H. Utoyo*, Mesker H.J Dirk* S.Bronto* dan Kaspar L.B
* Geological Research and Development Centre (GRDC); Jl. Diponegoro 57 Bandung
E mail: harryutoyo@grdc.go.id
Abstract
K-Ar age of volcanic rocks in Cipunegara, Subang is to reach of the absolute age dating, therefore to be easy to detect of the relation between volcanic rocks one to the other.
Generally volcanick rocks in the study area has been altered to sericite, carbonate and ore mineral. In which there are only three samples can be dated by the K/Ar method.
Andesite display the age of 58.99 ? 1.94 m.a (Upper Paleocene) and 36.88? 3.96 m.a ( Upper Eocene ) there are possibility show the oldiest of volcanic rocks in this area. The other rocks display of negative age, because of strongly alteration activities, and significance of the loss argon. Results of the K/Ar dating shows of magmatic activities have been two time periods, i.e during Lower Eocene and Upper Eocene in Cipu negara.
From : The 33rd Annual Convention & Exhibition 2004 Indonesian Association of Geologist