IJOG : Indonesian Journal on Geoscience
Vol 5, No 4 (2010)

The Evolution of Gajahmungkur Paleovolcano, Wonogiri, Central Java, as A Reference to Revize the Terminology of “Old Andesite Formation”

Syafri, Ildrem ( Faculty of Technical Geology, Padjadjaran University, Jatinangor 45363)
Sudradjat, A. ( Faculty of Technical Geology, Padjadjaran University, Jatinangor 45363)
Sulaksana, Nana ( Faculty of Technical Geology, Padjadjaran University, Jatinangor 45363)
Hartono, G. ( Geology Department, University College of National Technology Yogyakarta)



Article Info

Publish Date
27 Jun 2014

Abstract

DOI: 10.17014/ijog.v5i4.109Gajahmungkur is a Tertiary paleovolcano located in Wonogiri Regency, Central Java. The volcanic product of this volcano are widely distributed and composed of important elements of the stratigraphic sequence in the Southern Mountain area. The volcanic products so far have been simply classified as “Old Andesite Formation” which apparently is not in line with the stratigraphic code and the Indonesian Stratigraphic Code. The description of paleovolcano therefore might contribute to the revision of the “Old Andesite Formation”. The evolution of Gajahmungkur paleovolcano commenced with the formation of a submarine volcano, and then at the second phase a composite volcano emerged above sea level forming a volcano island. The third phase was the self destruction resulting in a formation of a caldera. Pumiceous components dominated the products. At the fourth phase, the activities began to decline producing more basaltic rocks. The statistical analysis of the interrelation between various physical properties of the clastic rocks leads to the identification of volcanic facies and the location of the paleovolcano vent.

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Journal Info

Abbrev

IJOG

Publisher

Subject

Earth & Planetary Sciences

Description

The spirit to improve the journal to be more credible is increasing, and in 2012 it invited earth scientists in East and Southeast Asia as well as some western countries to join the journal for the editor positions in the Indonesia Journal of Geology. This is also to realize our present goal to ...