Michel Cathelineau

Bio: Michel Cathelineau is an academic researcher from University of Lorraine. The author has contributed to research in topics: Fluid inclusions & Quartz. The author has an hindex of 43, co-authored 208 publications receiving 6761 citations. Previous affiliations of Michel Cathelineau include Nancy-Université & Centre national de la recherche scientifique.

Cation Site occupancy in chlorites and illites as a function of temperature

Abstract: A B S T RA C T : The relationships between the composition and the crystallization temperature of chlorites and illites have been investigated in different geothermal fields and in particular the Los Azufres system in Mexico, considered to be a natural analogue to experimental laboratories, as the main changes in physical and chemical conditions and mineralogy are related to progressively increasing temperature with depth. Temperature was estimated from combined geothermometric approaches, and especially from fluid inclusion studies on quartz coexisting with clays. The Al(lv) content in the tetrahedral site of chlorites, and the K content and total interlayer occupancy of illites increase with temperature. These chemical changes are mainly related to the marked decrease in the molar fraction of the Si(lv)-rich end-members (kaolinite for chlorites, and pyrophyllite for illites) which become negligible at ~ 300~ Other chemical changes, such as the variation in Fe and Mg contents, are partly influenced by temperature, but are strongly dependent on the geological environment, and consequently on the solution composition. The empirical relationships between chemical variables and temperature were calibrated from 150-300~ but extrapolations at lower and higher temperatures seem possible for chlorites. Such geothermometers provide tools for estimating the crystallization temperature of the clays, and are important for the study of diagenetic, hydrothermal and low-T metamorphic processes. Clay minerals are the most abundant minerals in most of the geological environments submitted to temperatures from 50 ~ to 350~ where estimation of the crystallization temperature of the clay minerals may be difficult. Most of the classical geothermometers cannot be applied, fluid inclusions may be absent, and experimental data are scarce. Nevertheless, such temperature estimations are of critical importance for geological studies related to oil field exploration, as well as for diagenetic and low-T metamorphic processes. 1"here are three types of chemical or crystallographic change occurring in the clay fraction of rocks which may indicate temperature of crystallization. (1) The changes in the clay mineral assemblages described in studies of the burial metamorphism of sediments (Weaver, 1959; Dunoyer de Segonzac, 1970; Perry & Hower, 1970; Velde, 1977) and the thermal metamorphism of rocks in geothermal fields (Schoen & White, 1966; Steiner, 1968; Tomason & Kristmannsdottir , 1972; Cathelineau & Izquierdo, 1988). However, only the boundaries between two mineral assemblages may yield a temperature estimate, largely restricting their use.

A chlorite solid solution geothermometer the Los Azufres (Mexico) geothermal system

Abstract: Chlorite constitutes a major hydrothermal alteration product of metamorphism of andesites, in the active geothermal system of Los Azufres (Mexico). Electron microprobe analyses performed on a set of crystals from each sample show wide variations in composition. Correlation coefficients among chemical constituents were calculated. It is shown that the tetrahedral charge is positively correlated with the octahedral vacancy and negatively with the iron content, and there is almost no correlation with the octahedral aluminium and magnesium content. A procedure is proposed to select end-members and substitution vectors, and to give a general formula for these chlorites. Their formation temperatures are estimated with great accuracy, combining results of microthermometric data on fluid inclusions from gangue minerals of chlorites (quartz, calcite), direct measurements in wells (Kuster equipment), and chemical geothermometers. Correlations between chlorite compositions, range and nature of site occupancy, and temperature are good. Formation temperatures of chlorites range from 130° C to 300° C. As no other thermodynamic parameter varies significantly in the studied field (composition of the host rocks, nature of the geothermal fluids, pressure, ...), these variations of site occupancy (mainly Al(IV) and the octahedral occupancy (6-Al(VI)-(Mg+Fe(2+)) = VAC) are considered mainly as temperature dependent. Molar fractions of each end-member show very different variations with increasing temperature: X-kaolinite decreases, and X-chamosite increases, while X-talc-3 brucite does not show significant change. From these data, activity coefficients and standard state chemical potential of major components, and molar free energy formation of chlorite have been calculated for each temperature of crystallisation.

Mixing of Sodic and Calcic Brines and Uranium Deposition at McArthur River, Saskatchewan, Canada: A Raman and Laser-Induced Breakdown Spectroscopic Study of Fluid Inclusions

Abstract: The richest U deposit in Saskatchewan, Canada, occurs in the McArthur River area, in the vicinity of the unconformity between the Athabasaca sandstones and an Archean to lower Proterozoic basement. Paleofluids related to the silicification of the sandstones and the formation of pre- and postore cements in breccias were studied using microthermometry, Raman microspectroscopy, and laser induced breakdown spectroscopy (LIBS) on individual fluid inclusions. A detailed reconstruction of the fluid composition in the system Na-Ca-Mg-Cl shows that two types of brines are responsible for the main quartz cements: an NaCl-rich brine (25 wt % NaCl, up to 14 wt % CaCl 2 , and up to 1 wt % MgCl 2 ), which is interpreted as a primary formation water that was expelled from bedded evaporites; and a CaCl 2 -rich brine (5–8 wt % NaCl, 20 wt % CaCl 2, and up to 11 wt % MgCl 2 ), which is considered to have formed during the interaction between the NaCl-rich brine and Ca-rich minerals in the basement and was introduced into the fault system and mixed with the NaCl-rich brine during the critical stage of U deposition. The pressure-temperature conditions of formation of the quartz cements are estimated to be 1,200 to1,400 bars and 190° to 235°C for the silicification events during the preore stage, and 500 to 900 bars after a pressure decrease from lithostatic conditions and slightly lower temperatures due to the mixing of the NaCl-rich brine with the cooler (approx 140°C) CaCl 2 -rich brine during the main stage of breccia sealing. Temperature and pressure drops combined with the effects of brine mixing appear to be key factors for the main stages of quartz cementation and U deposition at the McArthur deposit.

Chemical thermodynamics of uranium

Abstract: I. Introduction. Background. Focus of the review. Review procedure and results. The NEA-TDB data base system. Presentation of the selected data. II. Standards and Conventions. Symbols, terminology and nomenclature. Units and conversion factors. Standard and reference conditions. Fundamental physical constants. III. Selected Uranium Data. IV. Selected Auxiliary Data. V. Discussion of Data Selection. Elemental uranium. Aqua ions. Oxide, hydride and hydroxide species. VI. Discussion of Auxiliary Data Selection. Reference list. Authors list. Formula list. Discussion of selected references. Ionic strength corrections. Assigned uncertainties. The estimation of entropies.

Magmatic and Crustal Differentiation History of Granitic Rocks from Hf-O Isotopes in Zircon

Abstract: Granitic plutonism is the principal agent of crustal differentiation, but linking granite emplacement to crust formation requires knowledge of the magmatic evolution, which is notoriously difficult to reconstruct from bulk rock compositions. We unlocked the plutonic archive through hafnium (Hf) and oxygen (O) isotope analysis of zoned zircon crystals from the classic hornblende-bearing (I-type) granites of eastern Australia. This granite type forms by the reworking of sedimentary materials by mantle-like magmas instead of by remelting ancient metamorphosed igneous rocks as widely believed. I-type magmatism thus drives the coupled growth and differentiation of continental crust.