Chihuahua-Sacramento and tabalaopa-aldama aquifers of Chihuahua state, Mexico: linkage and importance of geostatistical and hydrogeochemical analysis

The objective of this study is to gather sufficient information to make a diagnosis of drinking water sufficiency in the Chihuahua-Sacramento and Tabalaopa-Aldama aquifers. By applying advanced statistical techniques, the goal is to find the variables that control the regional and intermediate flow systems and establish the characteristics of a heterogeneous aquifer. The variables chosen from those established were as follows: total solids (TS), nitrates (NO3), fluoride (F), and total hardness, among others. In order to establish a conceptual model, the results from all the sampling were carried out by the National Water Commission (CONAGUA) in the aforementioned aquifers and were used to obtain an approximate flow differentiation. The results showed a good flow differentiation. In addition, a group of mixed water was detected among the intermediate and regional flows. The increase in the average regional flow values suggests a rise in the incidence of an upward flow of the regional flow as a result of uncontrolled extraction.

Flow-Based Networking Architectures under Mixed Internet and Grid Traffic

Quality-of-Service (QoS) is a key issue for grid services provisioning. QoS architectures originally developed for the Internet such as DiffServ (DS) have been tested in grid environment. We present in this chapter the investigation on the potentialities of a new innovative Internet QoS architecture known as Flow-Aware Networking (FAN). FAN is a flow-based networking architecture and it appears as the most promising alternative to DS for QoS provisioning in IP networks. DS proceeds to traffic differentiation and QoS provisioning through IP packet marking whereas FAN consists in implicit IP flow differentiation and a flow-based admission control. A grid traffic session may be seen as a succession of parallel TCP flows with voluminous data transfers (e.g. GridFTP). In this chapter, we compare by means of computer simulations the performance of FAN and DS architectures under the mix traffic composed by Internet and grid services.

On the development of internal chemical zonation in small mafic dykes

Three dolerite dykes (Small, 3.2 cm; Middle, 13.5 cm; Thick, 50 cm) from Torsholma Island, SW Finland, reveal distinctly different internal zonation that becomes more complicated with increasing thickness of the dykes. The Small Dyke shows a systematic inward increase in normative Pl (An+Ab+Or) and a decrease in normative An (100*An/(An+Ab)), whole-rock MgO, Mg number (100*Mg/(Mg+Fetotal)), TiO2, K2O and Zr. The Middle Dyke exhibits the same compositional pattern at the margins, while the centre is distinguished by an abrupt increase in normative Pl and An, whole-rock Sr and Mg number. From the margins inwards, the Thick Dyke displays first a compositional pattern identical to that observed in the Small Dyke and the margins of the Middle Dyke. This is followed by a region where whole-rock MgO, Mg number and normative An start increasing inwards, while the transition to the centre of the dyke is characterized by a compositional pattern similar to that in the centre of Middle Dyke. The origin of chemical zonation in these dykes is attributed to the operation of three independent physico-chemical processes, namely: the Small Dyke formed exclusively by progressive changes in the composition of inflowing magma; the Middle Dyke by changes in composition of inflowing magma (margins) and concentration of plagioclase and olivine phenocrysts by flow differentiation (centre); the Thick Dyke by changes in composition of inflowing magma (margins),in situcumulate growth against dyke sidewalls (middle) and flow differentiation (centre). Systematic changes in these processes and, as a result, in internal chemical zonation, likely take place in response to crystallization of magma under less supercooled conditions with increasing dyke thickness. A comprehensive geochemical study of the internal zonation of small mafic dykes worldwide is required to develop a complete understanding of the processes operating in mafic dykes.

Geochemical evolution of a 10 m-thick intrusive body: the South Brenterc’h diabase dyke, Western Armorican Massif, France

The South Brenterc’h 9.5 m-thick diabase dyke belongs to the intermediate-Ti quartz-normative tholeiitic magmatism, which has intruded the western end of Britanny (France) near the Trias-Lias boundary. It has been previously identified as a "simple" dyke, resulting from a single magmatic injection. The present study is based on ten samples collected along a half transverse section of this dyke. Geochemical analyses and some textural parameters have been used to point out two flow-related differentiation processes, partially masked by alteration. These late magmatic mechanisms have induced subtle geochemical variations among samples, which sometime counteract each other. The processes pointed out here are (i) expulsion of phenocrysts from the borders during flow differentiation, likely by the way of an hydrodynamic grain dispersive pressure, and (ii) emplacement of a more evolved magma in the central part of the intrusion, probably due to a viscosity segregation mechanism during the flow.