Early Miocene adakite-like volcanism in the Balkuyumcu region, central Anatolia, Turkey: Petrology and geochemistry   总被引：1，自引：0，他引：1  

Elif Varol  Abidin Temel  Alain Gourgaud  Herve Bellon 《Journal of Asian Earth Sciences》2007,30(5-6):613-628

The Balkuyumcu region, located in the southwestern part of Ankara in the Izmir-Ankara suture zone (central Anatolia, Turkey), consists of basic andesitic, andesitic, dacitic and rhyolitic rocks extruded during the Early Miocene (20–22 Ma) as a result of post-collisional volcanism. Balkuyumcu volcanic rocks can be divided into two groups on the basis of their mineralogy and composition: The basic andesitic (BA) and andesitic, dacitic and rhyolitic (ADR) groups. The ADR and BA group of rocks have adakite-like and calc-alkaline characteristics, respectively. The ADR group has higher SiO₂ content, Sr/Y and La/Yb ratios and low MgO, Mg#, Y and Yb contents than the BA group. Both groups have nearly the same Sr, Nd isotopic compositions and display similar normalized multi-element patterns with enrichments in LILE and LREE, depletions in Nb, Ti, Zr, P and a lack of Eu anomalies. Major, trace element and Sr, Nd isotopic data indicate that both groups of rocks were derived from the same source but affected by different magmatic processes during ascent. The adakite-like rocks may have been produced by partial melting of thickened lower continental crust. Fractional crystallization also played a major role in their formation. However, the BA group rocks were derived from partial melting of lower continental crust that was probably delaminated. These rocks appear to have had limited interaction with mantle peridodite during ascent to the surface.  相似文献   

Hydrodynamical changes and their consequences on groundwater hydrochemistry induced by three decades of intense exploitation in a Mediterranean Karst system   总被引：1，自引：1，他引：0  

C. C. Bicalho  C. Batiot-Guilhe  J. L. Seidel  S. Van Exter  H. Jourde 《Environmental Earth Sciences》2012,65(8):2311-2319

The Lez karst spring, located in the Mediterranean basin (southern France) supplies drinking water to the metropolitan area of Montpellier (France) since the nineteenth century. Since 1981, an intense pumping is being performed directly in the main conduit with a maximum exploitation flow rate of about 1,700 l/s. To improve the understanding of groundwater origins and circulation dynamic in this karst system, as well as the impact of three decades of intense water exploitation, groundwater samples have been collected during various hydrologic conditions since March 2006. A previous hydrochemical study on the Lez karst system had been carried out before the installation of the pumping plant. This dataset was compared to the present one to identify possible changes on groundwater hydrochemistry. The results of this analysis indicate the existence of historical changes in water hydrogeochemistry and evidence a decrease of the deep compartment participation to the Lez spring outflow. This change in spring water hydrogeochemistry may be attributed to the intense pumping of the karst system and, in the absence of noticeable climatic changes, expresses the direct consequences of anthropogenic forcing on the overall functioning of the aquifer. This study aims to analyze the differences, to understand the water chemistry changes and to better foresee the aquifer evolution for the future.  相似文献   

On the inclusion of ground-based gravity measurements to the calibration process of a global rainfall-discharge reservoir model: case of the Durzon karst system (Larzac, southern France)     

Naomi Mazzilli  Hervé Jourde  Thomas Jacob  Vincent Guinot  Nicolas Le Moigne  Marie Boucher  Konstantinos Chalikakis  Hélène Guyard  Anatoly Legtchenko 《Environmental Earth Sciences》2013,68(6):1631-1646

This work examines the relevance of the inclusion of ground-based gravity data in the calibration process of a global rainfall-discharge reservoir model. The analysis is performed for the Durzon karst system (Larzac, France). The first part of the study focuses on the hydrological interpretation of the ground-based gravity measurements. The second part of the study investigates further the information content of the gravity data with respect to water storage dynamics modelling. The gravity-derived information is found unable to either reduce equifinality of the single-objective, discharge-based model calibration process or enhance model performance through assimilation.  相似文献   

Adakitic lavas in the Central Luzon back‐arc region,Philippines: lower crust partial melting products?   总被引：6，自引：0，他引：6  

Graciano P. Yumul JR    Carla Dimalanta  Herve Bellon  Decibel V. Faustino  Joel V. De Jesus  Rodolfo A. Tamayo  JR    Ferdinand T. Jumawan 《Island Arc》2000,9(4):499-512

Abstract Volcanism in the back-arc side region of Central Luzon, Philippines, with respect to the Manila Trench is characterized by fewer and smaller volume volcanic centers compared to the adjacent forearc side-main volcanic arc igneous rocks. The back-arc side volcanic rocks which include basalts, basaltic andesites, andesites and dacites also contain more hydrous minerals (ie, hornblende and biotite). Adakite-like geochemical characteristics of these back-arc lavas, including elevated Sr, depleted heavy rare earth elements and high Sr/Y ratios, are unlikely to have formed by slab melting, be related to incipient subduction, slab window magmatism or plagioclase accumulation. Field and geochemical evidence show that these adakitic lavas were most probably formed by the partial melting of a garnet-bearing amphibolitic lower crust. Adakitic lavas are not necessarily arc–trench gap region slab melts.  相似文献   

Assessment of groundwater recharge processes through karst vadose zone by cave percolation monitoring          下载免费PDF全文

Amaël Poulain  Arnaud Watlet  Olivier Kaufmann  Michel Van Camp  Hervé Jourde  Naomi Mazzilli  Gaëtan Rochez  Romain Deleu  Yves Quinif  Vincent Hallet 《水文研究》2018,32(13):2069-2083

Recharge processes of karst aquifers are difficult to assess given their strong heterogeneity and the poorly known effect of vadose zone on infiltration. However, recharge assessment is crucial for the evaluation of groundwater resources. Moreover, the vulnerability of karst aquifers depends on vadose zone behaviour because it is the place where most contamination takes place. In this work, an in situ experimental approach was performed to identify and quantify flow and storage processes occurring in karst vadose zone. Cave percolation monitoring and dye tracing were used to investigate unsaturated zone hydrological processes. Two flow components (diffuse and quick) were identified and, respectively, account for 66% and 34% of the recharge. Quickflow was found to be the result of bypass phenomenon in vadose zone related to water saturation. We identify the role of epikarst as a shunting area, most of the storage in the vadose zone occurring via the diffuse flow component in low permeability zones. Relationship between rainfall intensity and transit velocity was demonstrated, with 5 times higher velocities for the quick recharge mode than the diffuse mode. Modelling approach with KarstMod software allowed to simulate the hybrid recharge through vadose zone and shows promising chances to properly assess the recharge processes in karst aquifer based on simple physical models.  相似文献   

Mediterranean flash flood transfer through karstic area   总被引：1，自引：0，他引：1  

Vincent Bailly-Comte  Hervé Jourde  Axel Roesch  Séverin Pistre 《Environmental Geology》2008,54(3):605-614

Karstic aquifers influence flash floods propagation in Mediterranean countries. Near Montpellier, Southern France, discharge data are recorded on the Coulazou River upstream and downstream of the Aumelas Causse. Two gauging stations are used to describe the hydrodynamics of this binary karstic system. The first station characterizes the non-karstic catchment area. The second one is representative of the karstic part of the watershed. Records since April 2004 are used to understand how the river interacts with a karstic aquifer. Hydrograph analysis of three flash flood events is described. Corresponding discharge time series recorded at the two gauging stations are used to describe the modification of the hydrographs by auto- and crosscorrelations analyses. Finally, linear system analyses are used to provide the transfer functions of this binary karstic system according to the three flood events characteristics (initial conditions, volume, spatial distribution of rainfall, etc.). Theses functions summarize the hydrodynamic behaviour of the system: their shapes are indicative of the dynamics of the storage, the release and the contribution to surface waters.

Vincent Bailly-ComteEmail:

  相似文献   

Groundwater response to tidal fluctuations in a leaky confined coastal aquifer with a finite length     

Zhixue Zhao  Xiaoguang Wang  Yonghong Hao  Tongke Wang  Abderrahim Jardani  Herve Jourde  Tian‐Chyi Jim Yeh  Ming Zhang 《水文研究》2019,33(19):2551-2560

The study on the hydraulic properties of coastal aquifers has significant implications both in hydrological sciences and environmental engineering. Although many analytical solutions are available, most of them are based on the same basic assumption that assumes aquifers extend landward semi‐infinitely, which does not necessarily reflect the reality. In this study, the general solutions for a leaky confined coastal aquifer have been developed that consider both finitely landward constant‐head and no‐flow boundaries. The newly developed solutions were then used to examine theoretically the joint effects of leakage and aquifer length on hydraulic head fluctuations within the leaky confined aquifer, and the validity of using the simplified solution, which assumes the aquifer is semi‐infinite. The results illustrated that the use of the simplified solution may cause significant errors, depending on joint effects of leakage and aquifer length. A dimensionless characteristic parameter was then proposed as an index for judging the applicability of the simplified solution. In addition, practical application of the general solution for the constant‐head inland boundary was used to characterize the hydraulic properties of a leaky confined aquifer using the data collected from a field site at the Seine River estuary, France, and the versatility of the general solution was further justified.  相似文献   

Reply to Comment on “A cost-effective device and methodology to compute aquifer transmissivity and piezometry from free-flowing artesian wells”: technical note published in Hydrogeology Journal (2022) 30:1917–1931, by Alix Toulier,Patrick Lachassagne,Heru Hendrayana,Arif Fadillah and Hervé Jourde     

Toulier  Alix  Lachassagne  Patrick  Hendrayana  Heru  Fadillah  Arif  Jourde  Hervé 《Hydrogeology Journal》2023,31(3):849-851

Hydrogeology Journal -  相似文献   

Anomalous low palaeomagnetic inclinations from Oligocene—Lower Miocene red beds of the south-west Tien Shan, Central Asia     

Annick Chauvin  Herve Perroud  Mikhail L. Bazhenov 《Geophysical Journal International》1996,126(2):303-313

  相似文献   

Water table variations in Atacama Desert alluvial fans: discussion of “Evidence of short-term groundwater recharge signal propagation from the Andes to the central Atacama Desert: a singular spectrum analysis approach”*     

Benoît Viguier  Hervé Jourde  Véronique Leonardi  Elisabeth Lictevout  Linda Daniele 《水文科学杂志》2020,65(9):1606-1613

ABSTRACT

Using a statistical approach, Scheihing attempts to demonstrate the direct influence of recharge events in the Precordillera and the Andean Piedmont on water table variations in downstream alluvial fans. The author “unquestionably” discards the existence of ephemeral recharge processes in alluvial fans although they are frequently impacted by major floods. However, the author does not consider previous publications about recharge processes in arid alluvial fans, the hydraulic setting of the Pampa del Tamarugal Aquifer (PTA) and anthropogenic pressure changes in the PTA. Because the sustainable management of groundwater resources in drylands depends on a good understanding of hydrogeological processes, we propose a thorough reinterpretation of the short- and long-term PTA water table variations addressed by the author. In this comment, we illustrate the limits of the sole use of a statistical approach for characterizing both recharge processes and factors controlling the water table variations in the Atacama Desert.  相似文献