#TITLE_ALTERNATIVE#

• Main Author: Budi Setyawan NIM : 22096009, Wahyu
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/9573
• Institution: Institut Teknologi Bandung

<br /> <br /> <br /> <br /> <br /> Abstract: <br /> <br /> <br /> <br /> <br /> Modem sand deposits of fluvial, sandy beach and eolian enviromnent at Yogyakarta, Southern Part of Central Java. <br /> <br /> <br /> <br /> <br /> Present actual condition indicate that the Mount of Merapi and Southern Mountain region are situated in tectonic environment of Magmatic Arc of Oceanic Island Arc (Wilson, 1989 and Soeria-Atmadja, et al., 1991). Both regions are the source areas of modem sediments deposited in fluvial, sandy beach and eolian environment at Yogyakarta. The depositional environments are in such arrangement so that the sediments can pass through its respectively. <br /> <br /> <br /> <br /> <br /> Kali Opak drainage system is the main drainage system in the region. The river receives sediments from the dreams, which have its head at Merapi and Southern Mountain region, and then passing it through to the Indian Ocean. <br /> <br /> <br /> <br /> <br /> High percentage of rock fragments, with microlite or lath of plagioclase or vitric ground mass, and plagioclase characterizes detrital composition of the sediments. The sub-ordinate is pyroxene and opaque minerals, and then followed by hornblende and quartz in a small amount. <br /> <br /> <br /> <br /> <br /> According to sampling scale concept of Ingersoll (vide Ingersoll, 1990 and Ingersoll et al., 1993), modem sand deposits in the stream flowing on Merapi flanks (e.g Kali Borong-Code) are categorized as first order sands; in Kali Opak, 2-nd order; at Sandy Beach, 3-rd order; Sand Dunes, 3-rd order, and in Kali Oyo, 2-nd order sand of Southern Mountain region. <br /> <br /> <br /> <br /> <br /> Textural analysis resuks of the modem sand samples from Kali Boyong, Kali Opak, Sandy Beach and Sand Dunes line, respectively, showing that presentation fine sand fraction increase, and sit: tation become better. <br /> <br /> <br /> <br /> <br /> Detrital and geochemical composition analysis results of selected samples, from the samples far textural analysis, indicate: (1) percentage of rock fragments and plagioclase decrease while pyroxene and opaque minerals increase, and (2) percentage of A1203, MnO, CaO, Na2O and K20 go down, TiO2, Fe203 and MgO go up. <br /> <br /> <br /> <br /> <br /> All of the changes, textural as well as compositional, are in harmony one another. <br /> <br /> <br /> <br /> <br /> Although there are the changes in texture and composition of the sediments, provenance analysis on the sands of the every scaling rode give a consistence results among them and to the present condition.