Research Article
Tectonic Evolution of the Southern Negros Geothermal Field and Implications for the Development of Fractured Geothermal Systems
Table 1
Summary of field characteristics of the two fracture groups mapped in SNGF.
| | Group 1 | Group 2 |
| Fault rocks | Cohesive and cemented (cataclastic) | Generally noncohesive/poorly cemented Open fractures in some | Key alteration minerals | Abundant pyrite Amorphous silica Quartz Rare Cu sulfides | Abundant clays Quartz Native sulphur Zeolites, calcites, and gypsum | Kinematics | Mostly E-W (+/ā) sinistral | Mostly NW-SE oblique dextral | Host rocks | Older Southern Negros Fm. Host has been completely altered previously | All lithologies Both altered and fresh rocks | Alteration pattern | Restricted to fractures | Diffuse or restricted to fractures | Other key observations | ā | Usually related to recent (active/inactive) thermal activity |
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