Forum Geografi
Vol 31, No 1 (2017): July 2017

Caldera of Godean, Sleman, Yogyakarta: A Volcanic Geomorphology Review

Hill Gendoet Hartono (Sekolah Tinggi Teknologi Nasional Yogyakarta)
Adjat Sudradjat (Sekolah Tinggi Teknologi Nasional Yogyakarta)
Okki Verdiansyah (Unknown)



Article Info

Publish Date
01 Jul 2017

Abstract

Godean hills is located approximately 10 km westward from the Yogyakarta City. The landscape of Godean hills and plains is affected by various factors, such as lithology, geological structure, and sub-aerial process. The purpose of this study was to reveal the landscape of Godean. The method consisted of field study, morphological variables assessment, rock sampling, and laboratory analysis. The results of field mapping indicated that the landscape of Godean  is an isolated hill with a steep slope of 40° and an elevation of +231 m a.s.l, passed by the rivers flows from northeast to southwest that disembogue into the west part of Kulon Progo. The morphologhy of Godean hills varies including G. (Gunung/Mountain) So (+173 m amsl), G. Gede (+218 m a.s.l), G. Wungkal (+187 m a.s.l), G. Butak (+154 m a.s.l), and G. Berjo ( + 175 m a.s.l), dominated by the lithology of igneous rock, which is composed of porphyry andesite-microdiorite, pumice lapilli, and quartz rich lapilli-tuff. In addition, most of the igneous rocks have weathered and have been altered to clays, while the deposition from Merapi volcano formed a landscape with an altitude between +100–+150 m a.s.l surrounding Godean hills. Sentolo Formation was found in Kembang, Bantul, which is located approximately ±5km in the south of the study area N93ºE/12º,  while the distribution in the southwest and northeast relatively covers the Godean hills in curve shape. The results of the analysis provide information related with Godean landscape that it is the remains of the volcanic caldera, with various igneous rock types and volcaniclastics deposits, as well as endured the occurrences of hydrothermal alteration and mineralization. Further geophysical research is required to determine the configuration of igneous rocks under the earth's surface.

Copyrights © 2017






Journal Info

Abbrev

FG

Publisher

Subject

Earth & Planetary Sciences

Description

Forum Geografi, Indonesian Journal of Spatial and Regional Analysis (For. Geo) is an open access, peer-reviewed journal that will consider any original scientific article for expanding the field of geography. The journal publishes articles in both physical and human geography specialties of interest ...