| Summary: | <p>Recent sedimentation process in Yogyakarta Basin can be represented by the sedimentation by Progo River at the west and Opak River at the east of Yogyakarta. Variation and dispersion characteristic of major element and trace element in the sediment along both river is affected by the provenance. Based on XRF analysis of unconsolidated clastic sediment, it can be indicated that the sediment came from geochemically similar source rock charaterized by abundant major element of Si02, A 1203, FeO and CaO, and trace element of Ba, Sr, and V. The XRD analysis and petrography analysis indicate that the abundant minerals are plagioclase (oligoclase and labradorite) and pyroxene (augite, hypersthenes. enstantite, diopside and pigeonite). The sedimentary material in the upstream area is originally comes from intermediate igneous rock of the volcanic range at north (especially Merapi Volcano), while products of rock weathering from Kulon Progo Mountain Range and Southern Mountain contribute the sedimentary<br />
material in the middle up to the downstream area</p>
|
|---|