<![CDATA[Abstrak Lapangan panas bumi “F” berada pada Kabupaten Mojokerto, Malang, dan Pasuruan, Provinsi Jawa Timur. Karakteristik dari geokimia dan kondisi geologi daerah penelitian menjadi tujuan dari penelitian lapangan panas bumi ini sehingga menjadi model sistem panas bumi. Pada penelitian ini dilakukan berdasarkan metode geokimia berupa air, gas, dan isotop untuk penentuan dari temperatur bawah permukaan dan zona aliran fluida yang dikaitkan dengan kondisi geologi daerah penelitian. Secara geomorfologi daerah penelitian terbagi menjadi 14 satuan bagian gunungapi. Sistem panas bumi termasuk ke dalam liquid dominated system high relief. Terdapat empat manifestasi pada daerah penelitian, yaitu manifestasi air hangat, fumarol, dan solfatara. Tipe dari mata air berupa air bikarbonat, berdasarkan perhitungan geothermometer air didapati temperatur berkisar antara 152.02°C-166.17°C. Sumber gas panas bumi berasal dari magmatik. Perhitungan menggunakan geothermometer gas didapati hasil temperatur berkisar 255.34°C-306.63°C. Hal tersebut menunjukkan bahwa daerah penelitian termasuk ke dalam sistem bertemperatur tinggi. Analiis dari isotop menunjukkan bahwa sumber air berasal dari air meteorik dan andesitic water. Zona upflow berada pada Puncak Welirang sedangkan zona outflow berada pada bagian barat dan baratlaut daerah penelitian. Berdasarkan model geokimia panas bui daerah penelitian, gas CO2 secara dominan membentuk pembentukan dari manifestasi air dan gas. Struktur pada daerah penelitian menjadi jalur migrasi tersingkapnya manifestasi air pada daerah penelitian. Kata-kata kunci : Geokimia, isotop, outflow, sistem panas bumi, upflow AbstractThe "F" geothermal field is in Mojokerto, Malang, and Pasuruan, East Java Province. The characteristics of the geochemical and geological conditions of the study area are the objectives of this geothermal field research so that they become models of geothermal systems. This research was carried out based on geochemical methods in the form of water, gas, and isotopes for the determination of subsurface temperatures and fluid flow zones that are associated with the geological conditions of the study area. Geomorphologically the research area is divided into 14 volcanic units. Geothermal systems are included in the high relief liquid dominated system. There are four manifestations in the study area, namely manifestations of warm water, fumaroles, and solfatara. The type of spring in the form of bicarbonate water, based on the calculation of the water geothermometer, found temperatures ranging from 152.02°C-166.17°C. The source of geothermal gas comes from magmatics. Calculations using a gas geothermometer found temperature results ranging from 255.34°C306.63°C. This shows that the study area is included in the high temperature system. Analysis of isotopes shows that the source of water comes from meteoric water and andesitic water. The upflow zone is at the Welirang Peak while the outflow zone is at the western and northwestern parts of the study area. Based on geothermal geochemical models in the study area, CO2 gas predominantly forms the formation of water and gas manifestations. The structure in the study area is the migration pathway for the manifestation of water manifestations in the study area.Keywords: Geochemistry, geothermal system, istope, outflow, upflow]]>
