Zones of advanced argillic alteration with general low permeability (i.e., lithocaps) are common place in the shallow parts of porphyry and epithermal ore deposits and active geothermal systems. The study of structural control on alteration distributions is of paramount importance for exploitation purposes as it really influences the caprock efficiency. We present the results of a structural-mineralogical study carried out in the lithocap of the Allumiere-Tolfa epithermal system (Northern Apennines). We characterized the composition, textures and physical properties (i.e., in-situ permeability; relative rock strength) of alteration facies. We then integrated field structural analysis with analysis of a virtual outcrop model to reconstruct the geometry of principal fluid-corridors. It resulted that advanced argillic alteration was promoted by circulation of highly reactive fluid(s) along a complex network of NE- and NW-striking faults and fractures dissecting the acidic volcanic dome. Such structures likely developed in response to a local disturbance of the regional stress field due to the extrusion of the Tolfa dome, which controlled the syn-extensional mineralization of the Allumiere-Tolfa area.

Structural control on the alteration and fluid flow in the lithocap of the Allumiere-Tolfa epithermal system / Marchesini, Barbara; Tavani, Stefano; Mercuri, Marco; Mondillo, Nicola; Pizzati, Mattia; Balsamo, Fabrizio; Aldega, Luca; Carminati, Eugenio. - In: JOURNAL OF STRUCTURAL GEOLOGY. - ISSN 0191-8141. - 179:(2024).

Structural control on the alteration and fluid flow in the lithocap of the Allumiere-Tolfa epithermal system

Barbara Marchesini
Primo
Conceptualization
;
Marco Mercuri;Luca Aldega;Eugenio Carminati
Ultimo
2024

Abstract

Zones of advanced argillic alteration with general low permeability (i.e., lithocaps) are common place in the shallow parts of porphyry and epithermal ore deposits and active geothermal systems. The study of structural control on alteration distributions is of paramount importance for exploitation purposes as it really influences the caprock efficiency. We present the results of a structural-mineralogical study carried out in the lithocap of the Allumiere-Tolfa epithermal system (Northern Apennines). We characterized the composition, textures and physical properties (i.e., in-situ permeability; relative rock strength) of alteration facies. We then integrated field structural analysis with analysis of a virtual outcrop model to reconstruct the geometry of principal fluid-corridors. It resulted that advanced argillic alteration was promoted by circulation of highly reactive fluid(s) along a complex network of NE- and NW-striking faults and fractures dissecting the acidic volcanic dome. Such structures likely developed in response to a local disturbance of the regional stress field due to the extrusion of the Tolfa dome, which controlled the syn-extensional mineralization of the Allumiere-Tolfa area.
2024
fracturing; fluid-rock interaction; argillization; epithermal systems
01 Pubblicazione su rivista::01a Articolo in rivista
Structural control on the alteration and fluid flow in the lithocap of the Allumiere-Tolfa epithermal system / Marchesini, Barbara; Tavani, Stefano; Mercuri, Marco; Mondillo, Nicola; Pizzati, Mattia; Balsamo, Fabrizio; Aldega, Luca; Carminati, Eugenio. - In: JOURNAL OF STRUCTURAL GEOLOGY. - ISSN 0191-8141. - 179:(2024).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1700852
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