Jurnal Geoaplika (2010) Volume 5, Nomor 1, hal. 049 – 059 49 - ITB

Figure 1. Map of West Java and Banten showing the location of the
study area, i.e. at Cisolok, Sukabumi.
Type and characteristic of its surface
manifestation indicate that the geothermal
system of Cisolok and Cisukarame has a
shallow reservoir having very high
temperature. However, this geothermal potency
has yet to be utilized, except for tourism. This
is because, one of the reasons, the behavior of
Cisolok and Cisukarame geothermal system is
still unknown.
A geothermal system including reservoir
condition, type and sub surface flow pattern of
thermal water can be understood by studying
geothermal manifestations showing at the
surface as hot spring, hot pool, steaming
ground and hydrothermal surface alteration
(Hochstein and Browne, 2000, and Browne,
1978). By identification and correlation of an
active and fossil geothermal system, the
evolution of a geothermal system can be
understood, including change in reservoir
condition and sub surface flow pattern of
thermal water.
Geology
Morphology of the study area can be divided
into 3 parts, i.e. steep mountain, gentle
mountain and plain. The steep mountain forms
at northern and western parts of the study area.
Its elevation is above 200 m with the slope of
between 40 and 70. At the eastern part of the
study area there is a zone of gentle mountain
having elevation of less than 150 m and slope
of less than 30. The last morphology zone is
plain and occurs in south coastal area.
Regional geology of the study area is shown by
Sujatmiko and Santosa (1992). Cikotok
formation is the oldest rock exposing in the
western part of the study area. It has age of
early Oligocene and consists of volcanic
breccias, tuff and lava (Sujatmiko and Santosa,
1992). It is overlain by early Miocene Citarete
and Cimapag formations. The Citarete
formation consists of limestone and tuff units,
and the Cimapag formation is dominated by
breccias and conglomerate (Sujatmiko and
Santosa, 1992). Andesite and dacite then
intrude the southern part of the study area
during middle to late Miocene (Sujatmiko and
Santosa, 1992). In the western part of the study
area, igneous rock occurring is granodiorite to
granite covered by dacitic lava and pyroclastic.
Marine sediments and volcanic unit product of
Citorek unconformably covered the Cikotok,
Citarete and Cimapag formations during Plio-
Pleistocene. Quaternary rocks of andesite and
basaltic lavas product of Gunung Halimum and
volcanic breccias and agglomerates product of
Tapos then overlaid the area (Sujatmiko and
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