Review: Groundwater development and management in the Deccan Traps (basalts) of western India     

Shrikant Daji Limaye 《Hydrogeology Journal》2010,18(3):543-558

The Deccan Traps or the basalts of western India are the largest exposure of basic lava flows covering about 500,000 km². Groundwater occurrence in the Deccan Traps is in phreatic condition in the weathered zone above the hard rock and in semi-confined condition in the fissures, fractures, joints, cooling cracks, lava flow junctions and in the inter-trappean beds between successive lava flows, within the hard rock. Dug wells, dug-cum-bored wells and boreholes or bore wells are commonly used for obtaining groundwater. The yield is small, usually in the range of 1–100 m³/day. The average land holding per farming family is only around 2 ha. Recently, due to the ever increasing number of dug wells and deep bore wells, the water table has been falling in several watersheds, especially in those lying in the semi-arid region of the traps, so that now the emphasis has shifted from development to sustainable management. Issues like climatic change, poverty mitigation in villages, sustainable development, rapid urbanization of the population, and resource pollution have invited the attention of politicians, policy makers, government agencies and non-governmental organizations towards watershed management, forestation, soil and water conservation, recharge augmentation and, above all, the voluntary control of groundwater abstraction in the Deccan Traps terrain.  相似文献   

A low δLi lower crustal component: Evidence from an alkalic intraplate volcanic series (Chaîne des Puys, French Massif Central)     

Cdric Hamelin  Hans-Michael Seitz  Jean-Alix Barrat  Laure Dosso  Ren C. Maury  Marc Chaussidon 《Chemical Geology》2009,266(3-4):205-217

The intraplate volcanic suite of the Chaîne des Puys (French Massif Central) shows a complete petrologic range, from alkali basalts to trachytes. The significant variations of trace elements and radiogenic isotopes along the series strongly support the occurrence of crustal assimilation associated with fractional crystallization (AFC). The least contaminated basalts are clearly related to a HIMU-type reservoir (²⁰⁶Pb/²⁰⁴Pb > 19.6; ⁸⁷Sr/⁸⁶Sr < 0.7037; ε_Nd > + 4). The behavior of radiogenic isotopes suggests that the most likely crustal contaminants are meta-sediments located in the lower crust.The Li isotopic compositions of the lavas range from high δ⁷Li (> + 7‰) in basalts to lighter values in more evolved lavas (down to δ⁷Li ≈ 0‰). The mantle component, expressed in the least evolved lavas, has a heavy Li isotopic signature, in good agreement with previous δ⁷Li measurements of OIB lavas with HIMU affinities. The evolution of Li isotopic compositions throughout the volcanic series is in agreement with the AFC model suggested by the Sr–Nd–Pb isotopic systems. Although the behavior of Li isotopes during assimilation processes is currently poorly constrained, our calculations suggest that at least a portion of the lower crust beneath the Chaîne des Puys is characterized by a light Li isotopic composition (δ⁷Li < − 5‰).  相似文献   

Samuel Mandel: International Teacher of Hydrogeology     

Shrikant D. Limaye 《Hydrogeology Journal》1997,5(3):124-124

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Atypical hotspot chains: evidence for a secondary melting zone below the Marquesas (French Polynesia)     

Christelle Legendre  Ren C. Maury  Sylvain Blais  Herv Guillou  Joseph Cotten 《地学学报》2006,18(3):210-216

The atypical age/distance to the hotspot relationships observed for the Marquesas linear chain, which present a considerable scatter, are best explained considering (1) a Pacific plate motion of 10.5 cm yr^?1 in the N115°E direction and (2) rejuvenation of volcanism in Ua Huka island. New K–Ar ages show that the main hotspot activity in Ua Huka emplaced successively shield olivine tholeiites and post‐shield alkali basalts between 3.11 ± 0.04 and 2.43 ± 0.04 Ma. Then, after a quiescence period of 1.28 ± 0.06 Myr, two small basanitic volcanoes were emplaced between 1.15 ± 0.02 and 0.763 ± 0.013 Ma. With respect to the main hotspot volcanics, their lavas originated from weaker partial melting rates of a deeper source. Field, petrologic and geochemical arguments are consistent with the existence of a secondary melting zone located c. 140 km downstream the Marquesas hotspot, which produced the rejuvenated volcanics.  相似文献   

Partial melting below Tubuai (Austral Islands, French Polynesia)     

Martial Caroff  René C. Maury  Gérard Guille  Joseph Cotten 《Contributions to Mineralogy and Petrology》1997,127(4):369-382

Process identification diagrams based on trace element data show that mafic lavas from Tubuai, including alkali basalts, basanites, analcitites and nephelinites, result from different degrees of partial melting of an isotopically homogeneous mantle source. Our fractionation-corrected data are consistent with a batch melting model or a dynamic melting model involving a threshold value for melt separation close to 1% and degrees of melting ranging from 5–8% (alkali basalts) to 1.5–3% (nephelinites). The relative source concentration pattern, calculated using an inverse numerical method, shows an enrichment in highly incompatible elements. We propose that the Tubuai lava suite was derived from a two-stage partial melting process. Melting first affected the plume material located within the transition zone between garnet and spinel domains, producing alkali basalts and basanites. Then, the melting zone migrated upwards to the base of the overlying spinel-bearing lithospheric mantle, producing highly silica-undersaturated lavas. The lower lithosphere had previously been enriched by intrusion of pyroxenite veins representing plume-derived melts which percolated away from the main magma conduits. Received: 11 June 1996 / Accepted: 8 January 1997  相似文献   

Représentation graphique de la cristallisation fractionnée des séries volcaniques. Application aux séries alcalines     

J. Leterrier Nancy  R. C. Maury 《International Journal of Earth Sciences》1978,67(3):943-952

Résumé Les modalités de la cristallisation fractionnée des séries volcaniques peuvent Être suivies en reportant sur le diagramme rectangulaire R₁=6 Ca+2 Mg+Al; R₂=4 Si–11 (Na+K)–2 (Fe+Ti), (en nombres de millications dans l'analyse) les compositions des liquides successifs (laves aphyriques) et des phases qui fractionnent (phénocristaux, cumulats). A titre d'exemple d'application sont comparées deux séries alcalines de la Polynésie. La série basalte alcalin-phonolite de l'Île de Rapa (Australes) résulte de la séparation de minéraux du plan critique (olivine-plagioclase-clinopyroxène) du tétraèdre basaltique, alors que dans l'Île de Nuku-Hiva (Marquises) la différenciation conduit à des trachytes quartzifères en raison du fractionnement de phases hydroxylées sous-saturées en silice (amphibole et mica).

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The fractional crystallization sequence of volcanic series can be studied with the rectangular diagram R₁=6 Ca+2 Mg+Al; R₂=4 Si–11 (Na+K)–2 (Fe+Ti), (numbers of millications in the analysis) on which are reported the compositions of successive liquids (aphyric lavas) and fractionating minerals (phenocrysts, cumulates). The usefulness of this diagram is illustrated in the comparison of two alkali basalt series from Polynesia. The alkali basalt-phonolite association of Rapa island (Australs) is a result of the fractionation of minerals belonging to the critical plane (olivine — plagioclase — clinopyroxene) of the basalt tetrahedron. In the Nuku-Hiva (Marquesas) series, the origin of oversaturated trachtytes results from the fractionation of undersaturated hydrous minerals (amphibole and mica).

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Zusammenfassung Der Vorgang einer fraktionierten Kristallisation vulkanischer Reihen kann in folgendem rechtwinkligen Diagramm (Gehalte in Millikationen ausgedrückt) gut verfolgt werden: R₁=6 Ca+2 Mg+Al; R₂=4 Si–11 (Na+K)–2 (Fe+Ti), indem die Zusammensetzung der aufeinanderfolgenden Schmelzen (aphyrische Laven) und der auskristallisierenden Phasen (Phänokristalle und Kumulate) eingetragen werden. Als Anwendungsbeispiel werden zwei Alkali-Reihen aus Polynesian verglichen. Die Reihe Alkali-Basalt — Phonolit der Insel Rapa (Südliche Inseln) entstammt der Abtrennung von Mineralien, die auf der kritischen Ebene (Olivin, Plagioklas, Klinopyroxenen) des basaltischen Tetraeders liegen. Auf der Insel von Nuku-Hiva (Marquesas Inseln) hingegen, führt die Differentiation zu Quartz-Trachyten, bedingt durch die Fraktionierung in SiO₂-untersättigte und Hydroxyl-haltige Minerale (Amphibol und Glimmer).

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Melting of acid xenoliths into a basanite: An approach to the possible mechanisms of crustal contamination     

R. C. Maury  H. Bizouard 《Contributions to Mineralogy and Petrology》1974,48(4):275-286

Biotite gneiss xenoliths included in a basanitic flow in the Causses region (France) show several kinds of partial melting. Rhyolitic glasses appear at the expense of the quartz + feldspar assemblage; initially undersaturated latitic glasses at the expense of biotite + feldspar (+ quartz); lastly hyperaluminous products derivating from large phenoblasts of alkali feldspar. The microprobe study of these glasses, of their contacts with the host lava, as well as that of the neogenic mineral phases, show that contamination occurs through, at least, four possible processes:

1. Diffusion at the interface between two liquids of contrasted composition (rhyolitic and basanitic).
2. Mechanical mixing of two liquids of less contrasted chemistry (latitic and basanitic).
3. Progressive solution of a solid phase (quartz) into the magma.
4. Vapour phase transfers.

Qualitative magmatic contamination in alkalies (mainly K) and silica results from all these processes; quantitatively, the most important of them seems to be 4.  相似文献   

Magmatic source enrichment by slab-derived melts in a young post-collision setting, central Mindanao (Philippines)   总被引：28，自引：0，他引：28  

Fernando G. Sajona  Ren  C. Maury  Manuel Pubellier  Jacques Leterrier  Herv  Bellon  Joseph Cotten 《Lithos》2000,54(3-4):173-206

Central Mindanao was the locus of a Pliocene (4–5 Ma old) arc–arc collision event followed by basaltic to dacitic magmatism starting at 2.3 Ma, representing the most voluminous volcanic field in the Philippines. Lava compositions range from calc-alkaline to shoshonitic. Adakites and Nb-enriched basalts are among the magmatic products. All the lavas are Na-rich (up to 4.88%), with Na₂O/K₂O ratios from 2.5 to 6.5. Sr, Nd and Pb isotopic compositions are similar to MORB, except for some shoshonitic lavas that have slightly less radiogenic Nd ratios. K-enrichment in basalts can be related to both fractional crystallization (FC) at moderate pressures and to partial melting of an enriched source. Trace element systematics indicate that the sub-central Mindanao mantle is characterized by the presence of garnet, phlogopite, amphibole, and perhaps some titanate phase. The enrichment of this source is attributed to the interaction of slab-derived melts, i.e., adakites, with the arc mantle. This would explain the presence of Nb-enriched basalts, transitional adakites and high-magnesium andesites, as well as the bulk Na-enrichment and relatively unradiogenic character of the central Mindanao lavas. We envision an ion-exchange type of enrichment, in which the HFSE, LILE and LREE, mobilized during slab melting, are preferentially enriched in the metasomatized mantle, resulting in a diversity of post-collision magma compositions. The MORB-like isotopic signatures of the central Mindanao lavas preclude important contributions of slab-derived hydrous fluids, sediments, continental crust or an OIB-type contaminant. Slab melting after cessation of subduction is deemed possible by thermal rebound of previously depressed geotherms. Initial contributions to mantle enrichment in post-collision sites may thus come from slab melts. In most other cases of post-collision magmatism, however, this signature can be easily masked by enrichments coming from other sources, e.g., the continental lithosphere.  相似文献   

Composition des Sphalerites du District Minier de Hualgayoc (Perou)     

R. Borredon  M. Lafitte  R. Maury 《Mineralium Deposita》1983,18(3):437-442

Microprobe analysis of mineralisations from the district of Hualgayoc, Peru, shows a zonation of sphalerite compositions all around a rhyodacitic body. The differences in the iron content of sphalerites in veins inside the rhyodacite and in sedimentary strata may be explained by a contamination of the hydrothermal solutions by those strata.  相似文献   

Partition coefficients of trace elements: Application to volcanic rocks of St. Vincent,West Indies     

J. Dostal  C. Dupuy  J.P. Carron  M. Le Guen de Kerneizon  R.C. Maury 《Geochimica et cosmochimica acta》1983,47(3):525-533

Island arc basaltic rocks (basalts and basic andesites with SiO₂ < 56.5%) from the Soufrière volcano. St. Vincent, West Indies (prehistoric lavas and 1902 and 1979 eruptions) underwent extensive fractional crystallization at various levels during the ascent of the magma. Although the precipitation of minerals occurring in coarse-grained cumulate inclusions dominated the derivation of basic andesites from basaltic magma, the distribution of the trace elements is not consistent with a simple fractional crystallization process. The lavas have a partially cumulate character and were probably generated from similar but separate parental magmas. The partition coefficients of transition and large ion lithophile elements are given for clinopyroxene, amphibole. olivine, plagioclase and titanomagnetite in basaltic liquid which crystallized under well-defined P-T conditions. The temperatures obtained from the geothermometers based upon the distribution of the major elements are in good agreement with the data from trace element geothermometers.  相似文献