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61.
Origin of peraluminous granites and granodiorites, Iberian massif, Spain: an experimental test of granite petrogenesis 总被引:27,自引:0,他引:27
Antonio Castro Alberto E. Patiño Douce L. Guillermo Corretgé Jesús D. de la Rosa Mohammed El-Biad Hassan El-Hmidi 《Contributions to Mineralogy and Petrology》1999,135(2-3):255-276
The discrimination between potential source materials involved in the genesis of Iberian granites and granodiorites, as well
as the role of mantle-crust interactions, are examined using constraints imposed by melting experiments, melting-assimilation
experiments and Sr-Nd isotope systematics. The Sr-Nd isotope relationships indicate the existence of different genetic trends
in which juvenile mantle materials are involved by different mechanisms: (1) a source trend, traced by a particular evolution
of the pre-Hercynian basement and indicating mantle participation at the time of sedimentation; (2) a set of magmatic trends
traced by gabbro-tonalite-enclave-granodiorite associations, implying the incorporation of new mantle material at the time
of granite generation. These relationships strongly support a pure crustal origin for the peraluminous leucogranites, derived
from partial melting of crustal protoliths, and a hybrid origin for the peraluminous granodiorites. These granodiorites are
the most abundant granitic rocks of the Central Iberian zone (CIZ) of the Iberian massif, implying that processes of hybridisation
by assimilation and/or magma mixing played an important role in granitoid production during the Hercynian orogeny. These hypotheses
have been tested by means of melting and assimilation experiments. Melting experiments in the range 800–900 °C and at pressures
of 3, 6, 10 and 15 kbar indicate that: (1) several potential source materials such as Bt-Ms gneisses and metagreywackes are
suitable for the production of peraluminous leucogranite melts; (2) the melt compositions are always leucogranitic, regardless
of pressure; (3) pressure exerts a strong influence on the fertility of the source: experiments at 3 kbar produce more than
20 vol% of melt, compared with less than 5 vol% of melt produced at 10 and 15 kbar and at the same temperature. The melting-assimilation
experiments carried out at 1000 °C and 4, 7 and 10 kbar and using a proportion of 50% gabbro and 50% gneiss give high melt
proportions (more than 50 vol.%) and noritic residues. These melts have the composition of leucogranodiorites, and overlap
with part of the compositional range of peraluminous granodiorites of the Iberian massif. The generation of more mafic granodiorites
may be explained by the incorporation of some residual orthopyroxene to the granodiorite magmas. The low solubility of Fe + Mg
prevents the generation of granodiorite melts with more than 3 wt% of MgO + FeO at all crustal pressures. The large volumes
of peraluminous, hybrid granodiorites, produced by assimilation of crustal rocks by mantle magmas, imply that an important
episode of crustal growth took place during the Late-Palaeozoic Hercynian orogeny in the Iberian massif.
Received: 30 June 1998 / Accepted: 27 November 1998 相似文献
62.
Mario?GómezEmail authorView authors OrcID profile M.?Concepción Ausín M.?Carmen Domínguez 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(5):1107-1121
Modelling glacier discharge is an important issue in hydrology and climate research. Glaciers represent a fundamental water resource when melting of ice and snow contributes to runoff. Glaciers are also studied as natural global warming sensors. GLACKMA association has implemented one of their Pilot Experimental Catchment areas at the King George Island in the Antarctica which records values of the liquid discharge from Collins glacier. In this paper, we propose the use of time-varying copula models for analyzing the relationship between air temperature and glacier discharge, which is clearly non constant and non linear through time. A seasonal copula model is defined where both the marginal and copula parameters vary periodically along time following a seasonal dynamic. Full Bayesian inference is performed such that the marginal and copula parameters are estimated in a one single step, in contrast with the usual two-step approach. Bayesian prediction and model selection is also carried out for the proposed model such that Bayesian credible intervals can be obtained for the conditional glacier discharge given a value of the temperature at any given time point. The proposed methodology is illustrated using the GLACKMA real data where there is, in addition, a hydrological year of missing discharge data which were not possible to measure accurately due to problems in the sounding. 相似文献
63.
Pérez-Bella José M. Domínguez-Hernández Javier Cano-Suñén Enrique del Coz-Díaz Juan J. Alonso-Martínez Mar 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(6):1783-1797
Stochastic Environmental Research and Risk Assessment - The joint action of wind-driven rain and wind pressure is the main cause of water penetration in building facades, which causes various... 相似文献
64.
Eugenio Nicotra Marco Viccaro Rosanna De Rosa Marco Sapienza 《Bulletin of Volcanology》2014,76(8):1-24
Critical to understanding explosive eruptions is establishing how accurately representative pyroclasts are of processes during magma vesiculation and fragmentation. Here, we present data on densities, and vesicle size and number characteristics, for representative pyroclasts from six silicic eruptions of contrasting size and style from Raoul volcano (Kermadec arc). We use these data to evaluate histories of bubble nucleation, coalescence, and growth in explosive eruptions and to provide comparisons with pumiceous dome carapace material. Density/vesicularity distributions show a scarcity of pyroclasts with ~65–75 % vesicularity; however, pyroclasts closest to this vesicularity range have the highest bubble number density (BND) values regardless of eruptive intensity or style. Clasts with vesicularities greater than this 65–75 % “pivotal” vesicularity range have decreasing BNDs with increasing vesicularities, interpreted to reflect continuing bubble growth and coalescence. Clasts with vesicularities less than the pivotal range have BNDs that decrease with decreasing vesicularity and preserve textures indicative of processes such as stalling and open system degassing prior to vesiculation in a microlite-rich magma, or vesiculation during slow ascent of degassing magma. Bubble size distributions (BSDs) and BNDs show variations consistent with 65–75 % representing the vesicularity at which vesiculating magma is most likely to undergo fragmentation, consistent with the closest packing of spheres. We consider that the observed vesicularity range may reflect the development of permeability in the magma through shearing as it flows through the conduit. These processes can act in concert with multiple nucleation events, generating a situation of heterogeneous bubble populations that permit some regions of the magma to expand and bubbles to coalesce with other regions in which permeable networks are formed. Fragmentation preserves the range in vesicularity seen as well as any post-fragmentation/pre-quenching expansion which may have occurred. We demonstrate that differing density pyroclasts from a single eruption interval can have widely varying BND values corresponding to the degree of bubble maturation that has occurred. The modal density clasts (the usual targets for vesicularity studies) have likely undergone some degree of bubble maturation and are therefore may not be representative of the magma at the onset of fragmentation. 相似文献
65.
Innovative Germicidal UV and Photocatalytic System Dedicated to Aircraft Cabin Eliminates Volatile Organic Compounds and Pathogenic Micro‐Organisms
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66.
The distribution of several trace elements in different aqueous fractions has been studied in running waters from Sardinia (Italy). Trace elements and major components were determined in water samples collected at high- and low-discharge from rivers (90 samples) and streams (70 samples). At selected sites, total (non filtered samples) and dissolved (0.4 μm and 0.015 μm pore-size filtered samples) amounts of trace elements were determined, and the composition of the solid matter retained on the filters was investigated for estimating the eventual interrelationship. The elements B, Li, Rb, Sr, Ba, As, Sb, Mo, Tl and U in the studied waters showed small differences between total and dissolved amounts; dissolved concentrations were higher under low flow conditions, when the contribution of rainwater to the rivers was minimum; their concentrations were often correlated with total dissolved solids (TDS), and appeared to be related to the intensity of water-rock interaction processes. The elements Al, Fe, Mn, Pb, Zn, Cd, Cu, Co, Ni, Cs, Y, REE and Th were not related to TDS and/or major ions; they showed higher concentrations under high flow conditions; marked differences occurred between total and dissolved amounts; much lower concentrations were generally observed in the water filtered through 0.015 μm than in the water filtered through 0.4 μm, especially when sampling was carried out after heavy rain events that enhanced the load of solid matter in the water. These observations indicate an aqueous transport via sorption processes on very fine particles, such as Fe-oxide/hydroxide and clay mineral particles, which have been inferred by SEM-EDX analyses of the matter retained on the filters. 相似文献
67.
Exploration of deep sedimentary layers in Tacna city,southern Peru,using microtremors and earthquake data for estimation of local amplification 总被引:1,自引:1,他引:0
68.
The Burren: a glacial,karstic and biokarstic expression of a limestone plateau in western Ireland
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John P. McIlroy de la Rosa 《地球表面变化过程与地形》2016,41(11):1614-1628
The term glaciokarst describes a landscape where both glacial and karstic processes have contributed to geomorphological evolution and has been applied to a range of environments from the high arctic to the alpine Mediterranean. Nevertheless, glaciokarstic environments globally often exhibit significant variation in geomorphological processes and landforms due to these geographical differences. The Burren, County Clare, Republic of Ireland, is often quoted as a quintessential glaciokarstic landscape. However, the Burren and other similar environments would appear to lean towards one end of the glaciokarst spectrum, where solutional and biological processes have been dominant throughout the Holocene, in contrast to ice‐dominated glaciokarsts where karstic and biokarstic processes are temperature‐limited and cryospheric processes remain the principal geomorphological agents. Holocene landscape evolution and the development of a range of meso‐, micro‐ and nano‐scale karren features on limestone surfaces appears to be largely biokarstic in origin. Karstification of many glacially scoured limestone pavements would have begun under acidic soil cover, with biological soil processes contributing to smooth, rounded cryptokarstic surface forms. Holocene soil erosion is attributed to anthropogenic activity, climatic fluctuations and the evolution of the karstic groundwater system leading to vertical soil loss through widening grikes. Exposed limestone pavements subject to subaerial conditions often exhibit extensive lichen colonization which has been shown to influence the overall rate of karstification and contribute to the development of micro‐ and meso‐scale bioweathering features. Where cryptokarstic features have been exhumed from beneath soil cover, their evolution under subaerial conditions leads to intermediate, polygenetic karren features. In light of our current understanding of the Burren landscape, it is proposed that the term glaciobiokarstic may be a better expression to encompass the biological processes that have played a fundamental role in the evolution of the Burren and similar landscapes, without neglecting the contribution of glacial and inorganic karstic processes. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
69.
R. Domínguez M. 《水文科学杂志》2013,58(3):460-478
Abstract The estimation and review of discharge flow rates in hydraulic works is a fundamental problem in water management. In the case of dams with large regulating capacity, in order to estimate return periods of discharge flow rates from the spillways, it becomes necessary to consider both peak flow and volume of the incoming floods. In this paper, the results of the validation for several methods of assessing design floods for spillways of dams with a large flood control capacity are presented; the validation is performed by comparing the maximum outflows (or the maximum levels reached in the reservoir) obtained from the routing of the design floods with those obtained from the routing of the historical annual maximum floods. The basin of Malpaso Dam, Mexico, is used as the case study. Editor D. Koutsoyiannis Citation Domínguez, M.R. and Arganis, J.M.L., 2012. Validation of methods to estimate design discharge flow rates for dam spillways with large regulating capacity. Hydrological Sciences Journal, 57 (3), 460–478. 相似文献
70.
Roberto E. Galindo Domínguez William L. Bandy Carlos A. Mortera Gutiérrez José Ortega Ramírez 《Geofísica Internacional》2013,52(3):261-275
In August 2009, a marine geophysical survey was conducted in Lake Tequesquitengo (located in the state of Morelos, Mexico) to delineate the extent of the remains of a small town that has been submerged since the mid 19th century. The survey consists of the acquisition and mapping of magnetic, single beam bathymetric and side-scan sonar data. A dual receiver marine GPS navigation system was used to position the boat during the survey. Except for the larger structural remains that are visible on the side scan sonar images, the magnetic anomaly map proved to be most useful in delineating the extent of the town. These anomalies exhibit short wavelength components in the area surrounding a submerged church, with the shortest wavelength components being confined to the area immediately east of the church. These short wavelength components are only observed near the church; therefore, we propose that they delineate the buried remnants of the submerged town. 相似文献