Chapter 3 - Developments of auxiliary chemical geothermometers applied to the Los Humeros and Acoculco high-temperature geothermal fields (México)

Bernard Sanjuan Sanjuan (1) , Frédérick Gal (1) , Ruth Alfaro (2)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
2 INCIT-UMSNH - Instituto de Investigaciones en Ciencias de la Tierra, Universidad Michoacana de San Nicolás de Hidalgo

This final report regards the activities and results of two years of fieldwork and laboratory analyses performed in Los Humeros (LHGF) and Acoculco (AGF) geothermal fields, in the framework of the WP4.3 of the GeMex project. The report is organized in two parts, the first for Los Humeros and the second for Acoculco. Each part summarize and illustrates the scientific activities and approaches used to fulfil the aim of the Task 4.3. This task is included in the Workpackage 4 (Tectonic control on fluid flow) and it is aimed to the Geochemical characterization and origin of cold and thermal fluids. It involve the sampling and analysis of fluids from boreholes and surface (natural cold and thermal springs, gas manifestations, rivers, etc.) and quantification of degassing processes at the surface (in particular diffuse emissions in selected areas), and HT tracer tests. Various research groups involved in the task 4.3 performed sampling trip aimed to collect water and gas samples from natural manifestations, water wells and geothermal wells. Before sampling trips, each partner involved carried out an accurate review of the previous literature, in particular for what concern the geology, tectonics and fluid geochemistry in general. Field maps of sampling points and location of geothermal surface manifestations are included and discussed in Chapters 2, 3 and 4 (part 1 for Los Humeros) and in Chapter 2-part2 for Acoculco. Chemical and isotope analysis for water samples from some cold and thermal springs, cold wells and geothermal wells are included and discussed in Chapter 3 (part 1). Geothermometric estimations performed using classical and new auxiliary chemical and isotope geothermometers are discussed in this chapter, both for Los Humeros and Acoculco geothermal systems. Literature data of Los Humeros geothermal wells are also included and discussed in suitable diagrams in order to obtain information regarding the relationships between cold surface waters and hydrothermal/geothermal fluids.

Mots clés: auxiliary geothermometers; Los Humeros; Acoculco; geothermal field; well; thermal spring; chemical and isotope analyses; auxiliary geothermometers

Domaines: Géochimie

Bernard Sanjuan Sanjuan, Frédérick Gal, Ruth Alfaro. Chapter 3 - Developments of auxiliary chemical geothermometers applied to the Los Humeros and Acoculco high-temperature geothermal fields (México): In WP 4 – Tectonic control on fluid flow Task 4.3 – Final Report on characterization and origin of cold and thermal fluids - Deliverable D4.3. [Research Report] GEMex Deliverable D4.3, IGG-CNR, BRGM, UMSNH. 2019, pp.55-100. ⟨hal-03023133⟩