Heat flow, deep temperatures and extensional structures in the Larderello Geothermal Field (Italy): constraints on geothermal fluid flow

Influence of depth, temperature, and structure of a crustal heat source on the geothermal reservoirs of Tuscany: numerical modelling and sensitivity study

“…Porosity and thermal conductivity have been assumed as shown in Table 1. These are in agreement with literature values from the Larderello area (Bellani et al 2004;Romagnoli et al 2010).…”

“…They are non-uniformly distributed and emplaced at various depths, leading to rather large differences in surface heat flow (100-1000 mW/ m 2 ; Bellani et al 2004) in this inner Northern Apennine area. A correlation between the depth of this heat source and a high-amplitude seismic reflector (called K horizon) has been described, among others, by Bellani et al (2004), Cameli et al (1993Cameli et al ( , 1998, Gianelli et al (1997), Liotta and Ranalli (1999), and Vanorio et al (2004). As stated by Liotta and Ranalli (1999), "this horizon ranges in depth between 3 and 12 km, and can be followed almost continuously from the Tyrrhenian coast to the central part of the Apennines'".…”

“…The nature of the K horizon is still unknown, and since its first detection, several geological interpretations have been proposed: 1. a kinematically active rheological boundary which separates a brittle upper part from a ductile lower part (Cameli et al 1993); 2. a kinematic shear belt with entrapped fluids in fractured levels (Liotta and Ranalli 1999) located at the top of the brittle/ductile transition (Bellani et al 2004(Bellani et al , 2005; and 3. a contact aureole associated with mineralised breccias and tractites related to a thermometamorphic process in the contact zone between young (Quaternary) intrusions of granite and calcium-bearing silicate rocks (Bertini et al 2005). …”

Hydrogeochemical processes controlling water and dissolved gas chemistry at the Accesa sinkhole (southern Tuscany, central Italy)

“…The occurrence of ground collapses, basically produced by internal erosion and deformation processes caused by subsurface karstification (Williams, 2003;Sauro, 2003;Waltham et al, 2005), is likely favored by seismic activity (Del Prete et al, 2010) and circulation of CO 2 (H 2 S)-rich fluids (Duchi et al, 1986;Billi et al, 2007;Frondini et al, 2008). An enhanced hydrothermal activity in this area was interpreted as related to a heat flow anomaly (Gianelli et al, 1997;Batini et al, 2003;Bellani et al, 2004) and extensional structures coeval with the emplacement of granitoids at depth in the Late Miocene, exposed or drilled during mining exploitation (Serri et al, 1993;Dini et al, 2005;Benvenuti et al, 1994). Hydrothermal fluid patterns are currently controlled by Early Pliocene-Present high angle normal to strike-slip faults giving rise to local tectonic depressions (Bertini et al, 1991;Carmignani et al, 1994;Jolivet et al, 1998;Rossetti et al, 2011;Brogi et al, 2005;Liotta et al, 2010).…”

Гигантские Газо-Гидротермальные Системы И Их Роль В Формировании Пародоминирующих Геотермальных Месторождений И Рудной Минерализации

“…Они контролиру ют современные газо гидротермальные системы и крупнейшие пародоминирующие геотермаль ные месторождения (с энергетическим потенциа лом ≥100 МВт) Norton, Hulen, 2001;Rychagov, 2005]. К наиболее известным из таких систем относятся Гейзерс (США), Ларде релло Травале (Италия), Какконде и Матсукава (Япония), Камоджанг и Дараджат (Индонезия), Кошелевская и, возможно, Северо Парамушир ская (Россия, Дальний Восток) [Белоусов и др., 2002;Поздеев, Нажалова, 2008;Bellani et al, 2004;Hanano, Sakagawa, 1990;Rejeki et al, 2010;Stimac et al, 2001]. Обычно эти системы рассматривают ся только с позиции оценки геотермальных ресур сов.…”