin, New South Wales. 55 samples, mainly grey to drab sandstones, were collected from 9 diamond drill holes which penetrated the entire Narrabeen Group and the upper part of the conformably underlying Illawarra Coal Measures, as well as a sill emplaced into the coal measures. The samples included fully oriented cores. Additional reconnaissance samples from two further drill holes were also studied.Partial alternating field demagnetization and petrography indicate the magnetic remanence to be a stable DRM. Partial thermal demagnetization above 300°C or 400°C caused large increases in magnetic susceptibility. Partial chemical demagnetization did not cause significant changes in remanence directions.For the Coal Cliff Sandstone (basal Narrabeen Group, Triassic) the palaeomagnetic pole position (Normal) was calculated to be at 59°N 322°E (dp = 27°, dm = 29°), which agrees with previously published data. For the uppermost coal measures (Permian) the pole position was calculated as 58°N 340°E (dp = 09°, dm = 10°). Data for samples from the lower to middle coal measures yield a pole position which is between the new Permian—Triassic pole position and that for the underlying Middle Permian igneous rocks. The top of the Reversed “Kiaman Magnetic Interval” (Permian) may be near the Tongarra coal and Appin Formation boundary — (early) Late Permian. 相似文献
11.
D.J. Bell 《Geoforum》1994,25(4)
Part of the task of reconfiguring Political Geography must be to consider forms of political activism and participation other than those which have traditionally been the mainstay of the discipline. The rise of new democratic struggles and new social movements, including those around sexual politics, must be integrated into the agenda of a reformulated Political Geography. This paper considers some of the most pressing concerns of contemporary sexual politics—queer politics, sexual citizenship, and AIDS activism—as a way of opening up Political Geography to ‘sex’. 相似文献
12.
Alisdair Rogers 《Geoforum》1990,21(4)
The reasons for the recent revival of the debate about the inner cities and its implications for geographical thinking are analysed. Changing government policies towards inner cities since the initial declaration of intent by the Labour government in 1968 are described, and the more recent Conservative government emphasis upon privatization, enterprise, deregulation and flexibility is discussed. Academic interest currently focuses on the way in which the terms of the debate are set politically with the concept of the ‘inner city’ being defined and redefined according to the political priorities of policy-makers. Running parallel with this process is the ‘imagineering’ of place, whereby places are sold on the basis of deliberately created images. Discussion of the London Docklands highlights the mixed record of redevelopment compared with the images purveyed by government and other agencies. A ‘hidden agenda’ (of race or dismantling of local government power) is shown to underlie political rhetoric about inner cities. The inner city thus emerges as a key ideological battleground between contending political groupings. 相似文献
13.
Robert F. Shurtz 《Mathematical Geology》1994,26(5):639-649
Conclusion In closing, I think it not inappropriate to make clear—both toReply's authors and to the geostatistical community at large—that my purpose in pressing these issues is not mere whimsical or frivolous harassment.My purpose is to urge the mining industry, as I have done before (1984), to insist upon reserve estimation methods that are soundly based onall applicable mathematical principles undistorted by speculative interpretation, selection, or practice. My criticism of geostatistics is not so much of what its practitioners do — and of what I first did long ago (1959)—but of the undisciplined and misleading things its pundits say about what they do. 相似文献
14.
Hydrometallurgical processing and recovery of molybdenum trioxide from spent catalyst 总被引：5，自引：0，他引：5
Kyung Ho Park B. Ramachandra Reddy D. Mohapatra Chul-Woo Nam 《International Journal of Mineral Processing》2006,80(2-4):261-265
Hydrometallurgical processing of spent hydrodesulphurisation (HDS) catalyst for the recovery of molybdenum using sodium carbonate and hydrogen peroxide mixtures was investigated. The results indicated that the recovery of molybdenum was largely dependent on the concentrations of Na2CO3 and H2O2 in the reaction medium, which controls the acidity of the leach liquor and carry over of impurities such as Al, Ni, P, Si and V. Leaching process was exothermic and leaching efficiency of molybdenum decreased with increasing solid to liquid ratio. Large scale leaching of spent catalyst, under optimum conditions: 20% pulp density, 85 g/L Na2CO3, 10 vol.% H2O2 and 1 h reaction, resulted a leaching efficiency of 84% Mo. The obtained leach liquor contained (g/L): Mo — 22.0, Ni — 0.015 and Al — 0.82, P — 1.1, Si — 0.094 and minor quantities of V — 8 mg/L, As and Co — < 1 mg/L. Recovery of Mo from leach solution as MoO3 of 97.30% purity was achieved by ammonium molybdate precipitation method. 相似文献
15.
Jan Mangerud Stein Bondevik Steinar Gulliksen Anne Karin Hufthammer Tore Hister 《Quaternary Science Reviews》2006,25(23-24):3228
In order to compare radiocarbon dates on marine and terrestrial samples the former have to be corrected for a reservoir age. We present reservoir ages from dating 21 whales collected 1860–1901 and recalculating dates of 23 molluscs collected 1857–1926. Most of the whales were caught along the coast of Norway, but one is from France and one from Iceland. We assume the former mainly lived in the North and equatorial Atlantic and in the Norwegian Sea. Whales feed only on pelagic organisms and will provide the reservoir age for the open ocean surface water. However, they travel long distances and will integrate the reservoir ages of the different water masses along their way. Molluscs (dated from Norway, Spitsbergen and Arctic Canada) are stationary and monitor the sea water passing their dwelling site, but some also take up carbon from particulate food or sediment pore water. Coastal water also often contains some continental carbon. We present two different views on how to analyze and interpret the data. Mangerud recommends to use reservoir ages based on a combination of the whale and mollusc dates, i.e. 380±30 and 360±30 yr relative to Intcal04 and British oak, respectively, and a ΔR value of 20±30 for the surface water in the N-Atlantic and Norwegian Sea. Bondevik and Gulliksen maintain that the reservoir age—and ΔR—along the Norwegian coast is latitude dependant, with ΔR-values increasing from −3±22 in the South to 105±24 at Spitsbergen. Whales, reflecting North Atlantic open ocean surface water have lower ΔR (7±11) than most molluscs. 相似文献
16.
This report extends previous work ([Louda et al., 1998a] and [Louda et al., 1998b]. Chlorophyll degradation during senescence and death. Organic Geochemistry 29, 1233–1251.) in which we detailed type-I (alteration) and -II (destruction) degradation of chlorophyll with representative fresh water phytoplankton. The present study covers similar experiments with marine phytoplankton, namely, a cyanobacterium (“ANA” Anacystis sp), a coccolithophore (“COC” Coccolithophora sp.), a dinoflagellate (“GYM” Gymnodinium sp.) and two diatoms (“CYC” Cyclotella meneghiniana and “THAL” Thalassiosira sp.). Mg loss (‘pheophytinization') was rapid and continuous in all species under room-oxic conditions and slow or sporadic under anoxic conditions. The proportion of dephytylated pigments (pheophorbides-a, chlorophyllides-a), relative to the phytylated forms (chlorophyll-a, pheophytins-a), increased over the first year under room-oxic conditions and in room-anoxic conditions only in “CYC”. Pheophorbide-a was converted to pyropheophorbide-a within 15 months only in “THAL” and “ANA”, and slightly in “COC”. After 9–15 months of oxic incubation, “COC” was found to contain traces of purpurin-18 phytyl ester. Consideration of carotenoid pigments is also included herein. All fucoxanthin containing species, except “THAL”, exhibited conversion of fucoxanthin to fucoxanthinol in room-oxic conditions. Diadinoxanthin was rapidly de-epoxidized to give diatoxanthin within the first 2–4 weeks. Diatoxanthin then disappeared from all species by 15 months with a concurrent increase in a pigment which we tentatively identify as a cis-zeaxanthin. Incubations of pure cultures are found to be an effective way by which to model the early type-I reactions for both chlorophylls and carotenoids. The influence of oxygen during senescence-death and the onset of early diagenesis is of paramount importance. The absence of oxygen and, by inference, aerobic microbiota, retards the breakdown of these pigments dramatically. 相似文献
17.
Observations of H- and Z-variations made at ten temporary field stations along the Hyderabad—Bhadrachalam—Kalingapatnam (east coast) profile during February–March, 1973, are analyzed and discussed. The results are also compared with those of the Alibag (west coast)—Hyderabad profile, completed in May–July, 1970.It is found that the Z-ranges of quiet daily variations are enhanced one and a half times the Hyderabad value, and the H-ranges only very slightly reduced at the coastal station of Kalingapatnam. This coastal effect of 6γ in Zr at Kalingapatnam gradually decreases inland and probably exists upto Salur (70 km inland from the coast). At Bhadrachalam, both H- and Z-ranges of quiet daily variations are found to be enhanced, possibly due to induction effects from deep-seated conductors in the Godavari rift valley. The enhancement of both H and Z daily ranges at Jeypore in the eastern “ghats” (hills) is attributed to induced electric currents in conductors arising from the orogeny well below the “ghats”.It is difficult to separate the coastal effect from the orogenic effect, both of which seem to taper off and merge at Salur. 相似文献
18.
M. J. Bowden Prof. Dr. 《GeoJournal》1992,26(2):187-194
In the histories of colonial (pre-revolutionary) New England environment and landscape a three-stage process is recapitulated. An image of the past was formed which was factitious, but for reasons largely of self-glorification of the settlers the image was raised to the level of myth, memory of the actuality completely erased in one generation. Finally the myth became universally accepted by the populace — an invented tradition — the academy eventually giving it the stamp of (uncritical) approval and making it an established convention. Seven invented traditions/conventions are described: 1) The native American as Ignoble Savage living off the land but with no right to it, 2) the environment as a Desart Wildernesse, later transposed in the nineteenth century to an image of 3) the impenetrable primeval forest, 4) the culture shock of this primordial world stripping the settlers of English regional/cultural differences and making them instant Americans, or generalized (Puritan) New Englanders, 5) the colonial agricultural village as universal settlement pattern for colonists of this wilderness, 6) the fabled colonial green as characteristic of these villages, defensive base for conquest of the surrounding dark forest, and 7) the colonial New Englander as prosperous yeoman in a Jeffersonian garden. The reality and actuality that can be reconstructed belies the invention and convention on every count. In the cases of all seven invented traditions one can discern a period of image formation of variable length, a period of myth creation of about 25 years in which memory of the actual past was erased — usually periods of stress and self-doubt — and then a period when one invented a better and simpler past. 相似文献
19.
Aluminous parageneses containing gedrite, cordierite, garnet, staurolite, biotite, sillimanite, kyanite, quartz or spinel plus corundum are found as dark colored lenses in the polymetamorphic, multideformed Archean complex at Ajitpura in northwest peninsular India. Staurolite, like kyanite, is a relict phase of earlier metamorphism and is excluded as a paragenetic mineral in view of its incompatibility with quartz and gedrite and its lower X
Mg values than for garnet of the assemblage. Its stability here is attributed to zinc content of up to 3 wt%. The XMg in other ferromagnesian minerals decreases in the order: cordierite, biotite, gedrite, garnet, as found elsewhere in high grade rocks.The textural criteria and systematic partitioning of Fe and Mg in the ferromagnesian phases, excluding staurolite, indicate attainment of equilibrium during the second metamorphism. From tie line configurations in the phase diagrams, X
Mg ratios in the constituent minerals, and other petrographic criteria, it is suggested that gedrite — cordierite-garnet — sillimanite — biotite assemblage has been produced by the reactions: Biotite+Sillimanite+Quartz = Cordierite+Garnet+K-feldspar+Vapor (1) and Biotite+Sillimanite+Quartz = Cordierite +Gedrite+K-feldspar+Vapor (2) which occurred during partial melting of the rocks at fixed P and T conditions.By isothermal P-X(Fe-Mg) sections it has been demonstrated that release of FeO, SiO2 and other components modified the composition of the reactant biotite presumably by the substitution FeSi2 Al, whereby reaction 1 was replaced by reaction 2. Cordierite with higher X
Mg was produced with gedrite instead of with garnet, whose X
Mg is less than X
Mg of gedrite. Reaction 2 has been tentatively located in T-P space from the intersection of some continuous loops in the P-X(Fe-Mg) diagram at 700°C and also by other constraints. The discontinuous reaction 2 is located about 1–2 kilobars higher than reaction 1, which implies that it is difficult to distinguish between effects of pressure and those of melting on the X
Mg ratios of the reaction phases.The P-T calibrations of garnet — cordierite, garnet — biotite and garnet — plagioclase equilibria and the calibrations from other dehydration curves give temperatures near 700°C and pressure (assuming
) about 6 kilobars. 相似文献
20.
J. I. Gil Ibarguchi Francisco J. Martinez 《Contributions to Mineralogy and Petrology》1982,80(1):14-24
The core of the El Tormes thermal dome, situated in the central part of one of the main metamorphic belts of the Iberian Peninsula, is formed by garnet-cordierite-biotite-sillimanite pelitic gneisses. These rocks, that very often are cut by minor intrusions of Al-rich S-type granites, are metatexitic gneisses in which there exists garnet showing different stages of resorption and transformation into an aggregate of cordierite±plagioclase±biotite. The garnet, mantled and corroded mainly by cordierite, has never been found to occur in contact with the prismatic sillimanite of the matrix, thus indicating that the continuous reaction Gr+Sill+Q = Cd has taken place. The presence of corroded biotite inside the garnet-rimming cordierite of the aggregates as well as inside the cordierite of the matrix, which usually includes remmants of sillimanite, indicates that the continuous reaction Bi+Sill+Q = Cd+FK+H2O has occurred too. Therefore, a realistic net reaction for these aggretates should be represented by the univariant, at a given
, equilibrium: Biotite+Sillimanite+Garnet+Quartz = Cordierite+K-feldspar+H2O (1)The important garnet resorption near the anatectic granitic veins implies that this process is favoured by a decrease in
, this factor being otherwise buffered by the reaction (1) assemblage.The most probable P-T path, assuming these conditions, consistent with the AFM projection of the former (inferred) and present assemblages in the aggregates and in the matrix, implies a decrease in P coeval with a decrease in T (Fig. 4, path 2).The most reliable P-T determination for the final stage of garnet breakdown through reaction (1), based on the coexistence of the seven phase assemblage garnet — cordierite — biotite — sillimanite — plagioclase — potash feldspar — quartz plus melt, gives 695° C, 4.3 kbar,
= 0.5, The maximum pressure for this process, obtained from the garnet — plagioclase equilibrium, is 6.5±1 kbar at the same temperature.The estimates of the T for the garnet core-garnet included biotite pairs are consistently lower, ca. 550° C, than those obtained for the garnet rim-biotite in aggregates, ca. 645° C, or garnet rim-adjacent cordierite pairs, ca. 695° C.It may, therefore, be supposed that, during their evolution these rocks underwent first an increase in T and then, during the last stages, as garnet and biotite brokedown, a decrease in P and T. This represents an uplift of the core of El Tormes dome under high grade amphibolite to low pressure granulite facies conditions, accompanied by a process of partial melting with local decrase in
. It is suggested, from mineral growth-deformation relationships, that this process took place during the late hercynian deformation phases, P-3 or doming stage. 相似文献