SUTANTO, sutanto (2007) GENESA BATUAN VOLKANIK TERSIER DI DAERAH LAMPUNG BERDASARKAN ANALISIS GEOKIMIA DAN PENANGGALAN RADIOMETRIK K-ARGENESA BATUAN VOLKANIK TERSIER DI DAERAH LAMPUNG BERDASARKAN ANALISIS GEOKIMIA DAN PENANGGALAN RADIOMETRIK K-AR. WAHANA TEKNIK, 9 (1). pp. 1-11. ISSN 1411-014X
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Abstract
Abstrqct: ktmpung is located at the southeastern most part of Sumatra of the tertiary Sunda magmatic
arc, which results
from
the subduction of the Indian Ocean plate beneath the Sumatra Island. This region
covered mainly by the Mesozoic and Paleozoic metamorphic and plutonic basement and also by the
tertiary and quatemary volcanic rocks, while the magmatic activities was recorded at least since
Cretaceous. The volcanic rocks in this region are basalt, andesite and
ryolite.
These basalts and
andesites are pophyritic with abundant of plagioclase phenocrysts beside pyroxenes and hornblende,
while the
ryolite
consist quqrtz and sanidine as phenocryst in the pumiceous groundmass. The K-Ar
dating of tertiary volcanic rocks present the age of volcanic rocks in this region are 20,1 Ma to 12,8 Ma.
These rocks are geochemically typical of orogenic volcanic rocks with calc alkaline a!finity, Iow Ti
content and negative anomaly of Nb and Ti in the spider diagram. This orogen is resulted by subduction
of India oceanic plate beneath the Sumatra Island during Oligocene to Miocene. The variation type of
volcanic rocks from basalt to rhyolite and enrichment of Rb, Ba, K and light rare earth elements indicated that the magma in this region has been evolved.
| Item Type: | Article |
|---|---|
| Subjek: | Q Science > QE Geology |
| Divisions: | x. Faculty of Engineering, Science and Mathematics > School of Civil Engineering and the Environment |
| Depositing User: | sutanto sutanto - |
| Date Deposited: | 27 Jul 2017 03:16 |
| Last Modified: | 27 Jul 2017 03:16 |
| URI: | http://eprints.upnyk.ac.id/id/eprint/12462 |
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